eucalypts clonal culture in india

Eucalypts in India

Eucalypts in India

ENVIS Centre on ForestryNational Forest Library and Information Centre

Forest Research Institute(Indian Council of Forestry Research and Education)

P.O. New Forest, Dehradun - 248 006

EditorsPadam Parkash BhojvaidShailendra KaushikYash Pal SinghDinesh KumarManisha ThapliyalSantan Barthwal

DisclaimerAll efforts have been made to make the information as accurate as possible. The views expressedby the authors belong to them and do not necessarily reflect the views of the ENVIS Centre onForestry or the Ministry of Environment and Forests, Govt. of India. The ENVIS Centre onForestry is no way responsible for any liability arising out of the contents of the chapters. Anydiscrepancy found may be brought to the notice of the ENVIS Centre on Forestry.

© 2014, ENVIS Centre on ForestryAll rights reserved. This book or any part thereof must not bereproduced in any form without the written permission of the publisher.

ISBN: 978-93-5174-121-3

Editorial assitance and designingRuchi Gupta

Cover designSantan Barthwal

Foreword

Trees outside forest (TOF), mainly growing on private land, are the major source ofindustrial wood, small timber and fuel wood in India with an estimated potentialwood production of about 42.77 M m3 yr-1; it is many times higher than 3.18 M m3 yr-1

contributed by forest. This is despite the fact that TOF occupy only about 2.82 percent of geographical area of the country in contrast with 21.05 per cent area occupiedby forest. Among TOF, eucalypts are the most important group of trees and formbackbone of a thriving wood-based industry. In our march towards the national goalof 33 per cent forest and tree cover, the role of eucalypts and other fast growing treespecies is very critical. TOF are the saviours of forests due to their high productionfunctions. Research and extension are the key to strengthen this role.

Though TOF have higher productivity than forest, there is considerable potentialfor increasing it further in order to augment ecological goods and services accruablefrom them and reduce our dependence on imports. Indian Council of ForestryResearch and Education (ICFRE) has a sharp focus on applied research. This isgetting manifested in production of fast growing clones and seedlings, developmentof ecofriendly tools and techniques for maintenance of tree health and furtheringcomplete tree utilisation. Clones of eucalypt and other species produced by variousinstitutes of ICFRE are a significant outcome of these researches. Private companieshave shown an exemplary zeal in research as well as extension. The combined effortsof all have made eucalypt planting a rewarding land use option for farmers in diversesite conditions.

The independent developments in two production systems, namely, agricultureand forestry are leading to a logical culmination in crop diversification whereagroforestry has emerged as an eco- and income-friendly option for the growers.Various developments in the post-Green Revolution era, i.e., patent regime,agrochemical pollution, energy crisis, shrinking land holdings, etc. have createdan interface with challenges in forestry like low productivity, quality loss, pestproblem, rise in carbon dioxide content, etc. This has made trees like eucalyptmore relevant in the resolution of present crisis that is multifaceted in form of

demand and supply, clean environment, biodiversity conservation and carbonsequestration. I hope this book will help readers in exploring eucalypts in a morecomprehensive and meaningful way.

I appreciate the efforts of the editors to bring out this book.

(S.S. Garbyal)New Delhi Director General of Forests andMarch 24, 2014 Special Secretary to Govt. of India

ii Foreword

Preface

From a small introductory plantation in Nandi Hills near Mysore around 1790 byTipu Sultan, the ruler of Mysore, eucalypt has spread virtually over the entire countrycovering more than 4 Mha area. Due to its remarkable adaptability and highproductivity, this tree has, at all times, found favour with state forest departmentsand has been heartily embraced by private sector companies as well as individuals.This has rendered it as the most important timber species in India outside the naturalforest from standpoint of area as well as production. But for eucalypt, it would nothave been possible for the industry to meet its raw material requirement from sourcesoutside forest, as mandated by the National Forest Policy, 1988.

However, this extraordinary journey of eucalypt has not been very smooth –this tree had to face, and it still continues to do so, stiff opposition fromenvironmentalists. A flourishing eucalypt culture is a testimony of the fact thateucalypt has established its place beyond doubt and is here to stay. Eucalypt culturehas been driven by enterprising farmers and industry, and is backed by an effectiveresearch endeavour not seen for any other forest species in India.

A considerable change has occurred in eucalypt cultivation, utilisation andresearch since the last books on eucalypt in Indian scenario were published in thelate 1980s and early 1990s. Who would have thought that the tree which was underattack from environmental groups would one day form the backbone of forestry-based CDM projects duly fulfilling stringent international standards? On the flipside, who might have apprehended that eucalypt, which had superbly braved thediverse array of insects in India for over two centuries, would suddenly fall prey toa little-known pest by the name of Leptocybe invasa? Who could have imaginedthat Eucalyptus would cease to be the only genus of eucalypts? Of late, compositewood industry has also started using eucalypt wood for plywood manufacture.Clonal plantation has become a norm rather than exception. Many such noteworthydevelopments have taken place in eucalypt culture in recent times. It was, therefore,decided to bring out a publication that would provide up-to-date and comprehensiveinformation on this tree in context of India. Towards this goal, experts, representing

professional foresters, industry as well as researchers from all parts of India whohave been associated with this tree for a long time and specialised in varied disciplines,joined us in our efforts and made contributions on varied dimensions of eucalyptculture. The authors have not only provided a deep insight into their own spiritedworks, but also enriched their accounts with significant works of others to make thesynthesis quite comprehensive. We are highly appreciative of their splendid efforts.

A significant change took place in eucalypt taxonomy in 1995 when Hill andJohnson split Eucalyptus creating a new genus Corymbia. However, Corymbia hasnot been treated as different from Eucalyptus in this book since most of the forestryprofessionals in India are still not treating it separately.

It is hoped that this publication will provide the much sought-after informationat one place to eucalypt lovers and critics in India. Those working on other speciesmay also find the book useful as this tree is the torch bearer of contemporary forestryresearch in the country. Eucalypt possesses a pleasant present and promise for agreat future. We are sure that the book will continue to be relevant for several years.

We express our thanks to the Environmental Information System (ENVIS) of theMinistry of Environment and Forests, Government of India for financial support forpublication of this book. The encouragement and support received from Ms. VandanaAggarwal, Economic Advisor in the ministry deserves special mention.

The technical assistance received from Ms Vandana Uniyal during editing ofthe book is duly acknowledged.

Editors

iv Preface

Contents

FOREWORD iPREFACE iiiCONTRIBUTORS vii

1. Botany of Genus Eucalyptus 1H.B. Naithani

2. Domestication Strategies for Eucalypts in India 21Mohan Varghese

3. Status of Eucalypt Clonal Culture in India 60R.C. Dhiman and J.N. Gandhi

4. Eucalypt Improvement: Efforts and Achievements in India 117H.S. Ginwal

5. Eucalypt Improvement in Southern India 139N. Krishnakumar, V. Sivakumar and R. Anandalakshmi

Development of Clones of Eucalyptus camaldulensis forDryland Afforestation and Resistance to Gall Infestation 141V. Sivakumar and N. Krishnakumar

6. Eucalypt Improvement at ITC 149H.D. Kulkarni

7. Wood Structure and Quality of Indian Eucalypts: A Review 185Sangeeta Gupta

8. Advances in Genomic Research in Eucalypts 191Modhumita Ghosh Dasgupta

9. Eucalypts in Agroforestry 209R.K. Luna

10. Eucalypts in Agroforestry: Planting Designs 235J.V.N.S. Prasad and H.D. Kulkarni

11. Biomass Productivity, Carbon Sequestration and NutrientCycling of Eucalypt Plantations 244L.S. Lodhiyal

12. CDM Activities in Trees Outside Forests in North-West Indiawith a Special Reference to Eucalypts 267Padam Parkash Bhojvaid and Pramode Kant

13. Diseases in Eucalypts: Status and Management 280C. Mohanan

14. Cylindrocladium Disease of Eucalypts 315C. Mohanan

Molecular Studies on Eucalyptus Leaf and Seedling Blight 329Amit Pandey, Partha Sarathi Mohanty, Pooja Arya andShikha Arora

15. Current Status and Future Trends of Research on InsectPests of Eucalypts in India 339George Mathew

16. Invasive Gall Wasp (Leptocybe invasa) in Eucalypt andIts Management 346A.S. Vastrad and S.H. Ramanagouda

17. Eucalypts: Solid Wood Utilization Research in India 381Vimal Kothiyal

18. Composite Wood from Eucalypts 421D.P. Khali

19. Chemistry of the Genus Eucalyptus 429Inder Pal Singh and Jasmeen Sidana

20. Eucalypts in Pulp and Paper Industry 470Vikas Rana, Gyanesh Joshi, S.P. Singh and P.K. Gupta

vi Contents

Contributors

A.S. Vastrad DDSW, College of Agriculture, University ofAgricultural Sciences, Dharwad – 580 [email protected]

Amit Pandey Forest Pathology Division, Forest ResearchInstitute, Dehradun – 248 [email protected]

C. Mohanan Emeritus Scientist, Forest PathologyDivision, Kerala Forest Research Institute,Peechi – 680 [email protected]

D.P. Khali Forest Products Division, Forest ResearchInstitute, Dehradun – 248 [email protected]

George Mathew Forest Health Division, Kerala ForestResearch Institute, Peechi – 680 [email protected]

Gyanesh Joshi Cellulose and Paper Division, Forest ResearchInstitute, Dehradun – 248 [email protected]

H.B. Naithani Botany Division, Forest Research Institute,Dehradun – 248 [email protected]

H.D. Kulkarni Paperboards and Specialty Papers Division,ITC Limited, Khammam District,Sarapaka – 507 [email protected]

H.S. Ginwal Genetics and Tree Propagation Division,Forest Research Institute, Dehradun – 248 [email protected]

viii Contributors

Inder Pal Singh Department of Natural Products, NationalInstitute of Pharmaceutical Education andResearch (NIPER), Sector-67, S.A.S. Nagar,Punjab – 160 [email protected]

J.N. Gandhi Wimco Seedlings Division, WIMCO Ltd.Bagwala, Kashipur Road, Rudrapur – 263 153

J.V.N.S. Prasad Central Research Institute for DrylandAgriculture, Santoshnagar, Hyderabad – 500 [email protected]

Jasmeen Sidana School of Pharmaceutical Sciences,Lovely Professional University, Jalandhar-Delhi GT Road (NH-1), Phagwara – 144 411

L.S. Lodhiyal Department of Forestry and EnvironmentalScience, D.S.B. Campus, Kumaun University,Nainital – 263 [email protected]

Modhumita Ghosh Dasgupta Institute of Forest Genetics and TreeBreeding, Forest Campus, R.S. Puram,Coimbatore – 641 [email protected]

Mohan Varghese ITC Life Sciences and Technology Centre, PeenyaIndustrial Area, Phase I, Bangalore – 560 [email protected]

N. Krishnakumar Institute of Forest Genetics and Tree BreedingCoimbatore – 641 [email protected]

P.K. Gupta Cellulose and Paper Division, Forest ResearchInstitute, Dehradun – 248 [email protected]

Padam Parkash Bhojvaid Forest Research Institute, Dehradun – 248 [email protected]

Partha Sarathi Mohanty Forest Pathology Division, Forest ResearchInstitute, Dehradun – 248 [email protected]

Pooja Arya Forest Pathology Division, Forest ResearchInstitute, Dehradun – 248 [email protected]

Pramode Kant Institute of Global Warming and EcologicalStudies, Sector-125, Noida – 201 [email protected]

Contributors ix

R. Anandalakshmi Institute of Forest Genetics and TreeBreeding, Coimbatore – 641 [email protected]

R.C. Dhiman Wimco Seedlings Division, WIMCO Ltd.Bagwala, Kashipur Road, Rudrapur – 263 [email protected]

R.K. Luna Punjab State Forest Department,Forest Complex, Sector-68, Mohali – 160 [email protected]

S.H. Ramanagouda Kittur Rani Channamma College ofHorticulture (KRCCH), Arabhavi, DistrictBelgaum – 591 218

S.P. Singh Cellulose and Paper Division, Forest ResearchInstitute, Dehradun – 248 [email protected]

Sangeeta Gupta Botany Division, Forest Research Institute,Dehradun – 248 [email protected]

Shikha Arora Forest Pathology Division, Forest ResearchInstitute, Dehradun – 248 [email protected]

V. Sivakumar Institute of Forest Genetics and Tree Breeding,Coimbatore – 641 [email protected]

Vikas Rana Cellulose and Paper Division, Forest ResearchInstitute, Dehradun – 248 [email protected]

Vimal Kothiyal Research Planning Division, Directorate ofResearch, Indian Council of ForestryResearch and Education, Dehradun – 248 [email protected]

1

1. IntroductionEucalyptus, a well known genus of Australia, belongs to the family Myrtaceae,where Callistemon, Eugenia, Melaleuca, Psidium, Rhodomyrtus and Syzygiumare also members. Regarding the origin of eucalypts in Australia, the theory ofplate tectonics, supported by fossil evidence, show that the land mass was oncepart of a single super-continent Gondwana, comprising what is now known asNew Guinea, Antarctica, India, Arabia, Africa, Madagascar and South America. AsGondwana broke up in the Tertiary period, the Australian landmass driftednorthwards from Antarctica. It is believed that in the early part of this drift thecontinent experienced high rainfall and was characterized by a relatively uniformrainforest vegetation. The landmass gradually became drier and the ancient soilslost their fertility. The new land environment became totally unsuited to rainforestand it contracted, largely to the eastern seaboard. However, by the evolution ofnew adaptable forms some plant families were able to occupy the areas of lesscertain rainfall and soils of diminishing fertility. Notable examples are Myrtaceae,which spawned the eucalypts, and Mimosaceae, the distinctive phyllodinousAcacia spp. (Brooker, 2002).

2. ClassificationThe first specimen of the genus Eucalyptus was collected in 1770 by Joseph Banksand his assistant Daniel Carl Solander on the shores of Botany Bay on the east coastof Australia during Capt. James Cook’s first voyage to the Pacific Ocean. Beforethis, however, in 1688 William Dampier found a tree with gummy exudation which heconfused with Calamus draco which is known as ‘Dragon’s Tree’ and produces aresin called ‘dragons blood’.

The genus Eucalyptus was described and named by the French botanist L’Heritier in 1788 as E.obliqua. The name Eucalyptus consists of Eu which meanstrue and calyptus (kalypto) means to cover; referring to the united calyx and corolla

Botany of GenusEucalyptusH.B. Naithani

1

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forming lid or operculum which seals the flower till it blooms. Bentham and vonMueller (1866), without studying plants in the field, carefully examined and classifieddried plant materials brought from Australia and published ‘Flora Australiensis’which is considered, even today, as one of the best classification on the Australianflowering plants.

By 1866, total 149 species of Eucalyptus were named. Bentham and von Mueller(1866) classified them into five series based on their anther characteristics with thefifth series, subdivided into nine subseries. Further, Mueller (1879-84) carried outstudy of eucalypts in the Australian fields which Bentham could not take up. Hepublished several papers and a book ‘Eucalyptographica’. However, he was notable to propose a better classification for the eucalypts than the one by Bentham.

Maiden (1903-33) continued studies on eucalypts and published ‘A CriticalRevision of the Genus Eucalyptus’ with illustrated descriptions of all taxa knownup to that time. But he could not improve the existing order of classification.Blakely (1934) an assistant to Maiden, extended Bentham’s antheral classificationin his book ‘A key to the Eucalyptus’, a most comprehensive descriptive workever published comprising 500 species and 138 varieties.

A revision of the names and status of many taxa of eucalypts described byBlakely (1934) was done by Johnston and Marryatt (1962) in their work ‘Taxonomyand Nomenclature of Eucalyptus’. These names were again revised by Chippendale(1968) in a paper entitled ‘Eucalyptus nomenclature’.

Based on the extensive studies in eucalypts, Pryor and Johnson (1971) published‘A Classification of the Eucalypts’ in which the genus Eucalyptus of L’Heritier andthe closely related genus Angophora of Ceur are combined. The classification dividesthe genus Eucalyptus into seven subgenera. The subgenera are divided intosections, series, subseries, super species, species and subspecies; subgenera,sections, number of species in each section (Table 1).

Pyror and Johnson’s classification was deliberately extracodical (informal andoutside the International Code of Botanical Nomenclature). The system washierarchical (sections, series, etc.) and contrasts with the formal classification used byChippendale (1988), where only one infra-genetic rank (series) was used. This latterwork, however, made possible the formal reference of all species published up to 1988to taxonomic series, which is generally required in systematic papers.

The most recent major contribution to classification in the genus Eucalyptuswas made by Hill and Johnson (1995) who formally published a new genus,Corymbia, comprising two of the subgenera of the Pryor and Johnson’sclassification (1971), namely, Corymbia and Blakella. The rationale for this stepwas based on cladistic analyses of all the traditional Eucalyptus components atthe general ‘subgenus’ level and is corroborated by molecular studies of Udovicicet al. (1995).

H.B. Naithani

3Botany of genus Eucalyptus

Corymbia Hill and Johnson is a genus of about 113 species of trees. Species ofEucalyptus (introduced in India) were shifted to Corymbia by Hill and Johnson(1995) and are given below:

Corymbia citriodora (Hook.) Hill and Johnson (syn. Eucalyptus citriodora Hook.)Corymbia ficifolia (F.v.M.) Hill and Johnson (syn. Eucalyptus ficifolia F.v.M.)Corymbia gummifera (Gaertn.) Hill and Johnson (syn. Eucalyptus gummifera Gaertn.)Corymbia intermedia (F.v.M. ex Baker) Hill and Johnson (syn. Eucalyptus intermedia F.v.M. ex Baker)Corymbia maculata (Hook.) Hill and Johnson (syn. Eucalyptus maculata Hook.)Corymbia polycarpa (F.v.M.) Hill and Johnson (syn. Eucalyptus polycarpa F.v.M.)Corymbia terminalis (F.v.M). Hill and Johnson (syn. Eucalyptus terminalis F.v.M.)Corymbia torelliana (F.v.M.) Hill and Johnson (syn. Eucalyptus torelliana F.v.M.)

Some ambiguity, however, remains over relationship of the closely relatedgenus Angophora Cav. A recent study on the relationships within Eucalyptusconcluded that Angophora, Corymbia and Blakella form a monophyletic group(Sale et al., 1996). Perhaps all these recent studies should be considered merely ashypotheses that will contribute ultimately to an optimum system with furtherresearches. Brooker (2002) suggested that for a single genus consisting of thirteensubgenera (Table 2), namely, the five major subgenera of Pryor and Johnson (1971),

Table 1. The classification of Pryor and Johnson (1971) with examples of well-knownspecies in the taxa

Subgenus Well-known species and species group Blakella Corymbia Eudesmia Gaubaea Idiogenes Monocalyptus

Symphyomyrtus

Ghost gums (e.g. E. tessellaris) Bloodwoods (e.g. E. citriodora) Includes E.miniata and E. baileyana Comprises E. curtisii and E. tenuipes E. cloeziana only White mahoganies (e.g. E. acmenoides), stringybarks (e.g. E. globoidea), blackbutts (e.g. E. pilularis), ashes (e.g. E. obliqua), peppermints (e.g. E. dives, E. radiata) Red mahoganies (e.g. E. robusta), red gums (e.g. E. camaldulensis), mallees (e.g. E. polybractea), gums (e.g. E. globulus), boxes (e.g. E. polybractea), ironbarks (e.g. E. staigeriana).

4

Subgenus Angophora Sungenus Corymbia sensu Pryor and Johnson, 1971 Subgenus Blakella sensu Pryor and Johnson, 1971 Subgenus (E. curtisii) Subgenus (E. guilfoylei) Subgenus Eudesmia sensu Pryor and Johnson, 1971 Subgenus Symphymyrtus sensu Pryor and Johnson, 1971 Subgenus (E. ravertiana, E. brachyandra, E. howittiana, E. deglupta) Subgenus (E. microcorys) Subgenus (E. tenuipes) Subgenus Idiogenus sensu Pryor and Johnson, 1971 (E. cloeziana) Subgenus (E. rubiginosa) Subgenus Eucalyptus (=Monocalyptus in Pryor and Johnson, 1971)

the genus Angophora, a subgenus comprising the four tropical species with thesmall fruit, and six single-species subgenera – a system embracing demonstrablemorphological distinctions.

While comparative morphology is the basis for estimating natural affinities andresulting classification, the value of characters used varies greatly. Features such asbark have been traditionally used in keys and descriptions, but bark as a character isonly of medium reliability as its constant exposure to the elements results in attritionand colour change. Internal characters protected from outside influences are ofhigher reliability. In this respect, essential oils have been considered as possibleacids to testing natural affinities. Little success has been achieved and it may beconcluded that the developmental pathways for morphology and for essential oilsare not closely associated within the eucalypt plant (Brooker, 2002).

Metro (1955) recognized the name of some taxa which are believed to havehybrid origin (Table 3). Research work conducted at the Forest Research Institute,Dehradun, has resulted in the development of two promising interspecific F1 hybridsbetween E. tereticornis and E. camaldulensis, FRI-4 and FRI-5. These improvedvarieties have yielded three to five times more wood than the parent species over aten-year rotation, although the oil composition shows little improvement incommercial terms (Chaudhari and Suri, 1991).

3. Morphology

3.1. HabitEucalypts vary in general habit from shrub one metre high to the tallest 90 mhigh. Similarly the stem on one side are 2.5 cm in diameter whereas on the otherside there are buttressed trunks upto 6 m in diameter.

H.B. Naithani

Table 2. Proposed new classification of the genus Eucalyptus

Source: Brooker (2002).

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3.2. BarkGenerally speaking, the bark on the young branches of a mature tree is smooth,while on the lower part of the trunk, up to a few metres from the ground, therhytidom becomes more or less persistent and deeply furrowed. Therefore, whendescribing the type of bark, neither that of the trunk base nor of the twigsshould be taken into account.

Of the distinctions made in Australia, the following which seems most typical,but not, in any case, suitable for extensive interpretations were retained in thechapter.

3.2.1. Deciduous barkBark peeling off, when each layer is renewed, in long stripes as in E.globulus.Peeling off in rather broad plates, as in E. camaldulensis and E. saligna. Peelingoff in very small flakes or scales, as in E. citriodora or E. astringens (Fig. 1).

Botany of genus Eucalyptus

Taxon Probable parent E. affinis Deane and Maiden E. algeriensis Trabut E. antipolitensis Trabut E. bianqularis Simmonds E. bourlierii Trabut E. codieri Trabut E. globulus var. campacta Bailey cultivar E. gomphocornuta Trabut E. huberana Naudin (as applied by Blakely) E. insizwaensis Maiden E. longifolia var. multiflora Maiden E. maidenii var williamsonii Blakely E. mcclatchiei Kinney E. nortonniana Kinney E. occidentalis var. ornensis Trabut E. oviformis Maiden and Blakely E. patentinervis R.T. Bak.:syn E. kirtoniana F.v. M. E. polulifolia Hook. var. obconica Blakely E. trabutti Vilmorin

E. albens x E. sideroxylon E. camaldulensis x E. rudis E. globulus x E. viminalis E. globulus x E. urnigera E. globulus x ? Probble hybrid of E. nortonii E. gomphocephala x E. cornata Quite common in Australia. E. viminalis x several related species giving seven flowered umbels in contrast to the three flowers of E. viminalis Chippendale (1976) states that E. huberana Naudin is now accepted as a taxon E. globulus x ? E. longiflolia x E. robusta E. botryoides x E. pseudoglobulus E. globulus x E. ovata E. pseudoglobulus x E. maidenii Status doubtful E. pseudoglobulus x E. tereticornis E. robusta x E. tereticornis E. microtheca x E. populnea E. botryoides x E. camaldulensis

Table 3. Eucalyptus of hybrid origin

Source: Tewari (1992).

6 H.B. Naithani

Fig. 1. Barks

(a) E. citriodora

(c) E. paniculata (d) E. torelliana

(b) E. deglupta

7Botany of genus Eucalyptus

It is usually difficult to define the colour and surface texture of such barks becausethey are often characterized by adjoining patches of varying age, while the newerpatches are generally shiny and of fine texture with comparatively bright and variedcolouring. The old patches, ready to fall, are comparatively dull gray and less smooth.

All species with deciduous bark are grouped together in Australia under thetitle ‘gums’.

3.2.2. Persistent barkIf the subero-phellodermal layer is not renewed in depth, or if, for any other reason,the external parts of the rhytidom do not strip off periodically from the tree, the barkis called ‘persistent’.

When the bark ages, its surface oxidizes, darkens, becomes more or less pulverulent,and loses its specific characteristics. Such characteristics can only be determined byexamining the mature bark not at the trunk base, but at one-third of the tree’s height.

The simplest way to distinguish four categories of persistent bark is given below:3.2.2.1. Ironbark type: This bark is hard, with extremely short, or non-fibrous, breakingup into very small polyhedrons of hard corky texture when crumbled, with deeplongitudinal furrows. It is usually dark in colour, sometimes contains inclusions ofkinos, small masses of gum rich in tannin.3.2.2.2. Box type, short fibrous, pale in colour: This bark is pale gray, fibrous, finelyfurrowed or reticulated obliquely on the surface.3.2.2.3. Long-fibred brown bark: Thick bark is usually more or less dark brown withlong or very long fibres, deeply furrowed longitudinally. When the excrescences arepulled off, the long fibrous, often laminated, texture is revealed.

This category includes the ‘Transversae’, as in E. robusta or E. botryoides, and‘Stringybarks’ as in E. obliqua or E. scabra.3.2.2.4. ‘Peppermint’ and ‘bloodwood’ types: Dull gray to black bark, hard, withshallow irregular furrowing chiefly in two directions, creates an effect of scales moreor less oblong in shape. Examples of these are E. andreana, peppermints, andE. gummifera, bloodwoods.

4. Leaves

4.1. Juvenile LeavesOne of the essential features of most species of Eucalyptus is the presence, sometimeson adventitious branches, of juvenile leaves which are very different from the matureleaves. At times this difference is seen even on the branches themselves. In general,juvenile leaves show a wider range of shape and arrangement than do the matureleaves. It appears, however, that for any given species, the variability of shape ismore limited in the case of juvenile than in mature leaves.

8

In the seedlings of most species the first juvenile leaves are opposite inarrangement. Those which follow are either opposite or alternate according to species,and are still distinct in character from the mature leaves. These leaves can be observedeither on nursery plants at five to 50 cm of height, or upon tree shoots.

Two essential types of juvenile leaves have been distinguished in the followingdescriptions.

4.1.1. Opposite for numerous pairsFour to six, after that of the very first leaves, mentioned previously.

4.1.2. AlternateRelating to leaves beyond the sixth pair. Leaf shapes vary considerably but areusually broader than mature leaves. In species with opposite juvenile leaves, thelatter are often glaucous or glaucescent, sometimes cordate, amplexicaul or evenconcrescent and perfoliate. Finally certain groups are characterized by juvenile leaveswhich are downy or hairy in various forms, thus helping to identify the species.

4.2. Mature LeavesThe mature leaves of the eucalypts are always entire, coriaceous, often thick, stiff,highly cutinized and rich sclerenchyma. Almost always alternate, only occasionallyopposite or sub-opposite. Shape may be regarded as lanceolate in general. It varies,however, according to species, from very narrow lanceolate, almost linear to broadlanceolate, elliptical, oblong or even oval and orbicular. The leaves are often falciform.Their dimensions also vary considerably in the same species. Thus, when thelength and breadth of the leaves are given, excluding the petiole, not only theaverage, but also the extreme dimensions should be indicated.

Another useful character to the identification of the eucalypts is knowledgeof the leaf venation. Following types can be distinguished.

4.2.1. Pinniveined or spreadingIn this type, the fine regular lateral veins are nearly parallel or apparently onlyslightly reticulated. They make, at least in the central part of the leaf, or on theconvex side if the leaves are falciform, an angle of 60º or more with the medium vein.The marginal veining is usually fine and very close to the leaf edge. The leavescharacterized by such venation are usually lighter on the underside than on theupper side. The underside carries numerous stomata, the upper hardly any.

4.2.2. ObliqueWith this type, the venation is comparatively thick and irregular, often anastomosed,forming, atleast in the middle part of the leaf, or on the convex side if falciform, an angleof less than 60º with the medium vein. The somewhat sinuous marginal veining is

H.B. Naithani

9

comparatively distant from the leaf edge. This characteristics veining usually havesymmetrical faces of the same colour and carry stomata on both sides. A special typeof this venation has secondary veins at angles of less than 30º to the median vein, andsometimes even parallel to it. This is the longitudinal type of venation. This secondaryveining is more or less obviously visible, and is variously described as distinct,indistinct or intermediate. This is a feature difficult to measure and open to subjectivedetermination.

5. InflorescencesEucalypt flowers are rarely single, with the exception of E. globulus (Fig. 2). In mostcases they are grouped in inflorescences which are sometimes definite, as cymes oraxillary umbels; and sometimes indefinite, as panicles or terminal corymbs.

The axillary umbels are enclosed at the outset within envelope-like bracts. Thesebracts, however, are usually very fleeting, and disappear as soon as the umbelbegins to grow. They persist for a fairly long time in a few of the ‘box’ species. Eachflower may be similarly enclosed in bracts. The number of flowers making up eachumbel is not fixed. It varies, however, between limits which constitute gooddetermining features.

(d) E. globulus (e) E. tereticornis (f) E. torelliana

(a) E. alba (b) E. citriodora (c) E. deglupta

Fig. 2. Inflorescences


10

A certain number of species are characterized by three flowers to each umbel, asin E. viminalis. This rule only applies to buds, not to fruits, since a certain productionof the buds may not set. The peduncles of the umbels may also constitute a gooddistinguishing feature; i.e., varying length, cylindrical or flattened, rigid or drooping.The umbels of certain species are sessile as in E. stellulata.

6. BudsIt is customary to give the name ‘bud’ to what in reality is the flower of the eucalypts.The petals are joined in a single piece which covers the whole of the flower andseparates at the time of anthesis, which is called operculum. Its tip is often covered bya second tiny cap consisting of the calcycine whorl or the bracteoles, which disappearsvery early as with E. camaldulensis (Fig. 3). The description of the bud comprises,therefore, an account of the shape and diameter of the receptacle, the shape of thepedicel and of the operculum.

It is often impossible to decide where the receptacle begins and pedicel ends.For this reason the length of the buds is not indicated in the descriptions. Theshapes of the opercula are described in the following terms.

Conical operculum - E. rudisObtuse conical operculum - E. cladocalyxAcute conical operculum - E. tereticornisHorned or long operculum - E. occidentalisHemispherical operculum - E. maculataHemispherical apiculate operculum - E. amygdalina

- E. diversicolorRostrate operculum - E. camaldulensisOvoid operculum - E. salubrisOpercula of exceptional shape, as biretta, boss-shaped, or flattened.

(a) E. camaldulensis (b) E. tereticornis (c) E. torelliana

H.B. Naithani

Fig. 3. Buds

11

Sometimes in the same species, and often on the same tree, the shape of theoperculum is variable and can only be described with the help of at least two or threeof the above comparisons.

7. StamensThe classification of the genus Eucalyptus has been based, up to now, upon thecharacteristics of the stamens. Blakely (1934) divided the species into eight sections eachwith several subsections, according to the shape of the stamens. It is practically impossibleto distinguish between these subsections in the field or often even in the laboratory.

The descriptions which follow have, therefore, been limited to indicating onlythe section to which each of the stamens examined belongs. The chief characteristicsof the principal sections are summarized in the Table 4.


8. FruitsThe identification of eucalypt fruits has given rise to a real orgy of comparisonswith the strangest objects, and it is well justified to apply a reasonable check to this.The fruit is formed by the development of the receptacle and of the lower ovaryadhering to it (Fig. 4). The upper part of the fruit consists of four segments.

The scar left by the operculum after shedding forms an outside ring called thecalycine ring. The next ring inwards is the stamina ring. Then follows the disc, theontogenesis of which has not yet been completely described. Below, and inside thedisc is the upper part of the ovary which, on maturity, splits and separates into valves.

In some species, the calycine ring which is comparatively prominent in theflower, disappears completely as soon as the fruit is formed. In other species, as

Source: FAO (1965).

Table 4. Chief characteristics of stamens of eucalyptsGroup Fertility Tip of filament Shape of anther Mouth of sac Gland

Macrantherae Stamens almost all fertile

Subulate Cordate oval, oblong, orbicular

Distinct loculi opening into two lobes of auricular shape

Fairly large, situated in the upper half of the commissure, sometimes visible from the front

Renantherae Subulate Kidney- or heart-shaped, almost flat

Loculi divergent, sometimes coming together at tip

Very small or not apparent at upper tip

Porantherae Almost all fertile

Adnate or subulate

Globular or reniform

Fairly distinct loculi opening towards the top or laterally with round pores

Small at the upper tip

Terminales Numerous filaments without anthers

Adnate or anthers placed obliquely on the filament

Cuneiform rounded or almost square

Distinct loculi opening in terminal oval slits or round pores

No glands

12

in E. leucoxylon, the ring is fairly well developed but it is fine, and protrudesclearly beyond the disc. In these species, when the fruit ripens, the ring falls orremains partially attached to one of the fruits.

Consequently, the description of the fruit should cover the shape of thereceptacle and that of the pedicel of the disc, and also the position and shape of thevalves.

8.1. Shape of the Receptable Proper and Its PedicelThe shape of the receptacle is more or less merged with that of its pedicel. The lattermay be truncated or attenuated. The receptacle proper can usually be classified asglobular, ovoid, urceolate, campanulate, hemispherical, cylindrical or conical.

An ovoid or globular receptacle combined with a attenuated pedicel producesa pyriform fruit; combined with a short attenuated pedicel, a turbinate fruit. A cylindricalor urceolate receptacle combined with an attenuated pedicel produces a fruit shapedmore or less like a short club. It must be remembered that the size of fruits may varyconsiderably according to whether they develop and ripen slowly or, on the contrary,mature too quickly.

It is also advisable to be careful with the use of the term ‘striated’. It should beused solely to indicate the striation which appears when the non-sclerous tissuecontracts. The term ‘ribbed’ on the other hand is used to indicate the ribs that areclearly visible on fresh specimen.

8.2. Shape of the DiscIn the flowers or the young fresh fruits, the disc is virtually continuous with theupper part of the ovary. When the fruit ripens and desiccates, the distinction

(a) E. citriodora (b) E. tereticornis

H.B. Naithani

Fig. 4. Fruits

13

between the two becomes increasingly marked and is unmistakable when the valvesopen. According to whether the ovary evolves into a capsule, developed more orless than the receptacle so that the disc may become protuberant, remain flat, andusually thin, or become depressed. When protuberant, it may be concave, flat orconvex. In the latter case it is usually described as ‘dome-shaped’.

8.3. Position and Shape of ValvesThe valves may be comparatively short and triangular as in E. camaldulensis. Inthis case they simply represent the upper part of the ovary or they may have sharppoints formed by the rupture of the persistent base of the style. These sharp-pointedvalves may even be continuous and joined together in a single point owing to thepersistence of the whole style as in E. oleosa. In certain species the valves are fragileand drop off quickly when the fruit is ripe.

8.4. Exsert ValvesThe name ‘exsert’ is given to those valves the base of which is located noticeably atthe level of the calycine ring or clearly above it and when their points are beyond thewhole fruit as in E. camaldulensis.

8.5. Enclosed ValvesSuch valves have their base well below the level of the calycine ring beyond whichtheir summit may project slightly.

8.6. Level ValvesLevel valves are those which have their base level with or slightly below the calycinering, the points being at the level of, or slightly above the latter.

9. SeedsEucalyptus seeds vary greatly in size from less than 1 mm in E. populnea to morethan 2 cm in E. calophylla. Their colour varies from black (E. tereticornis) toyellow (E. camaldulensis), shape of the seeds also differ from being almost sphericalas in E. wandoo to cuboid in E. tetrodonta and subulate in E. curtisii and insculpture from shallowly reticulate in E. leucoxylon to deeply pitted in E. griffithii.The seeds of many species of the woody fruited blackwoods (subgenus Corymbia)are prominently winged; those of the paper-fruited bloodwoods (subgenusBlakella) are saucer-shaped and unwinged. Seed lots of subgenus Monocalyptusshow high uniformity whereas a great deal of variability is exhibited in the seedcharacteristics of the subgenus Symphyomyrtus. The seed may be cuboid,pyramidal, elliptical, etc. smooth or tooth-edged, whitish, grey, yellow, red, brownor black.


14

10. DistributionThe eucalypts have a natural latitude range extending from 7ºN to 43 º 39' S. Theirnatural distribution is clearly restricted to the east of the hypothetical line called‘Wallace’s line’ separating the Indo-Malayan and Austro-Malayan life types. Thisline passes between Bali and Lombok through the Makassar Strait with Sulawesi onits eastern side, Borneo to the west, then northeast through the Celebes Sea and thesouthern islands of the Philippines. This line leaves Mindanao on its western side.But, occurrences of E. deglupta have been reported from Mindanao. So ‘Wallace’sline’ was amended in 1978 drawing it east of Mindanao. Now the natural occurrenceof all eucalypts lies east of this amended line, with the possible exception of E. albain north Bali (Martin and Cossalter, 1975-76).

The number of species under Eucalyptus was estimated variously by differentauthors. However, Chippendale and Johnson (1983) estimated it to be 550-600 moreor less distinct forms, plus many hybrids; most of them are endemic to the Australiancontinent, Brooker (2002) estimated 800 species. The largest diversity is in south-western Australia. Indigenous species of Eucalyptus are found in the eastern partof Indonesia, such as E.deglupta ( from Celebes island), E.urophylla and E.alba(from East Nusu Tenggara), and E. pellita (from West Papua) (Table 5).

Almost all the species of Eucalyptus are adapted to a monsoon climate. Manyspecies can even survive a severe dry season, e.g. the cultivated species E. alba,E. camaldulensis, and E. citriodora. Only E. deglupta adapt to lowland and lower

H.B. Naithani

Table 5. Eucalyptus species from Indonesia and Papua New Guinea

Source: Carr (1972); Srivastava (1996).

S. no.

Species Distribution

1. E. deglupta Blume (incerate sedis) New Guinea, Papua, West Irian, New Britain, Ceram Celebes, Mindanao. May have been present in New Ireland

2. E. alba Reinw. ex Blume (series Subexseratae) Timor, Flores, Alor, Wetar, east Papua, Horn Island, also northern Australia

3. E. tereticornis Sam. (series Exseratae) East and West Papua, West Irian. Also eastern Australia, south to Victoria.

4. E. papuana F.v.M. East and West Papua. Also northern and central Australia

5. E. confertiflora F.v.M. (series Clavigerae (Maiden) S.T. Blake) East and West Papua and West Irian. Also northern Australia

6. E. polycarpa F.v.M. (series Corymbosae (Benth.) Maiden) West Papua, Australia

7. E. brassiana SW Papua, New Guinea, also Cape York, Queensland, Australia

8. E. leptopheleb F.v.M. Western Province, Papua, New Guinea (?), Cape York, Australia

9. E. pellita F.v.M. Western Province, Papua, New Guinea, NSW, Queensland, Australia

10. E. tessellaris F.v.M. Western Province, Papua, New Guinea (?), Cape York, NSW, Australia.

15

montane rain forest habitats. It does not grow naturally in areas with a pronounceddry season, but it occurs in areas where the annual rainfall is 2,500- 5,000 mm and themonthly rainfall usually exceeds 150 mm.

11. Introduction in IndiaEucalypt has long history in India. It was first planted around 1790 by Tipu Sultan,the ruler of Mysore, in his palace garden on Nandi Hills near Mysore. According toone version he received seeds from Australia and introduced about 16 species(Shyam Sunder, 1984). Subsequent to the planting of Nandi Hills, the next significantintroduction of eucalypts in India, was in 1843 when most extensive plantationswere established on the Himalayan slopes in the vicinity of Shimla, and in the NilgiriHills at an altitude of 1,500 to 2,500 m (FAO, 1965). Ahmad (1996) also stated its firstintroduction in the sub-continent dates back to 1843 as single trees arboreta androadside plants. Plantations of E. globulus were raised to meet the demand forfirewood from 1856 (Wilson, 1973). Between 1940 and 1950, due to politico-socio-economic conditions, overgrowing population and increasing demand of industries,necessity arose to raise vast denuded tracts with indigenous forest trees and somefast growing short rotation tree crops which required less care after planting andwere capable of growing over different sites. Eucalyptus was one such speciesmeeting the desired qualities (Dabral et al., 2000). From 1951 to 1954 large scale trialswere conducted in Uttar Pradesh, Bihar, Assam, Madhya Pradesh, Maharashtra andKerala (Chaturvedi, 1976), however, during 1959-1979 the area under eucalyptplantations increased significantly (FAO, 1979). Over 0.1 Mha of eucalypt plantationshave been established, mostly be state forest departments and forest developmentcorporations (Palanna, 1996). There are several reasons for raising large scale eucalyptplantations in the country; some are common and some are specific to each state.The most important common reason is to reclothe the denuded and barren hillyareas and replace low value natural forest (FAO, 1979).

Parker (1925) has given the list of over 100 species tried in India. Accordingto Bhatia (1984), 170 species/varieties/provenances of eucalypts have beentried in India upto 2,200 m with an annual rainfall range of 400-4,000 mm.E. tereticornis (Nandi Provenance, Eucalyptus hybrid of Mysore gum) provedsuperior in the edaphological adaptation. The species which have receivedcountrywide acceptance are E. tereticornis, E. camaldulensis, E. grandis,E.citriodora and E. globulus. Sahni and Bahadur (1972) have suggested trial ofeucalypts in different climatic zones of India based on their climatologicalrequirements.

Scrutiny of literature and herbarium specimens deposited in theherbarium of Forest Research Institute, Dehradun revealed that the following 70species (Table 6) of eucalypts were successfully introduced in India.


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Table 6. Eucalyptus species introduced in India

H.B. Naithani

Contd. on next page…

S. no. Botanical name Common name Place of introduction in India 1. E. alba Reinw. ex Bl. (=E. platyphylla F.v.M) Timor white gum Dehradun (U.K.) 2. E. albens MiQ. White box Nilgiri (T.N.) 3. E. albina Lindl. Grampians stringy bark Nilgiri (T.N.) 4. E. amygdalina Labill. Black peppermint Chaubbatia (U.K), Nilgiri (T.N.) 5. E. bicolor A. Cunn. River black box peppermint Dehradun (U.K.) 6. E. bosistoana F.v.M. Bosisto’s box Nilgiri (T.N.) 7. E. botryoides Sm. Bangalay, southern

mahogany Nilgiri (T.N.)

8. E. brachypoda Turcz. (=E.microthica F.v.M.) Flooded box Dehradun (U.K.), Delhi and Ludhiana (P.B.)

9. E. calophylla R.Br. ex Lindl. Marri Nilgiri, Shillong (M.L.), Satna (M.P.)

10. E. camaldulensis Dehnh Murray red gum, river red gum

Saharanpur (U.P), Nasik (M.H.), Shimla (H.P), Ambala (P.B.), Delhi, Nandi Hills, Mysore, Banglore (K.A.), Haryana

11. E. capitellata Sm Brown stringy bark Chakrata (U.K.) 12. E. citriodora Hook.(Corymbia citriodora

(Hook.) Hill and Johnson Lemon scented spotted gum

Dehradun (U.K.), Lucknow, Saharanpur (U.P.), Chandigarh, Poona (M.H.), Madhya Pradesh, Sriharikota, (A.P.), Dandeli, Mysore (K.A.), Valpoi, (Goa); Haryana, Tripura.

13. E. cladocalyx F.v.M. Sugar gum Nilgiri (T.N.) 14. E. crebra F.v.M. Narrow-leaved ironbark Dehradun (U.K.); Punjab; Nandi

Hills (K.A.), Nilgiri (T.N.); Haryana.

15. E. cosmophylla F.v.M Cup gum Nilgiri (T.N.) 16. E. dealbata A. Cunn. Trumble down gum Almora, Ranikhet (U.K.) 17. E. deglupta Blume Mindanao gum Dehradun (U.K.) 18. E. diversicolor F.v.M. Karri Nilgiri (T.N.) 19. E. drepenophylla F.v.M Bowen Ironbark Dehradun (U.K.), Hassan (K.A.);

Nilgiri (T.N.) 20. E. eugenoides Sieb. ex Spreng - Nilgiri (T.N.), Shimla (H.P.) 21. E. eximina Schau Yellow blood wood Shimla (H.P.) 22. E. exserta F.v.M. Bendo Saharanpur (U.P.) 23. E. ficifolia F.v.M. (Corymbia ficifolia

(F.v.M.) Hill and Johnson) Red flowering gum

Nilgiri (T.N.)

24. E. globulus Labill Tasmanian blue gum, southern blue gum

Almora, Ranikhet, Pithoragarh, Nawagon (U.K.), Northeast India; Mysore (K.A.), Nilgiri (T.N.); Haryana

25. E. grandis (Hill.) Maiden Toolur Dehradun (U.K.), Kerala, Kollimalais and Sevarayans (T.N.), Kerala.

26. E. goniocalyx F.v.M Spotted mountain gum, Monkey gum, mountain gray gum

Ranikhet, Almora (U.K.)

27. E. gummifera (Gaertn.) Hochr (E. corymbosa Sm); Corymbia gummifera (Gaertn.) Hill and Johnson)

Blood wood, red blood wood

Nilgiri (T.N.)

28. E. hemiphloa F.v.M White box, grey iron box, gum topped box

Shimla (H.P.), Nilgiri (T.N.)

17

... Contd. from previous page



29. E. intermedia R.T. Baker Pink blood wood Nandi Hills (K.A.) 30. E. kirtoniana F.v.M. Bastard mahogany Dehradun, Ranikhet (U.K.);

Lucknow (U.P.) 31. E. leucoxylon F.v.M. White iron bark, yellow gum,

blue gum Shimla (H.P.), Panchgani, (M.H.), Nilgiri (T.N.).

32. E. liniaris Dehn White peppermint Shimla (H.P.) 33. E. longifolia Link and Otto Woollybutt Shimla (H.P.), Bangalore (K.A.) 34. E. macarthurii Deane and Maiden Camden woollybutt, paddy’s

riverbox Nilgiri (T.N)

35. E. maculata Hook. Spotted gum Dehradun (U.K.), Srirangam island, Nilgiri (T.N), Bilaspur (M.P.).

36. E. maculosa R.T. Baker Red spotted gum Shimla (H.P.) 37. E. maideni F.v.M Maiden’s gum, spotted blue

gum Shimla (H.P.)

38. E. marginata Sm. Jarrah Nilgiri (T.N.) 39. E. melanophloa F.v.M Silver leaved iron bark Mandi (H.P.) 40. E. melliodora A.Cunn. Yellow box Dehradun (U.K.), Shimla (H.P.),

Nilgiri (T.N.) 41. E. microcorys F.v.M. Tallow wood Dehradun (U.K.), Nandi Hills

(K.A.) 42. E. nova-anglica Deane and Maiden New England peppermint Nandi Hills (K.A.) 43. E. obliqua L’Herit Messmate, messmate string

bark Nilgiri (T.N.)

44. E. ovata Labil Swamp gum Saharanpur (U.P.), Shimla (H.P.) 45. E. paniculata Sm. Grey iron bark, iron bark Dehradun, (U.K.), Saharanpur

(U.P.), Nilgiri (T.N.), Poona (M.H.), Morni Hills (Haryana)

46. E. pauciflora Sieb. ex Spr. (E. coriacea A. Cunn.)

Cabbage gum

Nilgiri (T.N.)

47. E. pilularis Sm. Blackbutt Nilgiri (T.N.) 48. E. piperita Sm. Sydney peppermint Nilgiri (T.N.) 49. E. polycarpa F.v.M Longfruited blood wood Yercad (T.N.) 50. E. polyanthemos Sch. Red Box Almora, Dehradun (U.K.);

Shimla (H.P.) 51. E. propinqua Daene and Maiden Small fruited grey gum, grey

gum Dehradun (U.K.), Kollimalais, Nilgiri (T.N.)

52. E. punctata DC. Grey gum Dehradun (U.K.), Shimla (H.P); Nashik (M.H.).

53. E. radiata Sieb. ex DC Grey peppermint Dehradun (U.K.), Kulu (H.P.); Nilgiri (T.N.)

54. E. regnans F.v.M. Giant gum Shimla (H.P.), Nilgiri (T.N.) 55. E. resinifera Sm. Red mahogany Dehradun (U.K.), Shimla (H.P.),

Nilgiri (T.N.) 56. E. risdoni Hook.f. Silver peppermint Shimla (H.P.) 57. E. robusta Sm. Swamp mahogany, swamp

messmate Ranikhet. Dehradun (U.K.), Barilly, Saharanpur (U.P.), Maharashtra, Nilgiri (T.N.)

58. E. rossii Baker and Sm. White gum Nilgiri (T.N.) 59. E. rudis Endl. Moitch Dehradun (U.K.), Hassan,

Banglore (KA.), Delhi 60. E. saligna Sm. Syney blue gum, blue gum Ranikhet, Dehradun (U.K.),

Amritsar (P.B), Shimla (H.P.), (M.H.)

18

... Contd. from previous page

A.P.= Andhra Pradesh; C.G.= Chattisgarh; H.P.= Himachal Pradesh; K.A.=Karnataka; K.L. Kerala; M.H.= Maharashtra;M.L.= Meghalaya; M.P.= Madhya Pradesh; O.R.= Odisha; P.B.= Punjab; R.J.= Rajasthan; T.N.= Tamil Nadu; U.K.= Uttarakhand;U.P.= Uttar Pradesh

12. UsesEucalypt planting is controversial in some countries where it has been plantedextensively. Critics assert that it i) has deleterious effect on the hydrological balance;ii) depletes the soil nutrients; iii) has an allelopathic effect leading to inhibition ofgrowth of other plants; and iv) has a deleterious effect on native animals. However,eucalypts have many uses, viz. the wood of eucalypts is used as a general purposetimber. It is suitable for light or heavy construction. In house building, its applicationsare for doors, window frames, interior finish and both light and heavy duty flooring.Because of its moderate durability and moderate resistance to insect attacks, thetimber is also applied for making objects that come in contact with the ground, likerailway sleepers, poles and posts. Other applications are in ship and boat building,vehicle bodies, joinery, boxes and crates, vates, carving, turnery, handles, sportinggoods and agricultural implements. The timber is suitable for the production of veneerand plywood, particle board, hardboard and wood-wool boards. One of the major usesof eucalypt is the production of pulp for paper manufacture. Eucalypt is also a veryimportant source of firewood, which generally burns very quickly because of the highoil content, while many produce a good-quality charcoal. Several species are beingused in reforestration activities.

The leaves and twigs of many Eucalyptus species contain eucalypt oil which isan important product for pharmaceuticals (for example as a liniment or cough

H.B. Naithani

61. E. siberiana F.v.M Silvertop ash, mountain ash, coast ash

Nilgiri (T.N.)

62. E. siderophloia Benth. Broad-leaved ironbark Dehradun (U.K.), Saharanpur (U.P.), Shillong (M.L.), Banglore (K.A.)

63. E. sideroxylum (A.Cunn.) Benth. Mugga Dehradun, Ranikhet (U.K.) 64. E. staigeriana F.v.M Lemon-scented ironbark Dehradun (U.K.), Saharanpur (U.P.) 65. E. stuartiana F.v.M. But But or apple Shimla (H.P.), Dehradun (U.K.) 66. E. tereticornis Sm. (=E. umbellata

(Gaertn) Domin Forest red gum, blue gum

Lalkua, Dehradun, Haldwani (U.K.); Saharanpur, Barilly, Lucknow, Plibhit (U.P.), Hazaribagh (C.G.), Mt. abu (R.J.), Srihrikota (A.P.); Hoshiarpur (P.B.), Sambhalpur (O.R.), Delhi, Mysore (K.A.), Ker., Bilaspur, Balaghat, Indore, Shivpuri (M.P.), Raipur (C.G.), Faridabad (Haryana).

67. E. terminalis F.v.M. Kulch or long fruited Bloodwood

Dehradun (U.K.), Mandla (M.P.)

68. E. tessellaris F.v.M. Carbeen or Moreton Bay ash Banglore (K.A.), Coimbatore (T.N.) 69. E. torelliana F.v.M.(Corymbia torelliana

(F.v.M.) Hill and Johnson) Cadagi

Dehradun (U.K.), Kollimalais (T.N.); Palghat (K.L.)

70. E. viminalis Labill. Ribbon gum, manna gum, white gum

Almora (U.K.), Shimla (H.P.)

19

medication), perfumes, and soaps and detergents. The oil is also used as adisinfectant and pesticide. Many species of Eucalyptus produce gum (kino), whichoften runs down the bole in large quantities. The bark of some species has tanningproperties. The flowers of many species produce good pollen and nectar for honey.Some species are planted as ornamentals.

ReferencesAhmad, T. 1996. Eucalyptus in Pakistan. In: FAO. Reports submitted to the Regional

Expert Consultation on Eucalyptus 4-8 October 1993. Vol. 2. Bangkok, FAORegional Office of Asia and the Pacific. pp. 146-155.

Bentham, G. and Von Mueller, F. 1866. Flora Australiensis: A description of the plantsof the Australian territory. London, L. Reeve.

Bhatia, C.L. 1984. Eucalyptus in India – Its status and research need. Indian Forester,110(2): 91-96.

Blakely, W.F. 1934. A key to the Eucalyptus. Sydney, Govt. Printer.Brooker, I. 2002. Botany of the Eucalyptus. In: Coppen, J.J.W. Ed. Eucalyptus: The

genus Eucalyptus. Vol. 22: Medicinal and aromatic plants industrial profiles.London, Taylor and Francis. pp. 3-35.

Carr, S.G.M. 1972. Problems of the geography of the tropical Eucalyptus. In: TorresStrait Symposium, Canberra, 6-8 December 1971. Bridges and barrier: Thenatural and cultural history of Torres Strait: Proceedings edited by D. Walker.Canberra, A.N.U. pp. 153-181.

Chaturvedi, A.N. 1976. Eucalyptus in India. Indian Forester, 102(1): 57-63.Chaudhari, D.C and Suri, R.K. 1991. Comparative studies on chemical and antimicrobial

activities of fast growing Eucalyptus hybrid (FRI-4 and FRI-5) with theirparents. Indian Perfumer, 35(1): 30-34.

Chippendale, G.M. 1968. Eucalyptus buds and fruits. Canberra, Forestry and TimberBureau. 96p.

Chippendale, G.M. 1988. Flora of Australia. Vol. 19: Myrtaceae-Eucalyptus,Angophora. Canberra, Australian Govt. Publ. Service. 542p.

Chippendale, G.M. and Johnson, R.D. 1983. Eucalypts. New York, Van NostrandReinhold. 368p.

Dabral, B.G.; Raturi, A.S. and Singhal, R.M. 2000. Water balance in Eucalyptusplantations. In: Singhal, R.M. and Rawat, J.K. Eds. Effect of growingEucalyptus. Dehradun, F.R.I. pp. 105-126.

FAO (Food and Agriculture Oganisation of the United Nations). 1965. Eucalyptus forplanting. Rome, Food and Agriculture Organisation of the United Nations.

FAO (Food and Agriculture Oganisation of the United Nations). 1979. Eucalyptusfor planting. Rome, Food and Agriculture Organisation of the UnitedNations. 677p.


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Hill, K.D. and Johnson, L.A.S. 1995. Systematic studies in the Eucalyptus. 7. Arevision of the bloodwoods, genus Corymbia (Myrtaceae). Telopea,6(2-3): 185-504.

Johnston, R.D. and Marrayatt, R. 1962. Taxonomy and nomenclature of eucalypt.Leaflet No. 92. Caneberra, Forestry and Timber Bureau. 24p.

Maiden, J.H. 1903-1933. A critical revision of the genus Eucalyptus. Sydney, Govt. Printer.Martin, B. and Cossalter, C. 1975-76. Les eucalyptus des lles de la Sonde. Boiset

Forêts des Tropiques. Nos. 163-165.Metro, A. 1955. Eucalyptus for planting. FAO Forestry and Forest Products Studies

No. 11. Rome, FAO. 408p.Mueller, F. 1879-84. Eucalyptographia. Melbourne, Government Printer.Palanna, R.M. 1996. Eucalyptus in India. In: FAO. Reports submitted to the Regional

Expert Consultation on Eucalyptus 4-8 October, 1993. Vol. 2. Bangkok,FAO Regional office of Asia and Pacific. pp. 46-57.

Parker, R.N. 1925. Eucalyptus in the plains of North West India. Indian Forest Bulletin,(New Series) Botany, 61: 1-34.

Pryor, L.D. and Johnson, I.A.S. 1971. A classification of the Eucalyptus. Canberra,Australian National University Press.

Sahni, K.C. and Bahadur, K.N. 1972. In: Symposium on Man Made Forests in India,Dehradun , 8-10 June, 1972. Proceedings and technical papers. Dehradun,Society of Indian Foresters. pp.1-13.

Sale, M.M.; Potts, B.M.; West, A.K. and Reid, J.B. 1996. Relationships within Eucalyptus(Myrtaceae) using PCR-amplification and southern hybridisation ofchloroplast DNA. Australian Systematic Botany, 9(3): 273-282.

Shyam Sunder. 1984. Forest development and Eucalyptus controversy in Karnataka.In: Workshop on Eucalyptus plantations, Banglore, 29 June 1984.Proceedings. Bangalore, Indian Statistical Institute.

Srivastava, P.B.L. 1996. Eucalyptus in Papua New Guinea. In: FAO. Reports submittedto the Regional Expert Consultation on Eucalyptus, 4-8 October 1993. Vol.2. Bangkok, FAO Regional Office of Asia and the Pacific. pp. 160-172.

Tewari, D.N. 1992. Monograph on Eucalyptus. Dehradun, Surya Publication. 361p.Udovicic, F.; Mc Fadden, G.I. and Ladiges, P.Y. 1995. Phylogeny of Eucalyptus and

Angophora based on 5S rDNA spacer sequence data. MolecularPhylogenetic and Evolution, 4(3): 247-256.

Wilson, J. 1973. The need for a rational utilization of the montane temperate forestsof South India. Indian Forester, 99(12): 707-716.

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1. IntroductionDomestication of a tree species is necessary for sustained productivity inplantations. Domestication essentially involves a sequence of repeated selectionsand mating carried out to bring about change in the gene frequencies (Eldridge etal., 1993). This technique, often referred as ‘tree improvement’, is used to alter thegenetic makeup of a species with the objective of improving its utility. A treeimprovement programme is normally planned and organized for a species to improvethe growth rate or form of the species, resistance to diseases and pests, suitabilityto the environment and its utility. The main objective of a breeding programme isto enhance productivity, genetic diversity is also important for sustaining theproductivity over generations. Most of the tropical tree species are outcrossedand adequate diversity is a prerequisite for production of outcrossed progeny.After identifying high yielding provenances, which is the first step in animprovement programme, concerted efforts are made to locate orchards in idealenvironments for good flowering and seed production. Compared to agriculturalcrops, domestication of forest trees has a very short history and even the mostmanipulated forest species is only a few generations removed from their wildancestors. The domestication process has been slow because of the long rotationperiod, irregularity in flowering and fruiting, and high levels of outbreeding withconsequent loss of genetic gain in subsequent generations. Eucalypt, the widelyplanted forest tree, was introduced as an exotic in many countries, including India.Tree improvement programmes were initiated in many countries, (Davidson, 1998)including India, using the extensive plantations originated from these earlyintroductions which were often haphazard and suspected to have originated froma restricted genetic base of few native trees. The early exotic plantations may notbe having many useful alleles of the original population and there would also bedeleterious effects of inbreeding. Eldridge (1978) suggested that in such situationsit would be wise to obtain fresh seeds from natural stands and enlarge the base.

Domestication Strategiesfor Eucalypts in IndiaMohan Varghese

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About 4 Mha of eucalypt plantations were raised (GIT, 2008) by forestdepartments, forest development corporations, pulp and paper companies, andfarmers in India. Eucalypt plantations are raised to meet the fuel, pulp and timberneeds without disturbing the natural forest cover. Eucalyptus camaldulensis andE. tereticornis are the major species grown in arid regions of the country.E. grandis is grown in over 3,000 ha in high elevations (Kerala and Tamil Nadu)and E. urophylla and E. pellita in about 15,000 ha in the high rainfall regions ofKarnataka (Amanulla, pers. comm.). The wide spread of the genus across thecountry was made possible with the emergence of ‘Mysore gum’, a land raceevolved from the early introduction of E. tereticornis and six other eucalypts andinter-specific hybrids of E. tereticornis in Karnataka state (Kaikini, 1961). Overthe years, a highly variable land race (widely referred as Eucalyptus hybrid) evolvedwhich was able to adapt to the different agro-climatic regions of the country; oftenquite distinct from the native locations in Australia (Davidson, 1998). This landrace is considered a mixture of pure E. tereticornis as well as some geneticsegregates of interspecific hybrids.

Wide segregation and variation in morphological traits were noticed in most ofthe Eucalyptus hybrid plantations and attempts were made to have some control onseed collected for establishing plantations. As early as in 1965, Venkatesh andKedharnath advocated selection of good trees in different regions and establishingseed production areas for supplying seeds for use in that area. They hoped that thisstrategy would help in restricting suitable adapted genotypes within a region andavoiding movement of seeds across regions with differing environments. Selectiveharvest of seeds from good trees resembling E. tereticornis was recommended toreduce segregation. There was, however, no control on seed collection and vastareas came under plantations of low yielding Eucalyptus hybrid origin.

The early introductions of E. camaldulensis and E. tereticornis to India werefrom southern temperate localities in Australia rather than the northern tropicalregions where the climatic conditions closely resemble the areas available in India(Boland, 1981) because of the inaccessibility and difficulties in collecting seeds.Boland (1981) observed shorter opercula typical of the southern provenances inthe eucalypt land race in India compared to the longer, horn shaped operculatypical of the north Australian provenances. From his observations on the seedmorphology and coppice shoots in Eucalyptus hybrid plantation, Boland felt therewas a mixture of E. camaldulensis genes in these plantations. This led to furtherdegradation and wide variation in growth and leaf morphology in the plantations.The yield is poor because of the hybrid breakdown compared to the pure speciesof E. camaldulensis and E. tereticornis (Davidson, 1998; Varghese et al., 2000b).

IUFRO coordinated international provenance trials for E. camaldulensis andE. tereticornis (Kumaravelu et al., 1995) were initiated during 1980s and suitable

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provenances were identified for various regions. Results from different provenancetrials indicated the superiority of the northern provenances of eucalypts to thesouthern provenances (Ghosh et al., 1977). The local Eucalyptus hybrid seed lotswere inferior in comparison to the ‘Petford’ and ‘Katherine’ provenances ofE. camaldulensis and ‘Laura River’ and ‘Kennedy River’ seedlots of E. tereticornis(Chaturvedi et al., 1989). The yield of the local land race averages around 7 m3 ha-1 yr-1

(Chandra et al., 1992) which is much lower to the pure species lines of E. tereticornisand E. camaldulensis (12-25 m3 ha-1 yr-1).Tree improvement was attempted in theexisting Eucalyptus hybrid plantations. Plus trees and seed stands were selected(Rathinam and Surendran, 1981; T.N.F.D, 1993) in virtually every state and progenytrials conducted (Kedharnath and Vakshaya, 1978; Vinaya Rai et al.,1980;Krishnaswamy et al., 1984) to estimate the genetic parameters and clonal seedorchards were also established. Inter specific hybrids, both naturally occurring(Kedharnath, 1980) and artificial (FRI-4 and FRI-5, Venkatesh and Sharma, 1978),were raised to exploit the hybrid vigour. Vegetative propagation of trees intensivelyselected from plantations (Lal et al., 1993, Tripathi et al., 1996 and Kulkarni, 2005)has helped to increase the yield considerably (20-25 m3 ha-1 yr-1, Lal et al., 1993) indry regions. In high rainfall regions of Karnataka, E. pellita and E. urophyllawere identified for planting from 22 species evaluated in field trials (Satishchandraand Madhav, 2002). Progeny (Satishchandra, 2007) and clones (Amanulla, 2007)selected from offspring of superior trees in the species trials were used for furtherplanting. Provenance tests were conducted for E. grandis in high elevations ofsouthern India (Subramanian et al., 1992). However in the absence of a plannedbreeding programme, with the best identified natural populations, these usefulbreeding techniques when employed separately, result in a dead end situation(Boland, 1981) and the gain obtained is not sustainable.

Davidson (1998), who studied the tree improvement status of eucalypts inAsia- Pacific countries, observed that eucalypt tree improvement in India hasremained uncoordinated and weakly supported from the point of view ofdomestication and breeding. In his report, Davidson (1998) provided differentapproaches that can be adopted for a sustained increase in productivity ofeucalypts. He emphasised the need for a short-term programme to achieve immediategenetic gain from the existing variation as well as a long-term programme to maintainsufficient diversity essential for success of selection in future generations. Headvocated several short term improvement strategies that would reduce theinbreeding effects and supply improved seeds for immediate planting requirementlike retaining good plantations of identified provenances or establishing seedlingseed orchards from identified trees.

There has been a taxonomic revision and the best performing provenancesidentified in the provenance trials of E. tereticornis (Chaturvedi et al., 1989) like

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Laura River, Kennedy River and Morehead River are included under E. camaldulensisnow (Brooker and Kleinig, 1994; Doran and Burgess, 1993). Encouraged by theimproved performance of these provenances, the provenance trials were thinned toremove inferior trees and use it as a seed stand to meet the immediate requirement ofplanting stock. The new plantations established over extensive areas with seedcollected from a few trees by agencies like Tamil Nadu Forest Plantation Corporation(TAFCORN) were definitely superior to Mysore gum trees. Seed from good treesselected in provenance trials was also used to establish seedling seed orchards toproduce improved seed (Varghese et al., 2001). These orchards are not suited as astarter material for a long-term improvement programme as the genetic base of theseed lots in the provenance trial is often as narrow as five to ten trees. Neverthelessthey serve as a useful short-term approach to meet immediate seed requirement ofplanting agencies. These orchards were useful until seeds were available from thelarge breeding seedling orchards and unpedigreed orchards established as part of aeucalypt breeding programme implemented in southern India (Doran et al., 1996).

2. Breeding Programme for E. camaldulensis and E. tereticornisA comprehensive breeding programme which recognises the changes in classificationwas implemented in southern India with greater emphasis on E. camaldulensis.Domestication of eucalypt was given a new thrust in India with new seedintroductions for improving the productivity. Bulked seed and family identified seedlots of best provenances identified in provenance trials were obtained from CSIRO,Australia (Doran et al., 1996) for implementing the programme.

2.1 Short-Term StrategyUnpedigreed orchards were established in southern India with mass selected seedthrough open pollination without retaining family identity. Seeds were obtainedfrom a large number of unrelated trees of suitable provenances from natural standsor from selected plantations of known origin. Stands were raised with a mixture ofequal amount of seed from all trees and thinned heavily, sufficiently early to promoteseed production in retained trees.

An unpedigreed orchard is relatively cheap and simple to establish andprovide a reliable source of fairly improved seed. Unpedigreed orchards of broadgenetic base after selective thinning can be used as interim source of seedduring the initial stages of a breeding programme. Even when a pedigreed breedingpopulation is established for long-term breeding, it is important to have anunpedigreed orchard as they offer a quick means of improved seed at an earlystage of improvement programme and will be quite useful in case the subsequentgenerations of the breeding programme fail to take off. Unpedigreed seedlingorchards or seed production areas (SPAs) were established as an interim measure

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to provide short-term gain, until the main strategy involving the establishmentof large, family identified progeny trials was raised, evaluated and progressivelythinned for seed production. Bulked seed from over 500 trees each ofE. camaldulensis and E. tereticornis of identified superior provenances wereused for establishing four unpedigreed seedling orchards (Varghese et al., 2009a).Small quantities of seed from other provenances were also included to maintaina broad genetic base. The orchards were established (Table 1, Fig. 1) at a drysite, Pudukkottai in Tamil Nadu (SPA 1 and 3) and a moist site, Panampally (SPA2 and 4) in Kerala state (Kamalakannan, 2007).These orchards bring about achance of mating between populations that are widely separated geographicallyin their natural range. In a species like E. camaldulensis with large geographicaldistribution, when widely differing seed lots are crossed, the adaptability ofsome seed lots to diverse environments can be combined with the vigorous

Table 1. Location of E. camaldulensis and E. tereticornis seed orchards

Fig. 1. Map showing location of seed orchards and genetic gain trial sites in southern India.


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growth of other seedlots. Synchronization in flowering is, however, a factor thathas to be managed to get the desired improvement. Provenance resource stands(PRS) of three Queensland provenances of E. camaldulensis, Kennedy River,Morehead River and Laura River (Doran and Burgess, 1993) were also establishedat Pudukkottai, Tamil Nadu, using bulked seed from individual provenances.The SPAs and PRS were selectively thinned to remove phenotypically inferiortrees (Varghese et al., 2000a).

Thinning was undertaken in two stages at two and four years in SPAs toavoid competition between trees and, for production of large crowns. Since pedigreeinformation was not available, phenotypic information was used for selecting goodtrees to be retained for seed production (Harwood et al., 1996). Thinning is neededto provide the optimum spacing necessary for a tree to express its genetic potentialand for good seed production. A suitable method was devised to retain 150-200best trees per hectare in the seed stand. The thinning procedure helps to removeinferior trees in unpedigreed orchards by excluding site heterogeneity and ensuringuniform distribution of retained trees in the stand (Hegde and Varghese, 2002).Index selection, that combines information on several traits of interest into a singleindex, was used since it enables the breeder to assign a total score to each individual(Zobel and Talbert, 1984). In a finite base population of progenies of selectedtrees, index selection is useful for simultaneous selection on multiple traits as wellas to predict the gain for each trait (White and Hodge, 1989). After dividing theplantation into 10 tree blocks, block averages and block adjusted values weredetermined for each individual tree for each trait as per Cotterill and Dean, 1990.Heterogeneity of site affects the accuracy in selection of trees as evidenced bythe skewed distribution of selected trees in certain patches when large blocks of90 trees were used. 10 tree blocks reduced the effect of site with emphasis ongenetic potential of the tree, as every tree is compared with nine adjacent treeswithin each block. Among the different selection indices attempted, ‘correlationindex’ that takes into account economic weights for traits of interest, correlationbetween traits, and block adjusted values of individual tree (Cotterill and Dean,1990) for computing the ‘index’ was found to be ideal (Hegde, 2003). After finalthinning at four years, seven to eight kg of seed can be collected annually from about25 trees in each orchard (Pinyopusarerk and Harwood, 2003b) so that the trees getenough time to recover for next seed collection. Seed is supplied from these orchardsto farmers to replace Mysore gum plantations (Varghese et al., 2004b).

2.2. Long-Term StrategyThe main breeding strategy followed is recurrent selection for general combiningability with open pollination in single populations retaining family identity (Eldridgeet al., 1993). A single plantation that was laid out initially as a progeny trial was

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strategically used to combine the base, breeding and propagation populations ineach site. The progeny trials provide information on family merit which is used as abasis for selection and breeding for the next generation as well as thinning forconversion to commercial seed orchards. These orchards are a source of improvedseed of wide diversity and adaptability to regions with similar agro-climatic conditions(Doran et al., 1996). Selection and mating are the key activities in this breedingprogramme. They accumulate genes which influence yield and adaptation, increasingover successive generations the frequency of the superior trees. A progeny trialwith large number of families of identified provenances after conversion to a seedlingseed orchard is expected to give about 20 per cent more gain than that obtained fromthe best provenance. The gain from a thinned seed production area is expected to bethe same as that obtained from a pedigreed first generation seedling seed orchard.Gains beyond the first cycle will normally depend on the accuracy in selecting thebest genotypes and management of inbreeding in orchards. Gains will be cumulativein the first and subsequent cycles (Doran et al., 1996).

First generation progeny trials were established as per the programme at threelocations, namely Panampally (Kerala), Pudukkottai (Tamil Nadu) and Sathyavedu(Andhra Pradesh) with 188 open-pollinated families of E. camaldulensis belongingto 18 natural provenances representing three distinct geographical regions ofAustralia (11 provenances from Queensland, 4 from Western Australia and 3 fromNorthern Territory) in 1996 (Hegde, 2003). Queensland provenances, particularlyPetford, Kennedy River, Gilbert River, Laura River and Morehead River showed clearsuperiority over provenances from the other two Australian regions at Pudukkottai.The differences among Australian provenances were less pronounced at Sathyaveduand Panampally, where there was no marked advantage of Queensland provenancesover those from the Northern Territory and Western Australia. Provenances from allthree regions in Australia displayed generally better growth than the Mysore gumselections (Varghese et al., 2008a). After evaluation, 10 per cent of the worst familieswere thinned out at two years. The best trees of the top 90 per cent of the familiesselected from the first generation seedling orchard and fresh infusion families will bethe base for the second generation orchards. Family performance data from secondgeneration orchards will facilitate ranking of parents retained in the first generationorchard thus helping in roguing by backward selection and enhancing the geneticmerit of the seed produced.

E. camaldulensis and E. tereticornis intergrade in parts of their natural range inQueensland (Doran and Burgess, 1993). Superior provenances such as Laura andMorehead Rivers, now classified as E. camaldulensis subsp. simulata by Brookerand Kleinig (1994) and also Kennedy River and Petford provenances are among thebest-performing natural provenances in arid regions of southern India. The clearsuperiority of Queensland seed lots at Pudukkottai in Tamil Nadu (Varghese et al.,

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2008a) clearly indicated that E. camaldulensis breeding population for this dry regionand similar regions should comprise primarily of selections from the best Queenslandprovenances. Petford (Queensland) provenance was reported to perform well inprovenance trials across several sites conducted by the Eucalyptus Research Centrein Andhra Pradesh where the annual rainfall is around 800 mm (Chaturvedi et al., 1989).The same observation was made by Ginwal et al. (2004a) and Singh and Prakash (2002)in field tests in Haryana and Punjab. This provenance is also found suitable in othercountries like Bangladesh (Davidson and Das, 1985) and Brazil (Moura, 1986) due toits inherent capacity for fast growth and stability across a wide range of climaticconditions (Ginwal et al., 2004a). Some planting agencies in India import native seedfrom Petford region for routine planting. Thus, it is important to establish good orchardsof North Queensland provenances of E. camaldulensis with sufficient genetic base toproduce quality seed for planting in India. Selections from seed lots of other regions inAustralia (northern territory and western Australia) and E. tereticornis could be retainedin breeding populations for regions receiving higher rainfall.

Native seed lots of E. tereticornis (91 families representing 13 nativeprovenances of Australia and Papua New Guinea were introduced in northern Indiaand tested at three diverse sites in Uttarakhand and West Bengal. North Queenslandprovenances performed better and, in particular, two provenances, viz., Walsh Riverand Burdekin River, Queensland ranked the best in that region (Ginwal et al., 2004b).Insouthern India, 37 open pollinated families of E. tereticornis belonging to 13provenances were evaluated in Tamil Nadu. Families from Helenvale provenance ofQueensland and Mt. Garnet showed superior growth on par with Kennedy Riverprovenance at four years of age (Ravi, 2008).

3. Balancing Gain and Diversity in Seedling OrchardsSeed orchards are expected to generate superior quality seed compared to otherunimproved sources. Selection methods for increasing gain are often opposed tostrategies for improving diversity of the seed crop. Different selection strategies canbe employed for enhancing gain. In combined index selection, weights are givenbased on individual and family values (Falconer and Mackay, 1996) whereas phenotypicselection ranks the individual based on its phenotypic value without considering itsfamily merit. An ideal strategy would be one that combines gain and diversity monitoredin terms of a quantified effective population number (Lindgren et al., 1996) withadequate representation from different families for production of outcrossed seed.When thinning is done in a half-sib progeny trial, the relationship between geneticgain and diversity must be well understood (Kamalakannan et al., 2007a).These factorsmust be assessed to adequately manage inbreeding in plantations and to plan seedcollection. Breeding values are normally used for culling inferior families and individualsto maximise gain. Fertility of trees also has to be considered as it ultimately decides the

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transfer of genes to the seed crop. The quality of seed from an orchard will be judgedfrom the possible gain and the diversity of the deployed crop. Genetic value of seedwill be determined by the breeding values and the maternal and paternal gametesproduced by the orchard trees. Loss of diversity and increase in relatedness areexpected in advanced stages of improvement. Improvement in gain is at the cost ofdiversity with each advance in generation. It is, however, important to monitor theconsequences of selection and thinning done to enhance gain. As relatednessincreases beyond a certain point, depending on the deviation from random mating,much of the desired benefits may not be achieved. Seed collection has to be plannedto prevent informal collection and dissemination which will soon lead to geneticdeterioration. When a species is introduced to a new location, there is a risk that theproportion of selfing will increase if seed is collected from isolated trees or from smallplots where only a few trees have commenced flowering. Inbreeding can also build upif seeds from only a very few mother trees are used to establish a stand so that the nextgeneration will be derived from mating between close relatives.

4. Role of Seedling Seed Orchards in DomesticationSeedling seed orchards (SSOs) are cost-effective means of making available an assuredsupply of genetically improved seed. Orchards established with introduced seed shouldbe intensively managed for abundant seed production and be isolated from otherstands by at least 100 m to reduce contamination. Thinning should be done to retainoutstanding trees. After introduction to a new location seedling orchards help torelease the ‘neighbourhood inbreeding’ in the native genotypes as the parent trees intheir natural habitat are usually surrounded by related trees and mating is normallyrestricted among them. This affects the quality of seed collected from these stands.But in a seedling seed orchard this is overcome by planting several unrelated trees ina small area and mating takes place between individuals that would not have cometogether in nature. Thus seedling seed orchards function as breeding populationsfrom where new favourable recombinants can be obtained. Seedling seed orchards arevery useful in combining seed production, genetic test and breeding for newrecombination. SSOs are highly flexible, easy to establish, cost-effective and veryeffective in short rotation eucalypt. Seed orchards offer the advantage of capturingyears of improvement done by an agency and deploying the same to a new location byimporting advanced generation seed. After one round of testing and elimination in thenew orchards, selections can be made for different agro-climatic regions.

Seedling seed orchards facilitate low-intensity breeding (Lindgren, 2003). Low-intensity breeding techniques are relevant in developing countries like India wherelarge quantities of seed are required by resource poor farmers. It can be a back-up toaggressive high-intensity breeding programmes with genetically narrow breedingstock (Cotterill, 1989). Seedling seed orchards also conserve genetic resources


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producing seed of reasonable gene diversity, genetic variability and adaptability tothe new location. They preserve options to initiate a breeding programme and supportintroduction and evaluation in new locations. A low-intensity breeding programmewill generally meet these goals, with more emphasis on genetic diversity than oneconomic traits. It is effective when resources may be too small and when the alternativeis the local genetic stock of low trait and genetic diversity. A high-intensity programmethat focuses more on gain may lead to substantial genetic erosion in the first generationas it accommodates fewer parents and a smaller breeding population. In tree breedingprogrammes there is a risk that methods suitable for large investment programmes areoften implemented with the intention of enhancing gain in small farmer holdings. Arobust low-intensity strategy is able to provide reasonable gain and keep inbreedingin check in community orchards managed by poor farmers. In ideal situations (especiallyfor E. camaldulensis in arid locations) these orchards are quite attractive, as theinvestment for planting stock production is low and gain obtained is comparable tothat of commercially available clones (Varghese et al., 2009a).

5. Evaluation of Orchard Dynamics for DomesticationSeedling seed orchards of eucalypts after evaluation and thinning, are expected to yieldadequate quantity of improved seed and enhance the productivity of plantations. Thoughsuitable provenances have been identified in provenance tests at various sites, verylittle information is available on the fertility of natural provenances or the suitability ofsites for locating eucalypt seed orchards. Since fertility and tree growth may not becorrelated, fertility variation has to be assessed for predicting the genetic quality of seedproduced from seed orchards. Progeny originating from orchards of the same seedorigin could vary depending on the flowering status and the fertility variation betweentrees. Excessive fertility of a few trees can lead to relatedness among progeny. Loss ofdiversity occurs from increase in coancestry levels in the orchard as a result of variableflowering among trees. The problem can be very acute if the number of flowering trees isvery low. Poor and irregular flowering is often observed in orchards that are not locatedon good flowering sites, and even on good sites, micro-site influences are important(Sweet, 1992). Genetic quality of seed crop from an orchard can be estimated based on itspredicted composition. The genetic value, relatedness and fertility of parental genotypesstrongly determine the genetic gain and diversity of progeny. Prediction of the gain anddiversity of progeny can be done based on fertility contribution and the number of seedand pollen parents in the orchard (Kang et al., 2001b). The following parameters can beused to evaluate the orchard dynamics and predict the quality of orchard progeny.

Sibling Coefficient ( ), which is the probability that two genes originate from thesame parent, compared to a panmictic situation, can be used to quantify the fertilitydifferences between orchard genotypes. Sibling coefficient is calculated from the

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number of fertile trees in the orchard (N) and individual fertility (pi) of each tree(Kang et al., 2003).

Effective Population Size (Ns) or Status Number (Lindgren and Mullin, 1998) is usedto characterize an orchard based on the number of unrelated trees that contributeequally to the gene pool. In an ideal situation when the trees in an orchard are assumedto be non-inbred and unrelated, status number is calculated as

Where pi is the contribution from individual genotype i to the gamete pool andN the total number of trees in the orchard.

For an ideal seed orchard where the fertility of the trees is uniform and there isno inbreeding or relatedness or migration, effective population size (Ns) of the seedorchard crop and total number of trees (N) is the same.

The relative population size (Nr) is used to compare the effective number oftrees that contribute to random mating, with the actual number of trees in the orchard.

Group Coancestry ( ) is the probability that two genes taken at random from thegene pool of the expected seed orchard crop will be identical by descent. The groupcoancestry of the orchard trees becomes the expected inbreeding in the seed crop.Group coancestry can be regarded as a measure of gene diversity lost during treebreeding operations. When all the trees in the orchard are unrelated and non-inbred,group coancestry can be calculated according to Lindgren and Mullin (1998).

Where pi is the probability that genes sampled at random from the gamete pooloriginate from genotype i.

The fecundity of each tree can be used as the probability of contribution ofeach genotype in determining the group coancestry ( ), which can be obtained byadding all possible pairings of gametes from orchard trees.

[1]

[2]

[3]


[4]

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6. Impact of Fertility Variation in Orchards

6.1. Unpedigreed OrchardsFertility status of unpedigreed orchards (SPA 1 to 4) of E. camaldulensis andE. tereticornis established at a dry site (Pudukkottai) in Tamil Nadu and a moistsite (Panampally) in Kerala (Table 2, Fig. 1) was evaluated at four years of age(Kamalakannan, 2007). The two eucalypt species differed considerably in fertilitystatus in the moist site. More than 73 per cent of E. camaldulensis trees werefertile at the moist site (SPA-2) in contrast to less than 25 per cent fertile trees inE. tereticornis (SPA-4). At the low rainfall site around 25 per cent trees were fertilein both species.The number of fruits produced per tree also followed a similarpattern. Fruit production was quite high (4,000-5,000 per tree) in E. camaldulensisat the high rainfall site whereas it was quite low (average 300 fruits per tree) inE. tereticornis (Kamalakannan et al., 2007b). In the dry location both species hadthe same fecundity (around 1,000 fruits per tree). Tree diameter had poor correlationwith fruit production.

Fertility variation was low in the E. camaldulensis (SPA-2) at Panampally asindicated by the sibling coefficient value ( = 2) whereas it was unusually high forE. tereticornis in the same site ( = 13). In the dry Pudukkottai site both species hadmore or less similar fertility variation ( = 7- 8). Even though there were almost threetimes more trees in the dry location, the effective population size in E. camaldulensisorchards was almost the same at both sites since almost 45 per cent of the treescontributed effectively to seed production in the moist site in comparison to a mere15 per cent effective contribution at the other site. Both species had more or less thesame effective population size at Pudukkottai (SPA-1 and SPA-3). Since manyE. tereticornis trees did not flower at the moist site, there were only about 14effectively contributing trees resulting in a low relative population size (7%) andhigh genetic drift. In spite of the fertility variation three of the orchards had lowcoancestry values and adequate predicted genetic diversity (except in theE. tereticornis orchard, SPA-4 at the moist site in Kerala).

M. Varghese

Table 2. Fertility variation and effective population size in eucalypt seed orchards at 4 yearsE. camaldulensis E. tereticornis Trait

SPA-1 SPA-2 SPA-3 SPA-4 SSO-1 N 525 182 478 192 354 Fertile trees (%) 26 73 30 23 19 ψ 6.7 2.2 8.0 13.4 17.4 Ns 78 81 60 14 20 Nr 0.15 0.45 0.13 0.07 0.06 N - No. of trees; ψ - Sibling coefficient; Ns - Effective population size; Nr - Relative population size

33

6.2. Pedigreed E. tereticornis OrchardIn family identified progeny trials fertility status assumes great importance. Fertilityvariation was investigated in a progeny trial of E. tereticornis in Tamil Nadubefore thinning. Thirty-seven open pollinated families of E. tereticornis belongingto 13 provenances representing distinct geographical regions of Australia andPapua New Guinea (28 from Queensland and nine from Papua New Guinea) wereevaluated for growth and fertility at four years of age. Four selected families andone routine seedlot of Mysore gum land race were used as control. Fertility washigh in Mysore gum trees so that 12 per cent of the trees, all from the land raceproduced 52 per cent of the fruits before thinning (Fig. 2). Based on phenotypicselection thinning was done to retain 20 per cent superior trees in the seed orchard(SSO-1). After thinning the fecundity was more skewed as 12 most fertile trees ofthe land race contributed almost 81 per cent of the fruits (Varghese et al., 2003).Sibling coefficient was high ( =17.4). This causes a big shift in the reallycontributing trees in relation to the actual number of trees in the orchard. In effectmany outstanding trees of the superior native provenances would not berepresented in the next generation thus reducing gene diversity and gainconsiderably. The seed crop will have over-representation from more productivelocal trees.

6.3. Role of Fertility in Gene Diversity of Seed CropFertility is an important trait for consideration in first generation introductions ofnatural provenances (Varghese et al., 2003). Poor fertility has been reported in

Fig. 2. Fecundity variation in pedigreed E. tereticornis seed orchard.


34

E. tereticornis stands in tropical moist environments (Arnold, 1996; Pinyopusarerkand Harwood, 2003a) in Asian countries. Fertility variation is expected to be lower inseed orchards than in seed stands (Kang et al., 2003) in a domesticated species orfor a species in its native location. Kang et al. (2003) reported an average value of2.62 for seed orchards of broad-leaved species. Generally sibling coefficient valuesmay be high in young orchards and during poor flowering years (Kang et al., 2003).It is observed that the moist location at Panampally, Kerala receiving about 1,400 mmrainfall is suitable for locating E. camaldulensis seed orchards ( = 2.2) but notE. tereticornis ( = 13.4). This point has been confirmed by the near similar patternof fruit production in two consecutive years (Kamalakannan et al., 2007b). Very poorflowering and seed production have been reported in locations receiving higherprecipitation (>2,000 mm) in Philippines and Vietnam and are thus unsuitable forestablishing E. camaldulensis orchards (Pinyopusarerk and Harwood, 2003b). Bothspecies seem to have similar fecundity at dry Pudukkottai site.

If there are not many flowering trees in the orchards, there would be a low effectivepopulation size compared to the actual population size, which would lead to loss ofdiversity in seed crop (Varghese et al., 2004a). Thus fertility observations need to berecorded periodically to ensure adequate diversity and outcrossing in the seed crop.Genetic quality and diversity of progeny from high fertility orchards likeE. camaldulensis at Panampally (SPA-2) is expected to be better than that ofE. tereticornis orchard at the same site (SPA-4) with low effective population size andpredicted gene diversity. The progeny originating from such low flowering orchardswould suffer from inbreeding due to related mating. Land races with high fecunditytend to dominate the seed crop as seen in pedigreed orchard (SSO-1) of E. tereticornisand hence only a small proportion of the expected genetic resources will be capturedin the next generation. Though the relative population size (Nr) in unpedigreed andpedigreed E. tereticornis orchards (SPA-4 and SSO-1) is similar, the composition ofprogeny would be very different since the expected inbreeding is higher in the pedigreedorchard due to high fecundity of many related trees of the local land race.

It is advisable to have large number of trees at sites where flowering is poor tomaintain an acceptable effective population size. There is a strong negativerelationship between sibling coefficient and fecundity of trees (Fig. 3). From a surveyof several eucalypt seed orchards in Asian countries, Pinyopusarerk and Harwood(2003b) recommended that seed collection could be done in orchards where 50 percent of the trees were fertile. When fertility is low, big orchards with large number oftrees can be effective in ensuring diversity in the seed crop. High stocking willensure a high effective population size as seen in E. camaldulensis orchard (SPA-1,525 trees) at Pudukkottai, which is almost on par with the corresponding high fertilityorchard at Panampally (SPA-2). Differences in fertility between trees could be genetic(Eriksson et al., 1973) or influenced by environmental factors (Hedegart, 1976) and

M. Varghese

35

management of orchard (Zobel and Talbert, 1984). As seeds are often in practicecollected only from a few good trees for plantation establishment, large orchardsensure sufficient outcrossed seed even in poor flowering years.

6.4. Outcrossing Rate in Seed OrchardIt is well known that the extent of inbreeding affects growth performance inEucalyptus. Inbred individuals, especially selfed individuals, display inbreedingdepression of growth (Eldridge et al., 1993). The rates of out crossing and inbreedingin seed orchards, therefore, have a crucial impact on the quality and performance ofseed delivered to growers. Petford provenance is reported to have very high outcrossing rate (mean multilocus outcrossing rate tm = 0.95) in its natural range (Butcherand Williams, 2002). Hence seed from this provenance is known to perform well intrials across several diverse locations. It is important to use superior germplasm(high outcrossing rate) as starter material for a breeding programme to ensuresustained productivity with domestication. There are not many reports of outcrossingrates in seedling seed orchards of E. camaldulensis. Butcher and Williams (2002)presented evidence that selection against homozygotes may be operative inE. camaldulensis.


Fig. 3. Relationship between sibling coefficient ( ) and fruits/tree in eucalyptorchards (SPAs 1-4; fertility at 8 and 9 years of age).

R2=0.7754

0 1000 2000 3000 4000 5000 6000

Fruits/tree

Sibl

ing

coef

ficie

nt

0

2

4

6

8

10

12

14

16

36

Mating system was assessed in the high fertility orchard (SPA-2) at Panampally(Fig. 1). Outcrossing rate was estimated in15 individual trees of SPA -2, located atdifferent positions across the orchard, using allozymes following procedures ofMoran and Bell (1983).Variation at each of the nine most variable allozyme loci inE. camaldulensis (Aat-1, Aat-2, Aat-3, Idh-1, Gpi-2, Mdh-2, Pgd-1, Ugp-1, Ugp-2and Ugp-3), representing six enzyme systems, were scored for 20 progeny from eachof the 15 parent trees. Multi-locus and single-locus outcrossing rates were estimated.

The multi-locus estimate of the out-crossing rate (in SPA- 2) was 0.86. The meansingle-locus estimate was 0.88. The multi-locus estimates of out-crossing rates for the15 individual mother trees ranged from 0.41 to 1.00, with selfing detected in five of the15 families. Higher outcrossing rates are usually expected in seed orchards due to theabsence of neighbourhood inbreeding as closely related trees are not planted adjacentto each other (Moran et al., 1989). However, there was not much difference betweensingle- and multi-locus outcrossing estimates in the Panampally stand, indicating thatinbreeding in the stand is primarily due to selfing rather than neighbourhood inbreeding.The multi-locus estimate of 86 per cent for the out-crossing rate is acceptable foroperational seed production, but the selfing rate of 14 per cent is higher than desirable.Outcrossing was higher (95%) in progeny trials of E. camaldulensis in Thailand(Butcher and Williams, 2002), and E. camaldulensis seed orchards in north Queenslandthat incorporated working beehives (94%) (Moncur et al., 1995).

Differences in flowering time among trees in the Panampally stand may accountfor the low outcrossing rates of some of the sampled trees. Trees which flower outof synchrony with the others in the stand (early or late flowerers) would be lesslikely to receive outcross pollen. A further point of interest arising from the allozymestudy in SPA-2 was the revelation that despite 73 per cent of the trees being fertile,22 per cent of offspring were full-sibs, indicating that some or all of the 15 openpollinated seed families sampled in this study received pollen from relatively fewpollen parents (Varghese et al., 2009a). Since the orchard originated from a seed mixof 514 trees of 14 natural provenances (Doran et al., 1996), it is necessary to examinethe timing of flowering in different trees to detect the extent of asynchrony inflowering. A similar study on a pedigreed E. camaldulensis orchard of similar originin Thailand revealed very high outcrossing rate (tm = 0.95) and nearly all progenygrown from that seed orchard were derived from cross-fertilisation (Butcher andWilliams, 2002).The quality of seed produced by the Panampally seed productionarea could be enhanced by monitoring the phenology of individual trees and avoidingcollecting seed from trees that flower out of synchrony with the others. Positioninghoney bee (Apis mellifera) hives near the stand during peak flowering times canalso be considered. A significant increase in seed yield and quality (tm= 0.75 no beesto tm= 0.94 with bees) was observed when hives were placed in natural stands ofE. camaldulensis in north Queensland (Moncur et al., 1995).

M. Varghese

37

Estimates of outcrossing rates for individual trees can be quite variable asreported by Jones et al. (2008) in E. grandis (tm=0.64-1.00) where some seedlotsshowed complete outcrossing with no self-pollination events. Campinhos et al.(1998) reported variation in individual outcrossing rates (tm=0.33-0.99) amonggenetically identical clones of E. grandis, that was entirely due to environmentalinfluences. Another study of E. grandis in natural populations showed a largevariation in outcrossing rates, with tmvalues ranging from 0.34 to 1.48 for individualtrees (Burgess et al., 1996). Variation in individual outcrossing rates in naturalpopulations has also been reported in other Eucalyptus species (Griffin et al.,1987; Peters et al., 1990). The variation could be due to pollinator density (Moncuret al. 1995), age of trees (Moran and Brown, 1980) or position in the tree canopy(Patterson et al., 2001). The time of flowering during a season may also affectindividual tree outcrossing rates, as trees flowering at the beginning and end of aseason may have less opportunity for outcrossing (Fripp et al., 1987). InE. grandis Jones et al. (2008) reported an average pollen dispersal distance of57.96 m, with the longest pollination distance being 192 m and 51 per cent ofpollen within the seed orchard travelled less than 50 m, and 77 per cent less than100 m. Despite the variation in maximum pollen dispersal distances in eucalyptspecies, the majority of pollen is dispersed locally with fewer occurrences of long-distance dispersal (Potts and Wiltshire, 1997). Strategies may be developed andimplemented to reduce the potential for gene flow from plantations. These mayinclude use of buffer zones and guard rows of non-compatible trees to catch themajority of dispersed pollen. Isolation from other compatible trees has proved tobe effective in reducing pollen contamination in seed production areas. Bufferzones of native rainforest were used to isolate E. grandis and E. urophylla seedorchards from production plantations in Brazil. Isolation distances of 400 m(Campinhos et al., 1998) and 800 m (Junghans et al., 1998) resulted in pollencontamination rates of 14.2 and 2.8 per cent, respectively. Other methods ofreducing the level of gene flow by pollen include manipulation of phenologicalpatterns and collecting seed when orchard trees flower asynchronously with othersurrounding compatible plantation trees.

7. Genetic Gain and Diversity of Orchard SeedlotsThe justification for any tree-breeding programme is the genetic gain actually realisedin improved plantations and the financial return on the investment in breeding(Eldridge et al., 1993). The gain is not limited to wood volume as a result of improvedgrowth rate but also covers a range of other traits including stem and branch form,wood quality, and resistance to pests and diseases. For an estimate of realised gain,it is necessary to establish comparative trials to determine whether and by howmuch the plantations have been improved.


38

Fruits/tree Seedlot Polymorphism (%) Kulwally

(site 1) Karunya (site 2)

Bhadravati (site 3)

SPA-1 SPA-2 SPA-3 SPA-4 SSO-1

30.7 29.8 28.1

- 26.2

244 256 246 72

249

29 5

42 -

104

19 36 18 13 34

Native seedlot Local seedlot Clone

17.8 18.8

-

27 -

16

0 358

-

2 - 0

Table 3. Diversity and fecundity of orchard progeny (3 years) in genetic gain trials

To evaluate the gain obtained from orchards, seed was collected from 25 treesof each orchard in five orchards (SPA 1 to 4 and SSO-1) at four years of age. Equalquantity of seed from each mother tree was combined to give five orchard bulkseedlots that were tested in genetic gain trials at three locations in southern India(Table 3, Fig.1). A single bulked seedlot of three Australian provenances ofE. camaldulensis (Morehead River, Laura River, and Kennedy River) was includedas a control in each trial. A commercial clone and ‘Mysore gum’ seedlot were alsoused as control (Varghese et al., 2009a). Seedlots from the four unpedigreed orchards(SPA 1 to 4) did not differ substantially in growth and survival in any of the trialsat three years, whereas the E. tereticornis pedigreed orchard (SSO-1) hadsignificantly lower survival than the SPA seedlots and controls. Survival of thisseed lot was at least 14 per cent lower than that of the other orchards at two testsites, and at least 50 per cent lower at the third site (Varghese et al. 2009a). Thelocal Mysore gum seedlot had lower growth than the progeny of SSO-1, but it hadexcellent survival (89%), so its predicted volume production on a per hectare basiswas much better than that of SSO- 1. The natural bulk seedlot comprising Kennedy,Laura and Morehead River provenances of E. camaldulensis displayed very similargrowth and survival as those of the SPAs at the three trial sites. The commercial cloneshad high survival but were only slightly higher in productivity than the natural-provenance seedlots. Though the SPA seedlots did not show much genetic improvementcompared to the natural provenance, their growth and survival is satisfactory foroperational planting in southern India with similar growth as the best commerciallyplanted clones and substantially greater volume per hectare than Mysore gum. Thepedigreed E. tereticornis orchard (SSO-1) had poor survival and growth compared tothe SPAs since the pollen pool was dominated by the local land race. The growth ratesof SPA seedlots achieved in the three performance trials are very similar to thoseobtained in tests of candidate clones at Karunya reported by Varghese et al. (2008a).

M. Varghese

39

This shows that seed collections from unpedigreed SPAs provide a low-cost optionfor mass production of superior eucalypt planting stock which is now quite popularamong farmers in southern India.

Despite no significant difference between SPA seedlots in overall growth,fertility variation in parent orchards had an impact on variability in growth andfertility of progeny. Variability in tree height, measured in terms of coefficient ofvariation (C.V.), was lowest in SPA-2 and highest in SSO-1 at all the test sites(Varghese, 2009). There was a significant positive correlation between fertilityvariation in the orchards (sibling coefficient) and variability in progeny (C.V. forheight) at all the test locations (Fig. 4). At three years, the fecundity of orchardprogeny (in genetic gain trials) was comparatively higher in one location (Kulwally,750 mm rainfall) compared to the other two test sites (Table 3) which highlights theneed for site selection in locating new orchards. In this location fruit productionper tree was significantly higher (~ 250) in progenies of three SPAs and SSO-1. Itwas comparatively low in E. tereticornis SPA-4 (72) and quite low in the naturalprovenance seedlot (27) and the clone (16). SPA seedlots had low fertility at Karunya(1,000 mm rainfall) but the local land race had high fecundity (358) followed by thatof SSO-1 (104). At the third site, Bhadravati (800 mm rainfall) fecundity was low atthree years but by five years of age, the fecundity increased significantly in threeof the orchard seedlots (SPA1-3) and followed a similar trend as that in Kulwally.The clone, natural provenance seedlots and the progeny of SPA- 4 had lowfecundity in all the test locations. One generation of domestication in the seedorchards increased the fertility of the orchard progeny, relative to the naturalprovenances, as shown by fruit counts in the genetic gain trials. It appears thatprecocious flowering is a highly heritable trait, and it has responded to selectionin the first-generation SPAs, as reported in E. globulus (Chambers et al., 1997).Fecundity will tend to increase in advanced generations but the status number(effective population size) would decrease if genetic erosion is not addressed.

First generation plantations or orchards are thus the critical entry points to anewly introduced location, where rapid loss of alleles can occur (Varghese et al.,2003). When assembling seed collections from superior trees for advancedgeneration breeding, the relatively low levels of flowering observed in the firstgeneration orchards even at nine years (Kamalakannan et al., 2007b) willsubstantially reduce the genetic diversity passed on to the progeny. Large orchardslocated at sites conducive to heavy flowering, would be required to capture mostof the newly introduced alleles in open-pollinated breeding populations (Zobel etal., 1988). In E. nitens, Swain et al. (2013) reported improved performance ofprogeny from higher fertility orchards (>40% flowering trees) than low floweringorchards (<20%). After three successive generations of breeding Verryn et al.(2009) reported 14 per cent improvement in tree volume with each generation in


40

E. grandis, in line with the classical breeding assumptions. Gain obtained will alsodepend on the planting strategy. Gain may vary when clones are planted inmonoclonal blocks, where there is competition between individuals of the samegenotype, compared to mixed planting of different clones (Stanger et al., 2011).The actual gain has to be evaluated at an appropriate scale rather than in small treeplots to avoid wrong predictions while evaluating large number of entries (Callisteret al., 2013).

7.1. Molecular Diversity of Orchard CropIn recent years molecular markers have been widely used in genetic studies of treepopulations (Newton et al., 2002; Peng et al., 2003). Generally seed orchard populationsoften show a high percentage of polymorphic loci and alleles per locus (Chaix et al.,2003). The percentage of polymorphic loci (Kimura and Crow, 1964) in seed orchardcrops was estimated and principal component analysis carried out using ISSR molecularmarkers (Kamalakannan et al., 2009) to evaluate the extent of genetic variationtransmitted from seed orchards to the next generation crop of new recombinants.

Principal coordinates analysis (Fig. 5) revealed separate clustering ofE. camaldulensis and E. tereticornis seedlots and separation between the orchardseedlots indicating differences in genetic composition of seed crops (Kamalakannanet al., 2009) .The local seedlot clustered midway between the two species indicatinga mix of genes of both species. The natural population grouped separately from theorchard crops indicating that mating between different provenances within theorchard has resulted in new combinations in the seed crop. Though the SPAsoriginated from the same parent seedlots, fertility variation has resulted in seedcrops that differ in genetic composition but still maintain adequate diversity andgain for establishing future plantations compared to the local seedlot.

8. Management to Modify Fertility Status of OrchardsFertility plays a very important role in converting the genetic value of the selectedtrees to gain in the next generation. From a diversity stand point it is better to havea fertile tree of slightly lower genetic value than to have a superior tree that does notcontribute to seed production. Unequal fertility can also cause deviation in themating pattern. Thus the major concern would be to have random mating of maximumnumber of trees of known genetic potential. This would be especially true in a firstgeneration seedling seed orchard where the species is initiated into domesticationprocess.

Application of flowering promoter chemical PaclobutrazolTM as soil drench iseffective in increasing fecundity and the number of flowering trees inE. camaldulensis and E. tereticornis orchards. The percentage of fertile treesincreased three to four times with its application, but the impact gradually reduced

M. Varghese

41Domestication strategies for eucalypts in India

Fig. 4. Relationship between sibling coefficient (fertility variation) in seed orchardsand variability (tree height) in progeny.

Fig. 5. Grouping of four orchard seedlots and control (native and local seedlot) usingprincipal component analysis.

E.c – E. camaldulensis, E.t – E. tereticornis

R2 = 0.728

R² = 0.969

R² = 0.443

0

0.05

0.1

0.15

0.2

0.25

0.3

0 5 10 15 20

Sibling coefficient

CV

for

heig

ht

site 1site 2site 3

42

(though significantly higher than control) in four years. Capsule production washigher in E. camaldulensis (two times) and E. tereticornis (five times) than controleven after three years of application (Varghese et al., 2009b).

8.1. Constrained Seed Collection and Mixing of SeedsTwo management strategies that can be used to reduce the impact of fertility variationon diversity of seed crop are constrained seed collection and mixing seed crops fromtwo consecutive years. Constrained seed collection (selective harvest) can be doneby restricting number of fruits from each parent tree (Bila, 2000; Kang et al., 2003;Varghese et al., 2006b). Equal seed collection helps to have uniform female contributionand remove impact of excessive fertility of few individual trees. Increasing the numberof male parents enhances the effective number (Lindgren and El-Kassaby, 1989), which,however, lowers the genetic value of the crop, as the additional male parents selectedare genetically inferior to the trees selected for merit. A combination of the two strategieswould serve to achieve both objectives as seed collection is limited to the superiortrees and higher diversity levels are maintained by contribution from males. Thisstrategy ensures reduced drift and inbreeding in advanced generations.

Mixing seeds from two consecutive harvests helps to enhance the overall fertilityand cumulative contribution in the seed crop than that of either harvest (Fig. 6). Thestatus number, relative population size and gene diversity can be enhanced with thisstrategy in E. camaldulensis and E. tereticornis SPAs (Kamalakannan and Varghese,2008). Mixing seeds harvested at eight and nine years of age helped to reduce thesibling coefficient to 2.21 from the first and second year values of 2.24 and 3.19 inE. camaldulensis orchard (SPA- 2) at Panampally. As a result the relative contributionof trees increased from 31 per cent to 45 per cent. Mixing two consecutive seedcrops in the low flowering E. tereticornis orchard (SPA-4) at the same site reducedthe sibling coefficient by 44 per cent and increased relative population size by 57 percent. At the arid Pudukkottai site, mixing two seed crops reduced the siblingcoefficient by 36 per cent and 50 per cent and enhanced the status number by 56 percent and 95 per cent in E. camaldulensis and E. tereticornis, respectively. Constrainedseed collection would substantially reduce sibling coefficient and enhance statusnumber in the orchards.

Selective harvest and genetic thinning and a combination of both are orchardmanagement options that can be used to increase genetic gain while maintaininggenetic diversity in seed orchards (Lindgren and El-Kassaby, 1989). The practice ofselective harvest improves only the genetic contribution of seed parents, while bothseed and pollen parents are improved with genetic thinning. When fertility variationis very high in orchards, genetic thinning should be done only after fertility evaluationof the trees. Constrained seed collection is very effective in reducing the impact offertility variation but is often not very feasible when large quantity of seed is required.

M. Varghese

43

Mixing seed crops from different harvests is an easy option which does notrequire much technical inputs for implementation. Seed orchard trees contributemore equally to the seed crop if seed crops from consecutive years are mixed. Thisstrategy would be very effective in species where the trees show alternate bearing

Fig. 6. Cumulative contribution in E. camaldulensis (SPA-2) and E. tereticornis (SPA-4)orchards.


SPA-4 E. tereticornis

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 0.2 0.4 0.6 0.8 1Proportion of trees

Cum

ulat

ive

cont

ribu

tion

Equal fertilityVarying fertility-yr1Varying fertility-yr2Constant seed-yr1Constant seed-yr2Mix seeds-yrs1,2

Admin

Stamp

44

tendency (Varghese et al., 2008b). Since the relative contribution of trees variesbetween years, the composition of seed crops vary and gene diversity of the seedmix would be equal to or more than that of the best crop. This strategy will be verybeneficial in domesticating a newly introduced exotic species as in the case ofE. tereticornis in tropical humid regions (Varghese et al., 2003). A similar observationwas made by Kang et al. (2005) in seed orchards of Pinus thunbergii where fertilityvariation for the combined seed crops was lower than that observed for any singleyear, implying that the genetic diversity of seed crop would increase if seeds collectedfrom different years are pooled. Diversity of seed from orchards of the same origin atdifferent locations could vary, since the fertility of trees vary between locations asseen in the case of E. tereticornis orchards (SPA 3 and 4). Mixing seed from differentorchards would, however, affect the performance at either site as the seed from anorchard is best suited to a similar site.

9. Implication of Diversity in Eucalypt DomesticationModification of a species to suit an exotic site involves adaptability to survive andperform well in the new location. The problems are acute in first generationintroductions and suitable strategies must be employed to reduce genetic erosion.Lack of awareness of this factor may result in unnoticed erosion in genetic base ofplantations. Balancing gain and genetic diversity is important in eucalypts becauseof the fast turnover resulting from short rotations. A seedling orchard providesopportunities for correcting fertility problems and producing seed for differentrequirements. Effective number of contributing trees may increase with generationsas seeds are collected from fertile trees, but the status number may decrease asinbreeding increases. The effective number of mothers can intentionally be forcedto become more similar to the real number by extracting seeds tree wise and discardingexcess seeds from mothers contributing most, or the prolific seed bearers may not becompletely harvested. This principle of equal seed contribution is widely used inestablishing what are known as extensive seedling seed orchards (Nikles et al.,1984; Varghese et al., 2000a).

Great emphasis is placed on gain and hence clonal plantations are becomingextremely popular (Lal et al., 1993). Though seed still remains the major plantingmaterial in India, clonal option (which is often a short-term strategy in most breedingprogrammes) has gained priority that massive investment is made on establishingpropagation systems for mass multiplication and deployment. A few clones are(based on preference of farmers) are often planted over extensive areas which canreduce the genetic diversity of the planting stock substantially. Low diversity canresult in outbreak of pest and disease epidemics as seen recently when some popularclones were devastated by gall wasp infestation (Jacob, 2010). In a time boundbreeding programme the top performing progenies can be cloned at the end of each

M. Varghese

45

generation of breeding. When a large number of vigorous progenies are cloned,they can be tested at different locations for deployment as clones and for developingclonal seed orchards for increased gain. It is desirable to have large breedingpopulations of families and pedigree identified clones in each generation. Thebreeding populations then get converted to seedling and clonal seed orchards thatprovide fair diversity in deployed seed, enhanced gain in the form of clones, andinformation on progeny performance of parents in the previous generation.

9.1. Deployment of Clones for Enhancing GainThe currently available commercial eucalypt clones originated as selections from anarrow base like provenance trials or from local Mysore gum plantations (Kulkarni,2005). Progeny trials and unpedigreed plantations of native seedlots offer anopportunity to select phenotypically outstanding trees of wide genetic base and tapearly benefit from a breeding programme by deploying first generation clones ofknown origin and diversity. Top trees identified in family trials and SPAs (referSection 2, Table 1) were cloned based on phenotypic superiority. As many as 78clones of E. camaldulensis and 27 clones of E. tereticornis were vegetativelypropagated from basal coppice of the selected ortets and tested at three diverselocations differing in annual precipitation in southern India. There was significantsite-by-clone interaction that only about 10 per cent clones were superior to naturalKennedy River provenance seedlot at one site whereas 96 per cent of the clonesoutperformed the control seedlot at another site (Varghese et al., 2008a). The clonetrials can be thinned to retain the top performing clones at each site for conversionto clonal seed orchards. Selections from orchard progeny at different locations canbe cloned and evaluated for suitability to each site. Seed orchards can thus be thebase for regular infusion of new clones to specific sites. The gains from deployingthe best 10 per cent of clones (from each trial) after evaluation was seen to vary (25-109%) depending on the suitability of the clone to the site (Varghese et al., 2008a).Clones popular in low rainfall regions when tested in a high rainfall location inKerala were inferior to natural Kennedy River seedlot, which clearly showed that itwas necessary to first introduce a seedlot and select clones rather than shift clonesacross contrasting sites (Harwood, 1999).

Clonal testing is suggested to achieve the greatest benefit in long-term breedingof eucalypt species (Danusevicius and Lindgren, 2003). The gains tapped fromclonal selection can be used to achieve enhanced gain in subsequent generationsthrough clonal orchards. It is desirable to have representation from large number ofclones as it offers more flexibility in using selective harvesting; to increase the effectof later thinnings; to get a more efficient overlap in phenology and to decrease theamount of selfing. Lindgren et al. (1989) developed linear deployment methods forbalancing the options for gain with that for gene diversity by deploying unequal


46

number of clones. This strategy helps to obtain as much gain as possible by deployingclones with high breeding value, while maintaining desirable levels of diversity withrepresentation from clones with moderate breeding value in low proportion, tomaintain diversity in an orchard.

A study was done to optimise thinning in clone evaluation trials of E. camaldulensisby using variable thinning intensity in different clones for conversion to clonal seedorchards (Ravi, 2008). Since these clones were intensively selected from large numberof entries in first generation seedling seed orchards, they offer a short term strategy, anopportunity for substantial improvement after a generation of testing in breedingpopulations. Linear deployment ensures that the number of ramets retained per clone islinearly related to the breeding value (Lindgren and Matheson, 1986) of the clone. Theaverage gain obtained from the clone is the product of the breeding value and numberof copies of the clone deployed. There has to be a balance in the number of ramets thatcan be included beyond which the benefit obtained is reduced resulting from inbreedingand loss of diversity. The easiest thinning option would be to eliminate the low rankingclones completely with truncation selection which also maximises the genetic gain. It is,however, not suitable for the first thinning in an orchard as it reduces the options forfurther thinning to address fertility issues. This calls for a balanced selection betweenmaximum gain by selecting very few best clones and the need for diversity by includingrepresentations from more entries using linear deployment strategies. The essentialdifference between the thinning strategies is the cut off limit, the intercept, whichdecides the lowest value of clones to be selected. When the intercept is chosen, theslope of the selection line decides the number of ramets in the lower ranking clonesresulting in a smooth line with less skew in distribution of the selected ramets.

Thinning strategies were evaluated at three years in clone trials of 87 clones with 15ramets each. Linear thinning when compared with truncation selection (removing allclones below the trial mean for tree height), would give greater gain and diversity. Sincethe primary objective of managing a seed orchard is to enhance gain, linear thinning ispreferred since it addresses both gain and diversity concerns at the same time. Simplemass selection based on phenotypic value is also an effective method of thinning clonetrials as it ensures adequate representation of clones and moderate gain. Phenotypicselection gives higher representation of clones than truncation selection but linearthinning is the ideal strategy for maximum gain and adequate diversity (Varghese et al.,2006a; Ravi, 2008). In advanced generations Kang et al. (2001a) recommended an effectiveclone number of at least 10 with an equal number of ramets per clone.

10. Domesticating Eucalypts for Sustained ProductivityThough enhancing gain is the primary objective of any improvement programme, abroad genetic base would be necessary for initiating a domestication programme.Low variability and high adaptability of outstanding provenances of E. camaldulensis

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– Kennedy, Laura and Morehead Rivers and Petford to several test sites indicatesadequate outcrossing and gene flow in the native stands. These natural seedlots,which are the starting material for domestication, may, however, have very poorfecundity in newly introduced sites (Varghese et al., 2009a). Thus extreme care hasto be taken to prevent rapid gene loss, at the first level of domestication, in a newlyintroduced site (Varghese et al., 2003).

We have seen in earlier sections of this chapter that despite high fertility variation( = 7-8) and poor flowering (30% fertile trees) in E. camaldulensis and E. tereticornisorchards in an arid location, the effective population size was comparable to that ina moist location which had high fertility (73% fertile trees), and the mean growth rateof the orchard seedlots also did not differ significantly. This is because, despite lowflowering, mating between genetically divergent provenances gives rise to inter-provenance hybrids, which is stable across generations (due to a complementaryeffect), and does not breakdown in subsequent generations (Nikles and Griffin,1992). But a high relative proportion of genes will be carried forward to the nextgeneration only in the high flowering orchards. There would be related matinghappening in next generation among progeny of low flowering orchards. Orchardswith higher proportion of fertile trees and relative population size will have offspringwith higher diversity, growth and survival compared to orchards with lower fertilityas reported in Eucalyptus regnans (Eldridge and Griffin, 1983).

Breeding populations for high and low rainfall sites will have different genotypesselected for adaptability, and should be separately maintained after evaluation offirst generation introductions at the respective locations (Varghese et al., 2008a).Fertility is to be monitored before seed collection to ascertain the coancestry levelsand effective population size in high rainfall locations as recommended byPinyopusarerk and Harwood (2003a). Breeding orchards and production orchardsneed to be clearly identified based on the diversity of the seed crop. A productionorchard can be stocked with the best or a few outstanding provenances to maximizegain. However, for sustained productivity a breeding orchard should have a broaddiversity to carry forward a high proportion of unrelated genes. Keeping siblingcoefficient levels below three would ensure acceptable effective population sizes inseed stands (Kang et al., 2003). For a successful domestication program, seedorchards should have acceptable levels of fertility variation and effective populationsize. The orchards should be evaluated for predicted inbreeding and moleculardiversity of the seed crop; and the realised genetic gain relative to currently plantedcontrols (Varghese et al., 2009a), before seeds are released for commercial planting.

11. Designing Seed Orchards Using Molecular MarkersIn long-term breeding programme, the intensity of selection applied over breedingpopulations restricts the number of genotypes retained in the final orchard, thereby


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decreasing genetic diversity and increasing the risk of inbreeding depression oversuccessive generations. Although molecular markers can reveal genetic diversity,they are not fully exploited to assess genomic diversity in traditional tree breedingprogramme (Glenn and Chaparro, 1996; Gaiotto and Grattapaglia, 1997; Grattapaglia,2000; Marcucci Poltri et al., 2003). In open-pollinated eucalypt seed orchards maleparentage is assumed to be random and derived from outcrossing. As a result, themale parentage contribution within and among the different families is unknown andrelationships among the progeny (half-sib or full-sib) are unknown. Molecular markersallow accurate estimation of genetic distance and genetic diversity.

Zelener et al. (2005) proposed a selection strategy using genetic diversityinformation measured at the DNA level in individuals pre-selected based on theirfitness. This strategy helps to decide whether to increase genetic gain (with loss ofgenetic diversity), or to preserve a high genetic diversity (at the expense of geneticgain), or to combine both scenarios. Individuals carrying unique allele variants wouldbe preserved in the seedling seed orchard and genotypes are separated into differentpopulations based on similarity indices. It is ensured that all alleles in the parentpopulation are retained in the seed orchard. This methodology for orchard designemphasizes individual and family selection, because the largest proportion (about 80per cent) of the total molecular variation in the population is found in individualswithin families, with a moderate proportion (15-18%) of the total genetic variationamong families within provenances. Thus, almost 90 per cent of the families will berepresented in the selected seed orchard in different proportions. Mating pattern,including pollen dispersal and gene flow within and between populations, will bemanaged to maintain the genetic structure of seed crop (Levin and Kerster, 1974),which in turn will influence the breeding population size and seed orchard design.

Differential family performance in open-pollinated progeny trials can be verifiedfor possible inbreeding depression resulting from selfing or mating between relatives(Matheson and Mullin, 1987; Hodge et al., 1996) before conversion to seed orchards.Direct comparison of growth rates of self-pollinated and outcrossed eucalypts havedemonstrated negative effects of inbreeding on seed viability and growth (Hodgson,1976; Griffin and Cotterill, 1988; Hardner and Potts, 1995). A positive association betweenoutcrossing rate and growth has also been reported in Eucalyptus grandis usingfamilies selected on the basis of different levels of prior inbreeding (Burgess et al.,1996). Differences in growth among families from the Petford region in provenance/progeny trials in Thailand (Pinyopusarerk et al., 1996) were found to be associatedwith differences in outcrossing rate (Butcher and Williams, 2002). Based on the superiorgrowth performance of populations of E. camaldulensis occurring between 14°S and18°S latitudes and 143°E and 145°E in north-east Queensland, the Petford region hasbecome one of the most important seed sources for plantations in the wet/dry tropics(Midgley et al., 1989; Doran and Burgess, 1993). Thus the major challenge in

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domestication is to first eliminate inbred individuals from the introduced populationand ensure that high outcrossing is maintained among the retained genotypes inbreeding orchard. Molecular information on diversity and genetic distance helps toimprove the genetic base in breeding programme. Molecular markers can be used toevaluate redundancy or deficiency in germplasm collections. Based on the levels ofheterozygosity the genetic base of a breeding population can be improved byintroducing material with high genetic variability from natural populations. Leite et al.(2002) evaluated genetic variability in a base population of E. urophylla before initiatinga breeding programme in Brazil. Muro-Abad et al. (2001) used RAPD markers as a toolto direct the hybridisation programmes in Brazil by choosing the appropriate genotypesbased on genetic distances for crossing clones of E. grandis and E. urophylla andmarkers can be used to analyze the progeny of interspecific crosses (betweenE. grandis and E. urophylla) to develop stable and productive genotypes and maintaingenetic diversity during selection.

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Pinyopusarerk, K.; Doran, J.C.; Williams, E.R. and Wasuwanich, P. 1996. Variation ingrowth of Eucalyptus camaldulensis provenances in Thailand. ForestEcology and Management, 87(1-3): 63-73.

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1. IntroductionEucalypt culture, from its first introduction in Mysore in 1790 (Shyam Sundar, 1984)till date, has remained under discussions and debates for its ecological, social,silvicultural, biotechnological, industrial and economic aspects. Foresters, farmersand its wood users have been fascinated by its potential to adapt to varied soilconditions with fast growth, capability of generating economic returns to growersand multiple and varied uses. With its first organized plantation by the forestdepartment on forest land in 1877 at Malabavi (Devarayanadurga), Tumkur district(Kadambi, 1944) to the present times, a lot has changed in its nursery and plantationculture, other technological innovations and their applications. Of these, its clonalculture is changing the landscape and fast occupying a space in agriculture andforest land-use in different states and regions of the country. Out of a total of over600 species (Turnbull, 1999); some 170 species, varieties and provenances ofeucalypts have been tried in India (Bhatia, 1984; Palanna, 1996). Eucalyptuscamalulensis, E. citriodora (Corymbia sp.), E. globulus, E. grandis, E. pellita,E. tereticornis, E. torelliana and E. urophyla, their hybrids and clones are nowwidely preferred for research and field plantations in the country. This paperdiscusses the present status of its clonal culture in the country and also presentssome significant work done in WIMCO/Wimco Seedlings Ltd. so far.

2. ApproachesEucalypt clonal propagation and improvement work is undertaken by a numberof government and private sector organisations in India. It includes state forestdepartments, state forest development corporations, research institutes anduniversities in government sector; wood based industry and individualentrepreneurs in the private sector. A classical clonal eucalypt programmeincludes identification and selection of superior trees; their mobilization byobtaining the first vegetative propagule and assembling in the propagation

Status of EucalyptClonal Culture in IndiaR.C. Dhiman and J.N. Gandhi

3

61

facilities; handling, preparing and multiplying them in adequate number for clonaltesting/screening; maintaining the assembled clonal material of the finally selectedones in juvenile and active growth stage for mass propagation; handling andmaintaining the planted cuttings for rooting in mist chambers; hardening andgrowing the rooted stock to desired size; and their transfer, planting andmanagement in the field. With so many and diverse stakeholders in eucalyptculture in the country, no single approach is uniformly followed in developingnew clones and their mass multiplication. The basic ingredients of all theapproaches in developing superior genotypes for cloning, mass multiplicationand planting for wood production, however, remain the same. Presently, thefollowing three approaches are commonly followed in development of clonesand their mass propagation for field planting.

Approach-I: Select individual trees (candidate plus trees or CPTs) from the existingplantations based on morphological traits like growth, crown, bole, branchingpatterns, disease and insect resistance; mobilize them by taking their first vegetativepropagule; rejuvenate them through serial vegetative propagation; produce rootedplants from juvenile shoots; plant and screen them in field testing or in clonalorchards; rejuvenate the selected individuals; establish vegetative hedges and starttheir mass multiplication by rooting the cuttings.

Approach-II: Collect seed from CPTs, inter- and intraspecific hybrids, and freshintroductions from other sources, germinate to grow seedlings, raise its plantations,screen the outstanding ones and include them in the production system as perApproach-I mentioned above.

Approach-III: Procure proven clones from the breeding institutes/organizations,establish their hedges/vegetative multiplication gardens and propagate clonal stockfor field planting.

There are only a few organizations those followed the complete protocol; manyothers just procure better performing clones and mass multiply them for sale/supplyto the growers. The initial eucalypt programme in WIMCO, ITC and some otherorganizations was started using first approach and is now carried forward by followingthe second one which is more stable and a sustainable support to strengthen theclonal programme. Human resources, material and techniques developed in WIMCOinitially and ITC thereafter helped in developing clonal eucalypt programmeselsewhere especially in the private sector. The main ingredients of a systematicclonal programme include development of clones, their induction in productionsystem, establishment and maintenance of cutting production systems, selectionand use of appropriate root trainers and potting media, environmentally controlled

Status of eucalypt clonal culture in India

62

rooting chambers, hardening polyhouses, and nursery infrastructure for production,handling and delivery of clonal planting stock.

3. Development of ClonesThis is an extremely important activity for initiating a sound and sustainable clonalprogramme which demands heavily on time, human and money resources. A littlemore effort at this stage helps in sound building of clonal programme by selectingreal outstanding individuals for their induction in the propagation system. Clonesincluded in operational programmes need to consistently perform in term of yieldand productivity, good coppicing behaviour, good rooting capacity of over 80 percent with or without root promoting hormones, and resistance to insects and diseases.Eucalypts are now planted by numerous small growers and also by the organizedforest departments and forest development corporations, the final performance testfor any clone is its acceptability among its growers and wood users. The process fordevelopment of new clones is complex which needs to follow an exhaustive and timeconsuming procedure from a very large starting population to the last stage of finalscreening of a few clones for their induction in the propagation system. Manyclones developed and named by some organisations (Table 1) have been of academicimportance only as they failed to get acceptance by the growers.

4. Indigenously Developed ClonesNew clones are normally named by prefixing names or coded words before the clonenumber by their developers. This is done to code the clones for their tracking inresearch and propagation, take credit and recognition for research work in developingthem, and as a market startetgy to sell them by their brand names. Some others areusing alphabets for species, hybrids, place of origin, etc. Again there is no uniformpattern and practice in naming them and in writing the abbreviated alphabets andnumerical characters with or without space, dash, underscore, etc. The names andthe series of the clones which find mention in the literature are given in Table 1. ITC-BCM clones are by far the widely accepted and planted clones throughout thecountry. Some others regularly planted ones include clones from Wimco under theseries WIMCO and W, KFRI under the series K, TNPL under the series TNET and afew others. Naming clones is a sensitive issue, and sometimes, the clone name maynot reveal the identity of the species or parents. Some breeders may not be willingto disclose the identity of parents and species.

There are some other series whose developing organisations could not betraced. For example, Balu et al. (2013) mentioned 221 clones being maintained in theInstitute of Forest Genetics and Tree Breeding (IFGTB) which were screened againstgall wasp and referred as N, G, TAF, LA, R, ITC, C, KFRI, K, APPNPI, APNPI, APNPP,PNKK, APNPP, APNC, FC, JK, MTP, P, PUL, RR, SPIC, ARM, APSVS, PSVS, PSVA,

R.C. Dhiman and J.N. Gandhi

63

Tabl

e 1.

Nam

e of

clo

nes,

thei

r se

ries

and

ass

ocia

ted

orga

nisa

tions

Status of eucalypt clonal culture in IndiaS.

no

. Se

ries

Ex

ampl

e Sp

ecie

s O

rgan

isatio

n R

efer

ence

1.

BCM

BC

M 4

13…

A

ll IT

C-P

SPD

K

ulka

rni,

2004

, 201

0

2.

Code

d#

7310

3092

A

ll

Wim

co S

eedl

ings

Ltd

. D

him

an a

nd G

andh

i, 20

04

3.

Wim

co, W

-T-,

and

W-

Wim

co 1

4..

All

WIM

CO L

td.

Dhi

man

and

Gan

dhi,

2004

4.

FRI

FRI-E

H-0

01

Hyb

rid

FRI,

Deh

radu

n ht

tp://

ww

w.ic

fre.o

rg/U

serF

iles/F

ile/In

stitu

te-

FRI-2

011/

FRI-

VRC

-121

011.

pdf

5.

IFG

TB

IFG

TB-E

C1…

E.

cam

aldu

lens

is IF

GTB

, Coi

mba

tore

. ht

tp://

ifgtb

.icfre

.gov

.in/p

df_f

iles/e

new

slette

r_j

an_m

ar_2

010.

pdf

6.

K

K-2

3…

All

KFR

I, K

eral

a Ba

lasu

ndar

an e

t al.,

200

0

7.

TNET

TN

ET-1

…

E. te

retic

orni

s TN

PL

Prat

hiba

n et

al.,

200

4

8.

D

D1…

E.

tere

ticor

nis

Wes

t Coa

st Pa

per M

ills L

td.

Chop

ra, 2

004

9.

DLD

, ET

DLD

3…

E.

tere

ticor

nis

Wes

t Coa

st Pa

per M

ills L

td.

Chop

ra, 2

004

10.

SA

SA 1

…

Uro

gran

dis

Wes

t Coa

st Pa

per M

ills L

td.

Chop

ra, 2

004

11.

P P

1…

E. p

ellit

a W

est C

oast

Pape

r Mill

s Ltd

. Ch

opra

, 200

4

12.

ERK

, ET,

SR

, R

ERK

-4..

NA

N

A

DBT

, 200

1

13.

SRY

SR

Y 1

6… (Y

eshw

ant)

NA

M

ahat

ama

Phul

e K

rishi

Vid

yape

eth,

Ra

huri,

Mah

aras

htra

So

lank

i et a

l., 2

000,

Dhy

ani e

t al.,

201

3

14.

EUM

TP,

ECM

TP, F

CR,

C, N

umbe

red

FCR

13..,

C 1

06..,

1, 3

, 4…

N

A

Fore

st C

olle

ge a

nd R

esea

rch

Insti

tute

, M

ettu

play

am, T

N

Ven

nila

et a

l., 2

011

15.

Num

bere

d -

NA

H

arya

na F

ores

t Dep

tt.

Kum

ar a

nd B

anga

rwa,

201

1

16.

Eu

Eu 3

…

E. u

roph

ylla

Th

e M

ysor

e Pa

per M

ills L

td.

Am

anul

la a

nd Ja

yaku

mar

, 200

4

17.

Eub

Eub

46…

E.

oro

phyl

la

The

Mys

ore

Pape

r Mill

s Ltd

. A

man

ulla

and

Jaya

kum

ar, 2

004

18.

EG

EG 2

57…

E.

gra

ndis

The

Mys

ore

Pape

r Mill

s Ltd

. A

man

ulla

and

Jaya

kum

ar, 2

004

19.

BP

BP 6

…

E. p

ellit

a Th

e M

ysor

e Pa

per M

ills L

td.

Am

anul

la a

nd Ja

yaku

mar

, 200

4

20.

HP

HP

26…

E.

pel

lita

The

Mys

ore

Pape

r Mill

s Ltd

. A

man

ulla

and

Jaya

kum

ar, 2

004

21.

GR,

JD

GR-

109.

., JD

-1..

NA

G

rasim

Indu

strie

s Ltd

. M

ishr

a, 2

004

22.

Oth

ers

T, H

, etc

. -

- M

ishr

a, 2

004

64

ET, etc. Many of these clones were obtained by the institute from the private sectorand research institutes and may have duplicate names for the same clone mentionedin Table 1. There is a possibility of a few other series clones used in research trials,clonal banks and field plantations which could not find place in the list given above.For example, Star Paper Mills have claimed of developing three eucalypt clonescapable of producing double the yield compared to seedling origin plantations (http://www.starpapers.com/spm.asp?page=sr) but their actual names could not be tracedin the literature nor confirmed from any other source. Mohan and Manokaran (2013)while screening clonal plantations of 110 clones for diseases in the states of AndhraPradesh, Kerala and Tamil Nadu mentioned them as numbered clones not related toany of the above series. Many a times the same clones are referred by overlappingnames. ITC clones are referred under the series of ITC-BCM, BCM, ITC and many ofthem are known among the growers with their simple numbers rather than codedwords prefixed with them. For example, clone BCM 413 is popularly known as clonenumber 413 and so on. The preference of the clones is gradually changing over theyears. A decade back ITC clones 3, 7 and 10 were more accepted among the growersin South India and elsewhere. These clones (except 7) are now not much in demandas they developed serious susceptibility to gall induction and little leaf diseasehence, replaced with those which could withstand some degree of resistance.Similarly, many clones of WIMCO which were earlier planted have been taken out ofproduction system on their becoming susceptible to gall, little leaf andCylindrocladium leaf blight (CLB).

The Protection of Plant Varieties and Farmers’ Rights Act, 2005 has provisions forregistration of clones/cultivars of tree species based on DUS (distinctiveness,uniqueness and stability) characteristics. The Plant Protection Authority has alreadyapproved DUS criteria for eucalypt clones and there is a possibility of getting clonesregistered with the authority. Presently, the clones have been released by somegovernment funded institutions like Forest Research Institute at Dehradun (FRI),Institute of Forest Genetics and Tree Breeding at Coimbatore (IFGTB), and privatesector without following the DUS criteria and without the approval of the PlantProtection Authority. Clone no. FRI-EH-001 developed from FRI Hybrid 1 by FRI andclones of E. camaldulensis, viz., IFGTB-EC1, IFGTB-EC2, IFGTB-EC3, IFGTB-EC4developed by IFTGB have recently been released by the concerned research institutes.

There have been some attempts to recommend clones adapted to specificproblematic sites (Table 2). Some clones have been categorized according to theiradaptability to different soil and site conditions, climatic conditions, susceptibility/resistance to diseases and insects, rootability and productivity (Kulkarni, 2004).

Similarly, Chopra (2004) categorized 23 clones of E. tereticornis, six of E. pellita,and 10 of Urograndis for different rainfall and soil site conditions. E. tereticornisclones recommended for moderate rain and dry climate with sandy soils are D1, D2


65

and DLD3; for low rain, dry climate, drought resistance are DLD 10 and DLD 13; formoderate rain and dry climate (>700 mm) with sandy loam soils are DLD 18; for lowrain and dry climate (upto 600 mm) as DLD 27, DLD 31 and DLD 66; for moderate rainand dry climate (>700 mm) are DLD 99, DLD 127, DLD 128 and DLD 130; for low rainand dry climate (<600 mm) are 14 ET 1, 15 ET 2, 16 ET2, 17 ET4, 18 ET5, 19 ET 6, 20 ET7, 21 ET 8, 22 ET 9, 23 and ET 10. Urograndis clones recommended for high rainhumid climate (>900 mm) and for sandy and clay soils are SA1, SA2, SA3, SA4, SA5,SA6, SA7, SA18, SA20, and SA24; whereas, E. pellita clones for high rain highhumid areas (>900 mm) and for sandy loams soils are P1, P2, P3, P4, P5 and P6. ThePunjab Forest Department has recommended eucalypt clones for different land usesas clone no. 413, 407, 316, 288, 2070 and 526; for land with hard pain as 413, 526, 288,407 and 316, and for water logged areas as 492, 498, 27, 10 and 469 (http://www.pbforests.gov.in/ choiceofspecies.html). Recently, Balu et al. (2013), Dhimanet al. (2010) and Dhiman and Gandhi (2012) also categorized clones according totheir resistance/susceptibility to gall induction.

Kulkarni (2010) reported productivity figures for ITC developed clones. It hasbeen tried to categorize these clones as per their documented productivity in differentproductive classes, viz., below 50 t ha-1, 50-100 t ha-1, 100-150 t ha-1 and 150-200 t ha-1

(Table 3). The most popular clones fall under categories of over 100 t ha-1 productivity.In north India, there are over a dozen clones commercially produced in the

propagation facilities and planted by the growers. These are 413, 411, 288, 316, 2045,2135, 2070, 2313 and 2306 (BCM series from ITC), Wimco 12, Wimco14 and Wimco 15(From WIMCO) and K 23 and K 25 (from KFRI). The presence of other clones isinsignificant. BCM 413 is by far the most widely produced and planted clone in thestates of Punjab, Haryana, Uttarakhand and Uttar Pradesh followed by BCM 288,Wimco 12, Wimco 14, Wimco 15, K25, etc.

5. Induction of Clones in Clonal Production SystemThe clones included in the production system are those which had already undergonecloning while they were field planted from past selected CPTs or may be thoseperformed outstanding in the existing field trials and need first time induction in theclonal propagation system. A number of propagation methods, viz., coppicing, rooting

S. no. Characters Clone number (ITC-BCM series) 1. Clear bole 1, 4, 6, 7, 27, 122, 223, 265, 266, 272, 274, 275, 284,

286, 288, 290, 316 and 319 2. High productivity 3, 6, 7, 10, 105, 130, 265, 266, 272, 274, 284, 290, 292,

316 and 319 3. Adaptable to refractory sites 1, 10, 71, 105, 115, 116, 128, 130, 223, 266, 271, 272,

274, 285, 290, 316, 405, 411 and 413 4. Disease resistance 1, 3, 6, 7, 288 and 316

Table 2. Some specific traits of few ITC clones


66

of cuttings, budding, grafting, layering, lignotubers and micropropagation are usedin one or other form for their vegetative propagation. The application of methodsdepends on the purpose of propagation, season, age of tree, use of chemicals andthe propagation facilities. The use of micropropagation and lignotubers is still in theexperimental stage; budding, grafting and layering are increasingly used for mobilizingthe selected superior trees and for developing plants in containers or in centralizedplaces for making crosses (Fig. 1a and Fig. 2), whereas, rooting of cuttings is nowoperationally used to mass multiply selected clones for plantation forestry. In India,the work on vegetative propagation of eucalypt was initiated at Wimco SeedlingsLtd. and the FRI (Tewari, 1992) and, thereafter, at other private and governmentagencies. The main methods used for cloning eucalypts with specific utility inplantation management, tree improvement and operational scale mass multiplicationare discussed below.

6. CoppicingStems and branches of many Eucalyptus species have dormant buds beneath thebark and sprout to give regrowth on cutting back/felling, girdling, damage andsometimes after fire (Jacob, 1955). This new growth is called coppice growth and thepractice of obtaining such shoots as coppicing. The practice of coppicing is appliedfor the regeneration of clonal and seed origin plantations for subsequent rotation ontheir harvesting. The history of its use could be traced back to Neolithic times(Crowther and Evans, 1984). Coppicing in eucalypts varies with species, clones,season, age of trees, stump height, nutrient status of stock plant, managementpractices, etc. Eucalyptus species grown in India are easy to coppice. Eucalyptclonal forestry has exploited this trait extensively in management of plantations ofboth clonal and seedling origin, tree improvement and operational production of

S. no. Wood yield (t ha-1) Name of clone 1. <50 147, 326, 330, 492, 501, 516, 540, 611 2. 50-100 1, 4, 8, 71, 84, 113, 116, 119, 124, 128, 142, 158, 159, 165, 222,

223, 236, 241, 276, 314, 317, 319, 320, 323, 328, 351, 355, 356, 359, 407, 409, 412, 415, 433, 436, 437, 438, 439, 458, 469, 470, 471, 498, 499, 514, 515, 522, 525, 526, 529, 532, 533, 534, 535, 541, 545, 547, 548, 566, 570, 585, 587, 588, 598, 607, 609, 612, 654, 670, 671, 2016, 2045, 2070, 2120, 2135, 2149, 2151, 2153, 2154, 2169, 2170, 2171, 2202

3. 100-150 3, 5,7, 10, 27, 52, 83, 99, 105, 115, 122, 130, 226, 265, 266, 269, 271, 273, 274, 275, 277, 284, 285, 315, 316, 318, 405, 411, 413, 417, 503, 513, 2145, 2253, 2254, 2306

4. 150-200 72, 272, 286, 288, 290, 291, 292

Table 3. Categorization of clones under BCM series as per productivity ofindividual clones


67Status of eucalypt clonal culture in India

cloned planting stock. In plantation management, coppicing is a simple, low cost,and reliable reproduction technique and, therefore, invariably employed forregenerating harvested eucalypt plantations with varying coppice rotations beforetheir replacement with fresh planting. Generally, eucalypt plantations can besatisfactorily coppiced many times. Mysore gum plantations in Nilgiri Hills, SouthIndia have been cut on a 10-year rotation for almost 100 years and still produce verygood coppice yields of fuelwood (Matthews, 1996; Doughty, 2000). In northernIndia, eucalypts planted inside agricultural fields is normally uprooted and replantedafresh, whereas, that planted on bunds is worked under simple coppice system for acouple of cutting cycles. Coppicing is more uniform in clonal plantations comparedto seedling origin ones due to genetical uniformity in the former case. Large gaps orfailed areas can be restocked through replanting. Harvesting of trees during wintersor monsoons produce abundant sprouts. First coppice rotation is not likely to reachmaximum vigour until the second succeeding coppice rotation (Jacob, 1955).Thereafter, there is a progressive decline in the regeneration of coppice shoots/stump and the vigour of the coppice shoots. Clonal plantations in many regions andstates of the country are normally harvested at four to six years and further managedfor two to three coppice rotations each for three to five years for production of rawmaterial for pulpwood, firewood, poles, stacks, scaffolding, MDF, particle board,etc. Coppice shoots on stumps, cut back near the ground level, are healthy andvigorous than those from stumps at higher positions above the ground.

Coppicing has also been used as a tool in eucalypt improvement and operationalcloning. It has also been extensively exploited as a link between selection of superiortrees and operational cloning from the stage of first obtaining the vegetativepropagule from CPTs to their final induction in production system. Fresh coppiceshoots collected from stumps on tree felling are considered juvenile, easy to rootand are used as first propagules to start their cloning. Once a mature tree isrejuvenated, it is maintained in a juvenile phase under active coppicing for makingcuttings. The juvenile mother plants are maintained as hedges for mass productionof shoot cuttings through coppicing, not necessarily from the main stem but alsofrom branches. The coppice sprouts are repeatedly harvested and the mother plantsare nourished and maintained with appropriate inputs of nutrients, irrigation andother cultural inputs. There are different kinds of hedges managed for shoot cuttingproduction (Fig. 1b).

7. MicropropagationUse of micropropagation especially tissue culture technique is widely advocatedfor mass multiplication of superior forest trees for field planting. The techniquealso finds mention for its use in cloning eucalypts in India (Gupta et al., 1981,1983, 1991; Kapoor and Chauhan 1992; Muralidharan and Padalai, 2000; DBT,

68 R.C. Dhiman and J.N. Gandhi

Fig. 1a. Patch budding for mobilizing mature CPTs.

Fig. 1b. Cutting production systems for operational scale cloning of eucalypts.

Admin

Stamp


2001) and in many other countries. According to DBT (2001) over 1.57 M tissuecultured plants have been supplied to different state forest departments, NGOsand other private growers. According to Kumar et al. (1993) 0.145 M tissuecultured plants were planted in Tata Tea Garden, Kerala by 1991. Muralidharanand Pandalai (2000) reported planting of 45,500 tissue cultured ramets of 28 clonesby the Kerala Forest Department. A very high multiplication rate of 100,000 plantsfor E. citriodora, about 50,000 plantlets for E. torelliana and 20,000 forE. camaldulensis can be produced in a year from a single nodal segment of amature tree (Gupta et al., 1980, 1981, 1983). The present status of micropropagationtechnique for eucalypt cloning is still at the experimental stage as the detailedresults of its field performance are yet not available. There is a mixed response ontheir field performance from whatever little information is available. Gupta et al.(1980, 1981) reported micropropagated plants of E. citriodora showing superiorperformance over seedlings grown from the same trees. Similarly Solanki et al.(2000) while reporting transferable agroforestry technologies mentioned a cloneSRY 16 that was produced by in-vitro shoot tip culture from stump coppice sproutsto have 66.3 per cent more height and 56.6 per cent more girth compared to seedorigin plants at 2½ years age. Some information on better performance of tissuecultured eucalypts is also reported by DBT (2001). Muralidharan and Padalai (2000),on the other hand, reported poor performance in term of survival, growth anddiseases susceptibility of E. tereticornis micropropagated plants over the rootedcuttings. The differences in survival were very large; i.e., 40 per cent formicropropagated plants and 80 per cent for rooted cutting plants after 21 monthsof field planting. The authors further indicated that there was constant mortalityof the micropropagated plants over the years. Kapoor and Chauhan (1992) alsoreported tissue cultured F1 hybrid each of E. citriodora x E. tereticornis andE. tereticornis x E. citriodora. In Brazil and some other countries, tissue culturehas been used as a tool for large scale production of micro cuttings for theirrooting in mist chambers (Assis et al., 2004). These micro cuttings obtained fromtissue cultured facilities are being now replaced with the mini cuttings from minihedges grown inside and outside polyhouses in some countries because of highcost of production and in difficulties in handling the highly demandingmicropropagation production systems. There are some commercial laboratoriesthose are producing tissue cultured eucalypts in the country (DBT, 2001). In India,most of the tissue culture research has centred on developing methods for culture,media and techniques to induce juvenility in trees (Dhawan et al., 1993). An enquiryon IndiaMART webpage will get a response from around half a dozen privatetissue culture labs showing interest to supply tissue cultured eucalypt plants. It isan indication that business in the production and supply of tissue culture plantsincluding that of eucalypts is also expanding in the private sector. However, a

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credible and repeated good performance of tissue cultured eucalypts, despitehundreds and thousands of such plants field planted, is yet to be accepted in theoperational forestry.

8. LignotubersThe main tuberous structures at the base of seedlings/saplings in many Eucalyptusspecies could be used for vegetative multiplication. These structures contain numerousbuds and regenerate shoots when the stem of the seedlings/saplings is damaged orcut back just above the lignotubers (Fig. 3). Like coppicing, regeneration of shootsfrom lignotubers also depends on season and species (Jacob, 1955; Bhatnagar andJoshi, 1973). Bhatnagar and Joshi (1973) have produced plants by using pieces oflignotubers treated with IBA (100 mg l-l) from two-year-old plants. This method is stillof theoretical significance and its operational application as mass multiplicationtechnique is limited. Lignotubers are formed only on seedling origin plants; theirformation in rooted cutting plants is yet to be reported. In New Zealand, 60 per cent offield plantations of radiata pine are clonal in nature and are established with clonalplanting stock produced through macropropagation of seedlings grown from controlcrosses with largely predictable genetical gains. The eucalypt improvement/hybridization programmes across the countries and regions have yet not reached astage when the progenies from such hybrids are considered highly genetically controlledand uniform to enable use of lignotubers from such seedlings for growing large scaleplantations.

9. Air LayeringAir layering has been used to get the first vegetative propagaules of some difficultto root tree species. It is performed on 45-60 cm long branches of eucalypt trees byremoving around 1 cm wide strip of bark, covering the debarked portion with wetmoss grass after applying 8,000 ppm IBA and tying the same with plastic strip toavoid moisture loss. Roots are formed in the moss grass within a month and layerson removal from the branches are planted in the containers or open beds. Widevariation in the success of layering is reported in eucalypts (Davidson, 1977). It hasbeen applied with success in E. robusta (Pryor and Willing, 1963) and E. deglupta(Davidson, 1974).

10. Grafting and BuddingGrafting and budding are important methods to clone mature eucalypt trees whichotherwise are difficult to mobilize through rooting of cuttings. Davidson (1974) trieddifferent grafting methods in eucalypts and indicated some serious problems ingraft compatibility among some species but has been highly successful with someothers. Cleft and tongue grafting methods have been increasingly used by joining


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scion and rootstock together in such a way that they readily unite and grow as oneplant. Matching the thickness of rootstock and scion is extremely important for thesuccess. The grafted portion of scion and rootstock is covered with narrow plasticstrip. The success rate increases with the use of actively growing and freshly collectedscion and also when the rootstock is maintained under active growth. Chandy(www.inseda.org/.../CD%20.../Eucalyptus%20Cultivation-467.doc) described abudding method for eucalypts in which good quality seedlings are used as rootstock.The seedlings are cut back at 5-7 cm above collar position, 3 cm long and 0.5 cm x 0.7cm strip of bark is cut from the top of the rootstock running downwards with thebase of strip attached to the main stem, scions are taken from selected brancheshaving an approximately same thickness as of rootstock, scion inserted in the cutmade on the rootstock and the point of union wrapped tightly with polythene strip.Sprouting of scion is usually noticed between 30-40 days and complete union isestablished within 60 days.

11. Rooting of CuttingsEucalypts were once considered hard to root species in India (Nanda, 1970;Gurumurti et al., 1988) and elsewhere (Paton et al., 1970). Cuttings collected frommature trees fail to root and are not suitable for mass multiplication and operationalplanting due to age factor. This method, therefore, could not be directly used bytaking cuttings from the mature trees but is increasingly exploited in operationalcloning once the mature trees are rejuvenated. Selected trees are mobilized bycollecting the juvenile sprouts from stumps on their cutting back or by collectingbudwood (buds and shoots) and their grafting on seedlings grown near theproduction facilities. The trees are rejuvenated by serial vegetative propagationwhich is performed till a stage adequate rooting percentage is obtained with orwithout root promoting hormones. Most organisations in India have followed thisapproach of cutting back the selected trees to regenerate stump sprouts for makingcuttings. The tree is cut down at the end of the winter, the beginning of the springand during rainy season. Sprouts developed on the stumps can be collected assoon as the growing stem does not remain too soft. This stage is normally achievedin 30 to 45 days after cutting back. Good coppicing trees get re-sprouted on theremoval of the existing shoots. The light coloured soft upper part of the sprouts isnot used for making the cuttings.

12. Establishment and Maintenance of Cutting Production SystemsThis is another extremely important back-end activity required for a successful clonalprogramme. It needs a lot of planning, space and professional skills to establish aconstant and regular supply of juvenile cuttings for propagation system. It needsexhaustive backward working for timely developing shoots through cultural and


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tending operations of mother plants maintained in cutting production systems. Anumber of cutting production systems are presently used for juvenile shootproduction (Fig. 1b). The rejuvenated plants are established in the cutting productionsystems both in outdoor and indoor polyhouses, which are commonly called as‘macro hedges’ and ‘mini hedges’. These are also invariably called as ‘vegetativemultiplication gardens (VMG)’, ‘stool beds’, ‘clone banks’, ‘clone gardens’, ‘clonal/cutting multiplication areas (CMA)’, etc. Plants in outdoor hedges (macro hedges)are planted at close spacing and nurtured with cultural and agronomical inputs forabundant and multiple shoot production. In some organisations space betweenlines is increased and that between plants is decreased for effective soil workingand weeding between the plant lines. Some facilities grow close spaced plantationsfor one to two years, cut back the saplings for coppice shoot production, harvestthe shoots at regular intervals, and allow one or two shoots/stems to develop tillthey are again cut back for coppice shoot production. Over time, this systemdeveloped into a closer spacing with 40,000 or more plants per hectare. Technologicalinnovations in management of hedges led to increase in ratio between hedges andarea planted in Brazil from 1:44 to 1:525 (1 ha of clone production area could produceclonal plants for 525 ha) (Higashi et al., 2000).

Clonal hedges need to be maintained in vigorous growth with appropriateirrigation, light, nutrients, etc. It is better to avoid multiplication of sprouts fromhedges which have been exhausted by repeated shoot harvesting too many times.In north India during winters, the growth of hedges is checked due to cool andfoggy environment, it takes longer to produce the same size sprouts and rootingefficiency than that in summer months. During winters, the removal of cuttingsshould be made carefully and the number of crops restricted in order to avoidexhausting them.

Mini cutting production system on mini hedges is the current production systemin many propagation facilities in India and abroad. Indoor clonal mini hedges areeasy to manage than larger outdoor gardens in some countries (Ianelli et al., 1996).This has greatly increased stock quality and cutting production efficiency. In somefacilities, these are planted in raised beds made up of fibre glass or cement concreteof varying lengths, 20 to 30 cm depth and 40 to 60 cm width. They are usually filledwith washed sand and irrigated by internal flow from one end to the other, by dripirrigation, and from above with drainage at one or both ends. Nutrition application inclonal hedges is an integral part of their management (Higashi et al., 2000) and acombination of macro- and micronutrients is regularly applied to maximize shootproduction. Harvesting cuttings from mini hedges begins 20 to 30 days after planting.Shoot tips of smaller length are harvested for use in cutting propagation. The cuttingis planted into the standard container and follows the standard propagation supportof misting and shading. Rooting in shoot tip cuttings is generally fast and better


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than semi-softwood cuttings and many times they may not require treatment by rootpromoting hormones for enhancing rooting. In shoot tips and mini softwood cuttings,the original apical shoots grow upward compared to side shoots that develop fromthe semi-hard cuttings. The result is a faster growing, and more vigorous nurserystock with mini cuttings. In addition, one of the roots tend to grow as main lateralroot similar to tap root straight down compared to growing from the side of the stemin semi-softwood cuttings (Fig. 4). During the successive generations of cuttings,some cuttings with a weak root system need to be avoided. The quality of thecuttings needs to be maintained through proper maintenance of mother plants inhedges and they may need replacement with fresh planting at regular intervals.

13. Selection and Use of Root Trainers and Potting MediaIntroduction of root trainer technology for seedling production in forest nurseries hasrevolutionized clonal culture of eucalypts. Initially, the technology was developedand introduced by Wimco Seedlings for growing planting stock of a number of foresttree species, including for clonal propagation of eucalypts and many other tree species(Rawat and Dhiman, 2002). Presently, the root trainers are life line for rooting eucalyptcuttings and many other species and all the propagation facilities in India areincreasingly relying on the root trainers for operationally feasible production systems.Size, shape and design of root trainers are extremely important features in the successof eucalypts clonal programme. An ideal root trainer cavity should have appropriatelength/diameter ratio, top/bottom hole ratio, and inner ridges/grooves for effectivemoisture retention, root development and plug formation during development of rootcuttings to their plantable size. Too long and narrow containers may not effectivelyform plug and those with small bottom holes may lead to plugging and coiling of roots(Fig. 5). Root trainers with large bottom holes drain out the rooting media and the plugformation also gets delayed. The first root trainer lot introduced by Wimco Seedlingsin India for raising tree seedlings was of 93 ml volume with block dimensions of 350mm x 215 mm, cavity length 87 mm, width 40 mm, cavity top diameter 40 mm, cavitybottom diameter 22 mm, inner ridges five in number, and thickness of cavity wall as 1mm. Presently, root trainers of different shapes, sizes and designs are available in theIndian market and the commonly used ones for rooting eucalypt cuttings are of blocktype (40 cavities/block) with volume of 60 to 110 ml, the most common being 73 mlvolume with 86 mm length, 37 mm top dia, 19 mm bottom hole, inner ridges four to sixin number and wall thickness upto 2 mm. Some propagation facilities use bigger andsmall dimensions root trainers that also include individual cavities with adequatespace adjusted between them on stands. In Brazil, the propagation facilities havemostly used the ‘Hawaiian dibble tube’ with about a 3 cm top circumference, 10 to 15cm length, and around a 50 ml volume (McNabb, 2002). Container size decides theplant size to be produced, large cavities produce large size plants and vice-versa. This



Fig. 4. Semi-hard wood top shoot (A), soft wood top shoot (B), and semi hard wood (C) cuttingsin rooting media (upper) and soon after rooting in around 18 days of their setting in mistchambers(below). A -represents mini cuttings collected from indoor and outdoor mini-hedgesin around 15-20 days, B as bud sprout cuttings from 2-3 years old stumps in 7- 10 days ofsprouting, and C made from coppice shoots from outdoor macro-hedges in around 35-45 days oftheir last harvest under North Indian conditions. Rooting is fast in B (average 8-10 days)followed in B (average 10-12 days) and than in C (average 12-18 days) cuttings underenvironmental controlled chambers. A and C cuttings need cutting tools to harvest from motherplants whereas, B could be simply pinched with hand/nails from the mother plants.

Fig. 3. Regeneration of shoot fromlignotuber.

Fig. 2. Manipulated crosses made on graftedplants. Left: flowers covered with paper bagsafter pollination, and right: capsuleformation after hybridization.

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is because the large sized cavities contain more potting media, nutrients, and space forroot development resulting in better growth of seedlings. However, large containersrequire more potting media and extra time for growth (Chandra and Gandhi, 1995;Dhiman et al., 1996; Sharma, 1996). A few production systems are using root trainerswith small cavities to effectively use limited space of propagation chambers andthereafter shift them to large cavities outside for their fast attaining the appropriatesize required for field planting. In some humid locations, high incidence of CLB forcespropagation facilities to culture plants in bigger cavities for avoiding crowding andallowing air circulation among plants to check disease spread.

14. Rooting MediaRooting media need to maintain an ideal combination of aeration and moistureretention for encouraging fast and uniform rooting and fast development of plugsin rooted cuttings. In addition, the media needs to be light in weight, well drained,inert, inorganic matter and free from pest and weed seed. The most common rootingmedia used in the country is horticultural grade vermiculite which has around fourgrades in the market. The fine quality vermiculite holds additional moisture, is notwell drained and, therefore, such media give poor rooting. Of late, many nurserygrowers in southern India have started using coco-coir waste which is available inabundance and at low cost. Some other rooting media used for rooting in India,viz., river sand and even rice husk sometimes, in combination with vermiculite aswell. Each medium has variability in gradients that affect the rooting efficiency. Insome countries, other rooting media are used in pure form or in mixture and theseinclude crushed pine bark, rice husk, grabbles, perlite, pumice, peat, Styrofoam,etc. (Landis et al., 1990). Too coarse rooting media like rice husk and grabblesencourage callusing at the base of cuttings with low rooting, whereas, too finemedia lead to excessive moisture retention and rotting of cuttings.

Potting media ingredients, their proportion, physical and chemical propertiesplay significant role in the growth and development of seedlings. Once the cuttingsget rooted, they need a nutrient rich feeding with irrigation water or rooted cuttingsare to be transferred to other cavities filled with nutrient rich media. In most of theproduction facilities first option is exercised where rooted cuttings are maintained inthe same root trainer cavities and are supplemented with nutrient rich irrigationwater or repeatedly sprayed with solutions carrying composite mixtures of essentialnutrients. The choice depends on the infrastructure and the technical resourceswith the production units. In some nurseries, rooted cuttings are placed on nutrientrich media for some time that allows the roots to penetrate the nutrient rich mediahelping the rooted cuttings to grow the desired size in a short period with greenflush of leaves, cut back the outgrown roots and supply the plants for field planting.Such plants are highly sensitive for field planting under extreme weather conditions


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and may lead to excessive disease infestation and desiccation. The potting media incontainers for shifted rooted cuttings, if practised, need to be balanced one thatmay contain soil, sand and compost in appropriate proportions with adequatenutrients.

15. InfrastructureRooting of cuttings has developed as the accepted method for operational cloningof eucalypts in India and many other countries. It demands certain regulatedenvironment of humidity, temperature and light conditions inside chambers. Theinside environment in specially designed chambers/polyhouses is modified withappropriate misting, cooling, aeration, and light arrangements. Variety ofpropagation facilities now exist for rooting of eucalypt cuttings in the country.They vary from a simple low cost huts covered with polythene sheets that maintainshigh humidity involving an expenditure of a few thousands rupees (Dhiman, 1995;Sharma et al., 2001) to highly sophisticated auto controlled mist chambers costingRs. 4 to 6 M per unit. The rooting environment is partially modified inside low costpoly-tunnels of a few m2 and auto regulated in large sized mist chambers of around1,000 m2 per unit. These units suit different users with limited and adequateresources for small and large scale operations with heavy investments. A largenumber of production facilities have installed multiple mist chambers to meet theirproduction requirements. Misting is created by specially designed nozzles whichare operated at regular intervals with water pumped with pressure; the timings ischanged based on the internal and external environment, season, cutting materialused (macro, mini and shoot tip cuttings). Cooling and adequate aeration is createdby blowing moist air from cellular pads or from brick bee hive structures installedon opposite sides of the exhaust fans. The light transmission to chambers ismaintained by transparent polysheet covers around it and shade nets stretchedbelow the polysheet covers. The cost of installation of these chambers and theirmaintenance is very heavy, it is necessary to use them effectively to realize theinvestments made thereon (Fig. 6). Normally these chambers should produce20,000-30,000 plants per 100 m2 of internal space. Some propagation facilities areeven getting higher production efficiency with some innovations. It is desired toinstall these chambers away from the trees and building structures to avoid partialshading inside chambers and also damage to polysheet cover from falling branches.The technical and professional human resource for running the entire operationare very essential than the fine technicalities of chambers. A professionalpropagator with simple huts can produce better clonal plants whereas highlysophisticated chambers have been failed with those who could not address othertechnical issues of handling eucalypt plants during pre- and post-setting ofcuttings for rooting and in maintaining the chambers in running conditions.


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16. Hardening ChambersRooted cuttings are produced under exacting environment inside chambers. Theseplants are unable to match the harsh climate outside especially in very hot locationsand, therefore, the rooted cuttings need to be kept for sometime under modifiedenvironmental conditions of partial shade with frequent irrigation preferably withsprinkler system or rose can. Shade nets with different shading effects are installednear the mist chambers for hardening the planting stock before it being maintainedunder open conditions for acclimatization. These structures vary from around a 100 m2

to over an acre depending upon the requirement of the propagation capacity. Someunits do not consider hardening chambers as essential infrastructure and are able toharden the rooted cuttings under open conditions.

17. Operational Rooting of CuttingsRooting of cuttings is affected by the species, clone, stage of juvenility in shoots,growing conditions of the hedges, origin of the cuttings, handling of sprouts andcuttings, rooting environment and other factors. The rooting time may vary from10 to 21 days in the operational rooting facilities. It is always advised to disinfectthe mist chambers after removing the last rooted lot. Bleaching powder at the rateof 0.80 kg per 100 m2 of chamber area is spread and the chamber is allowed to dryfor a couple of days before planting the new lot. Shoots from cutting productionsystems are brought in containers filled with fresh water, made into cuttings whichare again placed in containers having fresh water before their treatment. Minicuttings constitute the whole shoot collected from the mini hedges and there is nospecial preparation but for removal of the leaves from their lower parts whichotherwise impede their insertion in rooting media. Mini-cuttings or fresh top shoots/sprouts, therefore, can directly be planted in the rooting media, whereas semi-softwood shoots collected from hedges need conversion into 10-15 cm long nodalcuttings with the terminal leaf pair half trimmed to conserve moisture loss and topermit some photosynthetic activity during the rooting process. The cuttings aremade by removing the shoots just above the leaves to initiate new shoots fromauxiliary buds and root from the leafless bottom part inserted in the rooting media(Fig. 7). Cuttings are dipped in fungicide solutions for 5-10 min before the treatmentwith root promoting hormones. The cuttings are then drained before hormonaltreatment. A handful of cuttings made into a bundle, the basal part of which is thendipped in powder formulation of root promoting hormone-IBA having appropriateconcentration as per clone, species and cutting type before planting them in therooting media. Cuttings are planted either in root trainers or in beds filled withrooting media. Root trainers are used for simplifying the handling of rooted cuttings,though it is not always necessary to use them. Cuttings root equally good in bedsfilled with appropriate rooting media. The shifting of rooted plants from beds to


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containers is a little tricky issue and can only be handled with prior experience. Itis advised to place a shade net inside the chamber over the cuttings for someperiod depending upon physiological condition and age of cuttings andenvironmental conditions. Extra shade, many a times lead to rotting of cuttingsand too much heat may result in their desiccation. The mist is regulated by auto-settings; temperature, humidity and light conditions inside chambers are regulatedby shade nets and passing of moisturized air through cellulose pads and exhaustfans.

Rooting in commercially grown clones needs to be over 75 per cent and robustenough to grow out of the bottom of the containers during this phase (Fig. 8).After approximately 45 days, the rooted cuttings are removed from misting to anarea covered with shade nets for hardening. The hardening corresponds to theperiod between the acquisition of functional root system in the cutting and therecovery of an active aerial growth. This duration varies from three to four weeks.At this point, empty containers (dead cuttings) are removed and the live plants aregraded by size. Cuttings remain under shade for an additional 10 to 20 days and,then, are moved to full sunlight. After an additional 30 days they are ready forplanting in the field. During this process, the cuttings are routinely fertilized,usually through the irrigation system. Smaller plants maintained in separate blockof root trainers may need application of increased fertilization. At the end of thisperiod the rooted cuttings are adequately developed to allow them to grow to sizefor field planting. The duration between the insertion of the cuttings and its possibledispatch for plantations (15 to 20 cm height) is around three months and variesfrom one clone to another within the same species (Fig. 9). The clonal plants inroot trainers need a supportive and efficient carrier system that does not damagethem during transportation. A large number of carrier systems have been designedmainly by the traders who carry plants from a few kilometre to over a thousandkilometre from production facilities to their planting sites. Specially designed racksinside vehicles capable of carrying around 70,000 rooted plants per lorry to even1,500 to 1,800 on motor cycles are now in place. Clonal plants are now moved fromsouth to north, and west to east including trans-borders to even Nepal and Bhutanwherever and whenever demand for such plants is raised. Initially, the propagationfacilities helped in designing the transportation systems but now the traders areorganising it in an efficient way.

18. Extent of Clonal CultureEucalypt has emerged as one of the main trees planted on diverse land use in manyregions and states across the country. Besides, a few states not recommending itsplanting on forest land, it is increasingly planted by the individual growers ontheir land as cash crop. Precise information on extent of eucalypt culture including



Fig. 5. Some negative exposures with eucalypts clonal culture.

Fig. 6. Improved efficiency with effectivespace use of mist chambers is necessaryto realize investment.

Fig. 7. Cuttings set in root trainers (left) andin beds (right) filled with vermiculite asrooting media.

Fig. 9. Clonal plants ready for dispatch forfield planting.

Fig. 8. Some clones and chambers give over95 per cent rooting under favorable conditions.

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that of clonal plantations is not readily available. The activity of growing eucalyptplantations is so scattered that it is extremely difficult to estimate the area undereucalypts culture, including that under its clonal plantations as no singleorganization controls its nursery production, plant supply systems, field planting,harvesting and usage. Multiplicity of planting stock producers and plantationgrowers, planting stock production systems, planting designs, patterns anddensities, management systems and intensities, planting and harvesting cyclesand timings, land-uses, its users and promoters, etc., make all estimates for areaand extent of existing plantations under eucalypts as redundant. Planting eucalypts,which significantly vary over the period as growers make decisions on theirplanting and harvesting are based on market conditions, their economic andfinancial needs and also on the competition from other crops in the competingland use. Therefore, no forecast on area under its culture could be precise andaccurate with traditional documentation methods which have been used in Indianforestry. There are a few reports which provide some indicative information oneucalypt plantations, including its clonal forestry.

Forest Survey of India estimates and presents the forest and tree cover thatincludes species and volume wise tree inventory for forests and trees outside forests(ToFs). Eucalypts are also covered under this inventory. An analysis of the inventoryof eucalypts given in the India State of Forest Report 2009 and 2011 is presented inTable 4. This report of 2011 is based on the interpretation of satellite data capturedbetween October, 2008 and March 2009 which is further corroborated with groundchecks of selected sampled districts (FSI, 2009; 2011). Eucalypts were estimated tohave 146.208 M stems and 35.925 M m3 wood volume over 10 cm diameter in 2011report which represent 2.89 per cent and 2.32 per cent of total trees outside forests(ToFs) and their volume, respectively in the country. The increase of 47.83 per centin tree stems and 40.61 per cent in wood volume between 2009 and 2911 reports issignificant in eucalypt inventory as ToF. This was the period when eucalypt clonal


Year Diameter class (cm) 10-30 30-50 Over 50

Total Per cent of total ToFs

Number of stems (M)

2009 92.564 11.902 1.969 107.135 1.955 2011 130.038 13.135 3.125 146.298 2.89 Change in stems 37.474 1.233 1.156 39.163 0.935 Per cent change 40.48 10.36 58.71 36.55 47.83

Volume (M m3) 2009 11.767 5.139 4.422 26.449 1.65 2011 17.395 11.395 6.45 35.925 2.32 Change in vol. 5.628 6.256 2.028 9.476 0.67 Per cent change 47.83 121.74 45.86 35.83 40.61

Table 4. Status of eucalypt inventory as ToFs during FSI’s 2009 and 2011 reports

81

forestry started expanding due to seedling origin plantations becoming highlysusceptible to gall induction and little leaf infection. Conversion of 146.298 M treesinto area under its culture, at the rate of average 1,000 trees ha-1, works out to be 1.46or 1.5 Mha as ToFs in the country. A sizeable part of it could be considered underclonal eucalypt culture. Another important figure related to eucalypt culture in thecountry is given by GIT (http://git-forestry.com/download_git_eucalyptus-map.htm)as 3.924 Mha. One reason for the variation between these two figures could be thateucalypts grown on forest land are captured in a category of other species and is notincluded in the above figure of 1.5 Mha. Further, the FSI report captures tree inventoryover 10 cm diameter, eucalypts being fast grown trees raised for pulpwood, firewood,poles, etc. and many a times are harvested below 10 cm diameter and, therefore,such trees failed to be picked up in the FSI report. A large quantity of eucalypt woodis harvested from young trees even below 10 cm diameter for firewood and pulpwoodand this category is not included in the above inventory. The actual inventory of thetrees in usable category is likely to be much higher than what appeared in thisreport. Many of the trees which could not be picked up in that database would beharvested before the new report is released.

Eucalypts are now one of the main tree species planted on the forest land.Palana (1996) and Tripathi et al. (2010) claimed one Mha eucalypt plantations madeby the state forest departments and forest development corporations in the maineucalypts growing states, viz., Andhra Pradesh, Daman and Diu, Goa, Gujarat,Haryana, Karnataka, Kerala, Madhya Pradesh, Maharashtra, Punjab, Tamil Nadu,Uttar Pradesh and West Bengal, etc. Its plantations are raised under state and centrallysponsored schemes for firewood, small timber, poles, etc. Numerous states haveattracted funding for social and farm forestry projects in which eucalypt has beenthe main tree for farm forestry programmes for planting on field bunds, canal sidesand in marginal agricultural lands. Haryana is presently reported to grow and plant20 M eucalypt seedlings planted over 15,000 ha which represents 40 per cent of thetotal nursery stock grown in the state (Jotriwal and Chander, 2013).

Private sector especially pulp and paper mills have made heavy investmentin developing infrastructure for clonal propagation of eucalypts. Andhra Pradeshand Tamil Nadu have already witnessed fast expansion in clonal forestry ofeucalypts, including that among individual nursery growers. It has been estimatedthat around 100 M clonal plants of different eulaypt clones are produced by thesmall growers in south India alone (Kulkarni, 2013a). In north India, Haryana,Punjab and Uttarakhand clonal eucalypts have been grown for some time nowand its infrastructure is slowly expanding in these states including Uttar Pradesh.Forest corporations and forest departments in the states of Andhra Pradesh andTamil Nadu are among the first state government agencies to start eucalyptsclonal forestry. Andhra Pradesh Forest Development Corporation has grown


82

27,813.11 ha of seed origin and 26,991.39 ha clonal plantations of eucalypts byApril 30, 2009 (www.apfdc.apts.gov.in). Tamil Nadu Forest DevelopmentCorporation (TAFCORN ) has planted eucalypts in an area of 46,531 ha asstated in its report ending March 2011(http://www.tafcorn.tn.gov.in/ria.htm). Thecorporation was growing seedling origin plantation till 1999 but has launchedclonal forestry programme thereafter and planting about 1,500 ha yr-1, from theyear 2000 onwards. So far the corporation has raised 18,648 ha, clonal plantationsof eucalypts and is further adding up 3,000 ha clonal plantations every year.Presently, the corporation is using the ITC clones, viz., C-3, C-7, C-226, C-271and C-274 and TAFCORN Clones TAF-4 and TAF-52 which are reported to begall wasp tolerant as well as highly productive. Tamil Nadu Paper Limited (TNPL)initiated its clonal production centre during 2007 to produce 15 M clonal plantsannually with an investment of Rs. 40 M. It has established 8,000 m2 fogging andmist chambers, 4,000 m2 of hardening chambers and 2,500 m2 of open nursery(http://www.tnpl.com/TNPL PLANTATION.doc).

The present main players in producing planting stock of eucalypts and itssupply to numerous growers could be grouped as: (a) pulp and paper manufacturerspromoting its culture, (b) other corporate and companies producing clonaleucalypts for others, (c) forest development corporations, state agriculturaluniversities, etc., and (d) individual enterpreneurs including NGOs, etc. Theinformation has been collected through personal and indirect contacts and fromthe existing literature. Its synthesis, as presented in the Table 5, indicates thatapproximately 237 M clonal eucalypt plants are produced and around 200 M areannually planted in the country. Since eucalypts are planted on diverse pattern,densities and designs ranging from boundary plantations of a few hundred plantsha-1 to over 2,000 plants ha-1 in blocks, it is presumed that on an average 1,000


No. of clonal plants (M) S. no.

Sector Main contributor Capacity Presently

produced 1. Indian pulp and paper

manufacturers promoting its culture

ITC, Bilt, JK Papers, Harihar Poly Fibres, Orient Papers, Grasim Industry, West Coast, Star Papers, etc:

72 40

2. Other corporate and companies producing clonal eucalypts for others

WIMCO as corporate and other individual promoted companies

38 35

3. Government agencies Forest development corporations in AP and TN; Forest departments in Gujarat, Haryana and Punjab, state agricultural universities, etc.

27 25

4. Individual entrepreneurs All others including some NGOs promoted by some wood based industries

100 100

Total 237 200

Table 5. Status of clonal stock production in the country

83

plants ha-1, the total area presently planted with clonal eucalypts is estimated toaround 0.2 Mha. It may be a rough estimate as the scenario on its clonal plantationsis fast changing. There are attempts to create infrastructure in the private sectorincluding many individual entrepreneurs to get advantage of the favourable marketenvironment for its planting. Demand for clonal eucalypts is increasing in manylocations and its local production is not able to meet sudden requirement. Plantingstock for sale is transported from far off locations and is being sold in otherlocations wherever increased demand exists. Clonal stock produced in a particularstate will not necessarily be planted in that state only. However, it gives a broadpicture of clonal planting of eucalypts taking place in the country. Growers arenow replacing their old seedling plantations with the clonal ones in many locations.This is a healthy sign for effective use of land and genetic resources for thebenefit of the country. Some reports estimated 50 to 60 M clonal saplings beingplanted annually (Piare Lal, 2011; Dhyani et al., 2013).

19. A Case Study of WIMCO’s Eucalypt Improvement and CloningProgrammeWimco was the first corporate house (outside government sector) to initiatesystematic improvement and cloning work in eucalypts to develop it as an industrialwood in the country. Some of the work first time ever carried out on eucalypts inthe company 1984 onwards, include screening of candidate plus trees (CPTs) fromthe existing plantations; introduction of new germplasm and its screening; workingout vegetative propagation methods like budding, grafting, layering, rooting ofcuttings; rejuvenation of mature trees through serial vegetative propagation fortheir induction in clonal programme; establishment of clonal bank of selectedCPTs; introduction of root trainer technology for rooting of cuttings and largescale seedling production; establishment of mist chamber for rooting of cuttings;hybridization through manipulated crosses; field plantations with clonal plantingstock and their monitoring and documentation. While most of the research work isdocumented in the annual research reports which are widely circulated among theforestry and agriculture establishments in the country, some of it has also beenreported in the research papers (Chandra and Yadav, 1986; Chandra et al., 1998;Dhiman and Gandhi, 2004, 2005, 2012, 2013a, b; Dhiman et al., 2010). Eucalyptprogramme executed in the company with some salient achievements is brieflypresented below:

19.1. Screening of CPTs from the Existing PlantationsSystematic research on improvement, hybridization, and cloning of eucalypts wasstarted on creation of Wimco Seedlings Ltd. as a joint venture and subsidiary toWIMCO Ltd., Swedish Match and Hilleshog in 1984. The initial work was started



with the selection of 522 CPTs of E. camaldulensis, E. tereticornis and Mysoregum (Indian race of E. tereticornis) from the existing plantations on the forestland in north India. To track the CPTs in research and field plantations, a code wasdeveloped for each tree. For example, in an eight digit code assigned to eachselected CPT, the first two digits in the 73103092 numbered tree; i.e., 73 stand forthe year of estblishing the plantation where selected CPT was located, next 1 digitfor geographical zone of the plantation in the country, next two digits 03 for speciescode (hybrid in this case, whereas, 01 and 02 were for E. tereticornis andE. camaldulensis, respectively), and the last three digits 092 for the selected individualtree (Dhiman and Gandhi, 2004). The selection intensity was kept very high and itwas attempted to screen one out of around 1,000 trees in any stand. Out of these, 252CPTs were selected for further work based on a composite selection index dependanton height, diameter, clear bole, branch angel, bark traits, etc. (Table 6).

As a first step in the improvement of eucalypts, half-sib seed of these 252 treesincluding three local selections were collected, progenies raised, out of which theseedlings of 108 CPTs were planted on 55 ha land for monitoring their performance.These progenies were observed for eight years and the final data on height anddiameter of plants in this trial as presented in Table 7 clearly indicates wide intra- andinter-species variation in height, diameter and volume of selected CPTs.

Based on the growth and tree architect are data of the progenies of 108 CPTs, nineof them were finally selected for further multiplication and field trials. These CPTs were73103087 (016 -as tree No.), 73103081 (008), 67101006 (019), 65103395 (003), 73103087(014), 68103004 (015), 73103087 (002), 73103083 (007), and 73103083 (004). Many of theCPTs were also mobilized by collecting their first vegetative propagule which isdiscussed later in vegetative propagation section. The method of selecting CPTs contin-ued and was applied for selection of CPTs in species, seed source, clonal and hybridtrials for which the main criteria of selection remained the same. Some more selectionsmade in the subsequent species and seed source studies are given in Table 8.

Species Remark CPTs finally selected (no.) Number E. camaldulensis FGSI* 52 4 Local 6 6 E. tereticornis FGSI* 24 14 FGSU** 14 14 Local 6 6 Mysore Gum 136 124 E. grandis 2 2 E. tereticornis 9 7 E. urophylla 3 3 Total 252 180

Table 6. Number of candidate plus trees mobilized through budding and grafting

*FGSI=First generation source identified;**FGSU=First generation source un-identified.

85

Table 7. Performance of half-sib progenies of 108 CPTs after eight years of field trial

Contd. on next page...


S. no. Family and CPT No. Height (m) DBH (cm) Volume (m3)

1. 73103087 16 29.1 26.4 0.590 2. 73103081 8 31.6 23.7 0.516 3. 67101006 19 30.6 23.4 0.487 4. 65102395 3 27.1 24.5 0.473 5. 73103087 14 31.6 22.4 0.461 6. 68103004 15 30.6 22.3 0.443 7. 73103087 2 29.1 22.1 0.413 8. 73103083 7 28.1 22.2 0.403 9. 73103083 4 29.1 21.8 0.402

10. 67104006 6 28.1 21.8 0.388 11. 73103089 13 29.6 21.2 0.387 12. 73103083 2 29.6 21.1 0.383 13. 64103017 1 28.6 21.4 0.381 14. 67101016 5 27.6 21.7 0.378 15. 67104007 3 28.6 21.0 0.367 16. 68103004 14 29.1 20.3 0.349 17. 72103075 7 27.6 20.8 0.347 18. 64103029 10 29.6 20.0 0.344 19. 73103069 9 27.1 20.9 0.344 20. 72103075 9 27.6 20.7 0.344 21. 64103042 18 26.6 21.1 0.344 22. 73103087 3 28.1 20.4 0.340 23. 72103077 9 26.6 20.9 0.338 24. 64103403 6 28.6 20.1 0.336 25. 73103082 6 26.6 20.8 0.335 26. 68103001 19 29.1 19.8 0.332 27. 73103089 20 29.1 19.8 0.332 28. 68103005 16 26.6 20.7 0.332 29. 64103042 15 25.1 21.3 0.331 30. 64103041 12 28.1 20.1 0.330 31. 73103087 19 26.1 20.8 0.328 32. 64104302 9 28.1 20.0 0.327 33. 73103081 7 26.6 20.4 0.322 34. 64103014 13 28.6 19.6 0.320 35. 73103087 20 27.6 19.9 0.318 36. 64103017 7 27.6 19.9 0.318


Contd. from previous page...

Contd. on next page...

37. 64103042 13 29.6 19.2 0.317 38. 68103001 16 28.6 19.4 0.317 39. 64103033 9 24.6 21.0 0.316 40. 73103081 3 26.6 20.2 0.316 41. 73103075 4 27.1 20.0 0.315 42. 67101006 8 25.6 20.5 0.313 43. 68103007 1 28.6 19.4 0.313 44. 64103033 8 27.6 19.7 0.312 45. 64103035 2 28.1 19.5 0.311 46. 68103007 4 30.6 18.7 0.311 47. 68103001 10 28.1 19.5 0.311 48. 65103395 6 28.1 19.4 0.308 49. 68103004 5 29.1 19.0 0.306 50. 64103041 9 27.6 19.5 0.305 51. 64103011 10 28.1 19.3 0.304 52. 73103083 1 29.6 18.8 0.304 53. 65103391 15 28.1 19.3 0.304 54. 68103002 8 25.6 20.2 0.304 55. 65103391 19 27.6 19.4 0.302 56.. 68103004 2 28.1 19.2 0.301 57. 73103084 15 28.6 19.0 0.300 58. 73103067 2 27.1 19.5 0.300 59. 73103085 4 27.1 19.4 0.297 60. 64103406 5 26.6 19.5 0.294 61. 73103084 3 27.1 19.3 0.294 62. 64103023 6 26.6 19.5 0.294 63. 67104007 2 28.6 18.8 0.294 64. 64103033 2 28.1 18.8 0.289 65. 68103004 13 27.1 19.0 0.285 66.. 64103402 10 26.6 19.1 0.282 67. 64103404 5 28.1 18.5 0.280 68. 65103397 14 23.1 20.2 0.274 69. 72103072 7 27.6 18.4 0.272 70. 64103017 8 26.6 18.9 0.271 71. 68103001 16 27.6 18.3 0.269 72. Control 12 26.6 18.6 0.268

87

Contd. from previous page...

73. 64103404 7 28.6 17.8 0.264 74. 64103404 8 27.1 18.2 0.261 75. 65103395 5 26.6 18.2 0.256

76. 64103406 6 29.1 17.4 0.256 77. 67101016 2 28.1 17.4 0.248 78. 64103013 12 25.6 18.2 0.247 79. 64103031 3 25.1 18.3 0.245 80. 72103074 3 25.6 18 0.241 81. 64103031 13 26.6 17.5 0.237 82. 64103015 4 24.6 18.1 0.234 83. 68103002 9 26.1 17.5 0.233 84. 68103007 5 25.1 17.8 0.231 85. 64103040 1 24.6 17.9 0.229 86. 67104007 3 26.6 17.2 0.229 87. 64103402 3 28.1 16.7 0.228 88. 73103080 5 27.1 16.9 0.225 89. 64103402 6 26.1 17.2 0.225 90. 65103397 10 26.2 17.0 0.224 91. 64103013 18 27.1 16.7 0.220

92. 64103020 3 24.6 17.2 0.212 93. 73103088 4 23.6 17.5 0.210 94. 65103397 13 22.6 17.7 0.206 95. Control 2 21.6 18.0 0.204 96. 64103407 10 24.6 16.8 0.202 97. 64103040 14 24.6 16.7 0.200 98. 64103042 20 24.1 16.8 0.198 99. 66103097 6 21.6 17.7 0.197 100. 64103041 8 26.6 19.0 0.193 101. 64103013 9 21.1 17.3 0.184 102. 64103407 10 24.1 16.0 0.179 103. 64103028 8 20.1 17.4 0.177 104. 64103042 9 22.1 16.4 0.173 105. Control 10 22.1 16.2 0.169 106. 64103042 17 23.1 15.6 0.164 107. 64103013 19 21.1 16.0 0.157

108. 64103407 3 2.1 15.2 0.142 Mean 26.9 19.3 0.296 SD 2.3 1.9 0.1 CV(%) 9 10 26



Tabl

e 8.

Sev

enty

-thr

ee C

PTs

sele

cted

fro

m d

iffer

ent

spec

ies

with

the

ir t

raits

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em c

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ing

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Spec

ies

No.

of

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) C

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89

19.2. Species and Seed Source StudiesThe company is regularly evaluating and introducing germplasm of new seedsources and species from different regions and countries for screening newgenotypes for their constant improvement. In one such field trial, the performanceof 25 seed sources, out of which 10 were of E. camaldulensis, five of E. grandis,four of E. saligna, three of E. brassiana, two of E. urophylla and one of Mysoregum planted at 3 m x 2 m spacing at Bagwala during June, 1985, was monitored.The inferences were drawn based on growth data for nine years and the resultsindicated that the growth (height, dbh and volume) varied from species to speciesand provenance to provenance. It was concluded that the seed source(provenance) 13022 NW of Caboolture, 12970 SRF 194 Herberton Range, Qld. ofE. grandis and 13026 South of Calliope, Qld. of E. saligna yielded higher woodper unit area than that from the rest of the seed sources. The performance of seedsource 13395 of E. brassiana was the poorest. It was further inferred that basedon the CAI and MAI growth, a rotation age, of five years for E. brassiana and sixyears for E. camaldulensis, E. grandis E. saligna, E. urophylla and Mysore gum,was suggested (Table 9).

The outstanding trees were marked as CPTs and retained till 20th year (Table 10).Their growth indicated that CPTs of seed source 13022 of E. grandis exhibitedmaximum height growth (32 m), girth (173 cm), volume (1.493 m3) and fresh woodweight (28.15 q) followed by that of seed source number 13023 of E. grandis andCBJ-39 of Mysore gum. These trees were included in the clonal bank for furtherstudies.

Another species and seed source trial field planted during 1988 at our Researchand Development Chandain Farm with E. grandis , E. citridora, (both Tamil Naduseed sources), E. tereticornis (14857), E. citridora (13628), E. brassiana (13411)and E. camaldulensis (15223) confirmed that E. grandis (TN) performed the bestfollowed by E. tereticornis (14857) and E. citridora (13628). Growth of E. grandiswas quite balanced in comparison with E. tereticornis in term of height/diameterratio. Further observations on wood quality indicated that this species yielded whitecoloured wood which is suitable for even construction purposes as its trees havelong clean bole and wood is free from knots and twisted grain. The results of thistrial reconfirmed that E. grandis is suitable for growing in the high humid and warmlocations including Tarai region of north India. Some of the new generation clonesdeveloped by Wimco, viz., Wimco 12, Wimco, 14, and Wimco 15 showing highdegree of resistance to gall induction, little leaf and CLB have one of the parents asE. grandis.

In the latest trial, 18 provenances comprising 10 of E. urophylla, two eachof E. pellita and E. citriodora, one each of E. camaldulensis, E. alba,E. moluccana and E. longirostata along with seedlings of four species namely



Table 9. Performance of Eucalyptus species and their seed sources in Tarai region

Table 10. Growth performance of candidate plus trees at 20 yearsS. no. Species CSIRO

no. Height

(m) Girth (cm)

Volume (OB M3)

Weight (q)

1. 2. 3. 4. 5. 6. 7. 8.

E. cloziana E. grandis E. grandis E. grandis E. saligna E. saligna E. saligna Mysore gum

10691 12081 13022 13023 13026 13314 13341

CBJ-39

30 25 32 31 25 23 25 28

120 162 173 155 98

147 130 160

0.940 1.339 1.876 1.593 0.731 1.277 0.794 1.669

14.00 20.00 28.15 23.90 10.95 19.15 11.90 25.00

Initial After 72 months After 108 months Species Seed source Height

(m)

Height (m)

Dbh (cm)

Volume (m3)

Height (m)

Dbh (cm)

Volume (m3)

E. grandis 13022 67.0 22.8 17.7 0.210 30.7 21.9 0.428 E. grandis 12970 60.0 22.1 16.4 0.170 30.0 21.6 0.407 E. saligna 13026 74.0 19.1 17.7 0.170 22.2 24.2 0.378 E. urophylla 12896 73.0 18.9 16.0 0.140 24.2 21.1 0.313 E. grandis 13289 66.0 17.3 16.9 0.140 25.5 20.3 0.305 E. grandis 13023 41.0 18.2 15.5 0.130 28.7 18.1 0.273 E. camaldulensis 12181 60.0 21.3 14.8 0.120 20.4 20.4 0.256 E. camaldulensis 12964 63.0 18.3 15.3 0.120 22.8 19.4 0.249 Mysore gum CBJ-38 67.0 19.7 14.3 0.123 24.7 18.2 0.238 E. saligna 13027 62.0 16.2 15.1 0.110 24.4 18.0 0.211 E. cameldulensis 12338 64.0 16.7 13.9 0.090 19.6 18.7 0.199 E. cameldulensis 12963 68.0 15.6 13.7 0.080 20.4 18.2 0.198 E. grandis 12081 55.0 15.6 13.6 0.080 20.7 17.5 0.184 E. camaldulensis 12356 65.0 15.4 13.5 0.080 18.7 16.7 0.151 E. camaldulensis 12352 69.0 14.9 14.4 0.080 18.6 16.3 0.143 E. camaldulensis 12187 88.0 16.3 13.5 0.080 18.0 16.5 0.142 E. camaldulensis 12860 68.0 14.3 12.9 0.070 17.7 16.3 0.136 E. urophylla 13357 65.0 16.5 12.5 0.070 16.0 16.4 0.125 E. camaldulensis 12350 88.0 14.6 12.0 0.060 19.9 14.6 0.123 E. saligna 13263 42.0 15.2 11.2 0.050 18.9 14.4 0.114 E. saligna 13341 57.0 11.9 11.9 0.050 19.2 13.7 0.104 E. camaldulensis 12360 39.0 12.7 11.7 0.050 13.4 15.2 0.090 E. brassiana 13408 61.0 14.4 9.6 0.040 16.4 10.4 0.051 E. brassiana 13395 73.0 11.9 8.5 0.020 13.9 10.4 0.043 E. brassiana 13412 66.0 12.9 8.6 0.020 15.1 10.0 0.043

91

E. camaldulensis, E. citriodora, E. grandis and E. tereticornis as controls werescreened under two environmental conditions, viz., polyhouses and openconditions for growth, gall and CLB infestations. The data recorded at monthlyintervals from September 2009 to August 2010 indicated that seedlings maintainedunder polyhouse conditions had lower gall induction and CLB infection.Provenance No. 17841 of E. urophylla and Kennedy river provenance ofE. camaldulensis were moderately affected and seedlings of E. camaldulensis,E. grandis and E. tereticornis (control) were highly affected with infestation ofgall insect, whereas, other provenances including seedlings of E. citriodora(control plot) were completely resistant for gall induction. Maximum infestationof gall insect was noticed during the month of June 2010, whereas, maximuminfection of CLB disease was recorded during August, the same year. The fieldtrials of these species and seed sources have been established in Udham SinghNagar, Uttarakhand and are being monitored for growth and resistant to gallinduction, little leaf and CLB. The initial results indicated some highly resistantseed sources and trees against these threats.

19.3. Hybridization WorkEarly flowering of budwood sprouts on grafted seedlings provided an opportunityfor making controlled inter- and intra- species crosses. During the first attempt,60 crosses were made with 62 per cent success rate in 1985 itself. Fifty-sixindividuals comprising five fullsibs, viz., 64103031 x 72103070, 64103386 x CBJ-2,72103082 x CBJ-2, 73103073 x CBJ-2, selfing of 68103010 and one control (openpollinated) were planted at 4 m x 2 m during 1990 at Bagwala, Rudrapur. The datarecorded at the age of 48 months indicated that six individuals of two crossesand one halfsib were promising for height, dbh and volume growth. Based onthe field performance till 7th year, two hybrids, viz., 9 and 1 were selected andcloned for field planting (Table 11).

In 1993, 440 seedlings grown from 18 crosses and two controls were planted at4x4 m spacing at Chandain Farm. At 17 months, the survival was 59 per cent. The trial

Table 11. Field performance of initial hybrids made in WIMCO


Growth parameter with time (year) Parent No.

Height (m) DBH (cm) at Volume (m3) at

P1 P2 4 5 7 4 5 7 4 5 7

64103031 72103070 9 18.10 22.60 24.60 16.10 20.50 24.0 0.136 0.276 0.419

64103027 Half-sib 1 17.60 21.60 23.60 15.80 19.50 24.0 0.128 0.238 0.402

73103082 CBJ-2 20 19.10 21.60 25.60 15.50 19.50 21.5 0.133 0.238 0.351

73103082 CBJ-2 5 17.10 20.60 23.60 15.60 18.60 20.5 0.121 0.206 0.294

73103082 CBJ-2 26 18.10 21.60 24.60 14.20 17.10 20.0 0.106 0.182 0.292

73103082 CBJ-2 23 18.60 19.10 - 15.00 18.10 - 0.122 0.181 -

Weight (q)

14.00 20.00 28.15 23.90 10.95 19.15 11.90 25.00


monitored after five years indicates that CPT 67101015 as a mother parent producedeight trees which were more than 13 cm in diameter. This CPT was, therefore,considered as important female parent for making crosses thereafter. There wasculling of a very large poor performing individuals after two years (Table 12). Acouple of selections made from this trial were added in the germplasm.

Crosses (P1 x P2) Initial height (cm) Height (m) at 17 month

Cross no.

P1 P2

Planted (no.)

Survived (no.)

Mean SD CV Mean SD CV

1. E. grandis - 35 8 40 7.3 18 2.4 0.7 18 2. 67101018 CBJ-10 3 3 42 2.3 6 2.3 0.3 13 3. 64103017 Selfing 10 7 39 5.4 14 2.1 0.5 24 4. 67101018 72103075 34 27 40 5.2 13 2.1 0.7 32 5. 73103087 Selfing 2 1 37 2.5 7 2.1 0 0 6. 73103092 65103390 72 50 43 7.2 17 2 0.6 32 7. 65103390 73103090 34 19 44 5 11 1.9 0.6 30 8. 64103031 67101018 4 3 25 0 0 1.9 0.5 26 9. 64103017 67101018 40 28 40 5.9 15 1.8 0.5 25 10. 64103015 Selfing 5 3 34 4.9 14 1.8 0.8 43 11. 64103032 67101017 17 12 41 5.3 13 1.7 0.4 21 12. 65103400 67101018 40 25 37 6.1 16 1.6 0.5 33 13. 64103040 67101018 14 5 29 6.7 23 1.6 0.5 28 14. 64103015 67101018 40 19 46 4.8 10 1.5 0.5 32 15. 68103010 64103040 20 17 36 4.5 13 1.5 0.3 22 16. 67101018 65103400 8 17 40 4.3 11 1.5 0.3 17 17. 65103396 Selfing 19 6 43 5.7 13 1.4 0.5 37 18. CBJ-10 67101017 2 2 27 2.5 9 0.2 16 19. 67101017 64103017 6 5 42 3.8 9 0.9 0.3 31 20. E. crebra - 35 11 33 6.2 19 0.8 0.2 24

Mean (SD) CV - 440 268 38 5.6 15 0.4 25

Table 12. Performance of eucalypt hybrids at 17 months of age

In another trial, seedlings of the following crosses made in 1990 were fieldplanted the same year at 4 m x 2 m spacing. The results of this trial monitored for 20and 36 months revealed that only five fullsib and one control were outperformingand further retained for observations (Table 13).

19.4. Standardization of Vegetative Propagation for EucalyptsWimco soon after identification of CPTs started working on vegetative propagationfor their asexual reproduction and use in operational cloning and hybridization work.


Table 13. Performance of some of the hybrids after 20 and 36 months of field plantingCrosses (P1 x P2) No. Height (cm) after (month) DBH (cm) after (month) P1 P2 0 20 36 20 36

73103073 CBJ-2 11 26 420 13.3 3.1 10.4

64103031 72103070 9 26 392 13.1 3.1 10.0

72103082 CBJ-2 24 22 373 11.8 2.7 10.7

64103027 OP 3 16 355 11.4 2.7 10.4

68103010 Half-sib 4 26 361 11.6 2.4 11.6

65103386 CBJ-2 4 25 287 12.2 1.8 9.6

64103015 Half-sib - 29 195 - 0.8 -

The original CPTs selected from the forest plantations in 1984 varied from 9-21 years inage. Many authors proposed initiating cloning of mature trees from stump sprouts ontheir harvesting (Leakey, 1987). Most of the selected trees were from the plantationsgrown on forest land, their felling was regulated through working plan prescriptionand it was not possible to cut them immediately and get stump sprouts for makingcuttings. Cutting back of mature trees for generating stump sprouts for cuttings alsohas a disadvantage of losing the selected individuals if they fail to produce stumpsprouts due to poor coppicing efficiency, wrong felling season, also if the tree beingrelatively hard to root, and if the cuttings from sprouted shoots could not be plantedtimely. This destructive method may, therefore, lead to permanent loss of the certainselected trees; howsoever valuable they may be. Also, the methods for vegetativepropagation of eucalypts in India were not worked out by that period and, therefore,by using the experience from horticultural trees and literature, air layering, budding,grafting and rooting of cuttings were tried for their asexually reproduction andrejuvenation. The strategy worked well at least for initiating clonal propagation ofsuch selected genotypes which could be inducted in the propagation system. SelectedCPTs were mobilizated through air layering, budding and grafting; and rejuvenatedthrough serial propagation which is now a well accepted mean for such works.

19.5. Air Layering, Budding and GraftingSelected CPTs were assembled at Wimco’s R and D Centre by collecting and graftingtheir budwoods on seedlings for further cloning and improvement studies. Air layeringas a mean to mobilize mature CPTs was tried 1984 onward. It was performed on thebranches of mature trees of E. camaldulensis, E. grandis and E. tereticornis duringmonsoon season. However, the success rate was low and only a few mature trees weremobilized from plantations to our research centre. Simultaneously, budding and graftingwere also tried and these were found better more friendly in mobilizing mature trees ofeucalypts. Even union of scion and rootstock was better in budded plants than that ofgrafted ones. Budwoods were collected from the branches of selected CPTs, brought


in protected conditions (packed in moist jute bags) with proper identification marks,and patch and ring buddings were performed as fast as possible after receiving thebudwood. Budding was performed on the stems of already established seedlings atstem thickness corresponding to the thickness of scion shoot. Rootstock was cutback, above the budded position on the stem after 21 to 25 days of making the budding,whereas polythene wrappings were removed after 30 days of the budding. Plantshaving 1.5 to 2.0 cm diameter at ground level were used as rootstock for buddingwhich was attempted round the year though the success rate was low during summers(Table 14). Initially, it was used for mobilizing trees and when the sprouted shoots frombudwood of mature trees failed to give satisfactory rooting, serial propagation by re-budding was tried for rejuvenating the trees. It was noticed that successive budding

Species

E. camaldE. tereticMysore gMysore gMysore gMysore g

Time of budding Age of CPTs (yr)

Buds made Buds sprouted Survival (%) on 16.12.87

01.01.87 2 127 69 51 08.03.87 20 5 3 60 08.03.87 15 5 4 80 08.03.87 14 15 13 87 11.03.87 21 17 14 82 10.08.87 2 75 47 40 09.09.87 5 274 69 25 27.09.87 2 143 121 48 15.10.87 5 256 95 41 20.10.87 2 199 95 48 04.11.87 2 270 143 53 21.02.88 22 24 23 96 21.02.88 19 9 7 78 21.02.88 15 34 30 71

Table 14. Success rate of patch budding during different parts of a year

exhibited a more lasting juvenile stage followed by a new reversion to adult stage. Bytaking again a new scion from budded shoots for re-budding on seedlings, newprogression in juvenility could be obtained. After four to six successive buddingoperations, a sufficient juvenility was achieved and the rooting of the cuttings madefrom such fresh shoots was satisfactory with serial propagation within one year. Theresults of one of such experiment in increasing the rooting success of shoot cuttingsfrom rejuvenated shoots by serial budding are summarized in Table 15.

After 4th and 5th serial propagation, over 80 per cent rooting was achieved inmany species and clones. Results of patch budding performed for the mobilizingdifferent aged CPTs during 1987 at the R and D Centre are given in the Table 16.


Table 16. Effect of age of trees on the success rate of bud intake

Results indicate that the age of mother trees has no significant effect on thetake and survival of the buds. The success depends on temperature and humidityduring the period of budding and possibly more importantly, the care taken inbudding and that of budded plants. Survival is ultimately influenced by the extent ofcompatibility between scion and stock. The method has been modified to an extentthat now budding is performed at low levels of seedling stems, sprouted shoots cutback just above the budded position to get other sprouts, rooting attempted fromcollected sprouts, ramets planted on the ground, cut back near the ground andcoppiced for getting early rejuvenated material of mature trees.

Grafting was used as an effective and better option for hybridization work. Thebranch portions (around 15 to 20 cm long) collected from the crown having floweredin the recent past carry the maturity with them and the successful grafts even onjuvenile seedlings produced flowers much earlier than the seedlings (Fig. 2). Theshoots were cleft grafted on seedlings grown in pots or on the ground. It waspreferred to maintain the seedlings in pots than in open beds to maintain the size ofthe plants for making crosses by manually pollinating the flowers. Scion and rootstockunion was covered with the plastic strip to avoid moisture loss and the pots wereimmediately irrigated to increase the sap flow for the success of the union. Thegrafted plants maintained in pots were given extra care for the success of graftingand the hybridization work. Better success in grafting was observed between

Table 15. Effect of serial budding on the success of rooting of the cuttings

Age of CPTs (yr)

Buds attempted (no.)

Bud sprouting (%)

Bud survival (%)

2 814 58 85 5 530 31 100

14 15 87 100 15 5 80 100 16 34 88 80 20 9 78 100 22 5 60 100 24 41 90 100

Rooting (%) of cuttings made from shoots obtained from bud sprouts

Species Age of CPTs (yr)

1st 2nd 3rd E. camaldulensis 15 32 40 52 E. tereticornis 15 32 69 78 Mysore gum 23 38 58 69 Mysore gum 21 36 75 78 Mysore gum 15 24 25 42 Mysore gum 14 20 50 72


December and May though it could be performed around the year. During re-graftingstudies, it was possible to include 116 CPTs of Mysore gum, 22 of E. tereticornis, 15of E. camaldulensis and 2 of hybrids. Cleft, veneer and tongue grafting performedduring March to April at the R and D Centre during 1985 gave 100, 80 and 55 per centsuccess rate indicating that the former two methods could be operationally used inmobilizing the mature trees. To develop hybrids, emasculation of flowers just beforesign of rupturing of upper column and pollination was carried out for three conjunctivedays when the receptivity of stigma was recorded higher. Branches bearing controlledpollination flowers were covered with muslin cloth/paper bags after pollination andkept as such till capsule setting occurred.

19.6. Rooting of CuttingsEucalypts were once considered hard to root and all our efforts in the beginningfailed in getting its cuttings rooted. Juvenility, an expression of young physiologicalage of tissues with active vegetative growth and capability of easy rooting, hasbeen located near the base of trees (Bonga, 1982) and this character has beenextensively exploited in eucalypts to obtain first vegetative propagules of selectedmature trees for their clonal propagation. A very large number of the experimentswere conducted to produce juvenile sprouts for efficient rooting which have beendiscussed in the preceding section. In India, the coppice shoots from mature treesare collected at around 1½ months of their sprouting on cutting back the trees forachieving good rooting success. It was established in 1987 that stump sprouts of42 days age are suitable for giving best rooting in E. grandis.

Rooting experiments during 1984 completely failed due to lack of controlledrooting environmental conditions. The first mist chamber of less than 100 m2 wascreated at Wimco’s R and D Centre, Bagwala during December 1984 which wasthereafter used for standardization of rooting of eucalypt cuttings. This chamber,with bottom bed steam heating, controlled humidity and temperature inside, wasfirst ever rooting infrastructure that was created and used for successful operationalrooting of eucalypt cuttings in the country. The requirement of root promotinghormones (between 4,000 to 10,000 ppm) for cuttings of E. grandis, E. saligna,E. tereticornis and E. urophylla was also worked out through a series of experiments.The results of one of the initial experiment of rooting the cuttings with hormonaltreatment during 1985-86 are given in the Table 17.

Rooting response of individual trees is quite variable and is an important factorto select an individual for cloning. Based on the rooting results recorded at 30 daysof planting the cuttings, the rooting experiments with 95 CPTs indicate that while insome cases all the cuttings placed were able to develop roots, in others, not even asingle cutting rooted. In repeated rooting trials, eight clones of E. tereticornis, fiveof E. camaldulensis, 65 of Mysore gum and two of hybrids were recorded with over

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95 per cent rooting and the best clones in term of rooting per cent were 76102001,64103014, 64103026, 73103068, 72103071, 66103091, 78103256, 72103296 and 65103087.

WIMCO has been using a combination of approaches for producing andcollecting rootable cuttings from different mother plants for their mass multiplication.It includes stump sprouts, shoots from inside and outside macro hedges, shootsfrom mini hedges, and apex shoots from rooted cuttings still maintained in mistchambers, hardening chambers, and nursery rearing phase. The recent experienceindicates that the use of fresh bud sprouts even from the outdoor hedges comprisingof two to three years old mother plants produce very good cutting material for fastrooting similar to mini cuttings produced on mini hedges (Fig. 1b). These cuttingsdo not require treatment of root promoting hormones, their collection, planting andhandling is easy. Another approach used by us has been to maintain the motherplants in nutrient rich media in the large polythene containers (bags), buried insidesoil for their easy irrigation, repeatedly cut back to collect cuttings, maintain theseplants for three to four years as such before replacement with new ones (Fig. 1b).Another approach used is to take actively growing apex shoots from the rootedcuttings still maintained in the mist chambers post-rooting and pre-hardening phaseand even during their hardening phase outside mist chambers. These top shootcuttings have all the traits of mini cuttings and could be effectively used in case ofbuilding up of stock of those clones for which adequate cuttings are yet not availableand also as a mean to maintain the surplus stock during the seasons when theirdemand for field planting is less. This also helps in fast changing the composition ofthe multi-clonal production system by induction of new promising clones withouttheir formal induction in the cutting production systems. The limited stock ofpromising clones can be fast built up by combining the budding/grafting and rootingof cutting propagation methods. Each auxiliary bud of a new clone could be used asbudwood for grafting on seedlings origin plants and multiple sprouts from suchplants could be used for making cuttings and for fast building up the stock. Thetechnique, however, delays the transfer of the plants for field planting by retainingthem inside rooting and hardening chambers.

The harvested cuttings are given immediate dip in fungicide solution beforesetting in root trainers filled with rooting media and placement inside the mist chambers.


Table 17. Rooting success in shoot cuttings with and without application of IBAPer cent rooting Species

No. of clone

W ithout IB A IBA (10,000 ppm) E. camaldulensis 7 10.71 23.57 Mysore gum 21 4.3 25.91 E. tereticornis 18 7.16 10.5 E. urophylla 3 17 24


The misting is regulated 120 s at every 15 minutes interval. A partial shade is createdfor the initial four to five days depending on the health and type of cuttings. Themisting regime is changed to 60 s at every 30 minutes interval after the cuttings haveproduced roots. Rooted cuttings are shifted to the open conditions after aroundfour week period of their placing in the mist chamber. The 0.5 per cent solution ofwater soluble NPK 19-19-19 is applied at weekly intervals during this period andthey are protected from insect pest and diseases, need based application ofcarbendazim, dithane M 45, trizophos/metasystox are also made. Applications offertilizers and nutrients to the plants, from which cuttings are collected, have positiveresponse on rootability (Table 18). It was also noticed that cuttings collected closeto ground level gave better rooting. Electricity failure for even a couple of hours,which is very common in many parts of the country, not only affects the cuttingproduction and propagation system but also causes heavy monetary losses byquickly desiccating the mother plants and cuttings in chambers. It is desirable tohave electricity genset of matching capacity for supporting the propagation facilities.

Based on operational level clonal production system, we have tried to groupthe commercially grown clones according to their rootability. Clones giving low anddelayed rooting, for example, BCM 288 is in demand in certain locations and wepropagate it as it is being demanded by the growers. BCM 413 show good rootingbut is highly delicate in term of its exposure to diseases and insect pests. Itsproduction is again decided by the growers than by the propagation facilities.

20. Studies on Other Aspects Having Bearing on Clonal Culture

20.1. Root Trainers, Media, Culling and GradingRoot trainers were introduced by Wimco Seedlings for the production of tree speciesduring the year 1985. These were manufactured by the company till 1993 from thehigh quality PPL/PPCP with a UV inhibitor and we were the sole proprietor in theirproduction and supply in India to the government and private sector agencies. Theactivity was outsourced during 1994 and, thereafter, it was picked up by manyprivate entrepreneurs for large scale production and sale. Presently, around 20 Mtrays each with (average 40 cavities) are manufactured and supplied annually whichindicates their volume presently used in nurseries including for cloning of eucalypts.

S. no. Classification Name of clone 1. Very easy to root (>90%) Wimco 12, K 25, BCM 413, BCM 2045 2. Easy to root (80-90%) Wimco 14, BCM 316, BCM 411, BCM 526, BCM 2070,

BCM 2023, BCM 2306, BCM 2135, K 23 3. Moderate to root (<80%) Wimco 15, BCM 288, BCM 2313

Table 18. Categorization of clones on the basis of their rootability

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A lot of nursery experiments on potting media for rooting and seedling productionled to zero down to a couple of them for operational propagation facilities. Initially,2 mm thick pebbles filled in the bottom heated beds were used for rooting eucalyptcuttings in the mist chambers. There was increased callusing at the base of cuttingsand this media was changed with Badarpur sand which was tried for a longer period.Rice husk, river bed sand and a couple of other media in pure form and in mixtureswere also tried, yet vermiculite and Badarpur sand are economically viable goodrooting media for getting higher rooting success in beds, however, vermiculite ofhorticulture grade was found to be very good for rooting cuttings in root trainers.For seedling production in root trainers, a composite mixture of soil, sand and compostin varying proportions was finalized for their healthy growth. The first field trial ofeucalypt seedlings and clonal plants grown in root trainers was established in theforest area during 1986 and had shown superiority over the seedlings grown in thepoly bags.

Grading of rooted plants is an essential operation for improving efficiency anduniformity of planting stock for field planting. All the planted cuttings do not root andsprout exactly at the same time and some variation in plant size during their rootingand shifting from chambers to hardening and/or open conditions is inevitable.Practically, grading of clonal planting stock is done during the shifting of rootedcuttings from mist chambers to hardening chambers or open conditions and alsowhen planting stock is delivered for field planting. It is routinely done to grade samesize plants in different block root trainers and maintain their stock separately. Undersizeplants in separate root trainer blocks are retained a little longer till they attain sizerequired for field planting. Culling of planting stock has been widely discussed forimproving the uniformity of planting stock in forest nurseries before their delivery forfield planting (Landis et al., 1990). It, however, does not appear to have much importancein clonal nurseries of eucalypts until there are off type plants of other unidentifiedclones in a lot which need to be culled. A very large number of culling trials oneucalypts planting stock carried out from 1985 onwards, with as high as 90 per centculling, did not provide significant and long term gains in plantation survival andgrowth. In one such trial with half-sib population conducted during 1985, there wasnon-significant effect on growth after 12 months of field planting, while in anothertrial, 0, 25, 50 and 75 per cent culling of seedling planting stock produced insignificantdifferences in height (369, 390, 378 and 389 cm) and diameter (3.13, 3.34, 3.28 and 3.26cm) growth, respectively at 18 months age. The trial was followed till 6th year in the fieldand confirmed that culling intensity has no influence on height, diameter and volumeof trees even at that age. Since the cost of production of rooted cuttings is muchhigher than seedling planting stock and also the undersize rooted cutting plants ifgraded and nurtured in different root trainer blocks perform equally good in the field,there is no necessity on this operation to discard undersize stock, if not damaged in



the normal production systems, handling and transportation. However, clonal stockproduced from mature mother plants of varying physical and physiological ages maynot perform similar to the rejuvenated ones and such rooted plants having muchdelayed rooting may not be used for establishing hedges for cutting production.

20.2. Screening Clones for Emerging Threat of Diseases and Insect Pestsin North IndiaWIMCO’s R and D Centre is located in the humid and warm Tarai region which isknown for high temperature and high humidity during summers, long rainy season(lasted between 15th June to 2nd week of October 2013), deep and moist alluvial soilswith high water holding capacity, and high water table together provide favourableconditions for multiplication and infestation of number of diseases and insectpests. Of these, the little leaf disease, CLB and gall wasp, have been invariablyrecorded in epidemic forms atleast on nursery stock causing heavy damage to eucalyptculture and their infestation is regularly monitored and documented.

CLB reoccurs almost every year whenever predisposing factors favour itsmultiplication and infestation on number of clones. The existing clones have beenscreened and according to disease and to draw strategies for developing newversatile and resistance clones along with some control measures to effectively handleits infection. The R and D locality received 2,382 mm rainfall during the year 2008,which was 52 per cent higher than yearly average and appeared to have created veryfavourable conditions for development and infestation of CLB. The existingcommercially grown clones were also rated against CLB infection as per methodsuggested by Kolte (1985). Categorization of clones according to mortality of plantsand disease rating followed almost the same pattern among the tested clones (Dhimanand Gandhi, 2012) (Table 19).

Categorization of clones according to the mortality due to infestation ofCLB indicated maximum mortality in clones belonging to E. tereticorniscompared to clones of other species. Data presented in Table 19 also revealedthat W 183, W 36 and WT 165 belonging to E. tereticornis had more than 80 per

Table 19. Categorization of eucalypt clones according to plant mortality due to CLBS. no.

Mortality (%) Species Clone/seedling

1. >80 E. tereticornis W 183, W 36, WT 165 E. tereticornis 316, W 104, WT 37, WB 7, WB 10, WB 4, WB 9,

WB 35 2. 70-80

Urograndis 2135, Unnamed E. camaldulensis 2045, 3, 7, K 25 3. 60-70 E. tereticornis WT 51, W 231, Seedlings E. camaldulensis 413 4. 50-60 E. tereticornis WB 33

5. <50 E. camaldulensis 411, 10

101

cent plant mortality whereas clone 411 and 10 belonging to E. camaldulensisrecorded less than 50 per cent mortality during humid and warm conditions inmonsoon months. Maximum disease rating was recorded in clone 2045 belonging toE. camaldulensis and clones W 36, WT 151, WT 37, WB 9, seedling population ofE. tereticornis, whereas, lowest disease rating was found in clones 316 and WB7 of E. tereticornis (Table 20).

Species S. no.

Disease rating E. camaldulensis E. tereticornis Urograndis

1. >4.0 2045 W 36, WT 151, WT 37, WB 9, Seedlings - 2. 3.0-4.0 413, 3, 10, K-25 W183, WT 165, W104, WB 10, WB 33,

WB 4, WB 35 -

3. 2.0-3.0 411, 7 WB 6, W 231 2135, Unnamed 4. 1.0-2.0 - 316, WB 7 -

Table 20. Categorization of eucalypt clones according to disease (CLB) rating


Table 21. Disease rating of CLB on different eucalypt clones

These studies led us to add recently developed clones for their screening againstthis disease. Most of the commercial clones grown in the locality along with newlydeveloped WIMCO’s clones were also included in the screening and productionsystem and were subjected to rating against CLB during 2011. That year againexperienced very heavy rains during monsoon season. A detailed monitoring of CLBon 10 clones comprising three of E. camaldulensis, two each of E. grandis, hybridof E. urophylla x E. grandis and hybrid of E. tereticornis x E. camaldulensis, one ofE. tereticornis along with a seedling population of E. tereticornis (control)indicated significant variation in disease rating. Unnamed clone and seedlingpopulation of E. tereticornis registered maximum disease rating, whereas, clonesWimco 14 and Wimco 15 recorded minimum disease rating as given in Table 21(Dhiman and Gandhi, 2012). This led us to shift our propagation to relatively lessaffected clones.

Little leaf on nursery and field planted young eucalypt trees in north India arebeing recorded by us since September 2010. It was first recorded on clone BCM 316and unnamed urograndis clone at Rudrapur. The disease is being mainly recordedduring summer and rainy seasons and gets subsidized in post monsoon season. Adetailed monitoring of the disease at Rudrapur, clones BCM 316, BCM 2135 and

Admin

Stamp


unnamed clone along with seedling population of E. tereticornis registeredmaximum infection, whereas, clones Wimco 14 and Wimco 15 registered minimuminfection (Table 22).

S. no.

Average no. of galls/plant

Clone

1. 2.0-3.0 BCM 411, K 25, WB 4, WB 9, WB 35, BCM 2135, BCM 3 and Seedlings of E. grandis

2. 3.0-4.0 BCM 10, W 183, WT 51, WB 6, W 231 and Seedlings of E. tereticornis

3. 4.0-5.0 BCM 7, BCM 316, W 104, WT 37, WB 7, WB 10, WB 33 4. >5.0 BCM 413, BCM 2045, WT 6, WT 165

Table 23. Gall infestation on different eucalypt clones during the year 2008

WIMCO conducted first ever exhaustive survey for the gall induction on eucalyptsgrown in the states of Punjab, Haryana, Uttar Pradesh and Uttarakhand (Dhiman et al.,2010). Survey confirmed widespread gall infestation on eucalypts of all ages andclones throughout these locations. Screening 24 clones belonging to three speciesalong with seedling population of E. tereticornis and E. grandis as a control at nurserystage during September and November 2008 indicated that clones BCM 413, BCM2045, WT 6 and WT 165 recorded higher gall infestation whereas clones BCM 411, K25, WB 4, WB 9, WB 35, BCM 2135, BCM 3 along with seedling population ofE. grandis recorded minimum gall infestation (Dhiman et al., 2010) (Table 23).

A detailed monitoring of gall infestation on planting stock of 10 clonescomprising three of E. camaldulensis, two each of E. grandis, hybrid of E. urophyllax E. grandis and hybrid of E. tereticornis x E. camaldulensis, one of E. tereticornisalong with a seedling population of E. tereticornis (control) during the year 2011indicated clones BCM 411, BCM 2045 and seedling population of E. tereticornisrecording maximum gall infestation, whereas, clones Wimco 14, Wimco 15, BCM 413,BCM 2135, K 25, and one unnamed clone have recorded minimum gall infestation(Dhiman and Gandhi, 2012) (Table 24).

A number of field and nursery trials conducted for monitoring these threemajor threats to eucalypt culture for developing resistance clones by us yieldeduseful information. Chemical control against these three threats has completely

Table 22. Little leaf infection on different eucalypt clones during the year 2011

S. no. No. of little leaf per plant Clone 1. <1.0 Wimco 14, Wimco 15 2. 1.0-2.0 K 25, BCM 2070 3. 3.0-4.0 BCM 413, BCM 411, BCM 2045 4. >5.0 BCM 316, BCM 2135, unnamed and seedlings of E. tereticornis

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failed. Some measures on improving nursery hygiene have though helped in keepingCLB under some check. Our new hybrid clones, viz., Wimco 14 and Wimco 15 haveshown almost total resistance to the above three notorious diseases and insectpests, their field trials have also shown comparable growth with some of theproductive clones. It is hoped that these new clones will help us in handling theseserious threats to clonal culture in future. These clones are now mass multipliedand supplied to the growers. The gall infestation has also been monitoredthroughout the year and in all aged plantations, We observed two crucial seasons,viz., March-April and September-October when maximum gall induction wasrecorded. Two natural parasitoids, viz., Quadrastichus mendeli and Megastigmussp. have also been procured and introduced from the Director of Biological Control,Bangaluru, Karnataka and released them in the nurseries and plantations in theTarai region of Uttarakhand during the first week of June 2010. The gall inductionand little leaf have marginalized during the last two years, though these are notunder total control. Both have resurfaced during this year (2013) pre-monsoonseason on number of clones. Little leaf and gall induction have changed thelandscape of some clones which were earlier propagated and supplied for fieldplanting. This includes many good clones, viz., 3, 7 and 10 from ITC and WB 4,WB 9 and WB 35 from WIMCO which recorded heavy infestation, have now beenreplaced with new clones. These two biotic factors are also responsible forexpansion in clonal culture in north India as a very large planting stock of seedlingorigin and that of a few other clones being highly susceptible has now beenreplaced with clonal material of relatively resistant clones.

Important technologies developed in the company include: budding and graftingfor mobilizing CPTs at centralized place and their applications in rejuvenation,hybridization work on grafted plants; application of root promoting IBA between4,000 to 10,000 ppm, controlled environment for rooting cuttings, rooting media androot trainers for growing clonal and seedling plants for field planting, and the semihard wood cuttings need retaining half cut pair of terminal leaves during the rootingprocess. Most of these findings from numerous experiments still hold good and arebeing applied for operational cloning of eucalypts in the country. Work on cloningeucalypts has been well recognized long back by others as well (Tewari, 1992; Nairet al., 1997). Many of these techniques including construction of mist chambers


S. no. Average no. of galls/leaf Clone 1. <1.0 Wimco 14, Wimco 15, BCM 413, BCM 2135,

K 25, unnamed 2. 3.0-4.0 BCM 316, BCM 2070 3. >5.0 BCM 411, BCM 2045, Seedlings of E. tereticornis

Table 24. Gall infestation on different eucalypt clones during the year 2011


were extended to many of the state forest departments, forest developmentcorporations, wood based industry and research institutes through consultancies.Root trainers are now the lifeline for cloning eucalypts and raising seedlings innumber of nurseries, especially with the private sector. WIMCO has also exchangedits clonal germpalsm and expertise with other wood based industries and researchorganizations to initiate similar programmes. We also got our 17 old clones, viz.,76102001,76102002, 82102051, 64103041, 73103081, 72103170, 72103176, 72103177,72103178, 72103201, 72103215, 7210322, 72103254, 72103256, 72103280, 72103284,72103294 for pulp and paper characteristics in a paper factory in Haryana during1991 which concluded that two clones, viz., 82102051 and 72103284 were excellentfor paper production as the first one was capable of producing pulp with muchbetter strength and the second was capable of producing 3 per cent more pulp yieldthan the market procured pulpwood. Further, the rooting ability of clone No. 82102051(first in this case) was over 95 per cent. This study at that time confirmed thatcommercial clones need to be outstanding in biomass production, better in coppicing,rooting and also in their end use.

21. DiscussionThe method of vegetative propagation varies with the purpose of propagation. Use ofstem cutting is the most common means used for mass multiplication of selectedclones at operational level, whereas, budding/grafting is an effective tool for assembling,rejuvenation and building up the limited stock of some clones. Other means like layering,lignotubers and tissue cultures have also been used to a limited extent that too on trialbasis. Cloning helps in and effective use of genetic resources to produce clonal plantingstock for specific production sites, maximize timber production in quality and quantityby maintaining the genetic traits, better precision in yield forecasts, efficient biomassproduction through effective utilization of land resources, increased profits fromclonal trees, fast salvation of biomass production potential by inducting resistant andproductive clones in case the existing ones develop serious susceptibility to certainbio-agents, and homogeneous raw material production for improving efficiency andeconomy in quality product manufacturing. Cloning of eucalypts as a mean for largescale production of planting stock for field plantations was started in the Republic ofCongo in 1975 (Delwaulle et al., 1983), followed in Brazil from 1979 (Campinhos andIkemori, 1983) and thereafter expanded to many countries including India. Brazil drewwide appreciation for its large scale eucalypt clonal culture for production of pulpwood.Eucalypt culture in India and Brazil draws some similarities and comparisons. Bothcountries occupy first and second slot in eucalypts culture with 3.924 Mha and 3.752Mha, respectively (http://git-forestry.com/download_git_eucalyptus-map.htm) and,therefore, are leading nations in eucalypt plantations and the clonal culture is stillexpanding in both the countries. Brazilian clonal programme is older and undertaken in

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vast captive plantations, initially based on E. grandis clones but is now expandingwith those developed from other species and their hybrids, mainly promoted forpulpwood production, focussing on cellulose productivity per unit area which hasimproved from 6 t ha-1 yr1 with initial clones to 12 t ha-1 yr-1 with new clones and isexpected to reach about 16 t ha-1 yr1 with new hybrid clones (McNabb, 2002). Indianeucalypt clonal culture is based on clones initially developed from E. camaldulensisand E. tereticornis and is now fast expanding with those developed from other speciesand hybrids, is largely grown by small growers on their farm land with or withoutintegration of agricultural crops. The eucalypts in India are finding a place inmanufacturing panel products, including MDF, particle boards, veneer in addition topulpwood, etc. However, paper industry is working on clonal selection for efficientpulpwood traits (Kulkarni, 2004). Brazil had a typical planting programme of raising5,000 to 15,000 ha yr-1 during the start of last decade (McNabb, 2002). Indian clonalprogramme during that period was almost at the same level but since then it has fastexpanded especially after the seedling plantations became highly susceptible to gallinduction, little leaf and CLB infestations. India is presently planting an estimated 0.2Mha clonal eucalypts annually and is now a leading country in its clonal culture in theworld. The state of Andhra Pradesh has now developed as a hub for production ofclonal planting stock through small nursery growers who are supplying it across thecountry. This experience of producing clonal eucalypts that was initiated by some ofthe ex-ITC staff is also finding expansion in north India where many individuals arepresently developing a chain of propagation chambers.

Rooting of cuttings is the main vegetative method used for eucalypt cloning. Thesuccess in rooting of cuttings depends on clone type, season of taking and plantingthe cuttings, physiological status of the cuttings and mother plant, management ofcutting production systems, the age and size of the cuttings, the presence of leaves,their treatment with root promoting substances and the environmental conditionsinside the propagation chambers. Technological innovations helped in developingoperationally feasible methods for its mass multiplication and for their application inlarge scale clonal forestry. The old method of using coppice sprouts from tree stumpsfor making cuttings is under replacement with efficient cutting production systems inmacro and mini hedges. Budding and grafting are still effective to mobilize mature treesby taking first vegetative propagules without felling trees and their role will furtherincrease in hybridization work. The initial success in rooting the cuttings was achievedwith application of the root promoting hormones at the base of cuttings. Indole-3-butyric acid (IBA) in liquid and powder formulations with concentrations varyingfrom 4,000 to 10,000 ppm have been extensively used for this purpose. The use of IBAis now declining with mini cuttings in many Eucalyptus species and clones but is stillrecommended in some others (Brondani et al., 2012). More recently, it is also beingapplied in gel form (Brondani et al., 2008). In some countries especially in Brazil, the



cutting production system in tissue culture labs has also been effectively used forproduction of micro cuttings for their use in rooting in mist chambers (Assis et al.,1992). In micro cutting method, propagules are obtained exclusively from shoot apicesoriginated from micropropagated plants. Whereas, in mini cuttings, these could befrom axillary sprouts or apex shoots of rooted stem cuttings. The combination oftissue culture techniques with indoor hedges result in a number of significantimprovements in the production of planting stock, rooting efficiency, and uniformstock production resulting in more vigorous and uniform plantations. Mini cuttingproduction system and its use is slowly overcoming the technical, infrastructural,economic and operational limitations of micro cutting (micropropagation technique)that has been in use in Brazil and some other countries (Assis et al., 1992; Brondani etal., 2010a).

Mini cutting production system in indoor and outdoor mini-hedges in hydroponicand semi hydroponic systems in sand culture with intensive management has improvedefficiency in rooting, economy and operations. Some variants of mini cutting productionsystem have been applied for some tree species in India (Joshi and Dhiman, 1992, 1994;Dhiman, 1998) but are now being extended to eucalypts in the country (Bindumadhavaet al., 2011, Shanmugam and Seenivasan, 2012). There will always be a space for usingapex shoots of rooted plants which are still maintained in mist and hardening chambers,for one or two cycles for making cuttings in case of over production of some clones,building up of stock of those clones which have developed shortage in case of first timeintroduced clones. This system of collecting apex shoot cuttings from intensivelymanaged container grown stock plants rather than originating from field sprouting stumpsis also being advocated in some other countries (Mankessi et al., 2010). The continuouscoppicing of hedges result in harvesting cuttings of a variety of physiological ages andsizes (Xavier and Comerio, 1996). It is established that over a period of time, hedgesdevelop stress, the degree of juvenility begins to vary, they produce week shootsresulting in reduced rooting success, increase variability in rooting time, and increasedrejection. All of these result in higher production costs and lower planting stock quality.There are no long term studies to maintain the quality of cuttings from such hedges forrooting success and field performance. Such hedges are, therefore, constantly replacedwith new plantings at regular intervals which may vary to a few years.

Similarly, change is also taking place in propagation facilities in the country. Themajority of the infrastructure facilities used for rooting the cuttings in the past werehaving shade and mist system which are now being replaced with an automaticenvironment control system inside chambers. These are helping a great deal inoptimizing rooting time, and in maintaining appropriate humidity and temperature toavoid desiccation and rotting of cuttings with extremes of temperature and humidity.Clonal culture has undergone a significant transformation from a first mist chamber ofless than 100 m2 that was installed in Wimco Seedlings in 1984 to a single propagation

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facility spread over 12 ha capable of producing 25 M plants in ITC and further to alarge scale small growers adopting it as a mean for self employment especially in thestate of Andhra Pradesh. The root trainer technology has developed better synergy inrooting the cuttings and for developing the planting stock for field planting. There aresearches for newer root trainers and rooting media for effective use of space of costlyrooting chambers with improved rooting and clonal plant production. Discovery oflow cost coco-coir peat as rooting media for facilities located in south India is certainlya favourable development and the search for a few others is still going on.

The genus Eucalyptus represented by around 600 species with a very wide geneticvariability, ecological adaptability, resistance/susceptibility to diverse biotic and abioticagents, and breeding and reproductive systems provide enormous opportunity in itsculture on diverse land use in India and elsewhere. Its clonal forestry, based on narrowgenetic base, has already demonstrated much devastating effect on productivity andeconomic loss to growers from the recent outbreak of diseases and insect pests. Seedorigin eucalypt plantations from out-crossed populations are still very large in extentand genetically diverse as a result many individuals still survive against such threats.The recent three threats, viz., gall induction, little leaf and CLB have virtually createdhavoc in eucalypt culture including that in clonal plantations of susceptible clones inmany parts of the country. It has been amply demonstrated that seedling origin plantationshave shown wide range of individuals from no infection to highly susceptible types tothese threats and therefore there is always some salvage of productivity from traditionalseedling plantations in comparison to clonal eucalypts. The effect of the first two hasbeen wide spread and that of the third one specific to the warm and humid conditions atspecific locations. The impact of CLB infection is serious in Tarai region but has littleimpact a few kilometre away in Bhabar region in north India mainly due to local climaticconditions. All possible measures which include chemical and biological controls havemiserably failed in keeping their infection under control. Development of new relativelyresistant clones and their inclusion in the production system has helped in salvaging theclonal culture in the country. The research on these threats needs to be coordinated andcontinued for averting any such threat in the future.

Clonal eucalypts with tall, clear bole, narrow crown even at a relatively shortrotations and under relatively dense stands are more impressive in appearance thanthose from many other species in plantations and forests. Eucalypt clonal plantationshave been established since mid-1980s but its commercial plantations took practicalshape during the last two decades. In many locations where seed origin plantationshave been grown since long, new clonal plantations have started yielding betteryields and returns. In many other locations where tree culture with other specieswas already well established and more remunerative, some parties started itspromotion indicating that it will provide better returns than existing trees. This hasbeen a specific case in north India where poplar culture was well established and



many leading farmers who had earned better returns from poplar culture were temptedto plant clonal eucalypt on fertile farm land. Some of them have now harvestedclonal plantations and realized that clonal eualypts fall short in economic returnsand in its integration with intercrops than poplars. Integration of eucalypts withintercrops in block plantations is notional and resticted to the initial tree growth forone to two years with chilli, cotton, groundnut, turmeric, vegetables, etc. in southIndia, and wheat, sugarcane, fodder, vegetables, etc. in north India. There havebeen efforts to plant eucalypt in pair rows to provide larger strip between tree rowsfor cultivation of agricultural crops (Kulkarni, 2013b). However, many farmers inpoplar growing region still plant clonal eucalypts as their management is simple,less troublesome and demand for its wood is increasing beause of scarcity of theraw matrial for wood based industries. There have been some instances in the pastwhen the prices of poplar wood crashed in the market and many farmers shifted toeucalypt culture. Shifting crops which fetch higher prices from tree and farm produceis a common phenomenon in agriculture crop production in the country.

Handling propagation facilities and fresh plantations with clonal planting stock ishighly sensitive. Eucalypts are largely planted during monsoon season. Some growerswith assured irrigation facilities on farm land also plant it throughout the year. In certainlocations, it is desirable to shift production and planting of specific clones for specificseasons. For example, in some humid and warm locations of north India, widespreadinfestation of CLB kills lakhs of plants in nurseries and young field plantations duringheavy monsoon season. Though clone 413 is much demanded for planting, it is highlysusceptible to CLB. It is desirable to use resistant clones during this season or shift thepropagation cycle and field planting during pre- and post-monsoon seasons to avoidlarge scale damage to eucalypt nurseries and plantations from such threats.

The physical appearance of the clonal planting stock could mislead its silvicultualquality and may seriously affect its field performance. Many nursery growers areusing excessive nitrogenous fertilizers to boost the early growth immediately afterrooting in order to get the plantable size. Nitrogen rich stock is sensitive to the extremesof weather conditions, viz., desiccation to hot and dry weather, and infection to CLBduring humid season. It is also learnt from the market sources that some of the growersare keeping the root trainers on nutrient rich media soon after their shifting outsidechamber; these get fast growth, shifted on the stands for some time before dispatch tothe growers. Clonal plants during lifting for field planting need not to be excessivelyflush green by heavy application of nutrients especially nitrogenous fertilizers.

Effective plug formation in clonal stock raised in root trainers is extremelyimportant factor for making successful field plantations. When demand exceedsavailability, many nursery growers are passing on the planting stock to the growerssoon after shifting it from the chambers. This may be a stage when the developingroot system has yet not formed an effective plug. Plug is a stage when the root mass

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completely encircles the potting media and the plant gets easily extracted withoutdamage to its root system. While taking supply it is better to extract a couple ofplants from root trainers and ensure if an effective root plug is formed or wait forsome more time to avoid damage to the field planted stock. Over-stay of plants inlimited volume size root trainers is also not desirable as it blocks the bottom hole andfurther root development does not take place (Fig. 5). Such plants develop rootsystem with deformities similar to polythene bag grown seedlings.

Lodging of fast growing clonal origin saplings at one to two years age in thefield is a normal phenomenon observed with clonal eucalypts in many parts of thecountry (Fig. 5). In many cases farmers stack the stock by investing additional coststo straighten the lodged plants. The problem is more acute in case of close plantedclonal eucalypts where plants remain lanky and easily bend with gentle winds.Some eucalypt clones planted in sub tropical and plains near the Himalayan foothillsduring post monsoon seasons are heavily damaged by the frost. Presently, most ofthe clones grown in this region have been developed in south India where suchinjury does not occur due to tropical climatic conditions. Some hybrids betweenE. benthamii and E. dunnii are better suited to cold regions of Latin America (Assisand Mafia, 2007; Brondani et al., 2010b). The old WIMCO’s clones which weregrown in north India have now been taken out of production due to excessive gall,little leaf and CLB infection. Efforts are going on to develop new clones to handlefrost injuries that occur on recently introduced clones from south India. In the meantime, plantation of such clones during late autumn season should be avoided asmore damage is recorded on young plants than older ones.

Panel industry has accepted eucalypts for peeling, MDF, and particle boards anda very large quality of eucalypt wood is now finding usage for these products. Forpeeling, circularity of the stem for its conversion to veneer is extremely important. Astrong feeling has developed among eucalypt growers and users that clonal eucalyptsproduces trees with sunken and flat stems with cracks and these are not very suitablefor peeling (Fig. 5). Cracks on freshly felled logs could be effectively handled bytransporting the logs soon after felling to the wood working units for their immediatepeeling. However, flat and sunken stems in certain clones and in certain locations givevery low veneer yields and there is a need for finding solution to such defects.

Highly productive clonal eucalypt culture needs matching cultural and otherinputs to harness its true potential. Planting clonal eucalypt with low managementintensities on forest land is not as rewarding as that with high managementintensities on farm land. There is no precise recommendation on size of plantingpits for clonal eucalypts grown in root trainers and planted on well ploughedfields. Excessive termite attack on certain sites especially those located on sandysoils during monsoon and pre-monsoon seasons needs repeated drenching ofplants and soil around it with anti-termite chemicals. There have been some cases



of putting excessive fertilizers around the small pits surrounding the root plug ofplants during planting that has reported to cause mortality in such plantations.

22. ConclusionEucalypt clonal culture in India was introduced with vegetative propagation ofcandidate plus trees selected from the old plantations. It got well established withclones developed from selections made from numerous species and seed sourcetrials, and is now fast expanding with those being developed from inter- and intra-species hybrids. Clonal technology during its evolution also saw transformationfrom making cuttings from coppice shoots obtained from stumps trees, to usingmacro cuttings from outdoor clonal banks/CVMs/CMAs and, finally, using minicuttings from indoor and outdoor mini hedges. Similarly, propagation facilitieswitnessed changes in simple misting chamber to self controlled and regulatedenvironmental conditions inside mist chambers and hardening polyhouses, andalso in potting media and root trainers. Infestation of gall insect, little leaf and CLBhave posed new challenges to eucalypt culture but has also helped in expandingclonal culture by replacing seedling planting stock with relatively resistance clonesto these insects and diseases. The future of eucalypts clonal culture appears to bevery exciting in the country in view of chronic shortage of wood for industrial anddomestic use and eucalypts fast occupying the space for wood production. Thecontribution of private sector and small growers in this venture is undisputedlysignificant and the future synergies between research institutes and private sectorresearch would further strengthen its culture in India. It also needs some policy andinstitutional reforms for providing a favourable environment for sustaining andfurther expanding its culture and usage.

AcknowledgementThe initial work on eucalypt improvement and cloning in WIMCO/Wimco Seedlingswas done by Dr. J.P. Chandra. His contributions in the subject are duly acknowledgedby the authors.

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spp. (E. grandis and E. globules) through tissue culture. In: Dhawan, V.;Ganapathy, P.M. and Khurana, D.K., Tissue culture of forest tree species:Recent researches in India. New Delhi, IDRC-TIFNET. pp. 31-47.

Kumar, R. and Bangarwa, K.S. 2011. Genotype x Environemnt interatcion amongdifferent clones of Eucalyptus tereticornis Smith. Indian Journal ofEcology, 38(spl. issue): 110-112.

Landis, T.D; Tinus, R.W.; Mc Donald, S.E. and Barnett, J.P. 1990. The container tree nurserymanual. Vol. 1-5. Agriculture Handbook No.; 674. Washington DC, USDA.

Piare Lal. 2011. Clonal agroforestry plantations in India. In: IUFRO Symposiumon Short Rotation Forestry: Synergies for Wood Production and


Environmental Amelioration, Ludhiana, 10-12 February 2011. Proceedings.pp. 69-70.

Leakey, R.R.B. 1987. Clonal forestry in the tropics - A review of developments,strategies and opportunities, Commonwealth Forestry Review, 66(1): 61 -75.

Mankessi, F.; Toto, A.R.S.; Toto, M. and Monteuuis, O. 2010. Propagation ofEucalyputs urophylla x Eucalyptus grandis clones by rooted cuttings:Influence of genotype and cutting type on rooting ability. Propagation ofOrnamental Plants, 10(1): 42-49.

Matthews, J.D. 1996. Silvicultural systems. Oxford, Oxford University Press.McNabb, K. 2002. Clonal propagation of Eucalyptus in Brazilian nurseries. In: Forest

and Conservation Nursery Associations. National proceedings: Forest andConservation Nursery Associations - 1999, 2000, and 2001. pp. 165-168.

Mishra, A. 2004. Clonal forestry - A boon to growers. In: Parthiban, K.T.; Paramathma,M. and Neelakantan, K.S. Eds. Compendium on clonal forestry. Coimbatore,NATP-FCRI Publication. pp. 185-192.

Mohan, V. and Manokaran, P. 2013. Assessment of disease problems in differentclonal plantations of Eucalyptus spp. in South India. Journal of Academiaand Industrial Research, 1(9): 514-524.

Muralidharan, E.M. and Pandalai, R.C. 2000. Assessment of field performance ofmicropropagated teak and eucalypt. KFRI Research Report, 182. Peechi,KFRI. 21p.

Nair, K.S.S.; Chundamannil; Chacko, K.C. and Iyer, S.C. 1997. Private sector involvementin forestry research in India. KFRI Research Report, 121. Peechi, KFRI.

Nanda, K.K. 1970. Investigations on the use of auxins in vegetative propagation offorest plants. Final report of PL-480, Research Project, A7-FS-11. 215p.

Palanna, R.M. 1996. Eucalyptus in India. In: FAO. Reports submitted to the regionalexpert consultation on Eucalyptus. Vol. 2. Bangkok, FAO Regional Officefor Asia and the Pacific. 280p

Paton, D.M.; Willing, R.R.; Nicholls, W. and Pryor, L.D. 1970. Rooting of stem cuttingsof Eucalyptus: A rooting inhibitor in adult tissues. Australian Journal ofBotany, 18: 175-183.

Prathiban, K.T.; Paramathma, M.; Sriram, J.; Malathi, N. and Madheswaran, .M 2004.Clonal forestry approaches for the improvement of industrial wood species.In: Parthiban, K.T.; Paramathma, M. and Neelakantan, K.S. Eds. Compendiumon clonal forestry. Coimbatore, NATP-FCRI Publication. pp. 84-91.

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Shanmugam, P.S. and Seenivasan, R. 2012. Standardization of mini cutting clonalpropagation technique in Eucalyptus camaldulensis and E.terticornis spp.2012. Indian Forester, 138(4): 333-338.

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Sharma, J.K.; Balasundaran, M. and Florence, E.J.M. 2001. Establishment of a semipermanent field clonal propagation unit for Eucalyptus. KFRI ResearchReport; 204.

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1. IntroductionAs the global population grows and areas of native forest decrease, particularly indeveloping countries, tree plantations and agroforestry have become an increasinglyimportant source of timber, fuelwood and raw materials for pulp and paper. Eucalyptsare now being widely used throughout the world for wood, pulp and other treeproducts. Eucalypts are highly productive and well adapted to dry, infertile sites,and are important for degraded land that are no longer suitable for agriculture. Theyalso contribute in protection of land and water systems. In Asia, particularly inIndia, China, Vietnam and Thailand, eucalypt plantations support major industriesand contribute to alleviation of rural poverty.

Existing forests in India cannot meet national demand for firewood, timber andwood based products on sustainable basis because of low growing stock, poorincrements, inadequate financial and technological inputs, unbearable bioticpressures and serious degradation of forest resources (Piare Lal, 2010). Per hectaregrowing stock in forests in India has been estimated at around 69 m3 ha-1 for the year2005. It is significantly below the global average of 110 m3. The productivity ofIndian forests is low; i.e., 0.7 m3 ha-1 against the world average of 2.1 m3 ha-1. Evenplantations raised provide less than their potential. India is world’s biggest consumerof fuel wood with 40 per cent of the population dependent on fuel wood for basicenergy needs with a total demand in the range of 200-230 Mt. It is estimated that 100-115 Mt of fuel wood is extracted from natural forests, which is almost 6 to 7 timeshigher than the estimated sustainable supply of 17 Mt from the forests. Thisunsustainable exploitation leads to degradation of forests. Similarly, the requirementfor timber was estimated at 54.94 Mt for 2006. On the supply side, an estimated 28.81Mt is contributed by farm forestry, 9.38 Mt is harvested from forests and 2 Mtimported. That still leaves a gap of 14.74 Mt, much of this is exploited from forests.India is the fastest growing market for paper globally and the paper consumption isestimated to touch 13.95 Mt by 2015-16. Since the wood based industry in India is

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mainly plantation based, it is essential that more land must be brought underproductive plantations of trees species suitable for the making of paper for meetingthe future requirements.

In the present scenario when the demand of wood and wood-based productsis increasing day by day, interest is being concentrated on growing short rotationspecies to bridge the gap between the growing demand and inadequate supply ofwood. Eucalypts provide major raw material for the pulp and paper industries inIndia, so it is imperative that planting stock of high genetic quality be used toincrease the yield from plantations (Varghese et al., 2008). The pulpwood shortagein India created the need for quick growing species. The biggest single urge toplant eucalypts in large scale plantations was provided by the demand for woodfibre for the paper industry (Shiva et al., 1981). Achievements in genetic yieldimprovement of forest tree species have been less spectacular than that inagricultural crops because the forest tree species are more difficult to breed thanagricultural crops and due to their long generation times, prevalence of out breedingand the operational difficulties. These problems have restricted the large scale,commercial breeding of eucalypts and other forest tree species to random matingof selected trees on very limited experimental scale only as in seed orchards. Thereis a scarcity of information on realized gains from eucalypt improvementprogrammes in the country.

2. Historical BackgroundThe eucalypt tree originally came from Tasmania (Australia) and other Indo-Malaysian islands. There are approximately 700 species of eucalypt, all with greatenvironmental value; 37 of these species are of interest for the forest industry whileonly 15 are used for commercial purpose. Eucalyptus deglupta and E. urophylla arethe only two species not occurring in Australia.

Eucalypt was first planted in India around 1790 by Tipu Sultan, the ruler ofMysore, in his palace garden on Nandi hills near Bangalore. According to oneversion he received seed from Australia and introduced about 16 species (ShyamSundar, 1984). The next significant introduction of Eucalyptus was in the Nilgirihills, Tamil Nadu, in 1843, and later (1856) regular plantations of E. globuluswere raised to meet the demands for firewood (Wilson, 1973). E. tereticornis anda form of E. tereticornis known as Mysore gum (thought to be a hybrid) are themost widely planted eucalypts in India. This Eucalyptus hybrid represents abouthalf of the eucalypts planted in many parts of India (Jacobs, 1981), and is believedto be derived from one small stand of E. tereticornis the early introductions inNandi hills (Pryor, 1966; Chaturvedi, 1976). Lack of sufficient genetic variability(Ginwal et al., 2004 a, b) is one of the important reasons for low productivity ofeucalypt plantations in India as compared to other countries because this restricts

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the intensity of selection in insufficient base population. There are severalreasons for raising eucalypts under large scale plantations in India; some arecommon and some are specific to the region. The most important common reasonis production of wood for fuel, poles, construction and pulp.

The early introduction of E. camaldulensis and E. tereticornis to India werefrom southern temperate localities in Australia rather than the northern tropical regionswhere the climatic conditions closely resemble the areas available in India because ofthe inaccessibility and difficulties in collecting seeds (Boland, 1981).

3. Eucalypt Improvement in IndiaThe natural forests of the country are under pressure of depletion largely on account offirewood needs of the ever-growing population. If the gap between demand and supplyof firewood is not made up, it will further result in loss of natural tree cover. There is aneed to plant fast growing species to bridge the gap. Eucalypts had played a great rolein past to rescue the situation. However, the productivity of eucalypts is very poor inIndia, which is only about 10 to 15 m3 ha-1 yr-1 (Chaturvedi, 1973; Venkatesan et al., 1986).Consistent tree improvement efforts are, therefore, required to address this challenge.

Considerable efforts have been made in domestication and improvement ofeucalypts in India. A systematic genetic improvement programme for Eucalyptusin India was coordinated by Forest Research Institute, Dehradun (FRI) andInstitute of Forest Genetics and Tree Breeding, Coimbatore (IFGTB). However,few pulp and paper companies particularly ITC Ltd. initiated a pioneering workin tree improvement of eucalypts and commercial deployment of the productiveclones. Besides many state forest departments joined their hands in evaluationof the eucalypt germplam and clonal testing in the country. The overall objectiveof the tree-improvement programme was to identify species and/or provenancesor the genotypes worth planting. The following are the major areas where treeimprovement initiatives on Eucalyptus have been taken up with success:

• Introduction of species and their provenances• Evaluation and identification of adaptable and productive provenances of

successful species• Identification/selection of superior phenotypes• Clonal reproduction/propagation, testing and selection• Establishment of seed orchards and production of quality seeds• Development of hybrids through controlled crossing and their evaluation• Establishing breeding populations

4. Eucalypt Breeding SystemThe genus Eucalyptus belongs to family Myrtaceae and comprises about 700 species/varieties (Eldridge et al., 1994). The somatic chromosome number in eucalypt is 2n =

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22. It is a cross pollinated species resulting in wide variation and heterozygosity inthe population. However, the reproductive system of eucalypt offers ampleopportunity for self-pollination (Eldridge et al., 1994).

Eucalypt species normally develop chasmogamous flowers that are availablefor outcrossing and very rarely cleistogamous flowers that are obligately self-fertilized (Venkatesh, 1971; Venkatesh et al., 1973; Eldridge et al., 1994; Sharma etal., 2005). Chasmogamous flowers open and expose the stamens and styles to theenvironment. This allows the flowers to cross-pollinate with another individual.However, in cleistogamous flowers, the opercula show an unusual tardiness inshedding. They separate from the floral receptacle as usual, but do not shed andremain sitting on the styles even after withering and fruit formation. Selfing oroutcrossing of a species is both genetically and environmentally controlled (Fryxell,1957). The effects of selfing (other than cleistogamy) in eucalypts have beenreported. These include reduced seed set (Pryor, 1976; Griffin et al., 1987; Pottsand Sava, 1988; Tibbits, 1989), decreased germination per cent (Eldridge, 1978;Eldridge and Griffin, 1983), increased frequency of abnormal phenotypes (Hodgson,1976; Potts et al., 1987), depressed field growth and vigour (Eldridge and Griffin,1983; Potts et al., 1987; Griffin and Cotterill, 1988) and decreased nursery and fieldsurvival (Eldridge and Griffin, 1983; Potts et al., 1987). However, there are only afew reports, which indicate evidence of natural selfing due to cleistogamy ineucalypts (Venkatesh, 1971; Venkatesh et al., 1973). These reports are based onthe observations recorded on a single standing tree, that too only at seed andcapsule setting stage, and reflect less seed and capsule setting in the cleistogamousflowers than chasmogamous flowers.

In the year 2002 a provenance cum progeny trial of E. tereticornis comprising13 provenances and 91 families of Australian and Papua New Guinea (PNG) originwas established in the campus of FRI. Out of 91 families, one family (DS 000141)emanating from the CSIRO seed lot no. 13418 was spotted with cleistogamous flowers,while the other adjoining trees of different seed sources growing at the same siteshowed normal chasmogamous flowers (Sharma et al., 2005). This preliminaryobservation was made at an early age of 18 months when few trees of this familyshowed flowering. The effect of forced selfing, was examined in this family after 48months of field planting (Ginwal, 2010). Severely depressed seed set, germinationper cent, field growth and survival in relative comparison to other outcrossing familieswere noticed. Inbreeding depression were noticed in growth traits, viz., height, cleanstem height, DBH, branching and survival per cent, which increased with age.

The apparent presence of such forced self-families, in open-pollinated familieshas several implications for the management of tree improvement programmes. Ifseeds from open-pollinated seed orchards are used to establish new plantations,potentially achievable rates of gain may be compromised (Hardner and Potts,

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1995). The management of breeding populations has tended to avoid inbreedingbecause of its deleterious effects. The results revealed that cleistogamy inE. tereticornis causes severe reduction in growth and survival in plantations andmay lead to severe loss in productivity of wood. Hence a cautious approach maybe adopted while making selections for tree improvement and collection of seedsfor plantation programmes.

5. Species and Provenance TestingSpecies and provenance testing is a means to exploit effectively the existing naturalvariation for tree improvement programmes. Considerable species and provenancetrials were conducted between 1979 and 1983 with 58 species of eucalypts (Chaturvediet al., 1989). The initial results revealed that provenances of only two species,E. camaldulensis and E. tereticornis, performed well under rainfed conditions onthe plains of India, so later trials concentrated on 32 provenances of the formerspecies and 14 of the latter, tested at various locations. Several provenances of bothtest species performed better in height and diameter growth but none performedconsistently well in all experiments. Furthermore, none were resistant to the heavyfungal attack on E. camaldulensis (principally by Botryodiplodia spp., Corticiumsalmonicolor and Cylindrocladium spp.) which occurs in the region.

Similarly, some 170 species of eucalypts and provenances of few species weretried in India (Bhatia, 1984), out of which the most outstanding and favoured hasbeen the E. tereticornis and a form of E. tereticornis called Eucalyptus hybrid,popularly known as Mysore gum (Kushalappa, 1985). Other species which weregrown on plantation scale were E. camaldulensis, E. citriodora, E. globulus andE. grandis during this period.

Even though eucalypts are grown extensively in Tamil Nadu, research onidentification of provenance was not initiated until 1982. In that year, 15provenances of E. camaldulensis and 14 of E. tereticornis of Australian originwere evaluated at Pudukottai, a predominantly eucalypt growing district in TamilNadu, as part of an IUFRO trial (Kumaravelu, 1995). Three provenances ofE. tereticornis (Laura River, seed lot no. 10975 and 11953; Mt Garbine, seed lotno.13013 and Kennedy River seed lot no. 12947) and five of E. camaldulensis(Katherine, seed lot no. 12181; Richmond, seed lot no. 13008; Gibu River, seed lotno.12346; Gilbert River, seed lot no. 12963 and 12986) were found promising.Provenances of E. cloeziana were evaluated for five years in a high rainfall zone(2,000 mm to 3,500 mm) of Western Ghats (Manaturagimath et al., 1991). TheNorth-West of Cardwell QLD, provenance, showed the best performance in height,DBH and volume followed by South East of Gympie QLD.

Most eucalypt plantations across India are of Mysore gum, a land race consideredto be a mixture of pure E. tereticornis and genetic segregates of inter specific hybrids,


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displaying high variability (Kaikini, 1961). The growth of Mysore gum is quite slow,with mean annual increment of plantations averaging around 7 m3 ha –1 (Chandra etal., 1992), and a number of trials have demonstrated superior performance of certainnew eucalypt introductions (Varghese et al., 2001, 2008) or selected eucalypt clones(Piare Lal , 1993).

Pulp and paper company ITC Ltd. initiated a pioneering work in commercialdeployment of the productive clones for the pulp wood production. ITC importedseeds of various provenances of eucalypts from CSIRO (Australia) in the years 1986,1990, 1994 and 1995. The company established provenance trials in southern part ofthe country. Plus trees of E. camaldulensis and E. tereticornis were selected fromsuch provenance trials. Selected plus trees were propagated vegetatively from coppicecuttings in mist chambers. Root trainer technology was adopted for the production ofplants. The successful ramets were planted in gene banks. Promising clones wereshortlisted for growth, disease resistance and pulp and paper qualities. Clonal seedorchards (CSO) adopting the permutated neighbourhood design (Sekar et al., 1984)were established.

In 1995, IFGTB initiated a coordinated programme for eucalypts with freshintroductions of a wide genetic base from natural provenances of these species(Doran et al., 1996; Varghese et al., 2008). Provenance resource stands (PRSs) ofthree Queensland provenances of E. camaldulensis, Kennedy River, MoreheadRiver and Laura River (Doran and Burgess, 1993) were planted using bulked seed ofthese individual provenances. Progeny trials were established using family seedlotscollected from selections made in existing southern Indian provenance trials of bothspecies (Varghese et al., 2001). At the same time, new provenance-progeny trials ofE. camaldulensis were planted at three locations to establish a broad, pedigreedgenetic base for the breeding programme. Smaller progeny trials of E. tereticorniswere also planted. These trials were evaluated to identify suitable provenances fordifferent locations (Varghese et al., 2000). After evaluation, the trials were selectivelythinned for conversion to first generation seedling seed orchards (SSOs). The SSOs,SPAs and PRSs incorporate many thousands of trees of known natural provenance.Together, they comprise a large base and breeding population for geneticimprovement of E. camaldulensis and E. tereticornis in southern India (Varghese etal., 2008). Apart from the production of high-quality seed and ongoing geneticimprovement of the breeding populations, the improvement programme alsoenvisages deployment of outstanding individual selections in clonal plantations.

FRI initiated establishment of seed source evaluation trials of E. camaldulensisand E. tereticornis at various locations in northern part of the country. Similarly, ina provenance trial of E. camaldulensis, six seed sources from Australia were evaluatedat Seothi (Haryana), a semi-arid region of India. At the age of eight years, two seedsources, viz., Emu Creek Petford, QLD and Laura River, QLD ranked first and second

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for height and survival (Ginwal et al., 2004b). Similarly, provenance trials with 14provenances in E. camaldulensis conducted at two locations in drier tracts of Shimogadistrict by the Mysore Paper Mills Ltd., Shimoga also revealed that Emu Creek,Petford. QLD, Irvine Bank, QLD, Gibb River, WA, and Katherine, NT had promisinggrowth rates (Chandra et al., 1994).

Thirteen provenances of E. tereticornis representing 91 families from Australiaand Papua New Guinea were evaluated up to the rotation age; i.e., 10 years in acombined provenance-progeny test established at three locations. In general thenorth Queensland provenances performed better and in particular two provenances,viz., Walsh River, QLD and Burdekin River, QLD ranked the best. The performance oflocal seed source was inferior to the Queensland provenances. No geographic clonalvariation pattern was observed. Age-age genetic and phenotypic correlationsbetween heights and diameters were highly significant and positive. Heritability(narrow sense) values were intermediate for height and diameter at breast height incomparison to number of branches and clean stem height. The relative performanceof the top ranking provenances was consistent throughout age (Ginwal et al., 2004a).

In another evaluation trial conducted in the state of Punjab, five provenancesof E. tereticornis obtained from CSIRO, Australia revealed that provenances ofLaura areas and 20 km North of Mount Mollowy were significantly different from theprovenance of Kennedy River for tree height and diameter at breast height. Similarlyin a Provenance trial of E. tereticornis undertaken in Ferozepur Forest Division,Punjab in August, 1982 with 20 provenances revealed that Lekeland downs andKennedy River 0.34 km N of Laura provenances of E. tereticornis were significantlysuperior to all other provenance in terms of volume production (Kapur and Dogra,1987a). In case of E. camaldulensis, Gilbert River provenance revealed the highestbasal area and volume (Kapur and Dogra, 1987b)

Results from different provenance trials indicated the superiority of the northernprovenances of both the species of eucalypts to the southern provenances (Ghoshet al., 1977). Provenance trials of E. tereticornis established in many countriesindicate a significant superior performance of north Queensland provenancesparticularly Kennedy River in India (Chaturvedi et al., 1989, Ginwal et al., 2004b) andChina (Zhou and Bai, 1989), Laura and Cooktown provenance performed better inBrazil (Timoni et al., 1983), Mount Garnet and Laura, in Bangladesh (Davidson andDas, 1985), etc. The local Eucalyptus hybrid seedlots performed poorly in comparisonto the ‘Petford’ and ‘Katherine’ provenances of E. camaldulensis and ‘LauraRiver’and ‘Kennedy River’ seedlots of E. tereticornis (Chaturvedi et al., 1989).

The various trials so far conducted clearly indicate the superiority of Queenslandseedlots in northern and southern parts of the country and suggest that the nextgeneration E. camaldulensis and E. tereticornis breeding population should becomprised primarily of selections from the best Queensland provenances (Ginwal et


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al., 2004a, b; Varghese et al., 2008). In support of this, Petford (Queensland)provenance was reported to perform well across several trials conducted by theEucalyptus Research Centre in Andhra Pradesh where the annual rainfall is around800 mm (Chaturvedi et al., 1989). Improved performance of several native provenancesover the local land races demonstrated in provenance trials of E. camaldulensis,E. grandis, E. microtheca and E. tereticornis reveals that significant improvementcould be made by using selections from provenances like Petford, Gilbert River,Kennedy River and Morehead River of E. camaldulensis and Helenvale provenanceof E. tereticornis (Varghese et al., 2001).

6. Inter and Intra-Specific HybridizationFRI was the pioneer institution in initiating hybridization programme in eucalypt species.For the genetic improvement of eucalypts, hybridization work involving different parentspecies was initiated during 1966. A series of F1 hybrids, popularly known as FRI-4,FRI-5 to FRI-15, were developed by using different species combinations.

Based on the information available on crossability pattern in the genus, severalhybrid combinations were synthesized to increase the productivity. Certain hybridcombinations, viz., FRI-4, FRI-5, FRI-10, FRI-15 and FRI-16 have displayed a veryhigh degree of hybrid vigour under Dehradun condition and produced three to fivetimes more volume of wood than parent species (Venkatesh and Sharma, 1977a, b,1979, 1980). Second and third generation trials of FRI-4, FRI-5, FRI-15 and FRI-16have been laid out in the field to assess their growth performance. Promisingrecombinants have been selected from second and third generation trial for clonalmultiplication. Besides this, spontaneous F1

hybrids were picked up usingmorphological genetic markers. The accession numbers, their parental identity andthe year in which these were developed/identified are given in Table 1.

Some of the hybrids described above have been clonally multiplied throughtissue culture and deployed in the field under different eco-climatic conditions atBithmeda, Dehradun, Haldwani, Hoshiarpur, Hissar, Jodhpur, Meerut and Pantnagarfor evaluation of their performance. The performance of some of the hybrids withrespect to growth and wood characters has been described hereunder:

(a) F1 hybrids E. tereticornis x E. camaldulensis (FRI-4) and E. camaldulensisx E. tereticornis (FRI-5): In a pilot field trial established in 1972-73 at Dehradun,these hybrids have displayed hybrid vigour in respect of height and diameter andso in standing tree volume. An assessment made at age four years has shown thatF1 hybrids showed three fold superiority over their parental control and double toMysore gum (Mysore hybrid) in mean standing volume. Inter se comparison ofthe two hybrids has shown that FRI-5 is significantly superior in growth parametersto FRI-4 (Ginwal and Sharma, 2007).

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Table 1. Interspecific controlled and natural hybrids developed at FRI, Dehradun

Note: Numerals within the parentheses denote the tree numbers.A-Artificially cross-pollinated. N-Naturally pollinated

(b) F1 hybrids of E. tereticornis x E. grandis (FRI-6) and E. grandis xE. tereticornis (FRI-10): The F1 hybrids between E. tereticornis andE. grandis were found intermediate to parent species. These interspecifichybrids though intermediate to parental species in more than half of the totalnumber of contrasting characters studied (Venkatesh and Sharma, 1979) butis of interest because it involved E. grandis and E. tereticornis, the twoparent species, the former shows faster rate of growth, good stem form,provides best quality of pulp and prefers high rainfed areas while, the latteris drought tolerant and thus it is very likely that hybrids may be suited forintermediary zones (hybrid habitat).

(c) F1 hybrids of E. torelliana x E. citriodora (FRI-14) and E. citriodorax E. torelliana (FRI-15): These F1 hybrids have shown a very high degreeof sustained hybrid vigour in respect of height and diameter, the two majorparameters contributing towards wood yield. An assessment made at age 9½years has revealed that hybrids were superior to parent species, viz.,E. citriodora by 464.2 per cent and E. torelliana by 99.4 per cent with regardto volume of wood produced (Ginwal and Sharma, 2007).

7. Evaluation of F1 and F2 and F3 Hybrids for Wood Properties(a) Specific GravityWood properties of F1 reciprocal hybrids of E. citriodora and E. torelliana werestudied at FRI at the age 6½ years by taking cores from increment borer. The


S. no.

Accession number

Parental combinations Year

Female Male 1. FRI-2 A E. tereticornis (20) X E. camaldulensis (2)

(Northern form) 1966

2. FRI-3 A E. tereticornis (19) X E. camaldulensis (2) 1968 3. FRI-4 A E. tereticornis (20) X E. camaldulensis (2) 1970 4. FRI-5 N E. camaldulensis X E. tereticornis 1970 5. FRI-6 A E. tereticornis (14) X E. grandis (6) 1971 6. FRI-7 A E. tereticornis (19) X E. grandis (6) 1973 7. FRI-8 A E. tereticornis (17) X E. grandis (6) 1974 8. FRI-9 A E. tereticornis (16) X E. grandis (6) 1974 9. FRI-10 N Putative hybrid (natural,

reciprocal of FRI-6) 1974

10. FRI-13 A (E. camaldulensis X E. tereticornis) X E. grandis

1976

11. FRI-14 N E. torelliana X E.citriodora 1976 12. FRI-15 N E. citriodora X E. torelliana 1976 13. FRI-16 A E. tereticornis X E. camaldulensis (Southern form) 1997

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S. no.

Material

Specific gravity

Fiber length (mµ)

Wall thickness

(mµ)

Lumen diameter

(mµ)

1. F1 E. citriodora x E. torelliana 0.6161 1291.4 4.70 6.55 2. F1 E. torelliana x E. citriodora 0.5619 1168.0 4.15 10.65 3. E. citriodora 0.9253 970.8 6.66 8.15 4. E. torelliana 0.6599 1069.8 5.46 8.91

Table 2. Wood properties of Eucalyptus F1 hybrids, E. citriodora and E. torelliana at ageof 6½ years

results have shown (Table 2) that specific gravity of F1 hybrids was in the range of0.5619 (E. torelliana x E. citriodora) and 0.6161 (E. citriodora x E. torelliana),whereas the specific gravity of parent species was 0.6599 (E. torelliana) and0.9253 (E. citriodora). The F1 hybrids showed intermediate specific gravity ofwood as compared to parents (Kapoor, 1992). Pryor et al. (1956), reported thatwood properties of most Eucalyptus hybrids were intermediate or the same as theparents, and seemed to be under multiple factor control.

The second and third generation hybrids (F2 and F3) of E. citriodora andE. torelliana were also subjected to studies on wood properties (Verma et al.,2001). The specific gravity of wood for E. torelliana, E. citriodora, F2 E. citriodorax E. torelliana, F2 E. torelliana x E. citriodora and F3 E. citriodora x E. torellianawas found to be 0.6521, 0.8535, 0.6328,0.5697 and 0.5604, respectively (Verma et

Source: Kapoor, 1992.

al., 2001). Highest specific gravity of wood was exhibited by E. citriodora and thelowest values for the same were observed in segregating populations (F3)E. citriodora x E. torelliana. The F2 populations of reciprocal hybrids ofE. citriodora x E. torelliana showed intermediary values as compared to parentalprogenies.

(b) Fibre CharactersThe F1 reciprocal F1 hybrids of E. citriodora and E. torelliana had longer fibrelength, less wall thickness as compared to parent species (Table 2). The F1 hybridsof E. citriodora x E. torelliana and E. torelliana x E. citriodora have shown longestfibre length (1,291.4 ìm) and widest lumen diameter (10.65 ìm) as compared to parentspecies. So far as the wall thickness is concerned both the reciprocal hybrids haveregistered the lowest value as compared to parent species which is of interest frompulping and paper making point of view.

Fibre studies carried out on F2 and F3 generation hybrids of E. citriodora xE. torelliana have shown some plants which recorded higher values for fibre length,

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fibre width and lowest value for lumen diameter as compared to parent species(Verma, 1998). In F2 generation of E. citriodora and E. torelliana, the highestvalues recorded for fibre length, fibre width were 1,245.32 ìm and 18.43 ìmrespectively while in F3 E. citriodora x E. torelliana the lowest value recorded forfibre wall thickness was 4.60 ìm. However maximum lumen diameter was recorded inF3 E. citriodora x E. torelliana. All these parameters, besides others like kappa no,etc. are of great significance which contribute a lot to the quality of paper. Longerfibre will presumably lead to increase in higher tear index. It also affects the physicalproperties of the sheet such as the strength and rigidity, especially tearing strengthwhich decreases with decrease fibre length.

During 1996, the IFGTB with the technical support of Australia Tree Seed Centre(ATSC), CSIRO initiated a genetic improvement programme in E. camaldulensis andE. tereticornis. Experiments were carried out to develop dihybrid combinations suchas E. camaldulensis x E. tereticornis, E. tereticornis x E. grandis and E. tereticornisx E. alba and E. tereticornis x E. urophylla. The hybrids developed and tested inthe R and D paper testing laboratories of M/S TNPL and M/S ITC Ltd. Twocollaborative research projects aiming for production of dihybrid seeds in Eucalyptusand Corymbia were initiated by IFGTB with M/S TNPL and M/S ITC Ltd. during2010 and 2011, respectively. The projects were envisaged to deliver hybrid seeds fordeveloping high yield hybrid selections to support the ever increasing demand ofpaper pulp. As a pioneering event IFGTB was able to supply hybrid seeds to industrialforestry to widen the scope of selection and improve productivity (Source: IFGTBCoimbatore).

In addition to FRI and IFGTB, private industries like ITC Ltd. also developedintra-specific hybrids through reciprocal crosses between some of the promisingclones of E. tereticornis and inter-specific hybrids between selected clones ofE. tereticornis and candidate plus trees of other species of eucalypt (Piare Lal,2001). In ITC Ltd., the hybridization programme was initiated in 1994 and a breedingorchard was setup with E. alba, E. camaldulensis, E. grandis, E. tereticornis andE. urophylla. Inter-specific hybrids using parental combinations, viz.,E. tereticornis x E. urophylla; E. tereticornis x E. grandis; E. tereticornis xE. camaldulensis; E. tereticornis x E. alba and E. tereticornis x E. torelliana;E. urophylla x E. grandis were attempted. Major attention was focused ondevelopment of control pollinated hybrids followed by cloning of individualoutstanding hybrids showing good heterosis. A large number of hybrid clonesdeveloped from hybrid trees with good heterosis, were evaluated in Andhra Pradeshand Punjab. Some of the most promising hybrid clones tested in Punjab are 2004,2007, 2012, 2013, 2023, 2045, 2049, 2070, 2155, 3011, 3012 and 3018. Some of theseclones like 2070 and 2045 are already being planted on large scale (Piare Lal, 2001).Hybrids of Eucalyptus, viz., teretigrandis (E. tereticornis x E. grandis) and


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urograndis (E. urophylla x E. grandis) have adapted well to drought conditionsand are producing maximum volume of wood. These hybrids are now planted onlarge scale (Piare Lal, 2001).

8. Vegetative PropagationRooting of juvenile cuttings has great potential in improving the forest productivity.Leafy cuttings taken from very young seedlings or shoots developed fromlignotubers of most eucalypt species can be easily rooted in sand with bottom heatin about two to three weeks (Pryor and Willing, 1963). However, the capacity to rootby the cuttings declines very rapidly as the plants become older. In most of thespecies it becomes non-existent when they have passed the 15 leaf pairs stage. Forspecies, which do not coppice readily such as E. deqlupta, application of IAA andIBA promotes profuse coppicing on cut stumps (Davidson, 1977; Venkatesh, 1986),which then can be used for rooting purposes.

In India, work on clonal propagation of eucalypt was taken up by differentorganizations, viz., ITC Bhadhrachalam Paper Board Ltd., TERI and institutes underIndian Council of Forestry Research and Education (ICFRE). ITC BhadhrachalamPaper Board Ltd. has used the technology for production of clonal material oncommercial basis using the selected clones. More than 200 plus trees, selectedbased on desirable phenotypic characters, were cloned and significantly largedifferences in growth rates and disease resistance capacity of different clones wasnoticed in the field trials (Piare Lal, 1994). While ICFRE institutes under World Bankproject (FREEP) established vegetative multiplication gardens (VMG) of variouseucalypt species by assembling hedges of selected candidate plus trees (CPTs).The hedges were maintained in hedge gardens and produce juvenile shoot cuttingswhich gives 40-70 per cent rooting under mist condition and controlled temperature.

Rooting of leafy cuttings of eucalypt species/hybrids have been successfullyachieved (Vakshasya and Rawat, 1984; Chandra et al., 1988; Gurumurthi et al.,1988).The advances made in the techniques of vegetative propagation ofeucalypts are revolutionary from a tree breeding point of view as these help indeployment of the improved material in the field and utilize the genetic gains oftree breeding.

Propagation of more than a dozen species/hybrids of eucalypt adopting tissueculture (micropropagation) technique has been successfully tried from juvenile aswell as mature trees. At FRI, protocols for tissue culture of candidate plus trees(CPTs) of E. tereticornis (Bisht et al., 2000b), promising hybrids of Eucalyptus, viz.,E. tereticornis x E. camaldulensis (Chauhan et al., 1996), E. camaldulensis xE. tereticornis (Bisht et al., 2000a) and reciprocal hybrids of E. citriodora andE. torelliana, (Kapoor and Chauhan, 1992; Bisht et al., 2002) and FRI 16E. tereticornis x E. camaldulensis, southern form (Bisht et al., 1999) have been

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developed. The plantlets developed through tissue culture of F1 interspecific hybridswere used to establish hedge garden and subsequently used for clonal propagation(Uniyal, 2002).

By application of the techniques mentioned above, rapid genetic improvementwith higher yield of wood, both in terms of qualitative and quantitative traits, may beachieved under commercial management, if they are applied judiciously.

9. Plus Tree Selection and Clonal TestingProductivity and profitability of plantations of eucalypts have been revolutionisedwith the development of genetically improved, fast growing and high yielding clonalplanting stock. A comprehensive programme was initiated in south India by ITC Ltd.for the selection of superior trees with desirable characteristics such as straightnessof stem, growth, disease resistance, etc. Trees were selected from government(Andhra Pradesh Forest Development Corporation - APFDC) and farmers’ plantations.Initially a total of 64 candidate plus trees (CPTs) of E. tereticornis, E. camaldulensisand Eucalyptus hybrid (Mysore gum) were selected during 1989, later on this numberreached to 650 CPTs and 247 full sib CPTs. These trees were further cloned andevaluated in the field. A total of 86 promising clones were shortlisted from the fieldtrials. Out of 86 promising clones of ITC, 54 (63 per cent) have come from theprovenance seeds source obtained from CSIRO, Australia and 32 (37%) from localMysore gum (Kulkarni and Lal, 1995; Kulkarni, 2001). The provenance that gavemaximum clones are 8 km NW Black Mountain and 1 km N of Laura. Clones wereevaluated for comparative genetic superiority and G x E interactions. Nearly 123 trialplots in a 29 ha area have been established since 1989 in various soil types by thecompany. For ensuring wide and diverse genetic base of clones, more than 1,000CPTs have been cloned and tested in field trials for evaluating their comparativegenetic superiority and adaptability to different soil types. Eucalypt clones like 3, 6,7, 10 and 27 developed at Bhadrachalam formed the basis of initial clonal plantationssince 1992. However, clones 72, 105, 286, 288, 316, 407, 411, 413, 498 and 526 andhybrid clones 2004, 2012, 2045, 2049, 2070, 2155 are highly productive commercialclones with excellent bole form which are now being planted on large scale. Out ofthese clones 411, 413 and 526 have high tolerance and adaptability to alkaline soilsfollowed by clones 72, 105, 288 and 316. Clones 1, 99, 128, 130, 271, 272, 275 and 276are also fairly tolerant to alkaline soils. In addition to clones listed above, clonesnumber 265, 266, 274, 284, 290 and 292 and hybrid clones 2011, 2050, 2052, 2120,2121, 2149 and 2156 are popular in Andhra Pradesh (Kulkarni and Piare Lal, 1995;Piare Lal et al., 1997; Kulkarni, 2006).

About fifty good trees were selected from the four outstanding Australianprovenances (Kennedy River, Laura River, Mt. Carbine and Lake Land-down)identified in two provenance trials of E. tereticornis located at Pudukkottai and


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Karaikudi in Tamil Nadu state (Kumaravelu et al., 1995). Seeds from the selectedtrees were used to establish seedling seed orchards cum progeny trials at twolocations; i.e., Pondicherry (110 55’ N latitude, 790 52’ E longitude, 1250 mm rainfall)and Pudukkottai (100 23’ N latitude, 780 49’ E longitude, 650 mm rainfall) in South India.These seed orchard served as a useful asset for meeting the immediate seedrequirement of the Tamil Nadu Forest Plantation Corporation.

Superior trees of E. camaldulensis and E. tereticornis in south India were alsoidentified by IFGTB in the provenance progeny trials and in SPAs using phenotypicselection (Hegde and Varghese, 2002). Approximately 126 best trees of the top-ranking trees in un-pedigreed and pedigreed orchards at different locations werevegetatively propagated for establishing clonal trials. These trees were clonallypropagated and field tested to select promising clones which might out-performseed of the best natural provenances and clones that were commercially availablefrom other improvement programmes.

During the World Bank funded ‘FREE Project’ a comprehensive selection andevaluation programme on 11 forest tree species across the country was carried outand Eucalyptus was one of them. Following standard guidelines, ICFRE institutes,viz., FRI, AFRI and IFGTB were involved in the selection of CPTs. A total of 50 CPTsof E. camaldulensis were selected from the state of Punjab, 150 CPTs ofE. tereticornis were selected from U.P. and Uttarakhand and 100 CPTs of Eucalyptussp. were selected from Tamil Nadu. Many of these CPTs were cloned and deployedin seed orchards and vegetative multiplications gardens. Some of the seed orchardsestablished with the selected trees are in the stage of seed production. In Punjab,plus trees were also selected by the Punjab Agricultural University in plantations atfarmers’ field with comparison tree method (Sidhu, 1993). Only those trees wereselected as plus trees which had height more than 20 per cent; diameter more than 35per cent; and volume more than 150 per cent over the average of their respectivecomparison trees. Thirty one plus trees were selected and of them only 16 wereprogeny tested. Eleven progenies excelled, one equalled and four were below thecontrol in seedling height. A maximum of 51.3 per cent more height than the controlwas observed in the progeny of plus tree number 17.

Average productivity of commercial eucalypt clones is around 20 to 25 m3 ha-1 yr-1.under un-irrigated conditions. However, many farmers have achieved record growthrates of 50-58 m3 ha-1 yr-1 making farm forestry an economically attractive land useoption (Piare Lal, 1994). Significant improvements in quality of produce and reductionsin per unit production costs have also been possible with the use of true to type,uniform and genetically improved clonal planting stock of eucalypt (Piare Lal, 2001).

Clonal testing and release programmes in forest trees got a big boost after thedevelopment of the guidelines for ‘testing and releasing of tree varieties and clones’by ICFRE during the year 2008. Following these guidelines IFGTB made a comparative

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study and released four clones of E. camaldulensis for cultivation in farmlands.Demonstration clonal plantations of the released four clones were established. Effortswere also made to improve the quality of the seeds through progeny testing andestablishment of clonal and seedling seed orchards. Further, through systematicselection and multilocation testing, one clone of Eucalyptus hybrid (FRI-EH-001)(E. camaldulensis Dehn. x E. tereticornis Sm.) developed by FRI was released bythe Variety Release Committee of Ministry of Environment and Forests, Govt. ofIndia in the year 2011. The clone has a productivity of more than of 30 m3 ha-1 yr-1. Tofacilitate registration of these new clones, guidelines for distinctness, uniformityand stability (DUS) testing in eucalypt have been developed.

10. Production of Genetically Improved SeedSelection and management of seed production areas is a commonly adopted strategyrepresenting the first stage of tree improvement, after selection of the best speciesand provenances. Such seed production areas could be stands specially planted forseed production or they could be existing stands specially managed for seedproduction, provided their genetic origin is appropriate. Collection of seed frombetter than average stands which have been thinned early to remove inferior treesand to promote development of large crowns capable of heavy seed production isoften the quickest and best interim measure to meet the need of large quantity ofseed of known origin and with some genetic improvement.

Seed orchards are a means of obtaining large quantities of genetically improvedseeds relatively cheaply by allowing selected outstanding trees (plus trees) or theirprogeny to cross. Cuttings from the plus trees are used to establish clonal seedorchards or seedlings raised from seed collected from the plus trees are used to makeseedling seed orchard. In both cases, the orchards are isolated and managed forseed production. The seeds are produced by cross-pollination among the outstandingclones or progenies planted at a single plot. Seedling seed orchards have beencommonly used as production populations in breeding programs for short rotationtropical eucalypt (Eldridge et al., 1994). Seed orchards are expected to generategenetically good seeds and constitute a reliable, controllable and reproducible seedsource. Depending on the fertility and mating pattern in the orchard trees, the seedcrop may vary in diversity and vigour. Gains up to 20 per cent are anticipated overand above those from provenance selection once the pedigreed breeding populationgets converted to a seedling seed orchard (Doran et al., 1996). The gain expectedfrom thinned unpedigreed seedling seed orchards is about the same as that obtainedfrom a first generation pedigreed seedling seed orchard of the long term breedingprogramme (Shelbourne, 1992).

The IFGTB established pedigreed and unpedigreed seedling seed orchards inrepresentative sites in south India to evaluate the growth performance of the seedlots


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followed by thinning of inferior trees for quality seed production (Hegde andVarghese, 2002). Natural seedlots of E. tereticornis have poor flowering in peninsularIndia (Pinyopusarerk and Harwood, 2003a). Poor flowering has also been observedin the ramets of E. tereticornis established in clonal seed orchards in north India,particularly in Haryana and Uttarakhand, that is resulting in poor seed productionfrom the seed orchards. Poor and irregular flowering is often observed in orchardsthat are not located on good flowering sites, and even on good sites, micro-siteinfluences are important (Sweet, 1992).

Depending on the fertility and mating pattern in the orchard trees, the seedcrop may vary in diversity and vigour. Fertility variation in seedling seed orchardof E. tereticornis and E. camaldulensis in south India was studied at moist anddry sites at eight and nine years of age by Kamalakannan et al. (2007).E. camaldulensis on the moist location had 73 per cent fertile trees and low fertilitydifference at eight years, whereas, only 23 per cent trees were fertile in theE. tereticornis orchard at the same site and the fertility variation was high. In thedry location, fertility was almost the same in both species (Kamalakannan et al.,2007). High fertility variation has also been reported in a pedigreed E. tereticornisseedling seed orchard in Tamil Nadu (Varghese et al., 2002). High fertility variationin eucalypt seedling seed orchards particularly E. tereticornis indicate thateucalypts introduced to exotic environments are more variable (Kamalakannan etal., 2007) and a cautious approach need to be adopted in selection and deploymentof families in seedling seed orchards.

Demand for genetically improved seed and clonal material for establishmentof eucalypt plantations is increasing day by day. There is a need for coordinatedefforts in establishment of intensively managed seed orchards; clonal selectionand testing across the country so that the site-specific well adapted productiveclones of eucalypts are made available to the growers. Financial support from theindustries, particularly paper, pulp and plywood in addition to government, isextremely important in promotion and improvement of eucalypt in the country.Eucalypt is a tree with great environmental values. This well-managed asset is adriver of economic and social development of the country as it provides us withone of the best options for handling deforestation and is hugely beneficial to thesociety.

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Potts, B.M.; Potts, W.C. and Cauvin, B. 1987. Inbreeding and inter-specifichybridization in Eucalyptus gunnii. Silvae Genetica, 36(5-6): 194-198.

Pryor, L.D. 1966. A report on past performance and some current aspects of thecultivation of quick-growing species (mainly Eucalyptus) in India. IndianForester, 92(10): 615-622.

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Varghese, M.; Nicodemus, A.; Hegde, R. and Subramanian, K. 2001. Status of geneticimprovement of Eucalyptus in India. In: International Symposium on TropicalForestry Research: Challenges in the New Millennium, Peechi, 2-4 August2000. Proceeding edited by R.V. Varma, K.V. Bhat, E.M. Muralidharan andJ.K. Sharma. Peechi, KFRI. pp. 159-164.

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Venkatesh, C.S. and Sharma, V.K. 1977a. Differential heterosis in reciprocalinterspecific crosses of Eucalyptus camaldulensis and E. tereticornis. In:3rd World Consultation on Forest Tree Breeding, Canberra, 21-26 March1977. Proceedings. Canberra, CSIRO. pp. 676-682.

Venkatesh, C.S. and Sharma, V.K. 1977b. Rapid growth rate and higher yield potentialof heterotic Eucalyptus species hybrids FRI- 4 and FRI-5. Indian Forester,103(12): 795-802.

Venkatesh, C.S. and Sharma, V.K. 1979. Comparison of a Eucalyptus tereticornis xE. grandis controlled hybrid with E. grandis x E. tereticornis putativenatural hybrid. Silvae Genetica, 28(4): 127-131.

Venkatesh, C.S. and Sharma, V.K. 1980. An artificial inter-specific Eucalyptus hybrid(E camaldulensis Dehn x E. tereticornis Sm.) x E. grandis Hill ex Maiden.Euphytica, 29(2): 451-458.

Venkatesh, C.S.; Arya, R.S. and Sharma, V.K. 1973. Natural selfing in plantedEucalyptus and its estimation. Journal of Plant Crops, 1: 23-25.

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Verma, S.K.; Sharma, V.K. and Bagchi, S.K. 2001. Variation in specific gravity ofwood in segregating F2 and F3 populations of E.citriodora Hook. xE. torelliana F.V. Muell. Hybrids. Indian Forester, 127(4): 450-456.

Wilson, J. 1973. The need for a rational utilisation of the montane temperate forestsof South India. Indian Forester, 99(12): 707-716.

Zhou, W.L. and Bai, J.Y. 1989. Tropical eucalypts trials on Hainan island, People’sRepublic of China. In: Boland, D.J. Ed. Trees for the tropics: GrowingAustralian multipurpose trees and shrubs in developing countries. Canberra,Australian Centre for International Agricultural Research. pp. 79-87.

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1. IntroductionIn India, during 1790s about 16 species of Eucalyptus were introduced fromAustralia in Nandi Hills near Bangalore. During early 19th century, E. globuluswas introduced along with wattles in the Nilgiris and Kodaikanal in Tamil Nadu.The E. globulus for a long time served as an excellent raw material for paperindustries. Today as hilly areas are exempted from working of Eucalyptus andother species, raw material sources from these areas have stopped. However, theeucalypt leaves continue to be a source of income generation through oilextraction, especially for the women folk. Later, many more species of Eucalyptuswere introduced in south India as evaluation trials, as a result of which a highlyadapted land race, called Eucalyptus hybrid – widely referred as Mysore gum,was evolved and planted throughout India. During 1980s, due to inaccessibilityand difficulties in collecting seeds, the early introduction of E. tereticornis andE. camaldulensis to India was only from southern temperate localities ofAustralia rather than the northern tropical regions which have climatic similaritieswith Indian conditions. Results from different provenance trials indicated thesuperiority of the northern provenances of both the species of Eucalyptus tothe southern provenances. The local Eucalyptus hybrid seed lots performedpoorly (7m3 ha-1 yr-1) in comparison to the ‘Petford’ and ‘Katherine’ provenancesof E. camaldulensis (20-25 m3 ha-1 yr-1) and ‘Laura River’ and ‘Kennedy River’seed lots of E. tereticornis (12-25 m3 ha-1 yr-1).

Provenance trials established during early 1980s in Tamil Nadu revealedthe superiority of certain provenances, namely, Kennedy River, Morehead River,Laura River, Petford, Katherine, Gilbert River, Gibb River and Irvine Bank (Doranand Burgess, 1993; Brooker and Kleinig, 1994). Based on the growth performancein the different provenance trials, Institute of Forest Genetics and Tree Breeding(IFGTB) in collaboration with CSIRO, Australia initiated a comprehensivebreeding programme during 1995. Identified family seed collections from selected

Eucalypt Improvement inSouthern IndiaN. Krishnakumar, V. Sivakumarand R. Anandalakshmi

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native provenances of Australia for both E. tereticornis (42 families) andE. camaldulensis (132 families) were used to establish provenance-progenytrials.

Davidson (1998) listed different short-term strategies followed for obtainingeucalypt seeds for routine plantations in Asia-Pacific countries. Often seeds areeither imported from native stands of Australia or collected from the plantationsraised from native seed. Provenance trials are also used as seed stands after removalof inferior provenances.

Provenance trials of E. camaldulensis were established in three different sitesduring 1981, 1982 and 1986 in Tamil Nadu and assessed in collaboration withIFGTB which revealed the superiority of the provenances namely Petford,Katherine, Gilbert River, Gibb River and Irvine Bank. Amongst the best performingE. tereticornis provenances, viz., Kennedy River, Morehead River and Laura Riverwere designated as E. camaldulensis (Doran and Burgess, 1993; Brooker andKleinig, 1994).

Un-pedigreed and pedigreed seed orchards were established with about 200family identified seed collections from selected native provenances in Australia forboth E. camaldulensis and E. tereticornis by including the superior provenances.

2. Tree Improvement at IFGTB

2.1. E. tereticornis2.1.1. Provenance-progeny trialOne provenance-progeny trial was established in 1997 with seeds received fromCSIRO. The trial has 42 families comprising 17 provenances. The trial wasestablished at Karunya, Coimbatore during 1997. The trial was subsequentlythinned twice during the years 2000 and 2002 and converted into seedling seedorchard, and seeds are being collected from 2002 onwards.

2.1.2. Seed production areaTwo seed production areas were established during 1995 using the seeds receivedfrom CSIRO belonging to 506 trees of 21 provenances bulk. These orchards wereestablished in Panampally (near Coimbatore) and Pudukottai (each with 2 haarea). These seed orchards were thinned during 2000; seeds are being collectedsince 2002.

2.2. E. camaldulensis2.2.1. Provenance-progeny trialsThree provenance-progeny trials were conducted using the seeds received fromCSIRO during 1996. There are 132 families comprising 13 provenances. The trials

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were placed in Panampally, Pudukottai (Tamil Nadu) and Sathyavedu (AndhraPradesh). All these trials were evaluated and converted into seed orchards during2002; seeds are being collected.

2.2.2. Seed production areaTwo seed production areas were established 1995 using the seeds received fromCSIRO from 514 trees from 11 provenances bulk. These orchards were establishedin Panampally (near Coimbatore) and Pudukottai (each with 2 ha area). Theseseed orchards were also thinned during 2000; seeds are being collected since2002.

2.2.3. Clonal trials for Eucalyptus spp.Field trials were established for selection of promising clones. The details are givenin the box.

Development of Clones of Eucalyptus camaldulensis forDryland Afforestation and Resistance to Gall Infestation

Eucalypt is widely cultivated by farmers inthe states of Tamil Nadu, Andhra Pradeshand Karnataka. There is a heavy demand ofthis tree for pulp wood, pole as well as fuelwood. A large quantity of wood is producedby Tamil Nadu Forest Plantation Corporation(TAFCORN) and Andhra Pradesh ForestDevelopment Corporation (APFDC). Thewood produced by the corporations are soldmainly as pulpwood.

Eucalypt plantations are raised mainlythrough clones. Although each plant costsaround Rs. 10, still many industries producesuperior clones and sell to the farmers onsubsidized price. Private nurseries are also inthe market for production of clones. Poorfarmers purchase seedlings which cost Re. 1or less per plant. However, the genetic qualityof the seedlings is not known and often provesto be poor. Genetically improved seeds arebeing collected by the Institute of ForestGenetics and Tree Breeding at Coimbatore(IFGTB) from seed orchards since 2002 for

sale to farmers and other planting agencies.The corporations plant clones and seedlingsin 75:25 ratio to maintain the diversity intheir plantations. The paper mills alsodevelop clones which are made available toother agencies for mass multiplication andcultivation.

Generally, eucalypt is cultivated in dryareas under rainfed condition. On anaverage, the eucalypt clonal plantations inthe estates of TAFCORN produce about 60 tha-1 in a rotation of six years. The yield goesup to 150 t ha-1 in places where the surfacemoisture availability is high. The seedlingorigin plantations generally produce as lowas 25 t ha-1 during that period.

1. Clones of Eucalypt Released During2010The IFGTB has been working for theimprovement of eucalypt for the past twodecades. First generation provenance trialswere established in three different locations

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and about 100 clones were selected. Theclones were selected based on the superiorityof individual tree for height, diameter atbreast height and straightness of stem throughindex selection method. The clonal trialswere established in three different locations,viz., Coimbatore (Tamil Nadu), Sathyavedu(Andhra Pradesh) and Kulathupuzha(Kerala). Out of 102 clones, about 33 werefound promising across all the three trialsand these clones were compared with otherclones and seed sources for calculation ofclonal superiority. About 10 commercialclones and seed origin plants of Eucalyptuscamaldulensis (three entries) andE. tereticornis (two entries) and five clonesof Kerala Forest Research Institute (KFRI)were also included in the experiment forthe purpose of comparison. All the trialswere laid in randomized block design withfive replications. Each replication wasrepresented by three ramets except

Kulathupuzha where it was two ramets perreplication. Sufficient care was taken inselection of site for establishment of thesetrials. The trials were conducted in divergentclimatic and edaphic conditions. Therainfall and temperature and soil characterswere different in the selected sites. At thesame time, uniformity within the trial plotswas ensured. Trees were 3 m x 2 m plantedat spacing. One row of eucalypt clonal plants(local clone) was planted all along theborder. Weeding was carried out once in ayear before rain. Watering was restricted toplanting and initial period of establishment.Fertilization and soil amendments were alsorestricted to initial planting season. Everyyear, growth traits were recorded before rain.However, periodic inspections were carriedout once in two months for observing anyother pest incidence. Observations onflowering and fruiting were initiated afterthird year. Straightness was scored after

Table 1. Growth characters of eucalypt clones approved during 2010 (age: 7 years)S. no. Clone no. Height

(m) DBH (cm)

Single tree volume (m3)

Superiority (%) for volume above commercial clones

1. IFGTB-EC-1 15.17 13.53 0.120 33.3

2. IFGTB-EC-2 15.68 12.92 0.113 25.6

3. IFGTB-EC-3 13.48 11.68 0.097 7.8

4. IFGTB-EC-4 15.24 11.78 0.091 1.1

IFGTB EC 1 IFGTB EC 2 IFGTB EC 3 IFGTB EC 4

Fig. 1. Trees of different germplasm in field trial.


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seven years. The top four clones (Table 1,Fig. 1) which showed consistent betterperformance in all the three trials than thecommercial clones were selected.

2. Clones of Eucalypt Released During2014During 2008 to 2011, the species faced asevere problem due to an insect calledLeptocybe invasa, a tiny gall-producingwasp. Many of the plantations were totallywiped due to this infestation. Chemicalcontrol was not effective. The multiplicationof the insect could not be controlled by anymethod. Deployment of clones resistant tothis infestation was considered to be the mostreliable method to bring the infestation undercontrol. Hence studies were initiated to testthe clones under multi location trials andsimultaneously screen the available clonalpopulations for resistance to gall insect.

About 33 entries selected from variousprovenance trials, seedling seed orchards andseed production area during 2000 were massmultiplied during 2009 and used forestablishment of Clonal trials. The selectionswere carried out through index selectionmethod. The height and diameter at breastheight and straightness were given moreimportance for selection of trees. Theseselected individuals were coppiced and shootswere collected and VMG was establishedduring 2008. Plants were multiplied and clonaltrials were established in 18 different locations,namely, Mulughu, Warangal, Rajamundry,Tirupathi and Nellore in Andhra Pradesh,Gungarkatti, Halbhavi and Badami inKarnataka, Karaikal in Pudhucherry andKaraikudi, Ariyalur, Kalakurichi, Marakanam,Chinnadarapuram, Manikattipalayam,Kurum-papatti, Athipalayam and Kattumunurin Tamil Nadu. Clonal trials were establishedduring 2009 to 2010. The trials were

established with minimum three replicationsand 16 ramets in each replication. About 5commercial clones and already released fourclones of IFGTB were also included in thetrials. All the trials were laid in RandomizedBlock Design with about four replications. Treeswere planted at 3 m x 2 m spacing. Growthtraits were annually recorded and statisticallyanalysed. Gall resistance was observed inclonal assemblages present in Karunya,Sathyavedu and Coimbatore at coppice shootstage during the period from 2009 to 2011.

The growth performance and resistanceto gall, both were compared along with othercommercially cultivated clones. The studycame out with seven superior clones (Table2, Fig. 2) with three levels of gall resistance.The first set of clones was IFGTB-EC-11,IFGTB-EC-5, IFGTB-EC-9 and IFGTB-EC-7which are resistant to gall infestation. Thesecond set of clones was IFGTB-EC-8 andIFGTB-EC-10 which showed low susceptibilityto gall infestation. The third set of cloneIFGTB-EC-6 which showed moderate levelof susceptibility to gall infestation.

3. Efforts for Popularization of the ClonesThe eucalypt clones were released forcultivation in Tamil Nadu, Andhra Pradesh,Karnataka and Puducherry as the tests wereconducted in these states. These clones weremass multiplied and supplied to farmers freeof cost under National Agriculture InnovativeProject funded project on ‘a value chain onindustrial agroforestry in Tamil Nadu’ withForest College and Research Institute,Mettupalayam as the lead partner. IFGTBtook efforts to popularize these clones byway of establishing clonal demo plantationsin farmers’ lands free of cost. In addition,the clonal plants were also transferred toforest departments, forest corporations, papermills and other private nurseries.

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Table 2. Growth characters of eucalypt clones approved during 2014 (age: 3 years)


Clone no. Height (m)

DBH (cm)

Single tree volume

(m3)

Gall score (score increased from 0 to 4 with increase in

infestation)

Superiority (%) for volume above

commercial clones

IFGTB-EC-5 10.7 8.21 0.037 0.57 95.9

IFGTB-EC-6 9.23 7.64 0.033 1.90 73.0

IFGTB-EC-7 8.77 6.54 0.024 0.78 26.1

IFGTB-EC-8 8.89 6.61 0.024 1.02 25.5

IFGTB-EC-9 9.28 6.61 0.023 0.71 23.6

IFGTB-EC-10 8.83 6.60 0.023 1.39 20.1

IFGTB-EC-11 8.66 6.58 0.022 0.54 17.8

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3.1. Efforts for Mass MultiplicationVegetative multiplication gardens (VMG) havebeen established from the released clones atBharathiar campus, Coimbatore. About 500trees blocks have been established for eachreleased clone at 1 m x 1 m spacing. After sixmonths, the trees were felled and coppiceshoots are being collected regularly for mass

multiplication. Every day the cuttings aretransported to the nursery and planted forrooting. These VMGs have the capacity toproduce about 20,000 plants per month.

3.2. Clonal Demonstration PlantationsThe released clones of IFGTB wereplanted in blocks of about 400 trees

Fig. 2. Trees of clone IFGTB-EC-5 to IFGTB-EC-11 in field trial.

2.2.4. Genetic gain trials for Eucalyptus spp.Bulked seeds (from 25 randomly selected trees) were collected at four years of agefrom four orchards (unpedigreed orchards of E. camaldulensis from Pudukkottaiand Panampalli, to establish genetic gain trials in three locations (Karunya, Dandeliand Kulwalli). A local seed lot (land race) and a bulked natural Australian provenanceseed lot were used as control. The trials were evaluated for tree growth (height anddbh) at three years of age. In general, the difference in growth (height and dbh)between the progeny of unpedigreed orchards was not very marked. About 17 percent gain in height and 14 per cent gain in DBH was achieved by the seed orchardprogeny over the local seed lot.

2.2.5. Progeny trials for Eucalyptus spp.Seeds were collected from 50 selected clones of clonal trials converted to CSOsduring 2008 and progenies were raised and established as progeny trials at Hyderabad(Andhra Pradesh) and Pudukottai (Tamil Nadu). During 2009, seeds were collectedfrom a selected group of 50 clones; progenies were raised and established as progeny


IFGTB EC 9IFGTB EC 8IFGTB EC 7IFGTB EC 5 IFGTB EC 6 IFGTB EC 10 IFGTB EC 11

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besides other commercial ly plantedclones. These Clonal demonstrat ionplantation (CDPs) were established todemonstrate the super ior i ty of thereleased clones vis-a-vis the othercommercial clones. The clonal blocks ofspeci f ic c lones were establ ishedsequentially. Farmers can walk throughthe plantations and see the superiority ofthe released clones. The commercialclones and IFGTB released clones wereplanted alternatively. Although the clonalblocks were not replicated, however, theywere placed in random order. The CDPswere also established in the establishedclusters. Two CDPs were established inAravakuruchi taluk. One such CDP wasestablished at Nellore in association withAndhra Pradesh Forest Department.

3.3. Transfer of Clones through MaterialTransfer AgreementThe clones released during 2010 weresupplied to Tamil Nadu Forest PlantationCorporation (TAFCORN), Andhra PradeshForest Development Corporat ion(APFDC), Andhra Pradesh ForestDepartment (APFD) and Tamil NaduPapers and Newsprints Ltd (TNPL) free ofcost. These clones were given on Material

t ransfer agreement (MTA) with anagreement for mass multiplication andsupply to farmers. These clones were alsogiven to Bal larpur Industr ies Limited(BILT), JK Paper Mills, Rayagada, HariharPolyfibers, Karnataka, Seshasayee Paperand Boards Limited, Tamil Nadu, TheWest Coast Paper Mills Ltd., Dandeli,Karnataka and APPM, Rajamundri formass multiplication and supply to farmers.End-users have confirmed superiority ofperformance of these clones.

4. ConclusionIFGTB has a mandate to improve theproductivity of the plantations. Selection,testing and release of elite clones aremilestones for the genetic improvementof the species. Future goals have been setfor improvement of many more species.The increasing demand must be meteither by increasing the productivity of theavailable land or bring the marginal andwastelands under tree cultivation. Cloneswith drought and salinity tolerance needto be developed. In the next decade, focusmust be on hybrid clones for specific enduses like disease resistance, cellulosecontent and plywood qualities that areneeded by farmer and industries.

trials at Hyderabad, Pudukottai, Nellore, Karaikudi, Thiyagadurgam, Marakkanam,Chennai, Arimalam, Udumalaipet and Coimbatore. The progeny trials were establishedwith locally grown seedlots and commercially available clones for the purpose ofcomparison. The preliminary results showed positive response of certain familiesover clones.

A list of research trials on eucalypts, established by IFGTB is given inTable 1.

2.2.6. Demand and supply of Eucalyptus seedsIFGTB has been supplying improved and tested seeds of E. camaldulensis andE. tereticornis collected from the seed orchards of IFGTB since 2006. The demandfor seeds has mainly been from paper and pulpwood industries, state forestdepartments, forest development corporations, farmers and NGOs. The annualsupply of eucalypt seeds ranges from 5 to 60 kg. This demand is influenced byvarious factors like planting targets, programmes, policies, etc. The trend ofeucalypt seed supply by IFGTB is furnished in Fig. 1.


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Table 1. Research trials established under eucalypt improvement programme

The eucalypt is facing competition from other pulpwood species like casuarinas,Leucaena, Melia, Gmelina and thornless bamboos. However, there is a need forestablishment of more seed orchards, maintenance of already established orchardsand monitoring of the seed productivity on an annual basis. Community seed


S. no. Species Name of trial Year Area (ha) Location 1. E. camaldulensis SPA 1996 1.0 Panampally

2. E. camaldulensis SPA 1996 2.0 Pudukkottai

3. E. tereticornis SPA 1996 1.0 Panampally

4. E. tereticornis SPA 1996 2.0 Pudukkottai

5. E. tereticornis SSO 1996 1.0 Karunya Nagar

6. E. camaldulensis SSO 1996 2.0 Panampally

7. E. camaldulensis SSO 1996 2.5 Sathyavedu

8. E. camaldulensis SSO 1996 2.0 Pudukkottai

9. E. tereticornis SSO 1996 1.0 Pondicherry

10. Eucalyptus spp. Gain trial 2004 0.5 Karunya nagar

11. Eucalyptus spp. Clonal trial 2000 1.0 Karunya nagar

12. Eucalyptus spp. Clonal trial 2000 0.8 Sathyavedu

13. Eucalyptus spp. Clonal trial 2000 0.5 Kulathupuzha

14. Eucalyptus spp. VMG 2008 1.0 Bharathiar

15. Eucalyptus spp. Progeny trial 2009 2.0 Hyderabad

16. Eucalyptus spp. Progeny trial 2009 2.0 Pudukkottai

17. Eucalyptus spp. CSO 2009 2.0 Salem

18. Eucalyptus spp. SSO 2009 1.0 Nellore

19. Eucalyptus spp. CSO 2009 1.0 Nellore

20. Eucalyptus spp. SSO 2009 1.0 Karaikudi

21. Eucalyptus spp. SSO 2009 1.0 Thiyagadurgam

22. Eucalyptus spp. SSO 2009 1.0 Marakkanam

23. Eucalyptus spp. Progeny trial 2009 2.0 Karur

24. Eucalyptus spp. SSO 2010 3.0 Chennai

25. Eucalyptus spp. SSO 2010 2.0 Coimbatore

26. Eucalyptus spp. CSO 2010 7.0 Nellore

27. Eucalyptus spp. Clonal demonstration 2010 2.0 Athipalayam, Karur

28. Eucalyptus spp. Clonal demonstration 2010 2.0 Aravakuruch, Karur

29. Eucalyptus spp. Clonal demonstration 2010 2.0 Nellore R.L.

30. Eucalyptus spp. SSO 2011 1.0 Udumalaipettai

31. Eucalyptus spp. CSO 2011 1.0 Udumalaipettai

32. Eucalyptus spp. Clonal trial 2011 1.0 Udumalaipettai

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Fig. 1. Supply of Eucalyptus seeds by IFGTB over the past eight years

orchards of eucalypt as in the case of Casuarina and decentralized industrial orchardsare also required to promote quality planting stock production. IFGTB is in theprocess of establishment of second generation orchards and special purpose seedorchards.

3. Growth, Yield and EconomicsVery high productivity is possible under favourable conditions: growth of70 m3 ha-1 yr1 of wood in a four-year-old plantation at 3 m x 2 m spacing on a fertile,well-watered site has been recorded (Zohar, 1989). These conditions are seldomduplicated on the broad scale, and yields are generally much less. In the drier tropics,yields of 5-10 m3 ha-1 yr-1 are common whereas, in moister regions yield up to30 m3 ha-1 yr-1 may be achieved (Evans, 1982). In southern Vietnam, overall yield forthe species is 12 m3 ha-1 yr-1 at four years but better adapted provenances give yieldof 20 m3 ha-1 yr-1. Tree breeding and better management will quickly enhance theseyields.

In Tamil Nadu, about 25-30 t ha-1 at a rotation of 6 to 7 years was realizedthrough seedling plantations during early 1990s. Introduction of clonesincreased the yield up to 60-70 t ha-1 in six years rotation. With introduction ofnew clones, it is expected that the yield can go up to 70-80 t ha-1 in six yearsrotation.


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ReferencesBrooker, M.I.B. and Kleinig, D.A. 1994. Field guide to eucalypts: V3. Sydney, Northern

Australia Inkata Press.Davidson J. 1993. Ecological Aspects of Eucalyptus Plantations. In: Regional Expert

Consultation on Eucalyptus, 4-8 October 1993, Volume 1, FAO RegionalOffice for Asia and the Pacific, Bangkok. Proceedings.

Doran, J.C. and Burgess, I.P. 1993. Variation in floral bud morphology in theintergrading zones of Eucalyptus camaldulensis and E. tereticornis innorthern Queensland. Commonwealth Forestry Review, 72: 198-202.

Evans, J. 1982. Plantation forestry in the tropics. Oxford, Clarendon Press.Zohar, Y. 1989. Biomass production of short rotation Eucalyptus camaldulensis

Delm. stands growing on peat soil under a high water table in Israel. SouthAfrican Forestry Journal, 149: 54-57.


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1. IntroductionThe ITC Limited-Paperboards and Specialty Papers Division (PSPD), Bhadrachalamunit uses 0.6 Mt yr-1 wood from eucalypt along with other woods for manufacturingthe pulp and paperboards. A plan to grow 10,000 ha yr-1 of plantations was drawnto meet the raw material requirements of the mill on a continuous and sustainablebasis.

In the first phase, the company promoted social and farm forestry plantationsby distributing nearly 30 M seedlings and covered 9,441 ha with eucalyptplantations from 1982 to 1995. These plantations showed high genetic variations,poor survival and productivity. At that time the prevailing scene of eucalypt seedroute plantations was grim as the foliar blight disease caused by Cylindrocladiumspp. was quite prevalent in plantations. Apart from that, termites caused large-scale seedling mortality in plantations of young age. The outcome was that thesurvival of trees in plantations at harvest stage was 30 to 50 per cent andproductivity of 4 to 6 t ha-1 yr-1. Due to low yields, the plantations were noteconomical to the farmers as an alternative farming option. The other reasons forpoor productivity were hybrid break down, non-availability of quality seeds,primitive nursery practices, mismatch of species and provenances to site, closespacing, lack of follow up of correct package of practices (Kulkarni, 2001). Becauseof eucalypt controversy (Rajan, 1987), farmers were scared to take up plantations.

Therefore, two decades ago, farm forestry plantations were becoming unpopularin spite of the incentives, subsidies and National Bank for Agriculture and RuralDevelopment (NABARD) loans to the farmers. This adverse scenario changed, overa period of four to five years, from the year 1989 when the company decided tolaunch tree improvement programme (TIP) and promoted clonal technology basedplantations (Kulkarni and Lal, 1995).

ITC PSPD, Bhadrachalam unit launched a major plantation programme withtwo-fold objectives:

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1. Achieve self-sufficiency in wood based fibre requirements on a continuousand sustainable basis, and

2. provide agri-farmers a viable alternative land use option by improvingproductivity and returns.

The objectives of tree improvement programme set were:h Increase plantation productivity by at least three times,h reduce plantation harvest period,h adopt suitable spacing for better growth,h develop disease resistant, wind and drought tolerant and site specific clones,h improve silvicultural and fibre traits,h improve package of practices for raising plantations,h develop models and package for social and farm forestry to take tree,

improvement research to the field, andh make eucalypt farming a farmer friendly viable alternative option.

2. TIP LocationThe experimental site and Clonal Research Station is located at 17o 40' N latitude and81o E longitude. The altitude of the place is 100 m above mean sea level. The climateis sub-tropical with annual rainfall of 1,033 mm, mostly from southwest monsoon.The maximum temperature recorded is 49oC and minimum 10oC. The predominantsoils are red sandy and black cotton. Soils are either normal or alkaline. Saline soilsare also found.

3. TIP Strategies and MethodsEucalypt seeds were imported from CSIRO (Australia) in the years 1986, 1990, 1994and 1995 to raise provenance trials. Candidate plus trees (CPTs) of E.tereticornisSmith and E. camaldulensis Dehnh. were mainly selected from government and farmforestry plantations. Selected plus trees were propagated vegetatively from coppicecuttings in mist chambers. Root trainer technology was adopted for the productionof plants. The successful ramets were planted in gene banks known as clonalmultiplication areas (CMA) at a spacing of 1 m x 1 m. The clonal testing areas (CTA)were planted at 3 m x 2 m spacing in RBD with three replications. Ploughing of theplots was carried out annually. No fertilizers and irrigation was provided to the trialplots. Periodic measurements were recorded for girth, height and occurrence ofpests and diseases and promising clones were short-listed. Clonal seed orchards(CSOs) adopting the permutated neighbourhood design (Sekar et al., 1984) wereestablished in 3 ha area. Clonal demonstration plots (CDPs) were raised under theextension scheme. Inter- and intra-specific hybridization was carried out betweenselected best clones and other species of Eucalyptus. Half and full-sib progeny

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trials were laid out. Promising hybrids were cloned and planted in multi-locationtrials. Genotype x site interaction studies for various clones were carried out onnormal and refractory sites. A gene repository was also established for conservingclonal material. The wood morphology, proximate chemical analysis and strengthproperties of wood for pulp and paper and DNA finger printing studies were carriedout.

At the beginning of the programme, the main handicap faced was the non-availability of a wide genetic base for the improvement of eucalypt. Therefore, ‘breedthe best with the available best’ strategy was followed.

3.1. Gene ResourceThe genetic base deployed for improvement of eucalypt is based on the speciesE. tereticornis as it is most suited to this zone. However, other species ofEucalyptus such as E. alba, E. camaldulensis, E. citriodora, E. grandis, E. pallita,E. torelliana, E. urophylla, etc. were also involved for selection and hybridisation(Fig.1).

3.2. Candidate Plus Tree SelectionThe selection of the most desirable tree with characteristics such as straightness ofstem, annual growth rate, disease resistance, crown structure, wood density, fibremorphology, cellulose/lignin balance, bark: solid wood ratio, under-bark relation-ships, etc. were considered. Starting with the cloning of 64 CPTs during 1989, morethan 1,000 CPTs and 500 full sib CPTs have been selected and cloned. Out of 1,500selections, 107 promising clones were shortlisted and 63 per cent have come fromprovenance seeds source obtained from CSIRO (Australia) and 37 per cent fromlocal land race Mysore gum. The provenances that gave maximum clones are 8 KMNW Black Mountain and 1 KM N of Laura.

3.3. Vegetative PropagationFor most of the clones, the percentage of rooting of juvenile coppice shoots underintermittent mist conditions with 70 per cent relative humidity and 35oC temperature,was more than 70 per cent except for clone 6 which was less than 40 per cent. Roottrainer technology employed for growing the cuttings ensured low handling andtransportation cost in comparison to traditional polybag nurseries. Besides, the plantswere transported without any damage over long distances. Thus, ITC became the firstcompany in India to introduce root trainer technology on large scale.

3.4. Clonal Testing and Promising ClonesClones were evaluated from CTAs for comparative genetic superiority and G x Einteractions. Nearly 159 trial plots in 36 ha area have been established since 1989 in

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various soil types under rainfed conditions. As many as 107 promising clones wereshort-listed from the above trials. In the beginning of the programme, clones wereplanted without due regard to site. After a gap of three to four years, it was discoveredthat some clones were doing well and some were not in a given site. In general, blacksoils (normal, alkaline and saline) require specific ITC clones 1, 10 and 130 whichadapt well. But clone 10 does not tolerate saline sandy soils and it led to highmortality (up to 90%) in a two-year-old plot at Tangutur in Prakasam District of

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Fig. 1. Eucalypt improvement at ITC.

Base Population

E. tereticornisBlack Mount - 60Kennady River - 5Mt. Molley - 26Ruthcreek - 31Mysoregum - 299

E. simulateLaura - 44Kennady - 39

E. camaldulensisKatherine River - 19Maxwelton - 8Petford - 32Kennady River - 32

E. urophylla - 12E. grandis - 2E. alba - 1E. pellita - -C. torelbana - 1

1000 CPTs

CTACMAGXESILVI TRIALS

107 Promising Clones

Hybridization

CSO-7 Intraspecific-217 Interspecific-30

Hybrid Clones

New Eucalypt Forests

ProductionPopulation

BreedingPopulation

Wood ProductionPopulation

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Andhra Pradesh. However, in the same plot ITC clone 411 and 413 were performingwell with high productivity and survival. Normally, CPTs selected from black soil areto be tested first on black soil itself and later on other soil types as clones exhibit astrong affinity to the site of their origin. For example, ITC clone 351 that was selectedfrom black soil gave a yield of 22 t ha-1 yr-1 on similar site compared to 6 t ha-1 yr-1 onred soil (Table 1).


Clone 3: Origin from red soil Clone 351: Origin from black soil.

Table 1. Performance of two clones on red and black soilsRed soil Black soil CAI/MAI (under bark tha-1)

Clone 3 Clone 351 Clone 3 Clone 351 CAI at age 1 14.2 7.9 4.6 4.0 2 24.7 4.9 9.0 13.3 3 11.7 5.7 25.2 33.2 4 14.8 5.4 37.0 37.4 MAI at 4 years 16.3 6.0 18.9 22.0

The clonal testing method was later modified as testing was directly taken-up inthe farmers’ field by providing irrigation and fertilization. As a result, the woodvolume production went up by 10 to 40 per cent and harvesting was done at 2 to 3years period. The site-specific and commercial clones shortlisted are:

The most important commercial clones are:- ITC-3, 6, 7, 10, 27, 71, 72, 99, 105, 115,122, 128, 130, 223, 265, 266, 271, 272, 273, 274, 175, 277, 284, 285, 286, 288, 290, 292, 316,319, 405, 411, 412, 413, 417, 439 and 470.

The most adaptable clones for alkaline soils are:- ITC-1, 10, 27, 71, 99, 105, 115, 116,122, 128, 130, 158, 223, 266, 271, 272, 273, 274, 277, 290, 316, 318, 328, 410, 411, 412, 413and 417.

The plastic clones are :- ITC-27, 71, 83, 99, 105, 116, 128, 130, 147, 271 and 285.

3.5. Disease ResistanceThe outbreak of diseases caused by various fungi on eucalypt in nursery and fieldrevealed main pathogens as Cylindrocladium spp. and Alternaria spp. causing foliarblight disease. The resistant clones short-listed are ITC-1, 3, 6, 7, 288 and 316.Eucalyptus gall (Kulkarni, 2010a) caused by Leptocybe invasa (Fig. 2) created havocin nursery and plantations in the year 2008-09. ITC - clones 1, 320, 411, 413, 513, 612,2145, 2253, 2254 and 2306 were identified as gall resistant. Parasitoid Quadrastichusmendeli as a biological control agent was introduced from Israel. The gall is now under

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control. Clones such as ITC 10 and 27 are found to be highly susceptible. Little leafdisease (Kulkarni, 2010b) caused by thrips (Fig. 3) was found on all the clones. Theother insect Batocera rufomaculata (mango beetle) caused wide spread damage tothe growing shoot of three-month to one-year-old plants (Kulkarni, 2010c).

3.6. Productivity of ClonesThe survival percentage for majority of clonal plantations is more than 95 (Kulkarniand Lal, 1995). The productivity of ITC-Bhadrachalam clones thus range from 20 to 58t ha-1 yr-1. compared to 6 to 10 t ha-1 yr-1 from seedling origin plantations (Fig. 4). Apartfrom increase in productivity by four to six times, the rotation period has reduced by

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(a) Leptocybe invasa (b) Leaf gall

(c) Resistant clone (413) (d) Susceptible clone (27)Fig. 2. Eucalypt gall. (a) The insect pest, (b) the symptom, (c) the resistant and(d) susceptible genotype.

155Eucalypt improvement at ITC

Fig. 3. Vector (a-b), symptom (c) and causal organisim (d) of little leaf disease.

Fig. 4. Annual increment in CTA 21 at the age of six years at Bhadrachalam.

(a) Nymph (b) Thrips

(c) Little leaf (d) MLO

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half (Fig. 5). The root system invariably has a depth of 1.5 to 2.5 m with surface feederand anchor roots (Fig. 6). Therefore, farmers are now harvesting plantations at fouryears instead of seven years with uniform premium timber.

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Fig. 5. Clonal plantations from one to four years.

Fig. 6. Root system from one to four years.

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3.7. Volume Table for ClonesThe regression equation developed for eucalypt seedling based plantations (Rajan,1987) did not suit clonal plantations as the rhythm of growth was quite different.The regression equation and volume table for eucalypt clones was prepared(Chaturvedi, 1995).

Volume (over bark) V = 0.00352 + 0.0341 G2HVolume (under bark) V = 0.00258 + 0.0281 G2H

3.8. Yield AssessmentOne hundred plantations were felled in different districts to assess woodproduction for authenticating the CTA trial results. The farmers obtained the MAI(t ha-1) of 23 in Khammam, 28 in Prakasam, 21 in Guntur, 24 in Krishna and 39 inWest Godavari was obtained. The average MAI (t ha-1) works out to 27. Further,the farm forestry plantation average IRR per acre in different districts worked outto 40 in West Godavari, 48 in Khammam, 32 in Prakasam, 26 in Guntur and 30 inKrishna (MANAGE, 2003).

3.9. Clonal Multiplication Areas (Gene Bank)Since 1989, 33 ha gene bank has been raised with 0.22 million ramets in blocks at1 m x 1 m spacing in the mill premises. The CPT material was first planted in thegene banks. Gene banks are regularly coppiced at two years age for obtainingthe propagules for multiplication. Each stump has given 180 to 200 ramets withthree harvests and annually nearly 10 M plants are produced for planting.Recently, mini cutting area (MCA) has been developed and apical shoots areharvested for propagation which gives continuous supply of shoots throughoutthe year.

3.10. Clonal Demonstration PlotsClonal demonstration plantations (CDPs) raised by the company resulted in large-scale adoption of genetically superior ITC-Bhadrachalam clones of eucalypts by thefarmers and state forest departments/forest development corporations. Since 1989,more than 50 ha of CDPs have been established at various places in Andhra Pradesh.As ‘seeing is believing’, farmers’ meetings were regularly held in these plots whichenabled them to pick and choose the clones most suited for their land.

3.11. Clonal Seed OrchardsBest clones were planted in 3 ha area in (CSO). Fresh CPTs are now being selectedfrom the CSO based plantations as selections with new recombinations are givingnext generation clones. The major problem encountered in raising CSO was that theneighbouring fast growing clones suppressed the slow growing clones. Thus,

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planting in a mosaic design did not serve the purpose. Another problem encounteredwas non-synchrony in flowering of clones resulting in restricted gene exchange.

3.12. HybridizationThe hybridization programme was initiated in 1994. A breeding orchard was set upwith cleft grafted plants of E. tereticornis, E. camaldulensis, E. alba, E. urophyllaand E. grandis. The selected material was multiplied in large numbers by cleft grafting.The graft union was successful between E. tereticornis root stock and scion materialderived from E. alba, E. camaldulensis and E. urophylla. Graft incompatibility,however, was noticed in the case of E. torelliana. At seven years of age, the graftsin the breeding orchard have attained a maximum GBH of 58 cm and height of 10 m.The best results of grafting were obtained in the months of August to November.Almost all the grafts flowered at two to three years age.

Inter-specific hybridization was attempted to combine desirable complementaryattributes of promising clones and eliminate defects keeping in view the customers’(grower/mill) viewpoint, viz., high yields (volumetric productivity), felling cycle ofthree to five years (economic rotation), adaptability to sites, superior wood qualityand uniformity of raw material. The clones with well-defined traits (Table 2) wereincluded in the breeding programme.

Development of inter-specific hybrids such as E. tereticornis x E. urophylla.;E. tereticornis x E. grandis; E. tereticornis x E. camaldulensis; E. tereticornis xE. alba and E. tereticornis x E. torelliana; E. urophylla x E. grandis was attempted.One of the major problems encountered in breeding E. urophylla is that the floweringcoincides with the rainy season (August) leading to flower drop (before and afterfertilization). Therefore, E. urophylla is considered to be the male donor parent asthe pollen is collected in the month of August and is stored and used for pollinationin the months from October to January. Teretigrandis and Urograndis hybrids haveadapted well to drought conditions and producing maximum volume of wood. Thesehybrids are now planted on large scale. Recently, E. tereticornis x E. globulus andE. grandis x E. globulus hybrids have been successfully grown in the plots. By

H.D. Kulkarni

Character ITC clone number* Clear bole 1, 4, 6, 7, 27, 122, 223, 265, 266, 272, 274, 275, 284, 286, 288, 290,

292, 316 and 319.

High productivity 3, 6, 7, 10, 105, 130, 265, 266, 272, 274, 284, 290, 292, 316 and 319.

Adaptable to refractory sites 1, 10, 71, 105, 115, 116, 128, 130, 223, 266, 271, 272, 274, 285, 290, 316, 405, 411 and 413.

Disease resistance 1, 3, 6, 7, 288 and 316.

Table 2. Clonal characters for hybridization

*Species details not disclosed.

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controlled pollination between the best 32 clones of E. tereticornis, the derivedfull-sib hybrids have shown good heterosis at two years age. The full-sib progenytrial showed a maximum of 33 per cent improvement over the parents for productionof wood volume. Based on the performance of full-sibs, elite full-sib trees wereselected and cloned. Nearly 358 full-sib hybrid trees have been cloned. Thesehybrid clones have been tested on various sites. Heterobeltioisis studies on 18hybrid clones showed 82 per cent improvement in wood volume production overthe best parent. A few hybrid clones from the crossing of clone ITC-6, 10 and 27gave hybrid clones ITC-2011, 2014, 2045, 2050, 2052, 2053, 2120, 2121, 2149, 2155and 2156 which are totally devoid of the defects and surpassed in growth. Inaddition, some of the clones showed a narrow crown which is required for closerplanting at a spacing 3 x 1.5 m enabling harvesting of trees at three to fouryears age.

4. DNA Fingerprinting of Eucalypt ClonesThe advent of DNA fingerprinting has opened new vistas in molecular biologyas this technique has the ability to detect differences between individualsat the level of DNA. Nearly 90 ITC Eucalyptus clones were subjected to PCRbased randomly amplified polymorphic DNA (RAPD) technique and genetic mapsbased on DNA markers were prepared. The 90 clonal compositions included 44parental clones, 39 hybrids and seven clones of different Eucalyptus speciesand 12 primers were used for DNA amplification (Paramathma and Kulkarni,2005).

The amplified products varied in number and intensity among the clones(Table 3). Among 12 primers, OPR 05 exhibited monomorphism. Altogether 247amplified products were observed in the profiles of both parents and hybridsand out of which 224 products (90.70%) were polymorphic (Fig. 7).


Parents Hybrids Primers No. of

bands No. of

polymorphic bands

Per cent polymorphism

No. of bands

No. of polymorphic

bands

Per cent polymorphism

OPS 01 14 14 100.00 13 11 84.62 OPAL 03 15 15 100.00 17 16 94.12 OPAB 04 9 9 100.00 8 7 87.50 OPAB 05 9 8 88.90 15 15 100.00 OPAK 10 7 6 85.70 10 7 70.00 OPH 19 9 6 66.70 10 8 80.00 OPR 10 9 8 88.90 8 8 100.00 OPR 11 8 8 100.00 8 8 100.00 OPT 03 8 8 100.00 13 13 100.00 OPR 08 15 15 100.00 17 17 100.00 OPR 09 10 9 90.00 8 8 100.00 OPR 05 3 0 0.00 4 0 0.00

Table 3. Polymorphism observed in different primers

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4.1. Scoring of Amplified Products and Genetic Similarity MatrixIn case of parents, 15 amplified products were observed in the profiles (Fig. 8) while,in hybrids 17 amplified products with same primers (Fig. 7) were observed. Geneticsimilarity matrix for all pair-wise combination of parental clones revealed that thelowest coefficient value of 0.44 (highest genetic distance 0.56) was observed betweenITC-105 and 1 as well as ITC-45 (636) and 286. The highest similarity co-efficient of0.83 (lowest genetic distance 0.17) was observed between ITC-10 and 9. Similarly, forhybrid clones, the matrix revealed that the lowest 0.53 coefficient (highest geneticdistance 0.47) was observed between ITC-2135 and 2156 as well as ITC 2188 and2183. The highest coefficient value of 0.85 (lowest genetic distance 0.15) wasobserved between hybrids ITC-2153 and 2045 as well as ITC-2155 and 2053.

Fig. 8. RAPD profile generated by the primer OPR 08.

Fig. 7. RAPD profile generated by the primer OPAL 03.

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Fig. 9. Hierarchical clustering pattern of parents based on RAPD markers.


4.2. Cluster AnalysisBased on genetic similarity matrix of 12 oligonucleotide arbitrary decamers, phenetictrees were constructed (Fig. 9 and 10). Two major clusters were delineated (Fig. 9).Cluster-A had 23 ( ITC 99, 130, 128, 526, 417, 122, 157, 158, 147, 223, 272, 271, 292, 316,319, 266, 413, 632, 72, 273, 45 (636), 124, and 405) parental clones at coefficient levelof 0.57. Majority of clones in cluster-A belong to the local landrace Mysore gumshowing closer affinity. While, cluster-B had 21 (ITC 1, 3, 4, 7, 9, 10, 27, 83, 105, 285,288, 286, 115, 495, 274, 275, 277, 284, 290, 71 and 548) parental clones. Interestingly,clones ITC-1, 3, 4, 7, 9 and 10 belong to Australian provenance – 8 KM MW BlackMountain and the rest belong to Mysore gum.

For hybrids (Fig. 10), at a coefficient level of 0.67 cluster A had only five clones(ITC-2118, 2132, 2120, 2154 and 2124) while, in cluster B 34 (ITC-2011, 2014, 2151,2160, 2125, 2052, 2045, 2153, 2156, 2121, 2198, 2202, 2136, 2189, 2188, 2228, 2053, 2155,2149, 2069, 2147, 2152, 3017, 2019, 2149, 2023, 2144, 2139, 2135, 2204, 2169, 2183, 2207

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and 2040) hybrid clones occurred. The clustering pattern revealed that the hybridswith common parents were grouped together.

4.3. ApplicationBased on the RAPD finger printing studies, ITC 105, 1, 45(636) and 3 which expressedmaximum genetic distance were selected for further breeding and improvement. Theclones ITC-9 and 10 with maximum similarity and high wood yield are also consideredfor breeding with other clones. The DNA finger printing is also being used to registerthe clones as well as to maintain genetic purity in the gene banks.

5. Wood PropertiesThe wood morphological studies on 98 Eucalyptus clones and four seedlingscontrol grown at varied sites with differences in age, espacement and culturalpractices and there influences on various wood properties are presentedbelow:

Fig. 10. Hierarchical clustering pattern of hybrids based on RAPD markers.

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5.1. Factors Influencing Wood PropertiesIn order to identify the most suitable clone amongst from the widely representedfour clones for further development of pulpwood plantations, adjusted mean valuesof various parameters which varied considerably fitting into the model are representedin Table 4.

Table 4. Estimated adjusted means of clones with regard to selected wood properties

* Significantly lower value, ** significantly higher value

5.1.1. Tree size/volumeThe effect of the factors, viz., clone, location, age and spacing were examined. Allthe factors had significant effects on tree size. As number of trees per hectareincreased with closer spacing, tree size/volume decreased. However, with the increasein age, the tree volume has also increased. The adjusted mean value of ITC-6 wassignificantly lower than ITC-7, indicating that the ITC clone 7 may yield the highestvolume per tree with faster growth rate.

5.1.2. Basic density and moisture contentThe initial espacement alone did not explain significant variation in basic densityof wood. By and large wood density increased with age up to nine years in all theclones studied. ITC clone 4 displayed densest wood (710 kg m-3) which wassignificantly different from clone 6 with lightest wood. As the basic density valuehigher than 600 kg m-3) is not desired in eucalypts, for better pulp yield trees,clones such as ITC - 3, 6 and 7 are better compared to ITC 4. Among 98 clonesstudied, ITC 10 (699 kg m-3) and ITC 433 (676 kg m-3) also have high density. Bhat(1990) reported that aiming at faster growth does not necessarily affect the wooddensity. Although the initial moisture content in wood increased with age neitherthe espacement nor the particular clone had any effect.

5.1.3. Heartwood and bark percentageThough not related to espacement, heartwood percentage increased with age (forclone 3 at three years: 16 per cent; six years: 40 per cent and nine years: 56 per cent),after initiation at the age of three years in clone 3. No significant difference wasnoted among the clones. Bark per cent varied from clone to clone and increasedslightly with age (for clone 7 at three years: 12 per cent and nine years: 15 per cent),but the fitted model itself was not significant to explain the variation.


Clone no.

Tree vol. (m³ tree-1)

Basic density (kg m-3)

Moisture content (%)

Heart wood (%)

Fibre length (μm)

Fibre dia. (μm)

Lumen width, μm

2 x fibre wall thickness (μm)

Vessels (per mm²)

Vessel dia. (μm)

3 0.238 575.8 31.8 20.3 0.88** 19** 8** 10** 2.2* 131 4 0.169 613.9** 18.8 34.8 0.81* 16* 7 9* 2.6 136 6 0.138* 573.1* 21.4 32.2 0.86 16* 7* 9 2.5 144 7 0.346** 580.7 30.4 17.8 0.84 18 8 10 2.7** 141

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5.1.4. Fibre length, diameter, lumen width and double wall thicknessAll the factors had significant effects on the fibre length though the overall differencesamong the four clones were not statistically significant. It increases with the increasein number of trees per hectare with closer spacing and age of the trees. The fibrelength varied from 0.7 to 1 ì m and with age (for ITC-3 at three years: 0.82 and nineyears 1ì m). The fibre diameter varied from 13 to 20 ìm. All the factors had significanteffects on the fibre diameter and it decreased with the increase in number of trees perha. As age increases fibre diameter also increases. The adjusted means of clonesITC-3 vs 4, 3 vs 6 and 4 vs 7 differed significantly. Lumen width varied from 6 to 9.74ìm. Neither the number of trees per ha nor age had significant effects on fibre lumendiameter. With widest fibre lumen, clone 3 was significantly different from fibrelumen width of ITC 6. The fibre double wall thickness varied from 6.66 to 10.98 ì m.All the factors had significant effects on fibre wall thickness as it decreased with theincrease in number of trees per hectare and increased with tree age. The adjustedmean of ITC-3 was significantly different from ITC-4.

5.1.5. Tissue percentageThe percentages of vessels, fibres and parenchyma were not influenced by theclone age and espacement.

5.1.6. Number of vessels per mm² and vessel diameterThe vessel frequency varied from 1.38 to 3.28 per mm². Vessel frequency (number ofvessels) per mm² area decreased with age although espacement had no effect. Theadjusted mean of clone ITC 3 was significantly different from ITC 7. The vesseldiameter varied from 107 to 163 ì m . As number of trees per hectare increased, thevessel diameter also increased although the adjusted means of clones were notsignificantly different.

5.2. Between-Species DifferencesSpecies to species comparison revealed that wood of E. camaldulensis clone wassignificantly denser than E. tereticornis and Eucalyptus hybrids. Wood was also denserwith longer fibres in E. tereticornis than in Eucalyptus hybrids. Wood was also denserwith longer fibres in E. torelliana than in E. urophylla at the age of five years. Thelongest fibres were found in E. torelliana and E. urophylla while the densest woodwas in E. camaldulensis which is not the most preferred species for pulping.

5.3. Clonal ComparisonThe general comparison of the wood properties and tree size among clones revealedthat there could be significant differences in certain properties such as basicdensity, heartwood and bark contents, fibre dimensions (length, width, wall

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thickness) and vessel frequency (number per mm²). As a single factor, neither theclone, nor the age and espacement (number of trees per hectare) influenced thepercentages (volume) of vessels, fibres and parenchyma. This implies that theclones sampled in the study are quite uniform in wood composition in terms oftissue proportions (Fig. 11).

Clone ITC-3: (a) 1-year-old (x80); (b) 3-year-old and (c) 9-year-old trees (x40)Clone ITC-7: (d) 1-year-old (x80); (e) 3-year-old and (f) 9-year-old trees (x40)

Fig. 11. Transverse section of clones showing anatomical changes with age.


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5.3.1. Basic densityHowever, if basic density is considered as selection criterion with an averagevalue remaining within the threshold value of 600 kg m-3, two clones, viz., cloneITC-3 and 7 are the most desirable ones for pulping in view of their relatively longfibres (with a range of 0.77 to 0.97 mm from one to nine years) among the clonesstudied. If the rotation age of three years is to be fixed, ITC 3 appears to the mostpotential one as it merits most desired features such as growth rate (wood volume),basic density and fibre length. ITC 10 (699 kg m-3) and ITC 433 (676 kg m-3) appearto be the densest woods among the clones sampled. The density and structure ofhardwoods in relation to paper surface characteristics and other properties aresimilar to the studies conducted by Higgins et al. (1973). Comparison of woodproperties of clones ITC- 3 and 7 in three age groups indicates that clone 3 issuperior in tree size, basic density, fibre length at the age of three years althoughdifference at the age of four and five years were not of practical value althoughoverall growth was greater in ITC-7.

5.3.2. Fibre shape factorCross-sectional fibre shape (fd2-ld2/fd2+ld2) value was almost the same for allclones as clone 3 has value of 0.69 as against 0.67 of other three clones (ITC 4, 6and 7). This implies that cross sectional shape is almost similar among the variousclones.

5.3.3. Runkel ratioNone of the clones had Runkel ratio value <1 as clone ITC-3 and 7 displayed valueof 1.25 as against 1.28 by clones ITC-4 and 6. If this ratio is critical, clonal eucalyptsof young age may not meet the required fibre bonding in pulping.

5.3.4. Age effectAmong the various factors considered, age seems to be most crucial factorinfluencing the pulpwood quality of the clones up to nine years. Basicdensity, heartwood percentage and fibre morphology (length, diameter andwall thickness) improved with age from one to nine years in all clones whiletissue proportions and vessel diameter did not vary significantly. Basic densityand fibre length showed linear relationship with age increasing consistently.However, vessel frequency per mm2 area decreased accompanying a small increasein vessel diameter with age during the initial years of growth. Generally heartwood content increased and bark content decreased with age although variationwas very high depending on the site conditions. Trees in Jangareddygudemsites showed a tendency of higher percentage of heartwood as seen in ITC-3,115, etc.

H.D. Kulkarni


5.3.5. Effect of rotation ageIn order to ascertain the wood quality difference between three and five year rotationsof most potential clones, wood properties were compared between clones ITC-3 and7. Expecting a small difference in tree size, no significant difference was noticed inprime wood properties. This result implies that there is no economic advantage ofextending the rotation age from three to five years in terms of wood qualityimprovement in these conditions.

5.3.6. Site effectThe comparison of clone ITC-2011 and 2021 at the age of four years between fertileand poor sites revealed that wood property differences were not significantexpecting lower moisture content and wider fibre lumen in wood from fertile site(moisture: fertile = 24.4 per cent and poor = 20 per cent; lumen: fertile = 8.87 andpoor = 6.96 ì m).

5.3.7. Soil type and wood qualityWhen clones ITC-3, 7, 115, and 413 were compared at the age of four to six yearsbetween the sites with black soil and red soil, the former promoted GBH with highermoisture and heartwood contents with wider fibre lumen and thinner fibre walls.This suggests that black soil condition is more favourable for better tree growth andthinner fibres although higher heartwood and moisture contents are not desired bythe pulping industry. Similar earlier studies by Purkayastha et al. (1979) and Singhet al. (1986) on five different plantation sties of E. tereticornis in India indicatedinfluence of locality factor in the variation in wood specific gravity and fibre/vesselcharacteristics and their influence on surface properties of hard sheets. Majority ofclones have shown site specificity (areas with black soil and red soils) in respect ofgrowth, adaptability and productivity. Hence, in the first phase, the site-specificclones are shortlisted and then clones with best wood properties are promoted forlarge scale plantations (Kulkarni, 2004).

5.3.8. Irrigation/fertilization effectsClones ITC-3 and 7 were sampled from three to four years old plantations to comparethe wood properties from irrigated and rainfed conditions. As a response to irrigation,clones showed higher vessel percentage with larger vessels, for better conductionefficiency, and greater moisture content in the wood although the difference wassignificant only in ITC-3 for the former and ITC-7 for the latter due to small numberof samples studied. This tendency of higher vessel percentage is in agreement withthe index suggested by Carlquist and Hoekman (1985) with vulnerability ratio (vesseldiameter/vessel frequency per mm2) value being lower towards the drought condition,as it decreased from 59 to 56 from the irrigated to rainfed plantations in ITC-3. In

168

three years old ITC-3 from Jangareddygudem locality, the trend was clear forincreased tree height, GBH, basic density, fibre lumen width, vessel percentage,vessel diameter and vessel frequency in irrigated condition. Bhandari et al. (1988) intheir studies on kraft pulps of E. tereticornis bought out effect of locality on fibre/vessel characteristics and strength/surface prosperities of paper.

5.3.9. Coppice vs main cropTesting of three years old trees of clones ITC-3 and 7 indicated that the differenceswhere significant only for fibre with thinner walls with higher moisture content incoppice crops of ITC-3 while ITC-7 had longer fibres and higher percentage of bark.The study needs to be continued with testing larger number of clonal samples tosupport the current indicative figures.

5.3.10. Influence of tree heightWithin the tree, tissue proportions did not show consistent variation from the baseto the top. However, basic density, fibre length and heartwood percentage variedsignificantly. As shown in clone ITC-3, basic density increased initially from thebase upto 50 per cent of the tree height before it started decreasing to the top whilefibre length increased only upto 25 per cent of tree height level and then decreasedtowards the crown. Heartwood percentage decreased consistently from the base totop.

5.3.11. Superiority of clones over seedling controlThe comparison of ITC-3 with seedling crop at the age of three years indicates thatclones have gained superiority in pulpwood quality over the seedlings in Sarapakasite. Basic density was higher by 13 per cent and fibre length by 17 per cent withincrease in fibre diameter and wall thickness in clones ITC-3 and 7, respectivelywhile other parameters of fibre morphology were not significantly affected. At age ofsix years, the superiority was seen clearly in ITC-3 with longer fibres and less densewood having density value of 520 kg m-3 than the seedling crop having densityvalue of 648 kg m-3.

5.3.12. Wood basic density and fibre dimensions have long been accepted as themost crucial quality indicators of pulpwood. Low density and longer fibre woods aremostly preferred for pulping process for eucalypts. The basic density is generally anindicative of pulp yield of any species for raw material production as it is a measureof the mass of wood on oven dry basis. Fibre length is known to determine thetearing strength of paper. If low density aids impregnation due to a more open woodstructure, longer fibres promote higher tear index (Banham, et al., 1995). The studiessuggest that in eucalypts, the optimum basic density is around 480 to 520 kg m-3 and

H.D. Kulkarni

169

above the upper limit of 600 kg m-3 (Dean, 1995). The other crucial parameter of fibremorphology that favours the pulping properties is the ratio of double wall thicknessof fibre/lumen width of fibre and the value of upper limit is 1; the desired Runkel ratioof 2 x fibre wall thickness/lumen diameter is < 1. The pulpwood demand and qualityassessment studies are reported by Singh and Naithani (1994). Further, a detailedaccount of eucalypt for pulp and paper making are also given by Sharma and Bhandari(1983) and Tewari (1992). Hence, it is concluded that:

a. clones gained considerable superiority over seedling crop with optimalbasic density and longer fibres. Wood quality is significantly influencedby various factors such as clone, age, site/soil type, spacing, irrigation,etc. Age seems to be the most crucial factor that determines the pulp woodquality up to the age of 9 years,

b. among the 98 clones tested clones ITC-3, 4, 6, and 7 merit attentions inshortlisting the clones as most potential ones for commercial multiplicationbecause of their relatively modest wood density, longest and widest fibreswith wider lumen and thicker walls. However ITC-4 has denser wood (>600kg m-3 and shorter fibres making it the least favoured among the fourpotential clones identified,

c. clones with denser wood showed the tendency of having shorter fibresd. two clones, viz., ITC-3 and 7 are the most desirable ones for pulping in view

of their relatively long fibres and desired wood basic density around 576 to581 kg m-3, and

e. clone ITC-7 yields more wood per tree (greater growth rate).

5.3.13. Based on the wood morphology, site/soil and silvicultural practices out of98 clones studies, 31 potential clones (ITC-3, 6, 7, 10, 27, 99, 105, 122, 130, 222, 226,265, 271, 272, 273, 274, 285, 286, 288, 316, 405, 411, 412, 413, 501, 2045, 2069, 2070,2135, 2253 and 2254) of superior pulp and paper qualities are shortlisted for commercialcultivation in clonal plantation programme.

6. Improvement for Pulp and Paper Quality

6.1. Pulp AnalysisProximate chemical analysis and strength properties for 213 E. tereticornis clonesrevealed wide variation (Table 5). The ash content ranged from 0.37 to 4.2 per centwith a mean of 1.3 per cent. Clone ITC-319 showed minimum ash content while, ITC-2231 gave 4.2 per cent. The alcohol-benzene (A-B) extractive content ranged from1.24 (for clone 2294) to 8.4 per cent (for clone 266) with a mean of 3.3 per cent.Presence of more extractive content tends to increase the consumption of chemicalsduring pulping and reduce pulp yield.


170

6.2. LigninIn respect of lignin, ITC-2396 showed lowest lignin (24.7%) while, ITC-2324 had highestlignin content (35.7%). Out of 213 clones analyzed, 71 clones fall under 28 to 30 percent class intervals while, 9 clones in 34-36 per cent and 10 clones in 24 to 26 per centclass intervals (Fig. 12). The unbleached brightness of pulp varied from 24.4 to 39 percent and the average brightness was observed at 32.8 per cent. More lignin contentmeans high chemical consumption in cooking and bleaching of wood. Moreover,higher lignin has significant impact on refining and paper properties. Lignin ishydrophobic and contains chromophoric groups, therefore, pulp has poor swellingcharacteristics (Singh and Rawat, 2000). Hence, low fibre bonding results in low strengthproperties. Kappa number, a measure of residual lignin, varied from 19.1 to 29.7 withaverage value of 22 indicating variation in lignin content in the 213 clones analyzed inthe study. More bleaching chemicals are required to bleach higher amount of lignin.Sharma et.al. (1987) opined that more lignin has to be removed to produce easilybleachable grade pulp of satisfactory brightness by increasing active alkali chargeand pulp yield and kappa number decrease with increased chemical charge.

6.3. Cellulose and PentosansFor holocellulose content, the readings varied from 54.3 to 70 per cent with a meanvalue of 63.7 per cent. Out of 213 clones, nearly142 clones occurred in 61 to 66 per

H.D. Kulkarni

Parameter Unit Minimum Maximum Mean

Ash % 0.37 4.20 1.3 A-B extractives % 1.24 8.40 3.3 Lignin % 24.70 35.70 29.4 Holo-cellulose % 54.30 70.00 63.7 Pentosans % 9.00 17.20 13.9 Screen pulp yield % 44.00 53.00 47.9 Rejects % 0.23 4.10 1.2 Kappa no. 19.00 29.70 22.0 UBV cps 11.90 22.80 14.8 Brightness % 24.40 39.00 32.8 R.A.A. gpl 3.10 13.30 6.9 Solids % 11.00 19.20 14.4 Organics % 51.50 62.0 56.8 In-organics % 38.00 48.50 43.0 Bulk cc gm-1 1.34 1.97 1.7 Burst factor - 26.00 58.00 34.9 Tear factor - 44.00 78.00 54.3 Breaking length m 3900 8000 5194 Strength index - 20.00 85.00 41.0

Table. 5. Variation in pulp and paper properties for E. tereticornis clones

171

cent class interval followed by 41 clones in 66 to 70 per cent class interval (Fig. 13).The lowest holocellulose content of 51-56 per cent was shown by ITC-411 and 417which is not a desirable property. The highest holocellulose content of 70 per centwas shown by ITC-343. More cellulose content means better property for papermaking. The pentosans percentage varied from 9 to 17.2 with a mean value of 13.9.

6.4. Screened YieldThe important parameter for pulp properties is the screened yield. Eucalypts requireless chemicals (17%) to obtain 46 to 48.8 per cent pulp yield at kappa number 22 to20. The screened pulp yield for 213 clones ranged from 44 to 53 per cent with a mean


Fig. 12. Variation in lignin content in E. tereticornis clones.

Fig. 13. Variation in holocellulose content in E. tereticornis clones.

10

49

71

53

21

9

0

10

20

30

40

50

60

70

80

24‐26 26‐28 28‐30 30‐32 32‐34 34‐36

Lignin (%)

No.

of c

lone

s (n

=213

)

2

28

142

41

0

20

40

60

80

100

120

140

160

51‐56 56‐61 61‐66 66‐70

Holocellulose (%)

No.

of c

lone

s (n

=213

)

172

value of 47.8 per cent. Highest number of clones (51 clones) gave 49 per cent pulpyield (Fig. 14). The best performance at 53 per cent was shown by ITC-2129 while theleast performance at 44 per cent of pulp yield was shown by ITC-147, 319, 433, 2069,2261, 2262, 2264 clones.

6.5. Rejects, UBV and RAAThe clone 2008 showed higher per cent of rejects at 4.10 per cent while lowest valueof less than 0.5 per cent was recorded in 11 clones. The average value of 1.2 per centwas recorded for 99 clones out of 213 clones. Dadswell and Wardrop (1959) linkedrejects with that of density and opined that with increase in density of wood pulp,rejects also increase as well as tear and tensile indices decline. Unbleached viscosity(UBV) varied (range 11.9 to 22.8 cps) considerably with a mean value of 14.8 cps.Similar trend was also observed for other parameters like R.A.A, solids, organicsand inorganics.

6.6. BulkThe eucalypt clones showed higher bulk of 1.7 cc gm-1 (range 1.34 to 1.97). Stifffibres of eucalypts give more bulk due to which more open sheet and goodstrength in the wet state is obtained where eucalypt pulp show distinct advantagecompared to other hardwoods. The bulkier sheets with increased porosity givebetter drying on higher machine speed reducing the drying costs considerably.Therefore, higher bulk gives better printability on coated board with goodrunnability. Sharma and Bhandari (1983) reported that eucalypt that pulp withhigher bulk formed bulkier sheets than those with less bulk. In the present studyalso clones with high bulk values gave bulkier sheets. Bulk and stiffness arecritical to paperboards manufacture and is an important property of eucalypt

H.D. Kulkarni

Fig. 14. Variation in pulp screened yield for E. tereticornis clones.

7 9

23

45 4751

18

7 51

0

10

20

30

40

50

60

44 45 46 47 48 49 50 51 52 53

Screened yield (%)

No.

of c

lone

s (n

=213

)

173

clones which is employed for production of paperboards in ITCs mill atBhadrachalam. However, during a trial run with only eucalypt wood it wasobserved that there is high amount of fluff generation and fines are on higherside (4.5 to 4.7%) which creates problems at paper machine level. Blendingeucalypt fibre with other pulp wood species appears to be an answer to thisproblem.

6.7. Paper PropertiesStrength properties in respect of burst and tear factor and breaking lengthvariation was significant and indicated in the form of strength index which rangedfrom 20 to 85 with a mean at 41. The maximum breaking length of 8,000 m wasrecorded for ITC-2385 while the average breaking length was at 5,194 m.There are 40 clones showing strength index above 50 which are preferredfor paperboard making (Fig. 15). A strong and significant trend of low pulpyield and strength index with high content of lignin, rejects, kappa numberand AB extractives is observed with respect to ITC-7 of E. tereticornis(Table 6).


Fig. 15. Strength index for E. tereticornis clones.

6.8. Eucalyptus spp.Results of proximate chemical analysis and strength properties (Table 7 and Fig.16 to 19) indicate that the screened pulp yield was higher (49 to 52.8%) forclones of E. globulus, E. grandis, E. torelliana, E. urophylla and Urograndishybrids while it was on lower side (46%) for E. alba and E. camaldulensis. Thestrength index was high (above 50) for E. globulus, E. grandis and Urograndishybrid whereas, E. alba, E. camaldulensis, E. torelliana and E. urophyllashowed considerably lower strength index. Breaking length was invariably high

17

22

17

41 42

34

24

4 3 3 2 2 2

0

5

10

15

20

25

30

35

40

45

20‐25 25‐30 30‐35 35‐40 40‐45 45‐50 50‐55 55‐60 60‐65 65‐70 70‐75 75‐80 80‐85

Strength index

No.

of c

lone

s (n

=213

)

174 H.D. Kulkarni

Clone no. A-B extractives (%)

Lignin (%)

Holo-cellulose (%)

Kappa (no.)

Rejects (%)

Screen pulp yield (%)

Strength index

147 3.30 32.2 62.3 23.6 1.40 44 20.0 319 4.10 29.2 65.2 21.3 0.53 44 29.6 433 4.50 27.1 64.5 21.4 1.38 44 39.2 2069 2.86 31.3 61.4 25.0 2.21 44 29.9 2261 2.48 31.2 62.4 23.9 3.82 44 29.5 2262 3.20 28.3 67.0 24.8 0.94 44 42.3 2264 3.80 30.1 62.1 22.3 1.50 44 51.5

Table. 6. Low pulp yielding E. tereticornis clones with other properties

Fig. 16. Comparison among Eucalyptus species/hybrid clones for lignin.

26 26 27 2728 29 29 29 29 30

31 3133

0

5

10

15

20

25

30

35

E. torellina455

E. globulus (Ooty)

E. urophylla347

Urograndis2254

E. alba Urograndis2253

Urograndis (BCM)

E. grandis643

(HNL)

E. teriticornis(BCM

Clones)

E. grandis (Ooty)

Urograndis 283

(HPL)

E.urophylla348

E. camaldulensis678

Lign

in (%

)

Eucalyptus species/hybrid clones

Fig. 17. Comparison among Eucalyptus species/hybrid clones for holocellulose.

6060 61 61

6364

64 64 64 64

66

6868

54

56

58

60

62

64

66

68

70

E. grandis (Ooty)

E. alba E.urophylla348

E. camaldulensis678

Urograndis (BCM)

E. teriticornis(BCMClones)

E. torellina455

E. grandis643

(HNL)

E. urophylla347

Urograndis 283

(HPL)

Urograndis2253

Urograndis2254

E. globulus (Ooty)

Holo

-cel

lulo

se (

%)

Eucalyptus species/hybrid clones

175Eucalypt improvement at ITCU

nit

Mea

n Pa

ram

eter

U

225

3 U

225

4 U

(B

CM

) U

283

(H

PL)

E.u.

347

E.

u. 3

48

E.t.

455

E.g.

643

(H

NL)

E.

g

(OO

TY)

E.c.

67

8 E.

gl.

(Oot

y)

E.a.

Ash

%

0.

98

1.18

1.

59

1.10

0.

98

1.96

1.

89

1.79

2.

87

0.98

0.

74

0.40

A

-B ex

tract

ives

%

4.

10

2.69

3.

10

3.20

6.

20

4.90

4.

00

3.79

3.

11

4.60

3.

70

2.50

Li

gnin

%

28

.50

26.9

0 28

.90

31.0

0 26

.50

31.3

0 26

.10

28.9

0 29

.60

32.9

0 26

.10

27.9

0 H

olo-

cellu

lose

%

66

.40

67.7

0 62

.80

64.4

0 64

.20

60.7

0 64

.00

64.1

0 59

.80

60.8

0 68

.20

60.3

0 Pe

ntos

ans

%

15.6

0 16

.40

18.7

0 16

.60

13.8

0 11

.90

16.5

0 15

.79

11.6

0 15

.90

16.4

7 14

.10

Scre

ened

pul

p yi

eld

%

49.4

0 50

.18

49.0

0 47

.90

45.0

0 50

.40

51.7

0 52

.80

51.0

0 45

.67

49.0

0 46

.00

Reje

cts

%

0.70

1.

59

1.60

0.

90

0.70

1.

60

0.30

1.

16

1.10

0.

54

1.00

1.

40

Kapp

a

No.

22

.80

21.1

0 22

.00

23.0

0 24

.60

24.0

0 22

.00

22.2

0 21

.20

21.9

0 22

.00

21.0

0 UB

V

%

19.2

0 14

.20

15.1

0 17

.40

15.7

0 14

.80

17.2

0 20

.66

18.5

0 13

.00

15.0

0 14

.50

Brig

htne

ss

%

34.0

0 30

.00

32.1

0 35

.00

34.0

0 36

.00

34.0

0 36

.50

36.1

0 26

.90

35.0

0 36

.00

R.A.

A.

gpl

7.60

7.

10

6.80

9.

20

8.80

7.

90

8.60

9.

40

9.80

4.

00

9.50

8.

60

Solid

s %

13

.10

12.5

0 13

.50

14.2

0 13

.00

12.2

0 13

.70

14.1

0 13

.90

17.2

0 20

.00

18.4

0 O

rgan

ics

%

60.5

0 55

.40

56.0

0 61

.20

61.9

0 64

.50

63.7

0 54

.60

53.5

0 56

.80

55.0

0 53

.00

Inor

gani

cs

%

39.5

0 44

.60

44.0

0 38

.80

38.1

0 35

.50

36.3

0 45

.40

46.5

0 43

.20

45.0

0 47

.00

Bulk

cc

gm

-1

1.45

1.

68

1.80

1.

60

1.70

1.

70

1.61

1.

62

1.50

1.

80

1.40

1.

60

Burs

t fac

tor

- 44

.00

37.0

0 40

.00

41.0

0 35

.00

31.0

0 38

.00

44.1

0 49

.00

29.0

0 43

.00

38.0

0 Te

ar fa

ctor

-

63.0

0 63

.00

55.0

0 66

.00

51.0

0 55

.00

54.0

0 72

.00

65.0

0 42

.00

58.0

0 48

.00

Brea

king

leng

th

m

5980

56

90

5680

55

42

4900

48

00

5250

56

21

6420

39

00

6970

49

40

Stre

ngth

inde

x -

66.8

0 56

.90

51.8

0 62

.42

35.0

0 34

.00

44.5

0 72

.31

78.2

0 10

.00

70.7

0 35

.40

U =

urog

rand

is; E

.u.=

E. u

roph

ylla

; E.t.

= E

. tor

ellia

na; E

.g. =

E. g

rand

is; E

.c. =

E. c

amal

dule

nsis;

E.g

l. =

E. g

lobu

lus a

nd E

.a. =

E. a

lba

Tabl

e 7.

Pul

p an

d pa

per

and

stre

ngth

pro

pert

ies

for

clon

al E

ucal

yptu

s sp

ecie

s

176 H.D. Kulkarni

Fig. 18. Comparison among Eucalyptus species/hybrid clones for pulp screened yield.

Fig. 19. Comparison among Eucalyptus species/hybrid clones for strength index.

for E. globulus, E. grandis, E. urophylla and Urograndis hybrids indicating thatthe fibres are longer and stronger in comparison to E. alba, E. camaldulensisand E. tereticornis. Apart from the above, wide variation in lignin content isalso recorded between species while other parameters remained the same withless variation. The above results clearly show that best fibre for paper makingcan be derived from species such as E. globulus, E. grandis, E. torelliana,E. urophylla and Urograndis and other hybrids than pure species E. alba,E. camaldulensis and E. tereticornis. Seventeen clones of E. grandis from 643

4546 46

48 48

49 49 4950 50

5152

53

40

42

44

46

48

50

52

54

E. urophylla347

E. camaldulensis678

E. alba E. teriticornis(BCMClones)

Urograndis 283

(HPL)

Urograndis (BCM)

E. globulus (Ooty)

Urograndis2253

Urograndis2254

E.urophylla348

E. grandis (Ooty)

E. torellina455

E. grandis643

(HNL)

Scre

en y

ield

(%)

Eucalyptusspecies/hybrid clones

10

34 35 3541

45

5257

6267

71 7278

0

10

20

30

40

50

60

70

80

90

E. camaldulensis678

E. urophylla348

E. urophylla347

E. alba E. teriticornis(BCMClones)

E. torellina455

Urograndis (BCM)

Urograndis2254

Urograndis 283

(HPL)

Urograndis2253

E. globulus (Ooty)

E. grandis643

(HNL)

E. grandis (Ooty)

Stre

ngth

inde

x

Eucalyptusspecies/hybrid clones


to 659 numbers showed high pulp yield of 50 to 53 per cent but did not performwell at Bhadrachalam location. These E. grandis clones however, are performingwell at Hindustan Newsprint Limited (HNL), Kottayam, Kerala. E. globulus (bluegum) is not adaptable to Bhadrachalam site as it requires higher elevation andtemperate climate. The clones of above species gave excellent properties withrespect to pulp and paper properties and similar results are recorded by Tewari(1992) for eucalypt kraft pulps which give a unique combination of strength,bulk and opacity. This combination together with excellent sheet formationcaused by extremely small fibres makes Eucalyptus pulp as an ideal raw materialfor fine papers.

6.9. Age FactorThe data in Table 8 indicate that the proximate chemical compositions and strengthproperties of eucalypts are highly influenced by age. The lignin per cent increasedwith age from 23.4 to 27 and 28.4 to 31.3 for ITC-3 and 7, respectively. Similar trendwas also recorded for screened pulp yield 48.4 to 50.4 per cent for ITC-3 and 47.44to 49.8 per cent for ITC-7. Strength index increased from 30.33 to 46.38 for ITC-3and 37.8 to 46 for ITC-7 suggesting that the fibre strength is less at young agewhile the required strength in fibre is attained at four years. Other parameters didnot vary drastically.

Table 8. Age-wise analysis of ITC-3 and 7 for pulp and paper propertiesClone ITC-3 Clone ITC-7 Parameter Unit

1 Yr 2 Yr 3 Yr 4 Yr 1 Yr 2 Yr 3 Yr 4 Yr

Ash % 1.03 1.00 1.74 1.04 1.31 1.11 1.28 0.92 A-B extractives % 3.48 2.35 2.99 3.71 4.33 2.98 3.20 3.67 Lignin % 23.40 24.60 24.10 27.00 28.40 30.40 31.40 31.30 Holo-cellulose % 65.10 65.50 62.30 61.20 63.00 64.90 63.30 64.20 Pentosans % 14.39 14.57 14.54 15.54 15.28 16.44 15.70 16.90 Screened pulp yield % 48.40 49.30 50.40 51.00 47.44 47.60 48.40 49.80 Rejects % 1.10 1.12 1.46 1.87 0.59 0.69 0.86 1.11 UBV cps 13.70 14.50 14.90 16.00 14.10 14.20 15.50 14.90

Brightness % 35.30 35.20 35.30 35.20 28.40 31.40 33.50 35.90 R.A.A. gpl 7.00 5.30 7.00 5.60 6.30 7.00 7.60 8.10 Solids % 13.70 12.60 13.80 12.40 12.50 13.60 12.60 13.50 Organics % 54.60 55.40 56.20 56.80 54.00 55.60 56.80 57.90 In-organics % 45.40 44.60 43.80 43.20 46.00 44.40 43.20 42.10 Bulk cc gm-1 1.70 1.70 1.70 1.80 1.70 1.70 1.63 1.71 Burst factor - 29.50 30.50 35.00 37.00 30.00 31.00 33.20 35.60 Tear factor - 54.50 54.50 53.00 55.00 53.00 55.00 54.00 57.60 Breaking length m 4633 4661 5378 5438 5480 4986 5203 5280 Strength index - 30.33 31.61 41.78 46.38 37.80 35.86 39.2 46.00

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6.10. HybridsThe hybridization between best clones ITC-6, 10 and 27 was carried out in order toobtain hybrids with superior pulp and paper properties. Perusal of Table 9 reveals thathybrids clones ITC-2120, 2121 and 2156 have shown improvement with regard to screenyield and strength properties while marginal improvement in other parameters is alsoseen. Many hybrids have outperformed in the field as well as with pulp and paperproperties and are being planted on large scale in the catchment area of the company.

H.D. Kulkarni

Table 9. Comparison between parent and hybrid progeny for improvement of pulpand paper traits in ITC Bhadrachalam clones of Eucalyptus

Rao et.al. (1999) rated five Bhadrachalam clones of eucalypt (clone ITC-3, 4, 6,7 and 10) as high pulp yielding clones with high holocellulose content (66.64 to71.44 %), lignin of 24.92 to 30.17 per cent and pulp yield of 48.3 to 53.3 per cent.

Supply of fibre is the key issue facing the pulp and paper industry in India. Rawmaterial and processing costs raise serious concerns over competitiveness of theindustry. While considering the entire production chain from wood procurement topaper products, with optimum wood density (550 to 600 kg m 3), higher pulp yieldallows reduction in wood requirement and savings on wood cost. The unit cost ofthis extra pulp is the variable cost of bleaching and drying. Wood with high pulpwoodyield will have a lower chemical demand. Higher pulp yield with improved pulpstrength has cost advantage. Improved pulp yield reduces fixed costs (e.g. capitalcost per tonne of production). It is estimated that less alkali consumption, less useof bleaching chemicals, less power consumption, less wood requirement, moredigester productivity and more steam generation from lignin lead to sizable costsavings. The economics of harvesting, transport and processing are greatly improvedwhen the pulp yield is high. Pulp yield has a multiplier effect on costs for growing,harvesting, transport and processing (Dean, 1995). Therefore, breeding programme

Parent Hybrid clone

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Bulk cc gm-1 1.50 1.50 1.90 1.70 1.50 1.60 Burst factor - 39.20 39.80 31.20 43.00 43.80 40.00 Tear factor - 66.00 64.00 57.50 78.00 80.00 62.00

Breaking length m 5520 5350 4425 6000 6400 5400 Stre

ngth

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Strength index - 60.40 57.30 33.00 81.00 87.80 56.00

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should consider cost of pulp production and accordingly plan clonal developmentand deployment.

Eucalypt wood has been an important raw material for pulp production. Itscontribution to the world market of pulp is continuously growing (Kulkarni, 2008,2013). It is a very good wood source for the paper mills as the yield of many speciesof eucalypts is high and pulps are very easy to bleach to high brightness. Fibre ofeucalypts is highly valued in the world market as the fibres are small, in diameter, andhave relatively thick wall for their size. This fibre property leads to less flocculationand good sheet formation (Dean, 1995). The small fibre enhances opacity due toextra surface area for bonding and adds to visual appearance and better performanceduring processing and in end product (Tewari, 1992). The wall thickness impartsincreased porosity and better drying on higher machine speed. Further, the stifffibres of eucalypt give high bulk, more open sheet and good strength in wet state.Higher bulk gives better printability on coated board and good runnability.

Wood raw material quality sets the quality of pulp and paper. Within the 225eucalypt Bhadrachalam clones analyzed for proximate chemical analysis andstrength properties, there are wide differences in pulp and paper makingproperties. Pulp yield and strength properties are the important characteristicswhich are financially rewarding and advantageous to the paper mills. Top 25 clonesare ranked according to the pulp yield and strength properties index– ITC-3, 6, 7,10, 27, 158, 273, 274, 279, 286, 288, 411, 412, 2014, and hybrids 2050, 2121, 2129,2135, 2140, 2143, 2156, 2294, 2306, 2315, 2401 and are recommended for large scalemultiplication and planting under farm forestry programme (Venkatesh and Kulkarni,2002). Amongst them, eight clones have shown highest strength index (ITC-10,274, 288, 2129, 2140, 2143, 2306 and 2401).

Eucalypt clones with high productivity, best pulp and paper properties not serveany purpose if they are affected by gall disease caused by Leptocybe invasa insect.Clones resistant to gall (Kulkarni, 2010a) along with pulp and paper properties arerequired to be promoted in the plantation programme. Hence, clones ITC-1, 7, 320, 411,413, 513, 612, 2008, 2145, 2253, 2254 and 2306 now with moderately high pulp yield andstrength properties are being recommended for planting on large scale.

7. Clonal Nursery InfrastructureFor a successful clonal forestry programme, a good nursery is a pre-requisite. Amodern clonal nursery with an annual production capacity of 20 million Eucalyptusramets was established with indigenous technological know-how. Presently, theinfrastructure for clonal propagation includes 120 mist chambers covering an area of12,000 m2, hardening area of 5,000 m2 and 0.1 M m2 for open nursery. The clonaltechnology with root trainers has given considerable improvement in the productionof quality planting stock. The root development is better than seedlings raised in


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0 50.60

0 1.60 0 40.00 0 62.00

0 5400 0 56.00

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polypots as multiple roots seldom form in the root trainers and root coiling is totallyavoided. The outplanting results were quite high, thereby increasing survival andproductivity.

8. Package of PracticesApart from the superior genetic quality of the planting stock, site quality,adaptability of the clones to specific sites, implementation of the improved packageof practices and effective protection of plantations from damage by pests, diseasesand cattle are also important factors which determine the overall productivity ofthe plantations. Therefore, the company developed an improved package ofpractices for rising and maintenance of clonal eucalypt plantations anddemonstrated the benefits of the same to the farmers. Study of soil profiles andanalysis of soil samples was carried out to match adaptable clones to the plantingsites. Deep ploughing of the soil with disk ploughs or mould-board ploughs inboth directions is recommended for preparing the fields for transplanting of clonalsaplings. Spacing of 3 m x 2 m and 3 m x 1.5 m is recommended for the productionof poles and pulpwood, and larger spacing is desirable for production of timber(Table 10 and Fig. 20). Transplanting in 30 cm3 pits is carried out during the earlyparts of the monsoon rains so that plants establish and grow well benefiting fromthe good moisture availability throughout the monsoon rains. Soil in and aroundthe planting pit is treated with 2 ml of chlorpyriphos in one litre of water to preventdamage to the young clonal saplings by termites during the critical establishmentstage. Application of bio-pesticides like kodesa (Clistanthus collinus) forcontrolling termites was introduced as an eco-friendly replacement to chemicalpesticides. Cultural practices recommended include timely weeding and soilworking, protection against damage by insect pests and cattle and raising ofleguminous crops in between the 3 m wide rows for green manuring. In addition,inter-cultivation (agroforestry) with cotton, chilli, tobacco, pulses, vegetables,and horticulture plants was encouraged during the first year of planting whichgives additional earnings to the farmers. As most of the soils in India are deficientin nitrogen and phosphorous, application of fertilizers to supplement availability

H.D. Kulkarni

Table 10. Result of spacing trials of clone ITC-3 at the age of four yearsSpacing (m2) No. of trees GBH (m) Height (m) Volume (m3)

1X1 10,000 0.1500 10.30 0.009 1X1.5 6,666 0.1734 11.55 0.012 1X2 5,000 0.1957 12.25 0.016 1X3 3,333 0.2180 13.85 0.021

1.5X2 3,333 0.2069 13.05 0.018 1.5X3 2,222 0.2436 14.45 0.027 2X2 2,500 0.2537 14.57 0.029 2X3 1,666 0.2832 16.15 0.039 3X3 1,111 0.3213 18.00 0.055

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of these deficient plant nutrients is recommended. Soil and water conservationmeasures like raised field boundaries and staggered trenches are recommended inwell-drained planting sites for holding the rainwater. However, in low-lying areasor poorly drained heavy black cotton soils, drainage has to be improved duringthe rainy season. It was found that eucalypt plantations with Pisolithus tinctoriusecto-mycorrhizae showed excellent growth. Hence, this symbiotic association wasused in the clonal propagation wherein the rooting media was inoculated with thespores and it became part of nursery package of practices.

9. Clonal PlantationsThe company distributed more than 145 M clonal saplings to growers from 1992to 2013. More than 65,114 ha (Fig. 21) of clonal plantations have emerged over aperiod of 21 years under farm forestry programme promoted by ITC, which hascreated an estimated wood asset worth Rs. 16 billion* (US$ 290 million**).However, the all India figure of clonal plantations today is more than 0.2 Mha.These clonal farm forestry plantations are also acting as carbon sinksremoving an estimated 9.5 Mt of carbon dioxide from the atmosphere. Theseplantations have generated estimated 29.25 million person days of employmentopportunities over one felling cycle to the rural masses bringing in socio-economic prosperity.

* Green wood: per tonne value Rs. 3,000**1 US$= Rs. 55


Fig. 20.Tree volume observed in spacing trials of clone ITC-3 at the age of four years.

0.0090.012

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AcknowledgementThe author is grateful to Mr. Sanjay Singh, Divisional Chief Executive of ITC PSPD forencouragement and support of plantation research and development. Thanks are dueto the research, production, marketing and extension team of plantation departmentfor active support and encouragement. Thanks are also due to Dr. M. Parmathma andDr. K.T. Parthiban of TNAU, Mettupalyam and Dr. (Late) K.M. Bhat of KFRI, Peechifor undertaking wood properties and DNA finger printing studies, respectively.

ReferencesBanham, P.W.; Orme, K. and Russel, S. L. 1995. Pulpwood qualities required for cold

soda pulping process. In: CRC-IUFRO Conference on EucalyptusPlantations Improving Fibre Yield and Quality, Hobart, 19-24 February 1995.Proceedings edited by J.B. Reid; R.N. Cromer; W.N. Tibbits and C.A.Raymond. Hobart, CRCTHF. pp. 1-4.

Bhat, K.M. 1990. Wood quality improvement of Eucalyptus in India: An assessmentof property – variation. Journal of the Indian Academy of Wood Science,21(2): 33-40.

Bhandari, S.S.; Singh, S.P.; Singh, S.V.; Krishna Lal and Sharma, P. 1988. Effect oflocality on fibre/vessel characteristics and strength/surface prosperities ofkraft pulps of E. tereticornis. Journal of the Timber DevelopmentAssociation of India, 34(1): 16-22.

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Carlquist, S. and Hoekman, D. A. 1985. Ecological wood anatomy of the woodysouthern Californian flora. IAWA Journal, 6(4): 319-348.

Chaturvedi, A.N. 1995. Volume tables and the regression equation for clonal plants.New Delhi, Tata Energy Research Institute.

Dean, G.H. 1995. Objectives for wood fibre quality uniformity. In: CRC-IUFROConference on Eucalyptus Plantations Improving Fibre Yield and Quality,Hobart, 19-24 February 1995. Proceedings edited by J.B. Reid; R.N. Cromer;W.N. Tibbits and C.A. Raymond. Hobart, CRCTHF. pp. 5-9.

Dadswell, H.E. and Wardrop, A.B. 1959. Growing trees with properties desirable forpaper manufacture. APPITA, 12(1): 129-136.

Higgins, H.G.; de Yong, J.; Balodid, V.; Phillips, F.H. and Colley, J. 1973. The densityand structure of hardwoods in relation to paper surface characteristics andother properties. TAPPI, 56(8): 127-131.

Kulkarni, H.D. and Lal, P. 1995. Performance of Eucalyptus clones at ITC BhadrachalamIndia. In: CRC-IUFRO Conference on Eucalyptus Plantations ImprovingFibre Yield and Quality, Hobart, 19-24 February 1995. Proceedings editedby J.B. Reid; R.N. Cromer; W.N. Tibbits and C.A. Raymond. Hobart,CRCTHF. pp. 274-275.

Kulkarni, H.D. 2001. Eucalyptus hybrid breeding in ITC Bhadrachalam, India. In:IUFRO International Symposium on Developing the Eucalyptus for thefuture. Valdivia, 10-15 September 2001. Proceedings.

Kulkarni, H.D. 2004. Clonal forestry for industrial wood production: An ITCexperience. In: Parthiban, K.T.; Paramathma, M. and Neelakantan, K.S. Eds.Compendium on clonal forestry. Mettupalyam, Tamil Nadu AgriculturalUniversity. pp. 92-113.

Kulkarni, H.D. 2008. Private farmer – Private industry partnerships for industrial woodproduction: A case study. International Forestry Review, 10(2): 147-155.

Kulkarni, H.D. 2010a. Screening Eucalyptus clones against Leptocybe invasa Fischerand La Salle (Hymenoptera: Eulophidae). Karnataka Journal of AgriculturalScience, 23(1): 87-90.

Kulkarni, H.D. 2010b. Little leaf disease on Eucalyptus by thrips. Karnataka Journalof Agricultural Science, 23(1): 203-206.

Kulkarni, H.D. 2010c. Indigenous insect pests – Batocera and Apriona beetle attack onEucalyptus. Karnataka Journal of Agricultural Science, 23(1): 207-210.

Kulkarni, H.D. 2013. Pulp and paper industry raw material scenario – ITC plantationa case study. IPPTA, 25(1): 79-89.

MANAGE (National Institute of Agricultural Extension Management). 2003.Economics of ITC clonal Eucalyptus. Hyderabad, MANAGE. 10p.

Paramathma, M. and Kulkarni, H.D. 2005. DNA finger printing of clones of Eucalyptusspecies using RAPD technique. Final report. Mettupalyam, TNAU.


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Purkayastha, S.K.; Agarwal, S.P.; Farooqui, P.; Tandon, R.D.; Chauhan, Laxmi andMisra, N. 1979. Evaluation of wood quality of Eucalyptus plantations invarious states. Final technical report. Dehradun, FRI. 85p.

Rajan, B.K.C. 1987. Versatile Eucalyptus. Bangalore, Diana Publications. pp. 183-201.Rao, R.V.; Kothiyal, V.; Sreevani, P.; Sashikala, S.; Naithani, S. and Singh, S.V. 1999.

Yield and strength properties of pulp of some clones of Eucalyptustereticornis Sm. Indian Forester, 125(11): 1145-1150.

Sekar, S.; Srimathi, R.A.; Kulkarni, H.D. and Venkatesan, K.R. 1984. Computer designfor tree seed orchards. Indian Journal of Forestry, 8(2):153-154.

Sharma, Y.K and Bhandari, K.S. 1983. Eucalyptus for pulp and paper making: IndianForester, 109(12): 944-950.

Sharma, Y.K., Bhandari, K.S. and Srivastava, S. 1987. Assessment of tropical pines forpulping and paper making characteristics. Indian Forester, 113(2):127-139.

Singh, S.P.; Krishna Lal.; Bhandari, S.S.; Madhwal, R.C. and Singh, S.V. 1986.Variations in fibre/vessel characteristics and their influence on surfaceproperties of hard sheets of E. tereticornis grown in Bangalore andCoimbatore, Journal of the Indian Academy of Wood Science, 17(2): 65-70.

Singh, S.V. and Naithani, S. 1994. Pulpwood demand and quality assessment. In:IPPTA. IPPTA Convention issue, annual general meeting and seminar onenergy management in pulp and paper industry including co-generation ofelectrical power, 1992-93. Saharanpur, IPPTA. pp. 99-111.

Singh, S.V. and Rawat, J.K. 2000. Improving high yield pulps from hardwood speciesfor enhanced productivity. Inpaper International, 2-3(1): 14-17.

Tewari, D.N. 1992. Monograph on Eucalyptus. Dehradun, Surya Publications. 361p.Venkatesh, K.R. and Kulkarni, H.D. 2002. Eucalyptus clonal forestry – problems and

prospects. In: Conference on Clonal forestry – Problems and Prospects.Bangalore, NAEB. pp. 27-42.

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1. IntroductionIn India, large scale plantations of different species of Eucalyptus are being raisedin various states to meet the growing demand for its wood for different purposes.Besides its use in pulp and plywood, it has been found suitable for poles, crates,packing cases, agricultural implements, carts, tool handles, wall panelling, overheadpower, telecommunication lines, etc. The essential oil obtained from the leaves andflowers of Eucalyptus citriodora Hk. and E. globulus Labill. is of great value inmedicine and perfumery.

Due to factors like multiple uses, ecological compatibility, seed availability,ease of plantation establishment, site tolerance, disease resistance, stem form,growth vigour, etc., eucalypts are among the most favoured plantationspecies. The genus Eucalyptus consists of comprises of about 625 species andnumerous varieties and hybrids, of which, over 100 are reported to be introducedin India.

2. Wood Structure and IdentificationOwing to the different end uses of the woods of Eucalyptus species, it isimperative to establish the method of their correct identity, as apparently alleucalypt wood logs look alike. However, there are very few studies onidentification of different species of Eucalyptus through their wood anatomy inIndia as well as in other countries. Also, the homogeneity in the microstructuredoes not provide much scope in delineation of woods of Eucalyptus species.

In India, the two most referred studies on the wood microstructure andultrastructure of these species were carried out by Purkayastha (1982) and Agarwaland Chauhan (1988), respectively.

Purkayastha (1982) studied nine species, viz., E. calophylla R.Br. ex Lindl.E. camaldulents Dehn., E. citriodora Hk., E. globulus Labill., E. grandis (Hill)Maiden, E. maculata Hk., E. piperita Sm., E. tereticornis Sm., E. torelliana F.V.M.

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and categorised them in two broad groups on the basis of vessel arrangement andparenchyma distribution.

Agarwal and Chauhan (1988) studied wood structure of the above mentionednine species both under light microscope (microstructure) and scanning electronmicroscope (ultra structure). They distinguished them on the basis of variousanatomical characters, viz., vessel and parenchyma distribution, presence or absenceof crystals in parenchyma, percentage of triseriate rays and vestured pit morphologyas seen under scanning electron microscope. Their study shows that microscopicfeatures do help in wood identification but it is the ultra structure of vestured pits ofvessels and fibres that has been found more useful in distinguishing different species.Thus, all the above mentioned nine species were classified into two broad groupsbased on percentage of solitary vessels and types of parenchyma as has been doneby Purkayastha (1982), further separation of the species was made by difference inthe vesture morphology of vessel and the fibre pits.

It was observed that vessels are mostly in radial multiples and occasionallyin clusters and parenchyma is abundant, ranging from vasicentric to confluentand diffuse and sometimes aggregates in E. maculata (Fig. 1).

E. piperita has mostly solitary vessels, aligned in more or less oblique groups,parenchyma diffuse to aggregate (Fig. 2). The rays are generally uniseriate withbiseriation in the middle portion.

In E. globulus (Fig. 3) and E. torelliana (Fig. 4), rays up to three to four seriatehave been observed.

Crystals in parenchyma were reported to vary in their occurrence in differentspecies. They were present in E. calophylla, E. citriodora, E. maculata (Fig. 5) andE. tereticornis

Crystals are either absent or rare in E. camaldulensis, E. torelliana, E. globulus,E. grandis and E. piperita.

The observation in the vesture morphology of intervessel (Fig. 6) and inter-fibre pitting under scanning electron microscope revealed vessel pits ofE. camaldulensis, E. grandis, E. tereticornis and E. torelliana with coralloid-even (fine) vestures while those of E. calophylla and E. maculata were coralloid-uneven. The vessel pits of E. globulus and E. piperita were coralloid-warty andonly those of E. citriodara were dendroid-warty. Results obtained in this studyindicate the possibility of distinguishing woods of nine species of Eucalyptusthrough ultrastructure studies.

Considering the vast number of Eucalyptus species/hybrids and the studiescarried out so far, it is evident that wood microstructures do not provide muchscope in species identification. Wood identification, through ultra structurehowever, is not practical. Thus, future research should aim to develop molecularmarkers for delineation of Eucalyptus species/hybrids/clones.

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Fig. 3. T.L.S. of E. globulus showing bi- totri-seriate rays.

Fig. 4. T.L.S. of E. torelliana showingtri-seriate rays.

Wood structure and quality of Indian eucalypts: A review

Fig. 1. T.S. of E. maculata showing diagonalarrangement of vessels and vasicentric toconfluent parenchyma.

Fig. 2. T.S. of E. piperita showing diagonalarrangement of vessels and diffuse toaggregate parenchyma.

Fig. 5. R.L.S. of E. maculata showingcrystals in chambered parenchyma.

Fig. 6. T.L.S. of E. piperita showing intervessel pits.

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3. Wood QualityIn India, over the last few decades, silviculture and genetic engineering practiceshave been adopted to increase the productivity of eucalypt wood to meet the growingindustrial and domestic demand. However, besides aiming to increase the productivity,it was important to assess the quality of wood produced and ways to have moreuniform wood. Thus, a few wood quality assessment studies of plantations werecarried out to establish effect of site, growth rate, fertilizers, weeding, intercropping,etc. on wood anatomy vis-a-vis wood quality.

Anatomical parameters that were found useful in wood quality assessmentwere specific gravity, sapwood-heartwood ratio, fibre characteristics (fibre length,fibre diameter, fibre lumen diameter and fibre wall thickness) and proportion of tissue.

The earliest wood quality assessment studies carried out by Purkayastha etal. (1979) on E. tereticornis plantations raised in different localities in north andsouth India concluded that coefficient of variation of specific gravity in fiveplantations was about nine per cent while no significant difference in fibrecharacteristics was observed in three out of four plantations. This study led to thefact that there is a wide scope of selection for tree breeders. Bhat (1990) in a similarstudy on E. grandis and E. tereticornis also suggested scope of reducing rotationage and accelerating tree growth without significantly affecting the wood propertiesthrough selection. Bhat and Bhat (1984) stated that faster growth in E. tereticornisis slightly related to lower wood density, about nine per cent. According to Pande(2006) faster growth has positive impact on fibre characteristics of E. tereticornisclones.

Bhat et al. (1990) studied wood density and fibre length of E. grandis andestimated average density as 495 kg m-3 with no significant increase up to nine yearsof age while fibre length increased consistently with age.

Sidhu and Rishi (1997) in their work on 18 years old E. tereticornis concludedthat thickness of heartwood, bark and pith significantly decreases at higher boleheights from the base. Similarly, Shashikala et al. (2009) investigated variation in woodquality of 20 years old E. citriodora and also got similar.

Sharma et al. (2005) compared anatomy and properties of non-coppiced andcoppiced (after first felling) wood of E. tereticornis and reported non-significantdifference amongst them. This study is contrary to the study by Zobel and VanBuijtenen (1989) that states properties of coppiced wood different from those of theoriginal trees in having lower wood density and longer fibres.

Sreevani and Rao (2013) and Rao et al. (2005) in their findings on E. tereticornisclones of ITC, Bhadrachalam concluded that intra-clonal variation was significant inbasic density, fibre and vessel characteristics while variation in tissue proportion wasnon-significant. Inter-clonal variation was significant for all the parameters. On thecontrary, Pande and Singh (2009) reported non-significant radial variation in wood

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quality within the clones of E. tereticornis. However, they also found significantvariation between the clones. The study also concluded that fibre length of four yearsclones is comparable to eight to 10 years old seedling raised plantations of thisspecies.

Studies are well underway on wood quality assessment of promising hybrids ofEucalyptus developed by Forest Research Institute, Dehradun and few otherorganizations, which are planted at different sites and conclusive results are awaited.

The above studies are indicative of much scope for tree breeders to utilize thevariability within wood quality parameters in different species/hybrids/clones plantedat different sites. Few studies have been carried out to establish effect of fertilizers,weeding, intercropping, site, growth rate on wood quality. Sankaran et al. (2008) intheir study on E. tereticornis stressed upon weed management that increased yieldby 76-149 per cent; nutrient addition improved tree volume by 20-50 per cent.

The above works are indicative of nature of studies being carried out underwood quality assessment of Eucalyptus species and their hybrids planted at differentsites. However, the need of the hour is to develop validated growth models both interms of biomass and wood quality for different species/hybrids/clones along withprediction of their responses to different silviculture treatments, environment andsite conditions so as to cater to the needs of the plantation industry.

ReferencesAgarwal, S.P. and Chauhan, Laxmi. 1988. On the structure and identification of

Eucalyptus species. Indian Forester, 114(3): 145-151.Bhat, K.M. 1990. Wood quality improvement of eucalypts in India: An assessment

of property-variations. Journal of the Indian Academy of Wood Science(N.S.), 21(2): 33-40.

Bhat, K.M. and Bhat, K.V. 1984. Wood properties of 1-year old Eucalyptus tereticornisSmt. Australian Forestry Research, 14: 129-133.

Bhat, K.M.; Bhat, K.V. and Dhamodaran, T.K. 1990. Wood density and fiber length ofEucalyptus grandis grown in Kerala, India. Wood and Fiber Science, 22(1):54-61.

Pande, P.K. 2006. Impact of growth on wood properties and specific gravity variationsin clonal plantation woods of Dalbergia sissoo Roxb. and Eucalyptustereticornis Sm. Journal of the Indian Academy of Wood Science (N.S.),3(1): 27-39.

Pande, P.K. and Singh, M. 2009. Individual tree, intra-and inter-clonal variations inwood properties of the clonal ramets of Eucalyptus tereticornis Sm. IndianForester, 135(5): 629-646.

Purkayastha, S.K. 1982. Indian woods: Their identification, properties and uses. Vol.4. Delhi, Controller of Publications. 172p.

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Purkayastha, S.K.; Agrawal, S.P.; Tandon, R.D. and Chauhan, L. 1982. Evaluation ofwood quality of Eucalyptus plantations in various states. Technical report.Dehradun, FRI. 85p.

Rao, R.V.; Shashikala, S.; Sreevani, P. and Kothiyal, V. 2005. Clonal variation inbasic density and anatomical properties of Eucalyptus tereticornis offour to five years. Indian Forester, 131(9): 1187-1200.

Sankaran, K.V.; Mendham, D.S.; Chacka, K.C.; Pandalai, R.C.; Pillai, P.K.C.; Grove,T.S. and O’Connel, A.M. 2008. Impact of site management practices ongrowth of eucalypt plantations in the monsoonal tropics in Kerala, India.Pub. In: Workshop on Site Management and Productivity in TropicalPlantation Forests, Piracicaba, 22-26 November 2004 and Bogor, 6-9December 2006. Proceedings edited by E.K.S. Namibia. Bogor, CIFOR. pp.23-38.

Sharma, S.K.; Rao, R.V.; Shukla, S.R.; Kumar, P.; Sudheendra, R.; Sujatha, M. andDubey, Y.M. 2005. Wood quality of coppiced Eucalyptus tereticornis forvalue addition. IAWA, 26(1):137-147.

Shashikala, S.; Rao, R.V.; Shukla, S.R. and Chandrasekhar, K.T. 2009. Morphologicaland anatomical variations in the wood of Eucalyptus citriodora Hook.grown in plantation. Annals of Forestry, 17(2): 234-342.

Sidhu, D.S. and Rishi, L.B. 1997. Estimation of cross-sectional wood components inEucalyptus tereticornis Sm. at various levels of bole height. Annals ofForestry, 5(1): 39-42.

Sreevani, P. and Rao, R.V. 2013. Variation in basic density, fibre and vessel morphologyof Eucalyptus tereticornis Sm. clones. International Journal of Scientificand Technological Research, 2(7): 99-102.

Zobel, B.J. and Van Buijtenen, J.P. 1989. Wood variation: Its causes and control.Berlin, Springer-Verlag. 363p.

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1. IntroductionThe genus Eucalyptus belonging to family Myrtaceae, consists of more than 700species (Brooker, 2000). Most of the species are native to Australia and wereintroduced to India, France, Chile, Brazil, South Africa and Portugal in the firstquarter of nineteenth century (Doughty, 2000). Seven species including Eucalyptuscamaldulensis, E. grandis, E. globulus, E. pellita, E. tereticornis, E. urophylla andCorymbia citriodora were reported to be suitable for Indian agro-climatic conditionsand are widely planted in the subcontinent (Kallarackal and Somen, 1997; Kallarackalet al., 2002). In tropical and sub-tropical regions, E. grandis, E. urophylla and theirhybrids are highly preferred for pulp and solid wood production, while E. globulusis favoured in the temperate regions (Potts, 2004). It is one of the most widelyplanted hardwood tree in the world because of its superior growth, adaptability andwood properties which occupies 19.61 Mha globally. India ranks second in areaunder eucalypt plantation (3.943 Mha) after Brazil (4.259 Mha) (Iglesias Trabado andWilstermann, 2008).

Eucalyptus is a potential out-crosser (Gaiotto et al., 1997) and due to theunlimited free natural hybridization, the populations are highly heterozygous.Selection of elite plants for clonal propagation, seed orchard and hybridization arethe major attempts carried out by eucalypt breeders for genetic improvement ofthe species. Hence, extensive studies have been carried out on genetic diversityestimations at species and population levels using different marker systems likeRAPD (Grattapaglia et al., 1992, Costa and Grattapaglia 1995), ISSR (Gemas et al.,2004; Balasaravanan et al., 2005; Chezhian et al., 2010, 2012), AFLP (Gaiotto andGrattapaglia, 1997; Poltri et al., 2003), RFLP (Byrne et al., 1998; Butcher et al.,2002; Wheeler et al., 2003), SSRs (Muro-Abad et al., 2005, Ottewell et al., 2005,Arumugasundaram et al., 2011; Nagabhushana et al., 201) and DArT markers(Sansaloni et al., 2010). DNA markers were also used for species authenticationand hybrid validation (Rossetto et al., 1997; Balasaravanan et al., 2006), estimating

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outcrossing rate in open pollinated breeding populations (Gaiotto and Grattapaglia,1997), linkage disequilibrium estimation (Arumugasundaram et al. 2011) andfingerprinting (Kirst et al., 2005).

Eucalypts are targeted world-wide for genetic improvement programmes dueto their high commercial value. Nevertheless, they are still in early stages ofdomestication implying that understanding the genetic and genomic architectureof this genus is pivotal for breeding programmes (Poke et al., 2005; Myburg etal., 2007; Grattapaglia and Kirst, 2008). In the past two decades intensive researchhas been conducted on genetics and genomics to advance the process ofdomestication and targeted improvement of the species. Eucalypts are diploidand the number of chromosomes appear to be uniform across the genus (2n = 22;Oudjehih and Bentouati, 2006) and the genome size ranges from 370 to 700 Mbp(Grattapaglia and Bradshaw, 1994). The small genome size with less repetitiveDNA, high diversity and ability to produce large progeny sets has facilitatedconstruction of genetic linkage maps in different eucalypt species (Grattapagliaand Sederoff, 1994; Verhaegen and Plomion, 1996; Marques et al., 1998; Myburget al., 2003; Thamarus et al., 2002). QTL mapping in this genus has been appliedon tagging traits like wood properties, vegetative propagation, response to stress,juvenile traits, stem growth (Byrne et al., 1997; Verhaegen et al., 1997; Marqueset al., 1999; Shepherd et al., 1999; Myburg et al., 2001; Junghans et al., 2003;Kirst et al., 2004; Teixeira et al., 2011). A detailed list of QTL studies undertakenin different Eucalyptus species has been recently reviewed by Grattapaglia etal. (2012).

The first study on population based association study in tree species wasreported in E. nitens and two SNP markers from the CCR gene were correlated withmicrofibril angle, explaining approximately 5 per cent of the total phenotypic variation(Thumma et al., 2005). Allelic variation within four genes influencing wood propertytraits was demonstrated in E. nitens and a strong association between SNPs fromEni-HB1 and wood traits was reported by Southerton et al. (2010). Subsequently, inE. globulus, candidate gene based approach was used to investigate geneticassociations between SNPs identified from 11 candidate genes and correlated with19 wood property traits (Kulheim et al., 2011).

An alternate approach to identify markers for complex traits is through geneticalgenomics. The concept was initially proposed by Jansen and Nap (2001) whichsystematically associates gene expression traits with regulatory genomic regionscalled expression quantitative trait loci (eQTLs). It uses global transcript expressionlevels generated by microarray or transcriptomics in segregating pedigree to mapthe expression patterns and determine the relationship between genome andtranscriptome. In eucalypt, eQTL hotspots were identified for lignin biosynthesis,growth and wood basic density (Kirst et al., 2004; Kullan et al., 2012).

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2. Genomic Resources in EucalyptsThe genomic research in tree species was initiated to support the genetic improvementprogrammes and for developing diagnostic tools for conservation, restoration andmanagement of natural populations (Neale and Kremer, 2011). However, the majorbottleneck in pursuing genomic research in woody perennials are long generationtimes, large physical size, large genomes (especially in gymnosperms), lack ofpedigreed populations, lack of characterized mutations for reverse genetic approachand limited funding. Nevertheless, in the last few decades several research groupshave embarked on studying tree genomics with two major aims to support treebreeding programmes of managed plantation species for sustainable wood productionand management and conservation of natural populations (Neale and Kremer, 2011).With the advent of cost effective next generation sequencing (NGS) technologies.There are many research groups which are presently working on characterization ofunknown tree genomes. Till date major efforts on genomic research are limited onlyto four families (Pinaceae, Salicaceae, Myrtaceae and Fagaceae) and seven generaincluding Castanea, Eucalyptus, Picea, Pinus, Populus, Pseudotsuga and Quercus.The genomic studies in Eucalyptus species are well documented and they are brieflyenumerated below.

2.1. Eucalypt EST ResourcesExpressed sequence tag (EST) catalogues in eucalypts are widely available in publicdatabases and with private consortia (Keller et al., 2009; Rengel et al., 2009). A totalof 218,000 ESTs from E. grandis (23,000 contigs) are available with Arborgen Inc.(USA, http://www.arborgen.com/) while ForEST consortium (Eucalyptus genomesequencing project consortium, supported by FAPESP (Fundação de Amparo àPesquisa do Estado de São Paulo, Brazil, http://www.fapesp.br/english/) has 123,000ESTs from E. grandis. The Genolyptus consortium (Brazil, http://www.ieugc.up.ac.za/)has 120,000 ESTs from E. grandis, E. globulus and other species, and the Oji PaperCo. Ltd has 80,000 ESTs. Additionally, 2 M EST reads from xylem and leaf tissues ofE. globulus (X46, Forestal Mininco, Chile) is available in EUCAGEN (http://web.up.ac.za/eucagen/).

2.2. Eucalypt Microarray ResourcesGene expression studies in eucalypts to quantify transcript abundance have beenconducted using different platforms like microarray, sequencing of cDNA usingNGS platforms and SAGE. The availability of large EST datasets in public domainhas facilitated the designing of custom arrays for gene expression studies. The firsteucalypt gene chip was developed by Oji Paper Company including the 8K microarraywith 7538 genes from xylem tissues and 22k array with 22,000 genes from xylem, rootand flower tissues (Hirakawa et al., 2011). Subsequently, several researchers have

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developed custom-based oligoarrays to understand gene expression patterns duringdifferent developmental processes including wood formation (Kirst et al., 2004;Paux et al., 2004; Barros et al., 2009), adventitious root formation (Abu-Abied et al.,2012); ectomycorrhizal symbiosis (Voiblet et al., 2001), tension wood formation (Pauxet al., 2005) and temporal regulation of genes in developing xylem (Solomon et al.,2010).

In E. grandis, serial analysis of gene expression (SAGE) was used to profile thejuvenile cambial tissues and a total of 43,304 tags were generated and 3,066 unigeneswere annotated. The gene profile from the cambial tissue revealed the expression oftranscripts involved in general and energy metabolism, cellular processes, transport,structural components and information pathways (de Carvalho et al., 2008).

2.3. Gene Discovery ProgrammesThe gene discovery programmes in eucalypts are mainly focused to identifycandidates for association studies implicated in traits of interest. The predominantlytargeted trait for gene discovery in eucalypts has been wood property and variousEST resources and transcriptome studies have been dedicated to understand differentstages of xylogenesis. Several genes affecting wood formation were analyzed usingmicroarray and qRT-PCR (Paux et al., 2005; Qiu et al., 2008; Goulau et al., 2011) whilealternate studies of understanding gene functions using in planta approach arealso reported for transcriptional activator like EgMYB2 (Goicoechea et al., 2005),EgrTUB1 (Spokevicius et al., 2007) and fasciclin-like arabinogalactan proteins (FLAs)(MacMillan et al. 2010). Additionally, candidate genes like cinnamoyl CoA reductase(CCR) in E. nitens and E. globulus (Thumma et al., 2005), COBRA-like gene(EniCOBL4A) in E. nitens (Thumma et al., 2009) were associated with wood propertytraits. Pectin methylesterase (PME) was associated with solid wood properties inE. pilularis (Sexton et al., 2012).

2.4. Transcriptome ResourcesLarge-scale, high throughput methods have been developed for transcriptomicresearch which facilitate the expression analysis of all genes in a given sample orenable to detect differential expression of genes across two or more samples.Sequencing and annotating the expressed genes is informative and with the adventof the high throughput NGS platforms, transcriptome sequencing today is simpleand cost effective. The global transcriptome data can provide novel gene sequencesfrom uncharacterized and unknown genomes (using de novo assembly); allelicvariants can be identified across multiple samples; insertion, deletions and alternatesplicing sites in genic regions can be identified and transcript levels can be quantifiedacross multiple samples. This molecular information forms a highly valuable resourcetowards understanding the transcriptional network operational in a tissue under a

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given condition and also provides information on the probable allelic variations orexpression changes leading to altered phenotypes.

The first report on generation of robust EST collections in eucalypt using NGSplatform was in E. grandis (Novaes et al., 2008). Genes responsive to low temperatureconditions were identified from seedlings of E. globulus. Analysis of 9,913 sequence-reads resulted in the generation of 1,062 contigs and 3,879 singletons (4,941 unigenes)(Rasmussen-Poblete et al., 2008). In another study, over one million ESTs derivedfrom xylem tissues of 21 genotypes were reported and a total of 71,384 contigs wereassembled and annotated. Külheim et al. (2009) used the similar 454 sequencingplatform to discover SNPs associated with defence traits in four eucalypt species,E. camaldulensis, E. globulus, E. loxophleba and E. nitens. A total of 23 genes weresequenced in 1,764 individuals and 8,631 SNPs were discovered across the species,with about 1.5 times as many SNPs per kbp in the introns when compared to exons.

In 2010, an extensive expressed gene catalogue from xylogenic and non-xylogenic tissues was reported in E. grandis x E. urophylla hybrid (Mizrachi etal., 2010). In E. globulus, a global approach to understand the transcriptomedynamics during xylogenesis was initiated under the Geneglobwq project to identifygenomic hotspots of transcriptional activity. Concurrently, the microEGoprojectwas launched to identify and characterize the E. globulus microRNAs and theirtarget genes involved in wood formation (Paiva et al., 2011). The study provideda molecular insight to the major players determining the wood variability and itsend uses. Villar et al. (2011) reported the differential expression patterns usingtranscriptome analysis in two contrasting genotypes of E. alba and E. urophyllaX E. grandis during water stress conditions. The results demonstrated the tolerantand susceptible genotypes induced different stress signal transduction pathwayssuggesting genotype specific molecular responses to water deficit in eucalypts.The global transcriptome analysis of E. camaldulensis under water stress conditionwas reported by Thumma et al. (2012). The study revealed the differentialexpression of 5,270 transcripts under stress treatment and several SNPs wereidentified in these differentially expressed genes with allelic expression of severalof these variants correlating with total gene expression suggesting cis-actingregulation. The study generated a valuable repertoire of functional genes whichcan be used in association studies to identify markers for drought tolerance.

In a recent study, deep illumina RNA-Seq of developing floral buds ofE. grandis was conducted to identify key genes and regulatory elements underlyingfloral initiation, floral organ development and maturation and to understand thefloral transcriptional network (Klocko et al., 2013). The study is expected to providea set of genes for biotechnological intervention in eucalypt to accelerate floweringand breeding cycles or to engineer sterility for transgene containment in geneticallymodified trees.


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2.5. Functional Genetics and Genetic Transformation System in EucalyptGenetic transformation of eucalypt has been extensively researched and successfulprotocols are available for studying the transgene function. The sharing oftransformation model system would benefit the eucalypt research community intesting gene functions using in planta ‘gain in’ and ‘loss off’ function. InE. camaldulensis, the CPT1 clone was selected for its high transformation efficiencyby Oji paper company (Kawazu and Koyama, 2003). Arborgen and Nippon paper,Japan have robust transformation system and Arborgen has field trials of geneticallymodified eucalypts in USA and Brazil (unpublished). In recent years several groupshave reported successful transformation systems in E. globulus (Matsunaga et al.,2012), E. tereticornis (Prakash and Gurumurthi, 2009; Aggarwal et al., 2011),E. saligna (Dibax et al., 2010), E. camaldulensis (Mullins et al., 1997), E. grandis ×E. urophylla (de Alcantara et al., 2011), etc. An alternate aproach would be tofunctionally validate genes cloned from eucalypts in model systems of Arabidopsisand Nicotiana (Goicoechea et al. 2005; Baghdady et al. 2006).

2.6. Eucalypt ConsortiaIn Brazil, two large-scale eucalypt genomic research initiative projects including theForEST project and Genolyptus Project - Brazilian Network of Eucalyptus GenomeResearch were initiated in 2001 and 2002, respectively. The Genolyptus projectinvolved a nationwide network of seven universities and Embrapa (BrazilianAgricultural Research Cooperation) and thirteen forest based industries devoted toan integrated molecular breeding approach (Grattapaglia, 2003, 2004). The projectwas organized in nine subprojects and was conceived to establish foundation forgenome-wide understanding for molecular basis of wood formation and diseaseresistance in eucalypt species. The initiative involved generation of biologicalresources involving gene discovery, map generation and validation. Extensive studieswere conducted to consolidate and document the phenotypic diversity existing inthe species and to understand its underlying gene functions. The programme alsofocused on QTL detection, SNP haplotype discovery for association mappingtargeting the industrially important trait of wood-specific consumption.

2.7. The International Eucalyptus Genome NetworkThe International Eucalyptus Genome Network (EUCAGEN) is a community of morethan 130 eucalypt researchers worldwide and aims to facilitate the development ofgenomic resources for Eucalyptus species. The community is organized into WorkingGroups centred around several types of genomics resource development. Theworking groups of EUCAGEN focuses on bioinformatics, genome sequencing,physical genome mapping, genetic linkage mapping, genotyping and markerdevelopment, QTL mapping, association genetics and marker-assisted breeding,

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population genetics, phylogenetics, transcriptomics, proteomics, metabolomics,phenomics, functional genetics, genetic transformation and ecosystem phenotypes.

Several dedicated databases are available for eucalypt genome research. They include:EucalyptusDB: It contains the 4.5X and 8X draft assembly of E. grandis genomesequence.Eucspresso: A comprehensive database of more than 18,000 Illumina sequencedand Velvet assembled Eucalyptus transcripts and their annotations and expressionprofiles across different tissues (Mizrachi et al., 2010).Eucatoul: It presents the sequencing, assembly, analysis and annotation of largecollections of ESTs related to wood formation and frost tolerance (http://www.polebio.lrsv.ups-tlse.fr/eucatoul/).Eucawood: ESTs involved in wood formation with 3928 wood-related unigenes, 2,479contigs and 1,449 singletons are assembled in this database (Rengel et al., 2009).Eucacold: Eucalypt ESTs from transcriptome expressed during cold treatment werereported by Keller et al. (2009) and are available in this database. The distribution ofthe 11,303 annotated sequences (5,457 unigenes) was studied and the globalexpressional analysis of 1,554 randomly selected genes was conducted. This studyprovided a first indication of the Eucalyptus transcriptome composition under coldstress (www.polebio.lrsv.ups-tlse.fr/eucatoul/coldexpress). The ColdExpress alsoprovides the same genomic information.

2.8. Eucalyptus Genome Integrative ExplorerEucalyptus Genome Integrative Explorer (EucGenIE), an integrative explorer, wasmodelled after poplar resource, PopGenIE. It is a relational database system thatallows effective storage and retrieval of gene models and expression values and ispresented in a novel and intuitive ways. EucGenIE also provides access to commonanalysis tools such as homology searching and online clustering. The first versionof the EucGenIE database and online portal is available at http://eucgenie.bi.up.ac.zawebsite with restricted access (Hefer et al., 2011).

3. Eucalypt Genome SequencingThe first tree DNA sequence decoded was in Populus trichocarpa in 2006 due to itsrelatively compact genetic complement and small genome size that is 50 times smallerthan pine and only four times larger than Arabidopsis (Tuskan et al., 2006).Subsequently, two major eucalypt genome sequencing projects were initiated inUSA and Japan. The Kazusa DNA Research Institute in Japan released the draftgenome sequence of E. camaldulensis. The total length of the non-redundantgenomic sequences was 655, 922, 307 bp consisting of 81,246 scaffolds and 121, 194singlets. These sequences accounted for approximately 92 per cent of the gene-


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containing regions. A total of 77,121 complete and partial structures of protein-encoding genes were deduced (Hirakawa et al., 2011). The database containing thedraft sequence can be accessed at http://www.kazusa.or.jp/eucaly/.

The draft 8X assembly of the E. grandis (BRASUZ1) genome was released inJanuary 2011 in the USA (Phytozome [http://www.phytozome.net]) and in Belgium(BOGAS, [http://bioinformatics.psb.ugent.be/webtools/bogas]). The genomesequencing project was funded by the US Department of Energy (DoE) and performedat the DoE Joint Genome Institute (JGI) in collaboration with members of theEucalyptus Genome Network (EUCAGEN, [http://www.eucagen.org]) whocontributed genetic materials, linkage maps, EST resources and bioinformaticssupport. The assembly data revealed that the genome is approximately 691 Mb insize and arranged in 4952 scaffolds with 32,762 contigs. A total of 36,376 loci containingprotein-coding transcripts were annotated and 33,917 loci containing protein-codingtranscripts were mapped on 11 main linkage groups. Additionally, 9,939 transcriptswere detected with alternatively spliced sites and 9,741 were mapped to the 11linkage groups (Myburg et al., 2011).

Further, the 530 Mb of E. globulus (X46) genome was re-sequenced usingIllumina platform with approximately 40X coverage. The sequence data was comparedwith E. grandis genome and 75 per cent reads aligned with E. globulus. However,major difference was observed between both genomes including size (E. grandis is640 Mb and E. globulus is 530 Mb) and 78.6 Mbs of gaps was detected where nosequence from E. globulus aligned (Myburg et al., 2011). Approximately, 2.44 Msites detected were polymorphic/heterozygous across both genomes while morethan 5 M sites were homozygous. The mean divergence between E. globulus andE. grandis was about 1.5 per cent.

The complete chloroplast genome sequence of E. globulus (GenBank accessionno. AY780259) with an estimated size of 160,286 bp was reported by Steane et al.(2005). This genome ranks among the largest in land plants with an inverted repeat(IR) of 26,393 bp separated by a large single copy (LSC) region of 89,012 bp and asmall single copy (SSC) region of 18,488 bp. A total of 128 genes were annotated with112 individual genes and 16 duplicated genes in the IR region. Subsequently, thechloroplast genome of E. grandis was completely sequenced (Paiva et al., 2011;GenBank accession ID NC_014570) with a size of 160,137 bp with IR of 26,390 bp, anSSC of 18,478 bp, and the LSC with 88,879 bp in size. The chloroplast genomes ofboth E. globulus and E. grandis showed 99.57 per cent sequence similarity withcomplete congruence in gene organization.

4. Genomic Selection in Eucalypt ImprovementThe main aim of marker assisted selection (MAS) is to allow precise selection ofgenotypes at relatively low cost to substantiate genetic gains. Genomic selection

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(GS) or genome wide selection (GWS) is expected to cause a paradigm shift in treebreeding by improving speed and efficiency of selection (Grattapaglia and Resende,2011). It aims at incorporating all the genome – wide markers concurrently to capturethe ‘missing heritability’ of complex traits that QTL and association mappingclassically fail to explain. The characteristic feature of this approach is that all markereffects are estimated simultaneously rather that conducting the marker-traitassociation of selected markers on a representative pedigree. GS assumes that linkagedisequilibrium (LD) provided by dense genotyping is sufficient to provide insightinto QTL effects. The estimated marker effects are sufficiently precise, unbiased andaccurate as effect of large number of small-effect QTLs are also estimated in GS,which are usually not captured in QTL and association studies (Manolio et al., 2009;Makowsky et al., 2011). In GS the ‘training’ population involving several hundred orthousand individuals is genotyped for genome-wide marker panel and phenotypedfor target trait of interest. The data sets are then used to develop prediction models,validated and genome-estimated breeding values are calculated (Resende et al.,2012). GS has been routinely used in breeding of some dairy cattle (Hayes et al.,2009) and plant breeding (Eathington et al., 2007). The first experimental result of GSwas reported by Resende et al. (2012) in two eucalypt populations targeting growthand wood property traits. Substantial proportion (74-97%) of trait heritability couldbe captured by fitting all the genome-wide DArT markers simultaneously providinga new perspective to MAS in applied tree breeding.

The genomic resources in eucalypt are presently being harnessed in trait basedbreeding programmes and with the availability of high density markers for genotypingand robust statistical models for prediction and marker assisted selection acrossdifferent pedigrees may become a reality in near future.

5. ConclusionGenomic research in forest tree species gained impetus with the whole genomesequencing of P. trichocarpa followed by E. grandis. However, major resources arelimited to only seven genera. Nevertheless, with the rapidly evolving high throughputand cost effective sequencing technologies and robust computational pipelines,reference genome sequences in other uncharacterized tree species will be availablein future. Additionally, these affordable technologies can be applied for identificationof high throughput genetic markers and facilitate marker assisted selection in woodyperennials. The generation of genomic resources in plantation species like eucalyptwill also support the understanding on genome evolution, speciation, populationand ecosystem dynamics. The major challenge in tree genomics research would beto assemble technical manpower, garner higher investments and develop platformsfor unrestricted access to genomic resources, computational facilities and highthroughput phenotyping technologies.


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1. IntroductionEucalypts are exotic to India and the term ‘agroforestry’ is also new as it wasintroduced not more than half a century ago. Though the introduction of eucalyptsin the Nilgiri Hills in 1843 was mainly meant to increase the production of fuelwoodand as small timber for the British army cantonments, yet their marvellous fast growth,clear, straight and cylindrical bole attracted the fancy of landscapists, horticulturistsand the foresters. The popularity of eucalypts was never challenged as they startedto grow in the hitherto neglected scrub forests, wastelands and the unproductiveforests soon after their nursery technology was known to the foresters. Availabilityof simple technique of raising eucalypt plants in nurseries in a short span of threemonths, hardiness to grazing by cattle, suitability to grow in the drought-proneareas, capacity to regrow from coppice, capacitated them to replace the rather slow-growing indigenous trees, which could take years to establish the crop, wheneucalypts were ready for harvesting for a mid-yield. All these characters have wonthe acclaim for eucalypts all over the country in no uncertain terms that they pervadedthe houses of farmers and then, to their fields in the farm-forestry block plantations.Around 1956, a Eucalyptus hybrid, known as ‘Mysore gum’ became popular inMysore. Large scale plantations of this species were taken up in Uttar Pradesh.Eucalyptus grandis which was first introduced in Kerala for afforesting the grasslands emerged as the most important species for pulpwood plantations in Kerala. Infact, no other species has influenced the afforestation and reforestation programmesin India as much as eucalypts and they occupy a formidable position in theagroforestry.

The introduction of eucalypts in India was in the middle of times when theforests were receding, the demands for timber and firewood were rising, the stockingof the forests was thin and the productivity was at the lowest ebb. As per theestimates of the National Commission on Agriculture, 1976, the demand for fuelwoodin the country was 202 M m3 in 1985 and it was expected to rise to 225 M m3 by 2000

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AD. The total legitimate availability was, however, 127 M m³ on a sustainable basis.Same was the case of timber and industrial demands for wood. The forests of Indiawhich were known to be inexhaustible in the 18th century, were now classed as leastproductive and degraded. Foresters were on the lookout for a fast growing treespecies which could increase productivity of the forests.

For a tree to qualify for agroforestry it should have the qualities such as fastgrowth, no negative effect on the production of grains or else net returns to farmersmust compensate the loss due to less production of grains, provide shelter againstcrops and orchards, litter or organic matter to enrich the farmers’ land, fodder forcattle, fuelwood and small timber for domestic needs. Eucalypts, though, did notmeet most of the criteria, yet their capability to resist unfavourable soil conditions,the easy initial establishment, quick response to irrigation, fertilizers and productionof small sized straight knot-free timber which only a few of the indigenous treescould produce, soon became a favoured species of the farmers. Like conifers,eucalypts could be grown in close spacings, which would mean intensive cultivationin limited areas instead of managing extensive areas. The population of India wasincreasing at the rate of 2.78 per cent per annum which meant more houses forshelter, fuel wood to warm and cook and clothes and paper. The industry requiredraw material to manufacture the industrial quantities of consumables. Eucalyptswere the only species which could be grown in the farmlands to increase theproduction.

Eucalypts planting in India started taking shape through extension activities ofthe state forest departments in the late sixties and early seventies. It graduallygained momentum in all parts of India, especially in Punjab, Haryana, western UttarPradesh, Gujarat, Tamil Nadu, North Bengal and Andhra Pradesh. They were themost widely planted species in the foreign aided social forestry projects of theeighties in different states. In farm forestry component, eucalypts comprised 71.6per cent of the total trees planted. In Punjab, more than 3 per cent of the cultivatedarea was planted under eucalypts in only a decade (Saxena, 1991). In Gujarat, from1983-84 farmers planted 195 M trees which was four times the target. In Uttar Pradesh,farmers exceeded the original target of eight million seedlings by planting 350 millionseedlings between 1979 and 1984 (Goldin et al., 2002). Though, the earliest adoptersof eucalypts as a cash crop were the wealthiest farmers who had significant sourcesof off-farm income and who were seeking to minimize labour supervisionrequirements; it was soon adopted by the small and big farmers for production ofsmall timber, poles, firewood and local house constructional material in the form ofbeams. In some cases, planting of eucalypts was financed by urban capital. With theestablishment of new uses of eucalypts wood for pit props, crates, packing boxes,pulp wood and scaffolding, they were intertwined in the social, agricultural,economical and industrial applications in the country. With the course of time,

211

eucalypts have changed the agricultural landscape of the states like Punjab andHaryana where monocultures of paddy and wheat berefted the soil of its nutrientsand robbed off groundwater. Not only it has provided employment to the millions ofagricultural labourers in the lean period, but also yielded additional employment tothe wood cutters, transporters and the industrialists.

2. Decline of EucalyptusHowever, after mid-eighties, eucalypts plantations suffered a serious set back onmany counts. There were onslaughts on eucalypts for low economic returns andecological reasons though by not those who were to be directly affected. Inagroforestry, the primary cause for downfall of eucalypt popularity was the lowprices of wood in the market against the high expectation of the farmers. The priceboom in eucalypts was evident upto about 1984. However, by the 1986, the priceshad crashed; for example in Punjab, a seven- to eight-year-old tree, then projected tobe saleable at Rs. 150, did not sell even at Rs. 18 in 1988. In Gujarat, the price of a poleof 10-12 cm diameter fell from Rs. 60 in 1986 to Rs. 23 in 1988 (Saxena, 1991). InHaryana, a six-year-old tree could not be sold even at Rs. 10 as against the projectedsale price of Rs. 100 (Athreya, 1989). As the forest departments did not have anyagroforestry models developed at that time, people resorted to dense planting withnumber of stems ranging from 3,000 to 10,000 ha-1 with the main objective of earningquick returns at a short rotation. As the prices went down, there was a virtual panicamongst the farmers about the future of eucalypts plantations raised by them. Somefarmers uprooted the young plantations. This further resulted in a glut in the marketand the prices further collapsed. Number of reasons were offered for the collapse ofthe prices (Saxena, 1991). Perhaps one or more reasons were operative at one or theother time. The depression in eucalypts prices gave a fillip to poplar plantationsunder agroforestry systems. The plantation of poplar began around mid eighties whenWimco Ltd. endeavoured towards match wood production in collaboration with farmers.Poplars, being leafless in winter, were more suitable as cultivation of crops could bedone under its shade for three to four years. Some of the poplar plantation in agriculturesector could produce mean annual increment of up to 50 m3 ha-1 yr-1, the average being20 m3 ha-1 yr-1 as against a maximum average of 4.5 m3 ha-1 yr-1 achievable from forestryplantation. Since returns from poplar plantations were high as compared to eucalypts,large scale plantations of the species were raised, especially on irrigated, fertile andwell-drained soils in the states of Punjab, Haryana, Uttrakhand and Uttar Pradesh.However, geographically poplar plantations were limited to the belt falling under theTerai region of U.P. and Uttrakhand between 27º N and 30º N latitudes and in thePunjab plains between 290 to 320 N latitude.

Meanwhile, eucalypts had established their credentials as excellent source forpulp and paper, particle board and hard board industries; an excellent source of

Eucalypts in agroforestry

212

firewood and charcoal as well. Eucalypts timber is also used for light and heavyconstruction, railway sleepers, bridges, piles, poles and mining timber. IndianStandards are now available for its timber use for door frames, window frames,furniture, tool handles, packing cases and crates. As an agroforestry species, it hasbeen shown to be more remunerable than agricultural crops alone. E. tereticornis, isa major source of pollen in apiculture and produces a medium amber honey ofdistinctive flavour.

3. Resurgence of EucalyptusEarlier to 1992, people were largely dependent on seed route planting materialraised by the forest departments. A number of private nursery growers alsocontributed a large proportion of seedlings. These plantations were attacked bytermites and foliar blight disease caused by Cylindrocladium spp., resultantlythere was high mortality, and productivity was only 6 to 10 m3 ha-1 yr-1 which wasextremely low (Piare Lal, 2006). The other possible reasons for low productivitywere lack of availability of quality seeds and primitive nursery practices (Kulkarni,2002). This adverse scenario changed with the introduction of clonal technology.ITC Ltd. was the pioneer to adopt this technology in 1989, and developed 86promising high yielding, disease resistant and adaptable clones, which later cameto be known as ITC clones. The survival percentage of the majority of these cloneswas reported to be 95 per cent and the productivity ranged from 24 to 58 m3 ha-1 yr-1.Apart from increase in productivity by two to three times, the rotation period wasalso reduced by aproximately half. This reduced the rotation time of farm forestryplantations from seven to eight years to four to five years. Clonal demonstrationplantations raised by the company resulted in large-scale adoption of ITC clones ofeucalypts by the farmers and state forest departments. Further, distribution waspossible due to mass multiplication in the modern clonal nurseries. With the aim toraise raw material in partnership with farmers in consonance with the National ForestPolicy, 1988, the company has distributed more than 51 M clonal plants to growersbetween 1992 to 2006. The clonal technology with root trainers has given considerableimprovement in the production of quality planting material as well as in theimprovement of productivity. The current level of production of clonal eucalypts inIndia is mostly controlled by industrial houses and is estimated to be about 110 M yr-1,whereas the demand is about four to five times more (Table 1). The demand is expectedto increase still more, provided the plantlets are available at the nearest points ofplanting, and the cost of plants is reduced to half. The current price of plantlets isexorbitantly high at Rs. 800 to Rs. 1,200 per 100 plants, which increases the cost ofplantation enormously.

The planting of eucalypts has again shown an increase in the 1990s and theirproduction and growing stock in the non-forest areas has almost stabilized. It is

R.K. Luna

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Table 1. Production of clonal planting material of eucalypts in IndiaCompany Installed

capacity (M) Annual

production (M) Andhra Pradesh Paper Mills, Rajamundhry 5.00 5.00

BILT (Chandrapur, and Gadcharoli in Maharashtra and Koraput in Odisha).

25.00

20.00

ITC Bhadrachalam, Andhra Pradesh 30.00 20.00

J.K. Paper Mills, Odisha 10.00 8.00

Pragati Biotechnologies, Hoshiarpur, Punjab 15.00 10.00

Prakriti Clonal Agrotech, Ambala, Haryana 2.50 2.00

Star Paper Mills, Saharanpur, Uttar Pradesh 4.00 3.00

Tamil Nadu Paper Mills Ltd., Kavithapuram 10.00 10.00

West Coast Paper Mills, Dandeli, Karnataka 5.00 4.00

WIMCO Ltd., Rudarapur, Uttrakhand 10.00 7.00

State Forest Departments/Corporations 15.00 6.50

Others (Local units in Andhra Pradesh and Tamil Nadu) 20.00 15.00

Total 151.5 110.5

estimated that eucalypts has been planted over an area of 4.00 Mha. Besides, industrialhouses have also raised captive plantation of clonal eucalypts over an area of 70,000ha. However, in the northern states, the annual plantation rate of eucalypts has aninverse relationship with poplar plantation but it is not the only determining factor foreucalypts as other factors like high water demand, less compatibility with agriculturalcrops, low price regime than poplar and longer rotation period are the limiting factorsfor its plantation. A study by the Forest Research Institute, Dehradun had shown thatin Punjab there were two peak values of plantation during 1996 and 2003. During 1996,due to ban by the Supreme Court of India on felling and shifting of plywood industriesout of north eastern states of the country, the demand as well as price of poplarincreased to a great extent. It affected the annual plantation rates of eucalypts from1996 onwards. After 2001, the price of poplar started falling and again poplar plantationrate reduced to the minimum and the farmers resumed planting of eucalypts whichcontinued upto 2001. The data over the years reveal that people start raising treeswhen returns from tree crop appear to be more attractive than the alternative crops andthe prices remain stabilized over a period of time. The rate of planting has largely beendependent on the average market prices of the wood products. The higher the prices,the greater is the intensity of planting. Average market price and the rate of planting inPunjab indicate the trend (Table 2) .

4. Agroclimatic ZonesMainly five species of eucalypts are grown in different agroclimatic zones of the country.Performance of species varies considerably with the site and climatic conditions (Jagdish


214

Table 2. Average price of eucalypt wood in the market and their rate of planting over time

Chandra et al., 1994). While E. camaldulensis, E.globulus and E. grandis have restrictedadaptability, E. tereticornis (Mysore gum) has been planted in the country both in theforests and outside in the agricultural fields on a large scale-except in the north-easternstates. The species has usually been raised in areas experiencing 600 to 1,500 mm annualrainfall as it does not grow well in wet areas of eastern India and areas subject to diseasesin high rainfall areas of south India. In the arid regions of Rajasthan, Punjab and Haryana,it can be grown with initial working for two to three years (Table 3). The species hasproved to be frost- tolerant and can tolerate one to 15 incidences of frosts in a coldseason. E. camaldulensis can be planted in areas having saline and alkaline soils, sandyareas and soils deficient in nutrients experiencing very low rainfall. In the ravinous areas,E. tereticornis and E. camaldulensis can be grown. E. grandis and E. tereticornis can beplanted in grasslands without tree growth and vegetation (Luna, 1996). Most of theagroforestry plantations raised in India lie in the plains and lower altitudes of the hills upto an elevation of about 1,000 m. On the basis of site quality, it has been ascertained thatEucalyptus hybrid under agroforestry grow better in hot arid regions than hot semi-aridregions and hot sub-humid regions of Punjab (Luna et al., 2006). The suitability of thespecies in different agroforestry zones has been given in Table 3.

Table 3. Suitability of eucalypts species in different agroclimatic zones of India

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 Price per q (Rs.)

180

190

250

280

250

290

300

340

110

190

270

Rate of planting (stem ha-1)

0.350

0.466

0.429

0.259

0.226

0.317

0.356

.566

0.577

0.516

0.524

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S. no

Species Climatic zone Longitude (East)

Latitude (South)

Altitude (m)

Annual rainfall (mm)

State

1. E. camaldulensis Tropical and sub-tropical

77º-40 ́to 80º-05É

20º-45 ́to 32º-22Ń

Upto 1,800 250-625 Himachal Pradesh, Uttrakhand

2. E. globulus Mild temperate to cool tropical climate

76º30 ́to 77º45É

8º 0 to 11º 48Ń

1,500 to 2,343

1,270 to 2,500 but without snowfall

Kerala, Karnataka (Annamalai and Palni hills)

3. E. grandis Lower sub-tropical areas

76º45 ́to 77º20É

8º15 ́to 10º20Ń

800 to 1,500

2,000 to 4,000

Kerala (Plateau plains, high rainfall areas)

4. E. tereticornis Dry tropical to moist tropical areas

68º-92ºE 8º-32ºN Upto 1,000 400 to 4,000

Punjab, Haryana, Uttar Pradesh, Rajasthan, Gujarat, Madhya Pradesh, Maharashtra, Bihar, Odisha, West Bengal, Andhra Pradesh, Karnataka and Tamil Nadu

5. Eucalyptus citriodora

Mild temperate areas

70º 0 ́to 77º45É

11º0 ́to 11º 48Ń

600 to 1,200

Hilly areas

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5. Eucalypt Growing RegionsTree growing generally increases in areas where there is an intensive cultivation ofcrops, however, the tree growth has either declined as a result of overexploitation offorests decline in the tree stock (Warner, 1993). This is true for adoption of eucalyptsalso. After decades of growing monoculture of crops of rice, wheat, cotton or sugarcane,the farmers have been looking out for smart trees which could increase their overallproductivity without affecting the crop yield. In some areas, labour shortage or highwages rates have compelled farmers to switch over to eucalypts growing. It has alsopopularized after the number of cattle were drastically reduced and most of them werestall fed under the well known Government sponsored dairy development programmes.Most of the farmers in north India have been growing eucalypts mainly as cash crop(Arnold and Dewees, 1999). Eucalypts have matched with the development of marketingand establishment of industrial units consuming massive quantities of raw material. Atpresent, eucalypts occupy the most predominant species in the ‘trees outside forests’constituting from 12.10 per cent to 23.72 per cent of the total growing stock in any state(Table 4).

In Punjab, Haryana and western Uttar Pradesh, eucalypts are the most preferredspecies under agroforestry plantations. A kaleidoscopic view will reveal that eucalyptplantations in agroforestry sector have established distinctive regions in thecountry. Unlike poplar, which is confined from western limits of Punjab to easternlimits of western Bihar, eucalypts have been grown over larger parts of the countryranging from Ravi River in its western limits to Gangetic plains and Deccan plains,barring the eastern Himalayas, Garo and Khasi Hills, Western and Eastern Ghats.Within the intensive cultivation areas and elsewhere, the intensity of eucalyptculture is concentrated in certain locations particularly near the river basins, floodprone areas, and catchments of paper and paper board industries in the country. Theintensive eucalypt growing regions in different states in the country are given inTable 5.

6. SoilsEucalypts have been raised successfully in diverse kind of soils such as recentalluvial soils (Punjab, Haryana and Uttar Pradesh), Tarai soils (Uttarakhand),


Table 4. Growing stock of eucalypts in trees outside forestsState Growing stock of eucalypts

outside forests (M m3) Total growing stock of

trees outside forests (M m3) Percentage of eucalypts growing stock (M m3)

Punjab 6.79 19.85 34.22 Haryana 3.83 14.44 26.50 Gujarat 14.98 47.78 31.36

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lateritic soils (Bihar, Orissa and southern West Bengal), shifting sand dunes(Rajasthan), deeply cut ravines (Rajasthan), red sandy and loamy soils (Bihar,Madhya Pradesh and Orissa), skeletal rocky and murran soils, denuded hill slopes,red and yellow soils (Andhra Pradesh and Madhya Pradesh), black cotton soils(Gujarat, Karnataka and Maharashtra) and coastal alluvial soils (Tamil Nadu).Though grown on a diverse type of soils, its best growth is achieved in deep,fertile, well-drained loamy soil with adequate moisture. In Bhabar and Tarairegion of Uttrakhand, a bhabar soil with coarse texture and excessive boulderysub-soil, having deficient moisture supply is not found favourable for goodgrowth. Similarly, calcareous, alkaline and clayey soil in Bhabar and Tarai withpoor aeration are found unsuitable. It is also not suitable for growing on steepslopes, dry and waterlogged areas. Its growth is very poor in poor, solid andsandy soil, not resorted to irrigation. It cannot grow on sites having pH exceeding10.0, soluble salt content 0.7 per cent and possessing impervious pan (Kaushiket al., 1969). Its favourable soil textures are clayey loam, heavy clay (containingmore than 50 per cent clay), high to medium clay (35-35% clay), loam, sandyloam, sandy clay loam or sandy soil. Suitable soil pH range lies in acidic (6.5 to2.0).

Studies of the soils supporting Quality class I E. tereticornis in West Bengalshowed that these soils are light, acidic and have trends of laterisation of organic

Table 5. Intensive eucalypt growing regions in the country

R.K. Luna

S. no State Intensive eucalypts growing areas 1.

Andhra Pardesh Khammam, Telangana (Rangareddy), Warangal, Nizomabad, Medhak, Karimnagar, West Godavari, East Godavari, Prateasam, Nellore and Royalseema region (Anantapur, Karnool, Chittoor)

2. Chhatisgarh Bastar, Kanker, Durg and Raipur 3. Gujarat Dahod, Surat, Panchmahals, Bharuch, Sabar Kantha, Kheda and

Bhavnagar 4. Haryana Foot hills of Shiwalik hills, Yamuna and Gaggar River basins 5. Himachal Pradesh Una and Sirmour 6. Jammu and Kashmir Kathua 7. Karnataka Belgaum, Bangalore and Kumarapatnam area 8. Madhya Pradesh Chhindwara and Seoni 9. Maharashtra Chandrapur, Gadchiroli and Yadatmal 10. Odisha Korapur and Raygada 11. Punjab Bet and Mand areas of river Beas and Ravi, foothills of

Shiwaliks hills ranging from Ropar to Pathankot, Ferozepur, Faridkot, Abohar and Fazilka in the Malwa area

12. Rajasthan Hanumangarh, Sri Ganganagar and Suratpur 13. Tamil Nadu Pudukattai and Trichy 14. Uttar Pradesh Saharanpur, Muzaffarpur, Bijnour, Bulandshahr, Moradabad,

Rampur, Bareilly, Pilibhit, Shahjahapur, Sitapur, and Faizabad 15. Uttrakhand Hardwar, Roorkee and Rudrapur

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matter and breakdown of parent material into free silica and sesquioxides(Banerjee et al., 1986). Among the physical properties, presence of gravel, sandand water holding capacity seem to influence the height growth of eucalypts(Alexender and Thomas, 1985). The growth on old alluvial beds as well as onfresh river embankments and canal sides is exceedingly fast. On poor soils, afterearly height growth, the further growth stagnates. Therefore, poor and dry erodedlands are not suitable for raising economically viable plantations of this species.

7. Supply of PlantsIn the 1980s, eucalypts plants in the forest department nurseries were the majorsource of supply to farmers. The forest departments in various states have beengrowing eucalypt seedlings to the extent of 15-20 M yr-1. As the demand grew,the private people also established small nurseries in the intensive eucalyptsgrowing areas. As there was no regulation to monitor the growth of nurseries,the quality of plants deteriorated to a great extent. Many nurseries wereestablished under the National Afforestation and Eco-Development Board whereeucalypt plants were raised and distributed to the public. Later, the practice toraise eucalypt plants continued under the Employment Guarantee Scheme andafterwards under the afforestation activities of MGNREGA. Eucalypt seedlingshave been raised from the beginning in the polythene bags of various sizesranging from 10 cm x 22 cm to 15 cm x 22 cm. The raising of seedlings is veryeasy. Seeds are sown on raised beds under shade. No pre-sowing treatment isrequired. Rapid and complete germination is achieved under moist, warmconditions in presence of light. Seedlings are pricked out and transferred topolybags at the second leaf-pair stage after about six weeks of sowing. Seedlingsare planted out in the field when they reach a height of 25-30 cm. On an average,one kilogram of E. tereticornis seed produces 25,000-30,000 healthy seedlings.Most of plants raised by the state forest departments (SFDs) are supplied to thefarmers at subsidized rates. The rates of supply have escalated from Re. 0.25 in1980s to Rs. 8.00 per plant at present. Due to market trends, conflicting viewsabout the ecological role of eucalypt and introduction of poplar have affectedthe production and supply of eucalypt plants by the SFDs. A detailed study ofPunjab state shows that supply of eucalypt plants to the public has been about40 per cent of the total plants supplied (Table 6).

8. Patterns of PlantingEucalypts are mostly planted scattered in singles or multiples near the tubewells,labour huts, farmer houses, cattle sheds, or in rows along the farm paths, irrigationchannels, along the field boundary, boundary of fruit orchards or enbloc in theagricultural fields. In boundary planting, eucalypts are planted in a single row on


218

Table 6. Supply of eucalypt seedlings vis-a-vis total supply of all species in Punjab

one side, or on two, three or four sides of the field. The spacing generally varies from1.00 m to 2.00 m between tree to tree. Generally two to three rows of eucalypts areplanted at a distance of 1.0 m apart in a alternate fashion on the periphery of orchardsto protect the fruit trees from hot and desiccating winds in the arid areas. In theblock planting category, many agroforestry alternatives are possible:

(a) Eucalypt and crop in alternate row.(b) Eucalypt and crop in alternate strip.(c) Eucalypt and other trees in mixture.

The adoption of pattern depends upon the size of the holding of the farmer,number of family members, availability of labour and economic condition of thefarmer, experience of the tree grower, alternative or supplementary income fromother sources and marketability of tree produce. Most of the farmers adoptingeucalypts in the beginning of eighties, had been the absentee farmers in Haryanaand Punjab and the one having large size holdings. The marginal and small farmershad adopted row plantations or planted only a few scattered trees. Most of thefarmers prefer to plant trees in linear rows than in block plantations as the shadeeffect is the least in the former. As an example, in Punjab, the total volume in thescattered form (9.69 M m3) is more than in either block (2.68 M m3) or linear (6.22 Mm3) plantations (FSI, 2006).

9. Spacing in Agroforestry PlantationsPlant spacing is important to control the number and distribution of plants in theplantation area. In agroforestry plantations, optimum spacing has to becompromised between the cultivation of crops as well as maximizing the production

R.K. Luna

Year Number of eucalypt hybrid seedlings distributed (M)

Total number of seedlings of all species distributed (M)

Eucalypt plants distributed (%)

2000-01 1.03 2.27 45.35

2001-02 0.86 1.62 52.77

2002-03 0.84 1.65 51.00

2003-04 0.92 2.29 40.09

2004-05 0.76 1.89 40.35

2005-06 0.29 0.84 34.16

2006-07 0.21 0.69 29.88

2007-08 0.63 1.84 34.35

2008-09 0.64 1.64 38.73

2009-10 0.80 2.36 33.78

2010-11 0.76 1.86 40.82

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of wood and minimizing the costs of management and utilization. As a rule, whenit is proposed to raise agricultural crops in conjunction with plantation, widerspacing has to be adopted to protect the agricultural crops from shading as well asfor free movement of agricultural machines. Moisture plays an important role indeciding the spacing in agroforestry plantations of eucalypt. Wider spacing ispracticed in dry areas where soil moisture is the limiting factor. In irrigatedplantations, closer spacing is adopted, as the cost for irrigation increases withwider spacing. In shallow soils unless fertilized, the spacing will also have to bewider for providing more spacing for root development. In wet areas, on the otherhand, where ridges are prepared on drain ploughs, spacing has to be coordinatedwith the drainage pattern. Where there is market for small diameter stems, closespacing is usually adopted. Closer spacing can be adopted for production offuelwood, and small diameter poles for pulp wood or pit props. Also when mainobjective is to get the maximum production of saleable volume, closer spacing atshort rotation helps. With wider spacings and short rotation, there is a loss ofvolume production since the site is not fully occupied and the mean tree sizeincreases. The stem taper is also increased by wider spacing resulting in a reductionof the percentage conversion when the log is sawn. Keeping in view the aboveprinciples in mind, the farmers have adopted the various spacings as per therealization of harvestable produce (Maithani and Sharma, 1987).

There are a number of combinations in agroforestry plantations. Puttingplants 1 m apart in a row and keeping the distance between rows higher thanthis, gives higher yields in Eucalyptus hybrid plantations under agroforestrysystem (Table 7). The most common practice adopted in irrigated agroforestryplantations is to have two-row strips, on a wider soil-worked ridge 1.5 m wide,30-45 cm high, the planting in a row being done at 1m espacement. The distancebetween strips is kept 4 or 6 m depending on the cultivation practice. Anotherspacing that has become popular is 4 m x 2.5 m, wherein crops are cultivatedupto the rotation period of four years. In Haryana, a study conducted in 27villages in five districts found 1.0 m spacing in the boundary planting the mostcommon. In block planting, among the 14 types of spacing ranging from 2.5 m2

Table 7. Range of espacement for Eucalyptus hybrid


S. no

Object of planting Spacing No. of stems (ha-1)

Rotation (yr)

Remark

1. Fire wood 1 m x 1 m to 1.5 m x 1.5 m

10,000 to 4,444

5 Higher bark percentage and lower under bark diameters expected

2. Pulpwood and poles 2 m x 2 m 3 m x 2 m

2,500 1,667

6-8 Low bark percentage

3. Saw logs 3 m x 3 m 1,110 10-20 - 4. Windbreaks and

shelterbelts 1 m x 1 m to 1.5 m x 1.5 m

400 533

- -

One row Two rows

220

(2.5 m x 1 m) to 18 m2 (4.5 m x 4.0 m) area per plant, 4 m x 2.5 m was found the mostcommon (42%) followed by 2 m x 3 m or 3 m x 3 m (20%) (Kaul, 2008). The resultsof the experiments have proved that the closest spacing gives the highestvolume production, but at higher rotation of about 10 years, a very closespacing does not give as much as the survival rate decreases (Rawat et al.,2013). The diameter and volume production at different spacings at the age of sixyears is given in Table 8.

These trials indicated that when higher diameter classes are taken intoconsideration, close spacings still give high volume production at the age of sixyears. However, wider spacings of 5-6 m2 per plant gives more of volume productionat the age of eight to 10 years.

In the 1980s, seed route planted eucalypts were usually harvested at the ageof eight years. The foresters recommended espacement of 2.5 m x 2.5 m and 3 m x1.5 m which gave the maximum volume production of 106.1 m3 (u.b.) and 78.92 m3

(u.b.) at this age, whereas agricultural crops could be grown only for first twoyears (Lohani, 1980). Another popular spacing was 4.0 m x 2.0 m and 6.0 m x 1.0 mas practiced by the farmers in and Haryana, Punjab and Uttar Pradesh as agriculturalcrops could be grown for a longer period.

10. Plantation EstablishmentThe seedlings of E. globulus, E grandis and Eucalyptus hybrid can be usuallytransplanted when they attain 25-30 cm height in 45 cm3 or 30 cm3 pits. Areas to be

Table 8. Recommended spacings for eucalyptsS. no.

Spacing (m x m)

Average diameter (cm)

Volume ha-1

(m3) Survival rate

(%) 1. 1x1 9.0 148.00 56 2. 1.4x1.4 9.0 80.0 65 3. 2x2 10.0 36.0 63 4. 2.45x2.45 11.0 50.0 73 5. 3x3 13.0 60.0 91 6. 1x2 10.0 132.0 78 7. 1x3 10.0 119.0 75 8. 1x4 12.0 112.0 83 9. 1x5 13.0 115.0 93 10. 1x6 14.0 106.0 86 11. 2x0.5 8.0 114.0 58 12. 2x1.5 10.0 81.0 71 13. 2x2.5 11.0 66.0 81 14. 2x3 12.0 74.0 85 15. 3x0.3 10.0 288.0 80 16. 3.x0.6 11.0 152.0 88

R.K. Luna

221

intercultivated should be ploughed and harrowed. In dry and sloping areas, contourtrenching, continuous or interrupted is combined with pitting. In marshy andwaterlogged areas, mounds higher than anticipated water level are made for planting.In irrigated plantations, drainage channels are dug out along the rows of pits, thechannels are 30 cm to 45 cm in section with a depth of about 30 cm. Though plantingis done at the break of monsoon, eucalypt can be planted throughout the year,provided irrigation is available.

For planting clonal eucalypt, deep ploughing of the soil with disc ploughs ormould-board ploughs in both directions is recommended for preparing the fields.Transplanting in 30 cm x 30 cm x 30 cm pits is carried out during the early parts of themonsoon rains so that plants establish early benefitting from the moisture. Soil inand around the pits is treated with 2 ml of chloropyriphos in one litre of water toprevent damage against termites during the establishment stage. Application ofbotanical pesticides like kodesa (Cleistanthus collinus) for controlling termites isalso recommended (Kulkarni, 2002).

Cultural practices recommended include timely weeding and soil working,protection against damage by insect pests and cattle and raising of leguminouscrops in between 3 m wide planting rows for green manuring. In addition, intercultivation with cotton, chilli, pulses, tobacco, vegetables and horticulture plantsshould be encouraged during the first year of planting which gives additional earningto the farmers. As most of the soils in India are deficient in nitrogen and phosphorus,application of fertilizers is recommended. Addition of fertilizers late in winter maycause to produce new flush of leaves which may be vulnerable to frost.

Owing to its fast growth, eucalypts are a heavy feeder and requires supplements inform of organic and chemical fertilizers. Deficiency of nitrogen in soils is a limiting factorfor growth and can reduce the yield by almost 60 per cent. For maintaining the soilfertility, it is advisable to raise eucalypts with legumes as an intercrop. Deficiency of iron(Fe) is reported in agroforestry plantations in Punjab, which is exhibited by yellowing ofyounger leaves that extend towards the older leaves. In advance stage, the leaves havea bleached appearance. Six to seven sprays of 0.25 per cent (250 g FeSO4. 7H2O in 100 lof water) and 0.50 per cent (500 g FeSO4. 7H2O in 100 l of water) in nurseries and plantations,respectively are found to be better treatments (Dhanda et al., 2008).

Eucalypts require frequent but light irrigation during the first year for betterestablishment and survival under field conditions. Three to four irrigations per monthduring the summer and two irrigations per month during winter are sufficient foroptimum growth. Light irrigation is usually advisable through channels as heavyirrigation by flooding may uproot plants during strong winds. Generally, decline ingrowth is directly related to moisture stress or excess of water (Tewari, 1992).

Eucalypts are a good coppicer. Once the tree is felled, the stump throws manycoppice shoots. Best time for coppice in northern India has been found to be


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November to February. In dry areas, eucalypt coppices poorly. Coppice shootsshould be singled out to keep only one vigorous stem per stump, which will form thesecond crop. The yield in the first and second coppiced crops is more or less thesame, but it declines in the 3rd and 4th rotation by about 9 per cent and 20 per cent,respectively. Therefore, it is advisable to change the planting stock after the secondharvest (Rawat et al., 2013).

Organic matter and exchangeable potassium are depleted in soil under eucalyptplantations, but there are no signs of depletion of calcium and magnesium (George,1991). Substantial amount of nutrients are received back through inputs to the soilthrough litter fall, stem flow and through fall. Input of various nutrients by way ofgeochemical cycle and other means of biological fixation of nitrogen and gains ofnitrogen from atmosphere would compensate any loss of nutrients by woodharvesting. However, Eucalyptus being a fast growing species and particularly whenplantations are to taken under coppice system, fertilizer application (N and P) isdesirable for sustained biomass production.

11. IntercroppingIntercropping is usually recommended for two reasons. The foremost reason beingthat farmers care for trees when they care for crops. The second reason being thatregular irrigation and fertilizer application to crops benefit trees as well. However,tree and crop management is required to make the system economically viable. Asthe intensity of shade increases year after year, there is a need to select appropriateshade tolerant crops and standardise cultural practices that are complementary toeach other. Of all the agroforestry systems that are being practiced, the adverseeffects of single row boundary plantation are minimum. Studies on the effect ofboundary plantation of eucalypt on the yield of adjoining agriculture crops showedmaximum yield reduction of 64.4, 58.4 and 42.6 per cent in wheat, rice and potatocrops, respectively near the base of the tree line (Dhillon et al., 1979 and 1982) Thereduction in the yield is, however, dependent on the direction of tree line, itscomposition, spacing of trees, cropping season and type of agriculture cropcultivated. The minimum reduction in yield of crop sown on southern side andmaximum on northern side of the tree line is also noticed.

In Gujarat, eucalypts planted as windbreaks helped in increasing the atmospherichumidity and, thus, resulted in an increase in the yield of wheat and mustard by 23-24 per cent (Kumar, 1984). Similar trend was available in Andhra Pradesh for groundnut,pigeon pea and pearl millet where an increase in yield to the order of 40-43 per cent,39-47 per cent and 23-64 per cent, respectively was observed. In another study onthe effect of eight year old eucalypts hybrid plantation in Dehradun on kharif maizecrop found no significant reduction in yield because of moisture availability (Dadwaland Narain, 1984). The results of still another study indicated that single sided

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boundary plantations of eucalypts showed negligible adverse effects on wheatyield under irrigated conditions (Sharma and Unnikrishnan, 2000). The low yield ofcrops has been attributed to allelochemicals released by the leaf litter of eucalypts(Basu et al., 2000). It can, therefore, be concluded that eucalypts grown on fieldboundaries do compete with agricultural crops for water, nutrients and light to varyingdegrees, thereby, affecting crop production. However, eucalypts raised as windbreakor shelterbelt plantations under arid or semi-arid conditions has helped in increasingcrop production.

Low light intensity brings in decreased rates of photosynthesis under shade;affects relative growth rate, reproductive and ripening phases of crops and, thus,ultimately leads to loss of yield. Under certain tree canopy manipulation conditionsand choice of suitable crops maturing at suitable spatial times can only help to workout an integrated approach for maximum production of tree and agricultural cropyields. Therefore, there is a need to identify the suitable agricultural and horticulturalcrops which can grow well along with tree plantations with limited solar energyavailability.

Some of the crops that can be grown in the rabi season include wheat, mustard,potato, and fodders like barseem and oats that can be grown for the first two to threeyears depending upon the spacing and the intensity of shade. During kharif season,fodders like sorghum and pearl millet can be grown successfully after the first yearof planting. Out of fodders, cow pea and pearl millet are reported to yield higher thansorghum during the initial three to four years. However, after 4th year of plantation (4m x 2 m), yield of these intercrops is negligible. The vegetables that can be grown arecucurbits, ginger, potato and turmeric. Fast growing taller crops such as sugarcane,sunflower, sorghum, etc. should be avoided during the first year as these may suppressthe growth of young plants. The undercrop should be so rapid growing that it canexploit the relatively short period during which solar radiation penetration throughthe tree canopy is maximum.

The effect of eucalypt on agricultural crops is not very well researched and needsto be thoroughly investigated. There are a number of interactions between theatmosphere, tree and agricultural crops both above and underground. There is a lossin agricultural production because of the shade covering the agricultural crops andcompetition for nutrients and soil moisture. The presence of trees changes themicroclimate near the ground level by reducing the wind velocity, intercepting lightand heat radiation and also moisture. Reduced wind velocity reduces evapo-transpiration from understorey plants. The greater the leaf area and more horizontalare the leaves the greater would be the shading effect and evapo-transpiration.Eucalypts cast less shade on an average than other broadleaved species because ofdifferent leaf sizes and orientations. Interception of light radiation during daylightcauses reduced photosynthesis because of lower temperature and reduced evaporation.


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Effect of light intensity is well noted on the flowering, anthesis and yields. Still, thereare some crops which are shade tolerant and from which underground biomass can beutilized as food. There is a need to find out C3 crops which can be profitably grownunder tree crops as they are more efficient in utilizing light intensities. The minimumlight intensities that can be provided to undergrown crops and, accordingly, trees canbe geometrically spaced to achieve that minimum desirable light intensities. Only suchinnovative research can boost the agroforestry prospects and achieve the maximumproductivity from a unit piece of land.

It is, generally, believed that agricultural crops and trees meet their nutrientrequirements from different depths. Most of agricultural crops are spread over thetop layer of soil from 20 to 50 cm soil depth. However, a higher concentration offine tree roots in the soil layer upto 50 cm suggests that trees also obtain most ofthe nutrient requirements from the soil layer upto 50 cm. The main function of theroots reaching greater depths appears to be water uptake, particularly duringperiods of water stress (Bowen, 1984). The proportional abundance of fine rootsof agricultural crops, grasses and trees suggests that there is a tough competitionfor nutrients among these components in the top soil. The competition betweentree roots and crop roots is reduced by repeated ploughing in the surface soil. Butthe overall requirement of nutrients by eucalypts species. is found to becomparatively less than the annual agricultural crops (Ghosh et al.,1978). Moreover,the uptake of nutrients by eucalypts is not more than that of other hardwoodspecies. It may be possible to return 10-12 per cent more nutrients to the soil byleaving the bark and other logging residues to decompose and be incorporatedinto the soil (Chandrasekhran, 1984).

Some beneficial effects of eucalypts growing are also reported on the soilphysicochemical properties. With the accumulation of biomass, there is an overallenrichment of the nutrient pool, especially in respect of N, P and K which aregenerally applied in the form of inorganic fertilizers (Table 9) (Srinivas et al., 2000).

R.K. Luna

Table 9. Nutrient requirement in some crops (kg ha-1 yr-1)Crop P2O5 K2O CaO Eucalyptus spp. 1.4 58.6 34.8 Rye (grain + straw) 29.0 57.0 15.0 Oats (grain + straw) 34.0 69.0 15.0 Wheat (grain + straw) 30.0 53.0 15.0 Potatoes (tubers + residue) 45.0 210.0 79.0

12. Water ConsumptionIn India and elsewhere, planting of eucalypts has become controversial due toits alleged excessive water consumption and adverse effect on the ecology and

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hydrology of the tract. The reliable measure of water consumption efficiency byplants is the weight of biomass produced per unit volume of water consumed.Some guide can be made from the ratio of rates of evapo-transpiration to panevaporation for different species. E. camaldulensis is reported to have a verylow evapo-transpiration (Davidson, 1985). E. globulus is reported to transpireabout 347.5 mm equivalent, that is about 38 per cent of the total rainfall. Studiescarried out regarding water consumption by different species indicate that thevalue of water consumption per unit of biomass produced (litre/gm) is lower inE. citriodora (1.41) as compared to Dalbergia latifolia (2.59), Pinus roxburghii(8.87) and Populus casale (3.04) (Dabral, 1970). It was evident from the studythat fast growing species naturally consume more water to produce maximumquantity of biomass. Later experiments by Chaturvedi et al. (1984) also reportedsimilar results confirming that Eucalyptus hybrid consumed 0.48 l of water pergram dry matter production against 0.77 l by Dalbergia sissoo, 0.72 l by Acaciaauriculiformis, 0.50 l by Syzigium cumini, 0.55 by Albizia lebbeck and 0.88 l byPongamia pinnata. Further studies showed that maximum amount of water byeucalypts was consumed during rains and lowest during summer months, whenthere was shortage of soil moisture. These results indicated that eucalypts werean efficient utilizer of water depending upon the availability. Lima (1984) citingHolmes and Wronski (1981) has stated that in South Australia with annual rainfallof 700 mm or more, eucalypts forest would create a soil water deficit of 250 mmeach year, against 180 mm by annual crops meaning, thereby, that forested landwould yield 70 mm less runoff or recharge of groundwater in comparison toannual crops. This is particularly important when Green Revolution states arepassing through a great water crisis. The groundwater table in the states likeHaryana, Punjab and Uttar Pradesh has fallen down alarmingly, endangering thefood security of the country. In view of this situation, the agroforestry has toplay an important role to overcome the crisis through diversification of paddy-wheat rotation (Box 1).

13. Economics of Eucalypt PlantationsIn farms, where soil is well worked, deep and rich, eucalypts can give very highreturns on investments. Economics of these plantations have been worked out byvarious workers in the past at suitable spacings and at appropriate rotations. Theeconomic feasibility of Eucalyptus hybrid both with or without intercropping undervarying spacings of 2.5 m x 2.5 m, 3.0 m x 1.5 m, 4.0 m x 2.0 m and 6.0 m x 1.0 m aspracticed by farmers in Haryana, Punjab and Uttar Pradesh, were worked out (Mathuret al., 1984). The results are tabulated in Table 10.

The conclusions drawn were that eucalypts planting in combination withagricultural crops at 6.0 m x 1.0 m spacing with eight year rotation gave the


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Box 1. Changing Role of EucalyptsPunjab is predominantly an agricultural state with 82.56 per cent of its area under agriculture. Withthe introduction of high-yielding varieties of wheat and, subsequently, rice in the sixties with thetechnological inputs of chemical fertilizers and irrigation largely dubbed as ‘Green Revolution’, theproductivity of crops has changed tremendously, as a result Punjab got the title of ‘Grain Bowl ofIndia’. The policy to enhance the production of foodgrains has to be encouraged for meeting theemergent food situation in the country, especially during the seventies and eighties. Consequently,the production of foodgrains in Punjab has risen more than seventies, from 3.16 Mt in 1964-65 to25.30 Mt in 2000-01 (Punjab and Stock, 2000). However, over the times, the wheat – rice rotationnow covering more than 60 per cent gross of sown area, has created serious environmental problems.Both these crops use water intensively, thus, leading to large scale depletion of groundwater in manyareas. Rice, which is traditionally not grown in Punjab, now occupies 35 per cent of the area. During1965, rice occupied an area of 0.29 Mha whereas during 2010-11, it occupied an area of 2.7 Mha.The total demand of water for these high water guzzling crops, in the state is estimated at 4.38Mha m against a total supply of 3.130 Mha m from both canal and ground water resources, leavinga deficit of 1.251 Mha m. The deficit is met from overexploitation of groundwater table below thecritical depth of 10 metres. There are 9,35,000 tubewells to lift the underground water for irrigation.Due to incessant exploitation of groundwater, the water table in 110 blocks out of the total 138blocks in the state stands over exploited (more than 100%) and only 17 per cent area is under thesafe category for water development. The water table is going down at the more than 2 metres perannum in some districts of central Punjab. To meet this crisis, the government has proposed todivert 0.2 Mha of land from wheat-paddy rotation to agroforestry plantations. In the past, manygovernment schemes to allure the farmers to shift from wheat-paddy rotation to other crops havefailed. Agroforestry is possibly the new alternative because of promising high returns. Farmers arewilling to adopt clonal eucalyptus under agroforestry plantations. This will serve the goals ofsustaining the productivity of land, provide alternative agroforestry model to the farmers, increasethe forest and tree cover in the state, and conserve the water. Whereas, for production of one kg ofrice grain, 3,702 l of water are consumed, for production of 1 kg of dry biomass production ofeucalypts, 785 l of water is consumed (Davidson, 1985). Annual consumption of water both underwheat-paddy rotation and eucalypts based agro-based system is calculated as under:

Wheat-paddy cultivation systemRice production ha-1 =3,828 kg

Water required for one kgproduction = 3,702 lWater consumption ha-1 = 3,828 x 3,702 l

=14,171.256 m3 ha-1

Wheat production in rabi crop = 4,600 kg ha-1

Water consumed for one kgproduction = 1,654 lWater consumption ha-1 = 1,654x4,600 l

= 7,608.4 m3 ha-1

Total water consumption = 21,779.65 m3 ha-1

Total for 6 years @ 21,780 m3 ha-1 = 130,680 m3 ha-1

Eucalyptus-based agroforestry systemDry biomass production ofeucalypts ha-1 = 15 t per annumWater requirement for one kg ofdrybiomass production inagroforestry system = 785 l kg-1

Water consumption in one ha = 11,775 m3 ha-1

Biomass production of sorghumin kharif crop = 5 tWater consumption kg-1

production = 1,000 lWater consumption by sorghum = 5,000 m3 ha-1

Rabi crop of fodder = 5,000 m3 ha-1

Total 1st year = 21,775 m3 ha-1

Total 1st and 2nd yr@ 21,775 m3 ha-1 = 43,550 m3

3rd, 4th, 5th, 6th yr = 11,775 m3 ha-1 y-2

Total 3rd, 4th, 5th and 6th yr@ 11,775 m3 ha-1 y-2 = 47,100 m3


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highest net present value and benefit cost ratio at 12 per cent rate of interest inHaryana, Punjab and Uttar Pradesh. The internal rate of return was found to behigher for 4.0 m x 2.0 m spacing with intercropping in these states. The studyconcluded that for small farmers planting of eucalypts on bunds is economicallyviable without sacrificing the agricultural crops. It was recommended that cultivationof eucalypts at wider spacing in combination with agricultural crops at eightyears rotation ensures high economic returns (Mathur et al., 1984). Similar viewswere expressed by Dogra (1984) that eucalypt plantations on agricultural farmsproved to be highly economical giving an internal rate of return of 35 per cent to38 per cent without intercropping and 85 per cent with intercropping (Table 11).It was concluded that on good agricultural land where irrigation is available,intercropping must be practiced since opportunity cost of this land is high. In

Total consumption in six years = 90,650 m3 ha-1

Saving of water = 40,030 m3 ha-1

Total saving expected after bringing 0.1 Mha under agroforestry system = 4,003 M m3

...Contd. from previous page

Thus, by bringing a 0.1 Mha area under agroforestry system Punjab can save 4000 M m3

of groundwater over a period of six years. Moreover, water consumption by eucalypts can bereduced by planting trees apart or by thinning existing plantations, which the farmers won’tdo with agricultural crops. The faster trees grow because of their genetic make up or they aremade to grow fast by application of fertilizer. To accumulate more living biomass, the treehas to withdraw more water reserves. The decision, therefore, can be taken as to how quicklythe biomass is to be harvested or how quickly benefits from trees are required. A balance canbe struck between growing a large biomass or alternatively, growing a lesser biomass over amuch longer period of time to save water. Rate of biomass production (read water consumption)can be adjusted through cultural practices or by choice of species. As suggested, the density oftrees can also be adjusted keeping in view the annual rainfall, needs of other vegetation,livestock and human consumption.

Table 10. Economics of eucalypts growing under agroforestry systems at eight yearsrotation

(Labour rate Rs. 10.0 per manday).


Spacing No. of plants

Volume (u.b.) m3

NPV (@ 12%)

B:C (@ 12%)

IRR (%)

(a) Without cropping (i) 2.5 m x 2.5 m (ii) 3.0 m x 1.5 m

1,600 2,222

106.1 78.92

Rs. 21,422 Rs. 14,687

3.43 2.45

40 32

(b) With inter cropping (i) Bund planting

2m apart (ii) 2.5 m x 2.5 m (iii) 3.0 m x 1.5 m (iv) 4.0 m x 2.0 m (v) 6.0 m x 1.0 m

200 1,600 2,222 1,250 1,666

-

106.0 79.0 78.0

116.0

Rs. 31,681 Rs. 15,563 Rs. 8,727

Rs. 11,914 Rs. 17,022

2.32 2.08 1.57 1.88 2.17

-

64.6 40.0 73.0 63.0

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other words, good quality land should not be brought under eucalypts unlessinter cropping is practiced.

The productivity of clonal eucalypts is more than two to three times of the seedroute plantations. The experimental trials carried out by Pragati Biotechnologies haveindicated seven most productive clones with MAI ranging from 24 to 30 m3 ha-1 yr-1 atthe age of four years. Some clones are reported to produce 30 to 36 m3 ha-1 yr-1. Theanalysis of data from private agroforestry farms revealed that clone 288 gave MAI of48.79 m3 ha-1 yr-1 followed by clone 316 with MAI to the tune of 33.70 m3 ha-1 yr-1 at theage of 4 and five years, respectively (Luna et al., 2009). Studies in Haryana state haveindicated a yield of 50.2 t ha-1 yr-1 in a four year old irrigated clonal plantation. Theprofitability of this plantation was worked out Rs. 27,587 acre-1 yr-1. Even under rainfed conditions, a six year old clonal plantation gave 37.4 t ha-1 yr-1 which showed anincrease of about 179 per cent over seed route plantation. The profitability of thisclonal plantation was worked out to Rs. 27,249 acre-1 yr-1 which was about three timesof seed route plantation. Thus clonal plantations are a boon for the farmers (Sapra,2006). Many farmers in Punjab have achieved record growth rates of 50-58 m³ ha-1 yr-

1 making farm forestry an economically attractive land use option with better returnscompared to traditional crops (Piare Lal, 2006). Table 12 summarises the productivityof clonal eucalypts and the income generation.

In Andhra Pradesh, the farmers have harvested MAI (MT ha-1) of 23 in Khammam,28 in Prakasam, 21 in Guntur, 24 in Krishna and 39 in West Godavari districts. TheIRR per acre (%) in different districts worked out to be 40 in West Godavari, 48 inKhammam, 32 in Prakasam, 26 in Guntur and 30 in Krishna (Kulkarni, 2004). Some ofthe most important considerations which prompt farmers to adopt agroforestry as a

Land site type I II III IV Description of site

Undulating irrigated land

Fair quality irrigated land no

intercropping

Average quality irrigated land

Good quality irrigated land (intercropped)

Annual land rent (Rs. ha-1)

400 600 1,000 1,500-2,500

N.P.V. (Rs. ha-1) at 6%

26,802

31,794

42,732

47,811

15% 8,050 9,714 13,012 17,458 I.R.R. (%) 35 38 37 85

Table 11. Economics of eucalypts plantation on agricultural farms in Punjab

R.K. Luna

Table 12. The income from clonal eucalypts plantationsSpacing (m x m)

Year Average weight (q acre-1)

Total income (M Rs. acre-1)

Average total income (Rs. acre-1 yr-1)

4 x 2 7-8 1,200 0.30 37,000 4 x 2 3-4 350 0.06 15,000+crops 8 x 2 (block) 7 700 0.18 25,000+crops 2 (on field bunds) 7 350 0.09 12,500+crops

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preferred land use option are high productivity, better returns as compared to crops,long-term market demand, availability of genetically improved planting material andhigh quality extension services (Piare Lal, 2006).

14. MarketingAs compared to agricultural sector, the concept of marketing has not developed wellin the forestry sector. Not much work has been done in the country on theinterrelationships between production levels and marketing of tree products. Eucalyptgrowers throughout the country sell their produce to the private traders at the lumpsum price or on the basis of weight. Very few farmers prefer to cut the trees themselvesand bring the logs on their own transport to the nearby markets, where it is sold inauction by weight. The rates of wood in markets all over the country varyconsiderably in a particular season and also in different months its one particularseason, and also in different months at one particular place depending upon thequality as well as demand of the wood in the market. At the time of harvesting ofcrops during rabi and kharif seasons, the arrival of wood in the market declines,whereas with the onset of winter season, the market shows upward trends due toincrease in the demand of fuelwood as well as timber. Lack of efficient marketingsystem is believed to be the major factor in depressing returns from eucalyptsplantations in Punjab and elsewhere (Negi et al., 1996). There is a decline in producer’sshare in consumer’s rupee, with the increase in length of marketing chain. Theexisting marketing rules and customs also tend to complicate the marketing channelsand the middlemen take the advantages of the faulty market mechanism.

There is no follow up of the rigid rotations as the trees are felled as and whenthe need arises. Further, the harvest sales has an effect on the post-harvest sales toget competitive price in the regulated markets (Singh and Grover, 1998). There is aneed to educate the farmers by providing them the reasonable estimates of quantityand quality of wood in the standing trees through extension services. Sagar (1983)after examining the various aspects of utilization and the market prices of differentend users of eucalypts suggested to set up forest products price commission to fixthreshold prices of different end-use products in order to save the farmers from thevagaries of the market. Quli (2001) also agreed that lack of proper marketing facilityis a common feature for the villagers resulting in their exploitation by middle men.Some states like Haryana and Uttar Pradesh have set up forest corporations whichpurchase trees directly from farmers, but these purchases are estimated to about 0.1per cent of the total farm output of eucalypt trees.

Negi et al. (2001) reported that only 8 per cent of the farmers of Yamunanagardistrict preferred self-harvesting before marketing their produce. Whereas, rest ofthem sold their standing trees in the fields. The reasons for adopting sale of standingtrees were reported to be high labour input in harvesting, poor knowledge of sizes


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and logging techniques, lack of equipment for proper transport and communication,delay in payment by the traders and industrialists. Besides these, the malpracticessuch as under measurement of the sizes and weight and under assessment of thequality of tree products forced the farmers to sell their trees in standing condition. Thetypes of sale (pre-harvest or post-harvest) depend on many factors such as distanceof timber markets from plantation sites, number of trees available for sale, area underplantation, cost of felling and transportation, availability of labour and market price ofthe produce. Farmers with small area under tree plantation mostly disposed off theirtrees in standing condition through contractors. The farmers away from marketspreferred pre-harvest mode of sale as compared to the villages located near to timbermarkets due to high transportation costs. The study on marketing condition in Punjabby the FRI (2006) further revealed that the farmers were getting only 56.4 to 64.8 percent of the buyers’ price through this channel, as there were three to four intermediatorieswho shared the profit. The farmers incurred a number of charges (Rs. q-1) such asharvesting and loading, transportation, octroi, weighing, unloading, quality, discountand commission. The total of these charges came to almost 50 per cent of value ofwood. The study strongly recommended the establishment of Tree GrowersCooperative with the main function of securing sales and negotiating contracts.

15. Policy and Research NeedsThough most significant plantation species in the country, eucalypt has not receiveddue attention in the research circles. The productivity levels of the species differ toa great extent in the different agroclimatic zones as well as within the zones. Thefarmers are dependent on a very narrow genetic base of the species for planting. Allover the country, clones developed by the ITC Bhadrachalam are propagated andmultiplied extensively. The government departments have neither made efforts todevelop new clones nor taken pains to broaden the genetic base of planting materialfor supply to the farmers. Instead the uncertified planting material is sold to thefarmers at uncontrolled prices because regulations are not there on both the fronts.The government has not developed or institutionalized the mechanism to supportthe prices of eucalypts wood. The state departments are supplying the plantingmaterial without studying the future dynamics of demand and supply of wood in themarket. Most of the farmers are planting eucalypts at various spacings withoutknowing the silvicultural or economical aspects of planting under agroforestry. Evenafter half a century of eucalypt planting in the field, package and practices arewidely under developed or unknown to the farmers. The research institutions havebeen mainly working on biomass and mensurational studies preparing the yield andvolume tables, which have little applications for the farmers. In our country, both forpromotion of eucalypt as well as for the welfare of farmers, the species has to becultivated in association with agricultural crops.

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Therefore, research institutions should prioritise the research needs forworking out the interaction of crops, manipulation of tree canopies, substitutionof new agricultural crops, and the water and nutrient dynamics between trees andagricultural crops to give a new meaning to agroforestry. There is a tremendousscope for improvement of eucalypts to produce the disease free clones particularlyagainst the gall wasp (Leptocybe invasa), little leaf (Mycoplasma like organism),leaf blight (Cylindrocladium quinquenceptum) and psyllid of eucalypts whichare becoming a great threat in some intensive eucalypt planting zones in thecountry. The prioritization of policy and research needs on eucalypt are givenbelow:

15.1. Priorities• Development of high yielding and disease resistant eucalypt clones.

Widening the genetic base and diversity of clones by developing a largenumber of field tested superior clones with desirable genetic traits.Introduction of new germplasm of promising provenances and species.

• Development of package of practices for different agroclimatic zones of thecountry including correct choice of species/clones, spacings to be adopted,cultural practices, rotation, yield expectation and economics. Field testing ofclones for identification of site specific clones with high adaptability andproductivity.

• Certification of planting material and regulation on sale and proliferation ofunscientific eucalypt nurseries.

• Reduction of per plant cost of production of clonal planting stockparticularly improving the rooting percentage of vegetative cuttings.

• Interaction of agricultural crops and trees, manipulation of canopies oftrees toward the shade effect.

• Trials on new varieties of agricultural crops suitable for growing underpartial shade.

• Working out economics of eucalypt grown under agroforestry vis-à-visagricultural crops grown alone.

• Nutrient demands of eucalypt grown in association with agricultural cropsand grown alone.

• Water relations of eucalypt and agricultural crops.

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Eucalyptus growth. KFRI Report No. 27. Peechi, KFRI. 11p.Arnold, J.E.M. and Dewees, P.A. 1999. Trees in managed landscapes: Factors in

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Eds. Agroforestry and sustainable agricultural system. Boca Raton, CRCPress.

Athreya, V. 1989. Pilot study on experiences in farm forestry in Haryana. New Delhi,Athreya Management Consultants.

Banerjee, B.; Nandi, A.; Nath, S. and Banerjee, S.K. 1986. Characteristics of the soilssupporting quality I Eucalyptus tereticornis in South Bengal. IndianForester, 112(9): 762-771.

Basu, P.K.; Kapoor, K.S.; Nath, S. and Benerjee, S.K. 2000. Allelopthic influence: Anassessment of the response of agricultural crops growing near Eucalyptustereticernis. In: Singhal, R.M. and Rawat, J.K. Eds. Effects of growingEucalyptus. 2nd ed. Dehradun, FRI. pp. 218-225.

Bowen, G.D. 1984. Tree roots and the use of soil nutrients. In: Bowen, G.D. andNambiar, E.K.S. Eds. Nutrition of plantation forests. London, AcademicPress. 516p.

Chandra, B.K.; Kariyappa, G.S. and Manjunath, B.E. 1994. Evaluation of Eucalyptuscamaldulensis provenance trials in Karnataka. Indian Forester, 120(8): 670-676.

Chandrasekharan, K.S. 1984. Eucalyptus and forestry II. Times of India, 2nd October1984.

Chaturvedi, A.N.; Sharma, S.C. and Srivastava, R. 1984. Water consumption andbiomass production of some forest trees. Commonwealth Forestry Review,63(3): 217-223.

Dabral, B.G. 1970. Preliminary observations on potential water requirement in Pinusroxburghii, Eucalyptus citriodora, Populus casale and Dalbergia latifolia.Indian Forester, 96(10): 775-778.

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Davidson, J. 1985. Setting aside the idea that eucalypts are always bad. WorkingPaper No. 10. Rome, FAO. 26p.

Dhanda, R.S.; Gill, R.I.S.; Singh, Baljit and Navneet Kaur. 2008. Agroforestry modelsfor crops diversification in Punjab plains. Ludhiana, PAU.

Dhillon, G.S.; Singh, Surjit; Dhillon, M.S. and Atwal, A.S. 1982. Developingagrisilvicultural practices: Studies on the shading effect of Eucalyptuson the yield of adjoining crops. Indian Journal of Ecology, 9(2): 228-236.

Dhillon, G.S.; Grewal, S.S. and Atwal, A.S. 1979. Developing agri-silvicultural practices:Effect of farm trees (Eucalyptus) on the adjoining crops (India). IndianJournal of Ecology, 6(2): 88-97.

Dogra, A.S. 1984. Farm and agroforestry in south western Punjab. In: Mathur, R.S.and Gogate, M.G. Eds. Agroforestry in India. Dehradun, FRI. pp. 157-177.

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Ghosh, R.C.; Kaul, O.N. and Subha Rao, B.K. 1978. Some aspects of water relationsand nutrition in Eucalyptus plantation. Indian Forester, 104(7): 517-524.

Goldin, I.; Rogers, H. and Stem, N.H. 2002. The role and effectiveness of developmentassistance: Lessons from World Bank experience. [Available at: http://go.worldbank.org/16O8JRI6W0 ].

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Kaul, O.N. 2008. Biomass estimation study in Haryana Community Forestry Projectvillages. Final report. New Delhi, Institute for Sustainable Development. 32p.

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Kulkarni, H.D. 2002. Bhadrachalam clones of Eucalyptus - An achievement of ITC. In:Workshop on Forest Science and Forest Policy in the Asia-Pacific Region:Buildings Bridges to a Sustainable Future, Chennai, 16-19 July 2002.Proceedings. The author.

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Kumar, D. 1984. Place of Eucalyptus in Indian agroforestry systems. In: NationalSeminar on Eucalypts in Indian Forestry: Past, Present and Future, Peechi,30-31 January 1984. Eucalypts in India: Past present and future: Proceedingsedited by J.K. Sharma, C.T.S. Nair, S. Kedharnath and S. Kondos. Peechi,KFRI. pp. 257-260

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1. IntroductionIn India, the rapid increase in population and use of paper as environment friendlypackaging material, has led to a rapid increase in paper consumption. Increasing demandfor fuel, timber and other usufruct is causing heavy pressure on the limited forestresources in India. This has gradually led to degradation and shrinkage of forests bothin quality and extent. The Indian pulp and paper industry is the 15th largest industry inthe world and is, thus, an important industrial sector in terms of socio-economicdevelopment as it provides employment to nearly 1.5 M people (Suri, 2007). Thegrowth in demand for all grades of paper at present is between 7 to 9 per cent per year.High growth in the printing industry, heavy government investment on education andthe growing demand for paper as an alternative for plastic as packaging material willcontribute towards the further increase in demand in the years to come.

2. Pulpwood Demand and Supply Situation in IndiaIn India, the current total consumption of paper and paper board, includingnewsprint, is around 11.15 Mt of which 10.11 Mt is produced in India and 1.04 Mtis imported annually (Kulkarni, 2013). Of the total wood requirement, nearly 75 percent is being met from farm/social forestry sources and the remaining comes fromgovernment sources, mainly from forest departments and the forest developmentcorporations through auction (Kulkarni, 2008). The National Forest Commission(2006) also emphasized that forests alone cannot meet the growing requirementsof wood, hence agroforestry in private and community lands has to be promotedto bridge the shortfall (NFC, 2006).

3. Commonly Used Tree Crops to Meet the Pulpwood Demandin IndiaIn India, many fast growing plants were screened for their suitability for pulp andpaper making. This includes a large number of annuals and perennials. Some of

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them are Acacia auriculiformis, bamboo, Casuarina equisetifolia, Eucalyptusglobulus, E. grandis, E. tereticornis, Gmelina arborea, Grevillea robusta, Hibiscussabdariffa, Leucaena leucocephala, Moringa oleifera, Pinus taeda, P. radiata,Populus deltoides (poplar), Prosopis juliflora, Sesbania aculeata, S. aegyptica, etc.Among these trees, eucalypt, Leucaena, poplar and bamboo are the important plantswhich have desirable pulp characteristics and are grown widely for the pulpwood.These species are being accepted by farmers and are well integrated with the existingland use systems. The acceptance of tree crops is notable particularly in the state ofAndhra Pradesh, where the acreage under eucalypt and Leucaena has increasedrapidly in recent years. It is estimated that Prakasam district of Andhra Pradesh aloneproduces 0.7 Mt of wood worth Rs. 560 M annually from private holdings of farmers(Saigal and Kashyap, 2002). Tree growing as a commercial short rotation hasincreasingly become a profitable land use with the establishment of company/farmerrelationships, trading of wood in the open market, assured market, high returns fromtrees and supportive policies of the state government during the last decade.

3.1. EucalyptDuring 1970s and 1980s when seedlings were the only planting material, eucalyptsused to be planted at closer spacing. Often trees were spaced at 1.5 m x 1.5 m and incase of bund plantations close planting of 1 m x 1 m was followed. A rotation of sevento nine years was recommended for the pulpwood, whereas for commercial wood, arotation of 13 to 14 years was recommended for best technical results for seedlings inforest plantations as the current annual increment of E. tereticornis peaks in the fifthyear and then drops (Chaturvedi, 1989). The wood density increases with age andreaches a maximum at 13 to 14 years. Farmers were encouraged to plant eucalypts at adensity of more than 4,000 seedlings ha-1, in bund plantations the distance betweentrees was about 1 m.

However, the development of high yielding and disease resistant clones hasrevolutionized eucalypt cultivation in many parts of India. Private sector enterpriseslike ITC selected a large number of candidate plus trees of eucalypts, based on thesuperior phenotypes, from plantations raised by farmers and forest departments (PiareLal, 2008). These candidate plus trees were cloned under controlled environments,field tested and the superior clones were released for large scale cultivation. Majorityof these clones are from E. camaldulensis and E. tereticornis and few of them are theprogeny of the crosses from these species. The productivity of these clones underrainfed conditions ranges between 12 to 44 m3 ha-1 yr-1. In certain trials, the productivityof best clones has been more than 10 times the productivity of seedlings or the worstperforming clone (Piare Lal, 2001).

Much of the area with eucalypt clones is under farm forestry where the spacingadopted is 3 m x 2 m during the late 1990s and, subsequently, reduced to 3 m x 1.5 m.

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Intercropping is rarely practised and confines to the first year. Frequent tillage isbeing practised for controlling the weeds during the initial years and subsequentlyto incorporate the litter. Fertilizers are generally applied at the time of planting and,subsequently, at yearly intervals. The quantum of fertilizer application varies and upto 125 kg DAP ha-1 is applied. Trees are harvested after the completion of four yearsand the productivity level varies from 50-140 tha-1 in four years. The coppice isallowed to grow and generally two shoots are allowed. The subsequent harvests arealso made at four-year interval and, thus, a total of four harvests can be taken fromsingle plant crop of eucalypt. The commonly used 3 m x 2 m spacing (i.e., a densityof 1,666 trees ha-1) by farmers for eucalypt causes yield reduction in majority ofintercrops from second year onwards. For this reason, much of the acreage underplantations is confined to large-landholders.

4. AgroforestryAgroforestry is defined as land-use system that involves the deliberate retention,introduction or mixture of trees or other woody perennials with agricultural crops,pastures and/or livestock to exploit the ecological and economic interactions of thedifferent components for enhancing the productivity in unit area and time. Severalstudies have conclusively proved that the inclusion of trees in the agriculturallandscapes often improves the productivity of system besides arresting the landdegradation by controlling erosion. Trees reduce the erosivity of rainfall anderodability of soil through dissipation of energy of raindrops by surface litter, treecanopy, physical obstruction to the runoff, root binding activity and by enhancingthe infiltration through improvement in soil physical properties due to the additionof organic matter. In sloping areas, trees planted on contours/bunds/soil conservationstructures form a barrier and the barrier thus formed by trees acts as physicalobstruction for the runoff and helps to reduce the erosion. There is ample experimentalevidence that shows that soil loss can be greatly reduced by maintenance of a goodsurface cover formed by the tree based systems.

4.1. Eucalypts in AgroforestryThough the sole plantations of eucalypt in farm forestry mode are profitable indegraded lands, yet their adoption is limited to farmers who have large holdingand are resourceful. The adoption of these systems by small farmers who areexclusively dependent on agriculture are limited due to the absence of annualreturns from these systems as the returns are realised only after the harvest of thetree in the fourth year. Small farmers need annual returns for their sustenance anduse of crop residues of annual crops as fodder, which is one of the importantsources of income for small farmers. Increasing the possibility of intercroppingbeyond second year and improving intercrop yields in eucalypt-based

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intercropping systems not only provides regular income for the sustenance offarmers before eucalypt is harvested (four years) but also fodder for livestock,which are an integral part of the farming systems of the area. Intercropping ofannuals with timber trees compared with sole tree woodlots offers the advantagesof reduced tree establishment costs, income generation during the unproductivephase of the trees, efficient use of natural resources, and risk reduction fromcatastrophic fires (Garrity and Mercado, 1994).

4.1.1. Planting geometry and intercroppingOn-farm experiments were conducted by Central Research Institute for DrylandAgriculture, Hyderabad in collaboration with ITC during 2001-06 to study theeffect of wider row spacing on the tree growth and the intercrop yield. Thepossibility of intensification of the existing eucalypt system was studied by pairingthe tree rows and introducing the intercrops between tree rows without reducingthe tree density. The spatial arrangements evaluated were 3 m x 2 m (farmers’practice), 6 m x 1 m (single wide rows), 7 m x 1.5 m in paired rows (7 x 1.5 PR), 11 mx 1 m paired rows (11 x 1 PR) and 10 m x 1.5 m triple rows (10 x 1.5 TR). All thetreatments had the same tree density of 1,666 trees ha-1. In 7 m x 1.5 m PR, distancebetween any two sets of paired rows was 7 m and distance between rows within apair was 1 m and trees within the rows were spaced at 1.5 m apart. In 11 m x 1 m PR,the paired rows were spaced at 11 m, rows in the pairs were spaced at 1 m and treeswithin the row were spaced 1 m apart. In 10 m x 1.5 m TR, distance between any twosets of triple rows was 10 m, rows in the triple row set were at 1 m apart and treeswithin a row were at 1.5 m apart (Fig. 1).

4.1.1.1. Effect of planting geometry on tree growthThe tree survival at harvest was not significantly affected by tree geometry and thesurvival was 85 per cent in 7 x 1.5 PR, 88 per cent in 3 x 2, 90 per cent in 6 x 1, 92 percent in 10 x 1.5 TR and 95 per cent in 11 x 1 PR. Trees in 11 x 1 PR and 10 x 1.5 TRtreatments grew slightly taller than in 6 m x 1 m and 3 m x 2 m until about two yearsafter planting. However, the trees in 6 m x 1 m and 3 m x 2 m treatments also came upwell to measure as tall as in other treatments during the later years. The mean annualheight increment ranged from 3.36 to 3.62 m yr-1. Treatment differences on the basisof average height were not significant. At harvest, the trees in 3 m x 2 m attained thehighest dbh, which was about 13 per cent greater than the dbh of trees in 10 x 1.5 TR.Nevertheless, treatment differences for average dbh were not significant (P=0.05)during the study period. Thus, we did not observe any major impact of tree geometryon growth of eucalypt during four years of this study. It appears that the effect ofsingle and double row arrangements on the growth and size of trees evened out overtime (Prasad et al., 2010).


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4.1.1.2. Effect of tree geometry on biomass productionThe debarked bole wood is the marketable product for eucalypts grown for pulpproduction in this region. The 6 m x 1 m spacing produced the greatest fresh bolebiomass of 88 Mg ha-1 which was about 8 Mg more than that produced by 10 m x1.5 m TR (Table 1). The total dry biomass was also greatest with 6 m x 1 m treatment(59.5 Mg ha-1) and lowest in the case of 10 x 1.5 TR treatment (52.9 Mg ha-1). However,treatment differences were not significant (P = 0.05) either in terms of fresh or drybiomass of bole wood or other tree components.

Treatment Marketable biomass (bole) fresh weight (Mg ha-1)

Total biomass dry weight (Mg ha-1)

10 m x 1.5 m Triple rows

79.7 52.9

11 m x 1 m Paired rows 81.4 54.0 7 m x 1.5 m Paired rows 85.4 57.4 6 m x 1 m 87.9 59.5 3 m x 2 m Farmers’ practice

86.7 54.2

SED 6.9 5.9

Table 1. Marketable yield and total biomass of eucalypt planted in agroforestry atdifferent spacing arrangements at harvest, 51 months after planting at Bhadrachalamin Andhra Pradesh, India

Fig. 1. Pictorial presentation of planting geometries tried in on-farm experiments(*distance between trees not to the scale).


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4.1.1.3. Effect of tree geometry on intercrop yieldThe details about the intercrop and the management practices were furnished byPrasad et al. (2010). During the first cropping season after planting the trees (i.e.,2001 post-rainy season), intercrop yields were not affected by the trees in anyspatial arrangements. The adverse effect of trees on intercrops was significantfrom the second year onwards (i.e. 2002), which increased substantially in thesubsequent seasons. Cowpea intercropped in closely spaced eucalypt (3 m x 2 m)during 2002 yielded only 45 per cent of sole crop. During 2003 and 2004 post-rainyseasons, intercropped cowpea in all tree row arrangements produced significantlylower yields than sole crop. In these seasons, cowpea in 3 m x 2 m tree spacinggave only 121 kg ha-1 (17% of the sole crop) and 134 kg ha-1 (23 per cent of solecrop yield), respectively. Intercrop yields increased with increase in tree rowspacing (or alley width), but only the triple row arrangement produced 73 per centand 66 per cent of the sole cowpea in 2003 and 2004, respectively. Cowpea yieldsin other wider-row arrangements varied from 50 to 62 per cent of the sole crop in2003 and 39 to 59 per cent of the sole crop in 2004. In 2005, all the three grassesshowed similar yield potential in sole system with an average yield of 1.94 Mg ha-1

and system x grass species interaction was not significant. Hence, average yields ofthree grasses in different systems are given (Table 2). The narrow tree spacingallowed significantly lower grass yield at 0.88 Mg per ha compared with all otheragroforestry systems with wider row spacing for trees. Although the widest inter-row treatment (11 m x 1 m PR) produced the highest yield at 1.83 Mg ha-1, it did notdiffer from other wider-row arrangements which produced yields in the range of1.36 to 1.53 Mg ha-1. Among the different spatial arrangements tested on eucalyptsin agroforestry, the treatments 10 x 1.5 TR and 11 x 1 PR recorded significantlygreater intercrop yields compared with the closer spacing of 3 m x 2 m from secondyear onwards.

A large number of crops such as chickpea, lentil, wheat, mustard, berseem,blackgram and greengram can be grown with eucalypt in wider rows. The practiceof paired rows and wider row spacing in eucalypt has been taken to the farmers’


2001 2002 2003 2004 2005 Treatment Cowpea (kg ha-1)

Fodder (Mg ha-1)a

10 m x 1.5 m TR 1062 655 518 387 1.53 11 m x 1 m PR 965 594 441 342 1.83 7 m x 1.5 m PR 926 485 405 229 1.36 6 m x 1 m 865 408 353 285 1.58 3 m x 2 m 879 296 121 134 0.88 Sole crop 968 650 706 584 1.94 LSD (0.05) NS 118 102 57 0.56

Table 2. Yields of cowpea grown in the post-rainy seasons of 2001 to 2004 and foddergrasses in both rainy and post-rainy seasons of 2005 in sole and eucalypt-basedagroforestry systems in Andhra Pradesh, India

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fields in the states of Andhra Pradesh, Maharashtra, Madhya Pradesh by ITC-PSPD and considerable area has been planted with paired rows and wider rows.In Madhya Pradesh, where deep black soils and high rainfall coupled withavailability of life-saving irrigation assured intercropping being possiblethroughout the rotation of eucalypt (Fig. 3). This helped to realize intercropyields and returns from arable crops annually and helped to increase the returnssubstantially in small holding situation.

Fig. 3. Intercropping of wheat and chickpea in wider rows in Madhya Pradesh, India.Wheat in 8 m x 1 m paired rows Chickpea in 8 m x 1 m paired rows

Fig. 2. Intercropping of guinea grass (Panicum maximum) in paired rows in AndhraPradesh, India.

Guinea grass in 7 m x 1.5 m paired rows Guinea grass in 11 m x 1 m paired rows

5. EconomicsThe financial evaluation of eucalypt systems in comparison to the cowpea crop ispresented in Table 3. Cost of cultivation and net returns were higher with eucalyptagroforestry system followed by sole eucalypt system. Returns from the tree systemswere substantially higher in comparison to the arable cropping system. Returns werehigher in eucalypt based agroforestry by three times in comparison to sole cowpea.Intercropping of eucalypt in these wider rows gave 14 per cent higher net returns


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compared with intercropping in eucalypt spaced at 3 m x 2 m, 19 per cent higher returnscompared with that from sole tree woodlot and 263 per cent higher returns comparedwith that from sole crops. Though, tree cultivation required additional expenditurewhich was mainly due to the cost of the planting material, its transportation to thefield, pitting and planting, returns more than compensated the costs. Intercropping inthe initial years allows better cash flow during the initial years of plantation cyclewhen the returns from tree are not forthcoming.

6. Adoption of Eucalypt Based Agroforestry SystemsITC-PSPD has taken the concept of wider rows of eucalypts to the farmers’ fields andconsiderable area has been planted with the wider rows. Presently, an area of about4,000 ha is under wider rows. In the state of Madhya Pradesh, farmers are taking upsoybean crop during the kharif season and chickpea/wheat during the rabi season inpaired rows and are able to realize a biomass productivity of 75-100 t ha-1 in four yearsfrom eucalypt. Some of the farmers were able to capture the pole market. As a resultthey could get higher returns in shorter time without compromising much on intercrop.

7. ConclusionsEucalypts, either sole or in intercropping systems, are profitable alternatives forcrop diversification over annual crops and produce large quantities of wood fibre ina short period. Tree systems are less risky under rainfed conditions where cropfailures are common due to extremes in rainfall variability. It can be grown profitablyin degraded lands where intensive arable cropping cannot be practised according toland capability. The agroforestry systems of these trees, besides enhancing theproductivity, also contribute towards annual returns and effective utilization ofresources and contribute towards increasing the employment opportunities at thevillage level and address the food and wood security concerns. Potential exists for

Table 3. Financial analyses of sole eucalypt, sole crop and eucalypt-based agroforestrysystems in Andhra Pradesh, India

Values indicated by different letters are significantly different (P<0.05).


Net returns over year (Rs. ha-1) System/spacings Total cost (Rs. ha-1)

Gross return

(Rs. ha-1) (2001) 1 (2002)

2 (2003)

3 (2004)

4 (2005)

5

Total net return

(Rs. ha-1) Agroforestry systems 10 m x 1.5 m (Triple rows)

71,737a 171,178a -7,947a 3,347a 2,932a 700a 100,509a 99,441a

11 m x 1m (Paired rows)

71,362a 170,611a -9,693b 2,077a 1,690a -32a 105,204ab 99,246a

7 m x 1.5 m (Paired rows)

71,145a 170,581a -10,095b -431b 880b -2,246bc 111,360b 99,468a

6 x 1 m 71,437a 171,699a -11,493c -1,547b -74c -1,526b 111,569b 100,262a 3 m x 2 m (Farmers’ practice)

70,275a 157,774b -10,941c -3,965c -4,366d -3,853c 110,629b 87,503b

Sole eucalypt 49,545b 129,980c -22,325d -3,205c -3,205e -3,205c 112,375b 80,435b Arable cropping 30,842c 58,282d 10,886e 5,671d 7,524f 5,160d -1801c 27,440c

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further improving the biomass productivity and fibre production from theseagroforestry systems through intensive management practices and application ofoptimum level of inputs. Focused location specific research is required to reduce thetree crop competition, increase the productivity and profitability of these systemsas intensification of the existing systems is still possible in view of the high rainfalland better soils where these tree systems are normally grown.

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Suri, R.K. 2007. Emerging trends in environmental management in paper industry. In:8th International Technical Conference on Pulp, Paper, Conversion and AlliedIndustries, New Delhi, 7th - 9th December 2007. Proceedings. New Delhi,Inpaper International. pp. 64-73.


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1. IntroductionEucalypts are native to Australia belonging to family Myrtaceae. More than sevenhundred species of genus Eucalyptus are found across the world. The first botanicaldescription of the genus under the name Eucalyptus was made by Heritier in 1978(FAO, 1981). Eucalypts were first introduced from Australia to the rest of the worldby Sir Joseph Banks, a botanist in 1770s. A few eucalypts, thereafter, becamepopular in parks and as sidewalk trees in sub-tropical belt in the world. Some of theeucalypts were also found suitable as construction lumber (Kardell et al., 1986).The fast growth in eucalypts and insect and fungus resistant wood led to theestablishment of regular plantations at the end of 19th century when silviculturewas still in its infancy. Large scale plantations of eucalypts began after the WorldWar II, primarily as a result of development in the pulp and paper industry.

A significant introduction of Eucalyptus species (E. globulus) as a treecrop was made first in Nilgiri Hills in 1843, since then it has been introduced toseveral other parts; i.e., in Annamalai and Palni Hills in south India and also tonorthern parts of India but its regular plantings were started in 1856 to meetthe demands of fire wood (Wilson, 1973). Nowadays, Eucalyptus has becomeone of the most widely used genera in global commercial plantations. The firsteucalypt plantation by forest department was established in 1877 at Malabavi(Devarayanadurga) of Tumkur district, Karnataka (Kadambi, 1944). Until theend of the 19th century, the eucalypts were raised in small block plantationsand often for the experimental purposes. Most of the plantations in the countrylie in plains and lower altitudes of hills upto an elevation of about 1,000 m.Growth of Eucalyptus species is very fast in alluvial soils as well as on riverembankments. Eucalypts are most successful for easy afforestation in differentsoil types and areas including the coal mines. The Tarai soil of Uttarakhand isvery fertile (loam or sandy loam) and suitable for fast growing vegetation suchas eucalypt, poplar, bamboo, etc.

Biomass Productivity,Carbon Sequestrationand Nutrient Cycling ofEucalypt PlantationsL.S. Lodhiyal

11

245

Global forest plantation was 187 Mha in 2005, about 1.4 per cent of the totalworld available land area. Of this, 36 per cent planted area was located in the tropicsand 64 per cent in the non-tropical regions. The tropical forest plantation area morethan doubled from 1995 to 2005, and on an average, the growth rate of tropical forestplantations was 8.6 per cent per year (FAO, 2006; Arias et al., 2011). Plantationforests are important sources of timber that alleviate the pressure on native forestsfor commercial forest products and are viewed as an effective means of short-termcarbon sequestration (Turner et al., 1999; Silver et al., 2000; Curlevski et al., 2010).More than 20 Mha land is under eucalypt plantations in more than 90 countriesaround the world (Booth, 2013).

The plantations are generally mono-specific and have been managedsuccessfully and sustainably for many years. Nevertheless, concerns have beenraised about the costs of fertilizers, reduced biodiversity, and productivity lossesfrom pests and diseases (De Bell et al., 1987; FAO, 1992). Eucalypt has multifarioususes; its timber is used for construction, furniture, plywood, medicine, oil, fuel wood,paper and pulp, etc. Eucalypts are used as poles and have excellent wood for pulpingpaper and rayon. The wood of these species is heavy, therefore, good for firewoodand charcoal making. The short-rotation plantations can regenerate through differentprocesses such as natural, artificial and coppice growth.

Biomass is a dry weight of living organisms; i.e., plants or animals. In case offorests and forest plantations, vegetation biomass is total dry weight of vegetationlayers; i.e., tree, shrub and herb in a unit area of land. The biomass stock and itsstorage rate in plantations plays significant role for providing the tree productsand mitigating the climate change problems. Biomass estimation is essential fordetermining the status and flux of biological materials in an ecosystem as well asfor the understanding of its dynamics (Anderson, 1970). Leith and Whittaker (1975)pointed out that forest biomass, if measured and analysed in its proper context aspart of production, gives an overall picture of ecosystem functioning. Swank andSchreuder (1974) described that tree biomass quantity per unit area of landconstitutes the primary inventory data that needed to understand the flow ofmaterials and water in the forest ecosystems. However, the biomass andproductivity estimates of tree species vary from place to place due to variation inclimate, soil, temperature and rainfall (Lodhiyal et al., 2002). Therefore, it isimperative to assess the biomass accumulation, productivity, carbon stock, carbonsequestration and nutrient cycling performance of tree species growing in differentecological zones in the country.

Biomass is an essential aspect of studies of carbon cycle (Ketterings et al.,2001; Cairns et al., 2003). There are two methods to estimate forest biomass, one isdirect and another is indirect (Salazar et al., 2010). Direct methods, also known asdestructive methods, involve of felling of trees to determine biomass (Parresol,

Biomass productivity, carbon sequestration and nutrient...

246

1999; Salazar et al., 2010). Indirect method means the estimation of stand biomassbased on allometric equations using the measurable parameters. The use ofcircumference (girth) at breast height (cbh or gbh) alone (expressing the basal area)for aboveground biomass estimation is common to many studies that showed dbhas one of the universally used predictors, because it shows a high correlation withall tree biomass components and is easy to obtain accurately (Heinsoo et al., 2002;Antonio et al., 2007; Zianis, 2008; Razakamanarivo et al., 2012).

Nutrient use efficiency (NUE) can be defined as the net primary productionper unit of nutrient lost from forest vegetation and recognized that the annuallosses must be replaced by uptake (Vitousek, 1982). The net primary productionrate per unit differs with species because of differential nutrient accumulation fromthe soil. In the production process, the photosynthesis plays a positive correlationwith nutrient concentration in leaves (Mooney et al., 1978; Mooney and Gulmon,1982). However, NUE can be increased substantially by adaptations to minimizeannual losses and to increase the internal reuse of nutrients. Small (1972) statedfollowing two mechanisms that increase the internal conservation of nutrients in

Fig. 1. E. camaldulensis plantations (5-year-old) in Tarai region of Uttarakhand.

L.S. Lodhiyal

247

trees: (i) lower leaf turnover and (ii) higher re-absorption (re-translocation) ofnutrients before leaf shedding (abscission). The NUE differences in forests mightbe due to differences in species among the sites. NUE differences might alsoappear within a species as a result of responses to differences in nutrientavailabilities of sites.

2. Vegetational AnalysisFor the estimation of biomass, productivity, carbon and nutrients of eucalyptplantations, one hectare sample plot of eucalypt plantation was selected. Forqualitative analysis, the sample plot was divided into four replicate sub-plots of 50m x 50 m (0.25 ha) and adequate number of trees in a sample plot (equal number oftrees in each sub-plot) were measured. The height and diameter/circumference (dbh/cbh at breast height (1.37 m) of trees are measured by Ravi multimeter and treecallipers/meter tape, respectively. The mean value was used when the linear regressionequation for each component was developed with component weight in studiedplantation. In case of understory vegetation, the height and diameter of individualshrub species was measured. A regression equation for each shrub can be developedfor the estimation of shrub biomass and increment. The density of shrubs can bedetermined in each sample plot estimates using quadrats of 2 m x 2 m size placedrandomly in eucalypt plantation. The herb layer was analysed by using sufficientnumber of quadrats of 1 m x 1 m size in plantation.

3. Biomass EstimationBiomass is estimated through regression equation and various other methods; i.e.,leaf area index (LAI), normalized differential vegetation index (NDVI), etc. for treeand shrub species that occur in the forest and other land use area. However, thebiomass and productivity of herbs/grasses layer is the total dry weight in a unit areaobtained after harvest at their peak growing season. For the estimation of biomassand NPP, although energy gains by photosynthesis and energy losses by respiration,herbivory and litter fall are individually of considerable interest, it is the combinedoutcome of these processes that has greatest concern to ecosystem managers andecologists (Kimmins, 1987). Earlier foresters have been interested in standing croprather than biomass but with the development of more complete utilization of trees,biomass is becoming their major focus. Selective harvest is one of the biomassestimation methods that give actual information of biomass accumulation of forestand or plantation, which was earlier developed by Ovington (1962), Whittaker (1966)and Newbould (1967). In a study, the fresh weight of each tree component wasestimated in the field in each plantation. About 500 g fresh weight of each separatedcomponent was brought to laboratory in polyethylene bag and oven dried at 600C toestimate actual dry weight of component of eucalypt plantation site. A linear


248

regression equation for each component was developed for each site plantation.The data of each component of tree was subjected to regression in form of Y=a+b X,where Y is the dry weight of a component (kg) and X is the mean dbh of tree at breastheight (dbh,1.37 m) of each eucalypt plantation. Thus, the developed equation ofeach component was used with mean dbh and multiplied by tree density to get thecomponent biomass (B1). The total vegetation biomass of plantation was determinedafter summing up of each layers biomass; i.e., tree, shrub and herb. In present study,the biomass was 66.83 t ha-1 (aboveground 52.93 t ha-1) in 5-year-old Eucalyptustereticornis plantation in Tarai region of Uttarakhand. This estimate is comparedwith biomass estimates of eucalypt tree plantations reported for different parts ofworld by several workers in Table 1.

4. Productivity and Its EstimationProductivity is generally reported in terms of the weight, volume or energy contentper hectare per year. Net primary productivity (NPP) of a given type of vegetationgenerally increases as one moves from temperate to tropical areas and within thegiven climatic region, the productivity increases as one moves from drier habitats towetter habitats (Kimmins, 1987). He also stated productivity in many forestecosystems declines, if soil becomes excessively wet. Forests, generally, exhibitproductivities comparable to agriculture (slighty lower than it). The surprising factis that forests are located generally on less fertile sites, in more severe climates andreceive far fewer aids to production; i.e., fertilizers, insecticides, etc. Most of theprimary productivity measurements have been based on some indirect quantitysuch as the amount of substance produced, the amount of raw material used, or theamount of by-product released. One of the greatest difficulties in determining theproductivity of a particular ecosystem is assessing whether the system is in dynamicequilibrium or a ‘steady state’ or not. In steady state ‘inflows’ balance ‘outflows’ ofmaterial and energy. The rate of production is in equilibrium with the supply or therate of inflow of the minimum limiting constituent. The following methods can beused to measure productivity:

⇒ Oxygen measurement method (Penfound, 1956; Ovington, 1962; Woodwelland Whittaker,1968; Odum, 1969, 1996).

⇒ Carbon dioxide method (Transeau, 1926; Huber, 1952; Inove et al., 1958;Lemon, 1960, 1967; Musgrave and Moss, 1961; Monteith, 1962; Woodwelland Dykeman, 1966; Woodwell and Whittaker, 1968; Odum and Pigeon, 1970).

⇒ Disappearance of raw materials method (Odum, 1996).⇒ The pH method (McConnell, 1962; Beyers et al., 1963; Beyers, 1964, 1965;

Cooke, 1967; Gorden et al., 1969).⇒ Productivity determinations with radioactive materials (Ryther, 1954; Odum

and Golley, 1963; Thomas, 1964; Strickland and Parsons, 1968).

L.S. Lodhiyal

249

Not

e: D

=den

sity

of

euca

lypt

tre

es p

er h

ecta

re;

TB=t

otal

bio

mas

s of

tre

e la

yer;

AG

B=

abov

egro

und

biom

ass

of e

ucal

ypt

tree

spec

ies.

*

The

abo

vegr

ound

bio

mas

s re

pres

ents

the

euca

lypt

onl

y in

mix

ed p

lant

atio

n.

Tabl

e 1.

B

iom

ass

estim

ates

of

plan

tatio

ns r

epor

ted

for

diff

eren

t tr

ee s

peci

es b

y re

sear

cher

s in

Ind

ia a

nd e

lsew

here


Per

cent

allo

catio

n fr

om a

bove

grou

nd b

iom

ass

Ref

eren

ce

Spec

ies

Age

(y

r)

D (n

o.)

TB

(t

ha-1

) A

G B

(t

ha-1

) Bo

le

Bark

Br

anch

T

wig

Fo

liage

E. g

rand

is 5

1,65

0 -

97.6

83

.8

- 6.

6 4.

6 4.

6 Ta

ndon

et a

l., 1

988

E. re

gnan

s 10

1,

075

- 31

9 82

.1

- 13

.0

- 4.

8 Fr

edric

k et

al.,

1985

a

E. sa

ligna

8

829

- 12

9.8

80.9

-

13.4

1.

2 4.

4 Fr

edric

k et

al.,

1985

b

E. g

lobu

lus

07

- -

123

66.2

11

.1

7.1

7.3

8.3

Neg

i et a

l., 1

984

E. te

retic

orni

s 5

2,00

0 67

.47

54.1

4 73

.5

7.3

6.6

1.6

11.0

Ba

rgal

i et a

l., 1

992

E. te

retic

orni

s 8

2,00

0 12

1.03

10

1.77

64

.9

7.1

15.7

2.

3 10

.0

Barg

ali e

t al.,

199

2

E. g

rand

is 27

-

- 39

4 -

- -

- -

Turn

er a

nd L

ambe

rt, 2

008

E. p

ilura

lis

33

- -

270

- -

- -

- Tu

rner

and

Lam

bert,

200

8

E. te

retic

orni

s 15

32

0 48

.05

41.7

8 -

- -

- -

Prag

asan

and

Kar

thic

k, 2

013

Mix

ed p

lant

atio

n

11

1,01

0-1,

212

76.7

-93.

1 19

.8-4

6.1

- -

- -

- K

hann

a, 1

997;

Bau

hus

et a

l., 2

000,

20

04; F

orre

ster e

t al.,

200

4

Mix

ed p

lant

atio

n

10

600-

818

426-

550

90-2

28*

- -

- -

- Sa

mra

j et a

l., 1

977

Mix

ed p

lant

atio

n

5 2,

500

58.5

-65.

2 17

.9-2

0.6*

-

- -

- -

Forr

este

r et a

l., 2

004

Mix

ed p

lant

atio

n

20

2,50

0 30

0-41

5 22

3-28

7*

- -

- -

- D

e B

ell

et a

l.,19

89,1

997;

Bin

kley

et

al.,

199

2, 2

003

Mix

ed p

lant

atio

n

3.9

1,66

7 11

0 71

* -

- -

- -

Vez

zann

i et a

l., 2

001

Mix

ed p

lant

atio

n

7 1,

333

- 16

7-21

3*

- -

- -

- Li

ttle

et a

l., 2

002

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ed p

lant

atio

n

6 2,

400

82-9

9 60

.1-7

9.0*

-

- -

- -

Zhan

g, 2

003

Mix

ed p

lant

atio

n 6

2,55

5 62

-83

37-6

5*

- -

- -

- X

iao

et a

l., 1

999

Mix

ed p

lant

atio

n

10.1

37

5-48

0 88

-169

72

-170

* -

- -

- -

Brist

ow e

t al.,

200

6

E. te

retic

orni

s 5

2,50

0 66

.83

52.9

3 76

.6

7.7

5.9

1.7

8.1

Pres

ent s

tudy

250

⇒ The chlorophyll method (Ryther and Yentsch, 1957; Margalef, 1961, 1967;Aruga and Monsi, 1963; Odum, 1996).

In a sample plot of eucalypt plantation, diameter of marked trees wasmeasured and re-measured after one year interval in September/October. Forestimation of productivity of each component in each plantation, in the sameregression equation of each component which was developed through harvestmethod earlier, each component in each plantation was used. The allometricequation of each component and mean diameter obtained after one year periodwas used and multiplied by the tree density to get the biomass (B2). The netincrease in biomass ( B=B2-B1) yielded annual biomass accumulation. Thesum of the B values for the different components yielded net biomassaccretion in the trees. The values of litter fall component; i.e., leaf and twigadd to each respective component as the mortality of fine roots occurs duringthe growing period but estimation of such fine root mortality is not possible,therefore, method as used by Kalela (1954), Orlov (1968), Ogino (1977), Lodhiyalet al. (2002) and Lodhiyal and Lodhiyal (2003) is applied. The fine rootproduction and leaf litter fall have no correlation in the large data set as per theobservation of Nadelhoffer and Raich (1992). But, it is better to use the one-fifth of litter fall production to the respective tree component which is supposedto be an equivalent of fine root mortality. However, fine root production in treespecies is gross under-estimation (Harris et al., 1980; Vogt et al., 1982, 1986;Fogel, 1983). The net production of all components sums up to give total netproduction of trees in each eucalypt plantation. For shrub layer, an adequatenumber of shrub individuals of differing diameter and height was marked withwhite/yellow paint and, then, their basal diameter measure and re-measuredafter one year period in the selected study plantation to get the actual diameterand height increment.

For the estimation of biomass and productivity of shrub species, an allometricequation was used as followed by Lodhiyal et al. (2002). Biomass of herbs wasestimated at the peak period; i.e., in September/October. The herb biomass assumes tobe equal to its productivity in each plantation. The sum of net productivity of tree,shrub and herb layer yields the total productivity of vegetation in each plantation site.

In this study, tree layer net primary productivity of eucalypts plantation was20.3 t ha-1 yr-1. Present NPP estimate is compared with the estimates of variousother eucalypt plantations reported for different regions in the world in Table 2.

5. Litter Fall EstimationLitter fall is important component of nutrient cycling in a forest and its inputsdepend on a variety of factors such as species, age groups, canopy cover, weather

L.S. Lodhiyal

251

conditions and biotic factors. Litter fall is important as the source of the majorityof the nutrient taken up annually by plants. It forms a superficial organic layer thatplays an important role in the protection of soil against erosion and in regulatingsoil moisture status. Organic matter favours the activity of soil organism, andpromotes soil aggregation and a favourable structure and porosity. Litter, whenreaches the surface of the soil, undergoes physical and chemical degradation inthe process of decomposition.

To assess litter fall production in eucalypt plantation, a study was carriedout by the author for one-year period. The litter fall input was measured byplacing random appropriate litter traps (20) in each plot (04 litter traps each ineach sub-plot) on the floor of eucalypt plantation. The size of each litter trapwas 50 cm x 50 cm having 15 cm high wooden side fitted with a nylon net bottom.Litter was collected at monthly intervals on each sampling date from July to Juneand brought to the laboratory in polyethylene bags. Samples were then sortedinto leaf, twigs and miscellaneous components; i.e., bark and reproductive parts.Samples were separated component wise, cleaned and weighted after oven dryingat 60°C to constant weight. After weighing, the litter components were groundfor nutrient analysis. In the study, 3.82 t ha-1 yr-1 litter fall production was foundfor E. tereticornis in five-year-old plantation. This value is compared with theestimates reported for eucalypt plantations of different species in differentregions (Table 3).


Table 2. Net primary productivity estimates (NPP) of plantations reported foreucalypt tree species by various researchers

Species Location Age (yr)

Density (tree ha-1)

NPP* (t ha-1 yr-1)

Reference

E. tereticornis India 5 2,000 17.4 Bargali et al., 1992 E. tereticornis India 8 2,000 20.4 Bargali et al., 1992 E. grandis - 5 - 16.4 Turner and Lambert, 2008 E. piluralis - 7 - 15.7 Turner and Lambert, 2008 E. grandis - 27 - 27.9 Turner and Lambert, 2008 E. piluralis - 33 - 24.4 Turner and Lambert, 2008 E. tereticornis India 5 2,500 20.3 Present study

Table 3. Litter production of eucalypt plantations in different studiesSpecies Location Age

(yr) Density

(tree ha-1) Litter fall (t ha-1yr-1)

Reference

E. grandis New South Wales - - 7.3-8.7 Turner, 1986 Eucalyptus hybrid India 2-8 2,000 0.81-6.50 Bargali et al., 1992 E. regnans Australia 10 1075 6.4 Fredrick et al., 1985a E. tereticornis Australia 2-8 - 0.8-6.5 Rogers and Westman, 1981 E. tereticornis India 5 2,500 3.82 Present study

252

6. Forest Floor Biomass EstimationForest floor biomass plays a significant role in the structure and functioningof forest ecosystems by acting as a nutrient reservoir for the intra-systemcycling processes and improves the infiltration rate and water holding capacityof soils (Teller, 1968). In warm humid environment, rapid and completedecomposition occurs, therefore, permanent organic accumulation was notfound by the author in a study of forest floor biomass. Forest floor biomass ofplantation was collected by using quadrat of 1 m x 1 m size. Each quadrat wasplaced randomly in each plantation once during rainy, winter and summerseason. Forest floor biomass components were categorized into fresh leaf litter,partially and more decomposed litter, wood litter including twigs, bark andbranches, miscellaneous litter consisting of inflorescences, flowers and fruits,litter parts of shrubs and herbaceous litter (living and dead) (Lodhiyal et al.,1995; Lodhiyal and Lodhiyal, 1997a, b and Lodhiyal et al., 2002). The herbaceousstanding shoots (live and dead) were harvested at ground level (Green, 1959;Line, 1959; Lodhiyal and Lodhiyal, 1997a, b; Lodhiyal et al., 2002). Thereafter,the material was collected in polyethylene bag and brought to the laboratoryfor oven drying at 60°C and weighed. Forest floor litter biomass forE. tereticornis was 4.24 t ha-1 at the age of five years. Thus estimate is comparedwith the estimates reported for various Eucalyptus species in different regionsas given in the Table 4.

7. Turnover of LitterThe turnover rate (K) of litter is calculated by the formula given by Jenny et al. (1949)and Olson (1963), K=A/(A+ F) where A is the annual litter increment (i.e., annuallitter fall) and F is the biomass of the litter at steady state. Turnover time (t, years) isthe reciprocal of the turnover rate and is expressed as t = 1/K. In a study by theauthor, F represented the biomass of standing crop of partially and more decomposedlitter during the winter season and A was taken as annual tree litter fall plus shrub

L.S. Lodhiyal

Table 4. Forest floor biomass estimates reported for eucalypt plantations indifferent studies

Species Location Age (yr)

Density (t ha-1)

Forest floor biomass (t ha-1)

Reference

E. tereticornis India 5-8 2,000 3.91-5.16 Bargali et al., 1992 E. regnans - 4-17 - 4.7-11.0 Frederick et al., 1985a E. regnans - 50 - 47.0 Feller, 1980 E. obliqua - - - 18.3 Attiwill et al., 1978 E. grandis - 27 - 17.4 Turner and Lambert, 1983 E. grandis - 2-27 - 3.0-9.5 Bradstock, 1981. E. tereticornis Tarai, India 5 2,500 4.24 Present study

253

litter (i.e., equal to foliage biomass) plus herb litter (equal to peak aboveground herbbiomass). The turnover rate and turnover time of E. tereticornis ‘hybrid’ was 0.83and 1.20, respectively. Turnover rate and turnover time of litter was 0.84-0.96 and1.05-1.19 for Eucalyptus hybrid plantations reported by Bargali et al. (1992). Theturnover time was 1.25 years reported for E. viminalis, 0.81 year for E. saligna(Richards and Charley, 1977), 1.25 years for E. grandis (Turner and Lambert, 1983)and 3.55 years for E. obliqua (Attiwill et al., 1978).

8. Carbon Sequestration PotentialCarbon sequestration through forestry has the potential to play a significant rolein ameliorating global environmental problems such as atmospheric accumulationof GHGs and climate change. Thus the potency of biomass, carbon and carbonabsorption above ground surface in industrial plantations of hybrid eucalyptincreased in line with increasing plant age (Latifah and Sulistiyono, 2013). Plantedforests today cover around 264 Mha and absorb an estimated 1.5 G t of carbon fromthe atmosphere each year (FAO, 2010). A planted forest in a temperate zone cansequester about 4 t ha-1 yr-1 of carbon (FAO, 2010).

The author estimated biomass based on regression equations which weredeveloped through harvest technique. The carbon content of vegetation wassurprisingly constant across a wide variety of species. Most of the information forcarbon estimation described in literature suggest that carbon constitutes 45 to 50per cent of dry matter (Onrizal, 2004). The estimation of carbon stock and carbonsequestration in different eucalypt plantations was determined using the biomassand productivity values by applying the method given by Magnussen and Reed(2004). Total carbon stock was 31.74 t ha-1 (aboveground carbon 25.14 t ha-1) forE. tereticornis at the age of five years. Present estimate can be compared with theestimates of carbon for various eucalypt plantations in different regions bymultiplying biomass value in Table 1 with 0.475. Total net carbon sequestration(NCS) was 9.64 t ha-1 yr-1 reported for E. tereticornis at the age of five years.Present estimate can be compared with the estimates reported for various eucalyptspecies plantations in different regions by multiplying productivity estimates(Table 2) with 0.475.

9. Nutrient Use EfficiencyNUE is the ratio of net primary productivity (NPP) and net nutrient uptake (NNU)calculated for forest tree species. The ratio of NNP/NNU of trees indicates theproduction efficiency of tree with regard to uptake of nutrients (N, P, K , etc.). HigherNUE ratio of trees means that the tree is more efficient for nutrient use. However ifthe NUE ratio of a species is less, this means that the species demands more nutrientsfor its dry matter production and productivity. Species differ in the rate of primary


254

Table 5. Nutrient use efficiency (NUE) index on the basis of net primary productivityper unit nutrient uptake in different forest and plantation vegetation

production per unit of nutrient accumulated from the soil (Table 5). Cole and Rapp(1981) reported that the annual circulation of nutrients in coniferous is much lowerthan deciduous forests because of lower leaf turnover of coniferous forest species.However, Waring and Schlesinger (1985) found that nutrient re-absorption is higherin loblolly pine needles than re-absorption from deciduous forests leaves; this isespecially so when the amount of re-absorption is expressed in percentage of annualrequirements. This mechanism showed that the coniferous forests have higher NUEthan deciduous forests of the world. The higher NUE in coniferous forests wasattributed to frequent occurrence of coniferous forests vegetation on nutrient poorsite and in boreal climate with slow nutrient turnover in the soil (Waring andSchlesinger, 1985).

Nutrient use efficiency among different tree species varies because of variationin nutrient demand of species and also their occurrence in varied ecological andsoil sites. Even in the same species, it also varies with the variation of soil andclimatic conditions of site for e.g. shisham grows in bhabar (poor nutrient and lessfertile and low water table site) is as efficient as in Tarai (nutrient rich fertile andhigh water table site), however there are differences in soil nutrient status. Thetree species which grows well only in fertile soils needs high amount of soil,moisture and nutrient. It is stated that such tree species always needs more nutrientsfor dry matter production due to poor efficiency of nutrients. For example, manyexotic tree species like poplar (Populus deltoides), eucalypt (E. tereticornis), etc.are being grown in our country. As far as poplar is concerned, it grows well infertile soils having high water table. Poplar is less nutrient efficient, it means thatit demands more nutrients than eucalypt which is less nutrient demanding. Thisindicates that eucalypt produces higher biomass even at low nutrient level incomparison to poplar (poplar needs fertile soil for higher biomass production as ithas the low NUE ratio).

L.S. Lodhiyal

Production per unit nutrient uptake Forest type Age (yr)

N P K Ca Mg

Reference

Deciduous forest >100 143 1,859 216 130 915 Cole and Rapp,1981 Coniferous forest >100 194 1,519 354 217 1,559 Cole and Rapp,1981 E. tereticornis 8 302 5,025 - - - Bargali et al ., 1992 P. deltoides 8 176 1,569 - - - Lodhiyal et al., 1995 Dalbergia sissoo 30 155 1,893 - - - Lodhiyal, 2000 D. sissoo 30 152 2,197 - - - Lodhiyal, 2000; Lodhiyal

and Lodhiyal, 2003 Cassia siamea 8 100 1,670 - - - Pacholi, 1997 Gmelina arborea 8 99 1,755 - - - Pacholi, 1997

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10. DiscussionThe biomass productivity of eucalypt plantation varies considerably dependingon the site, the edapho-climatic conditions and inputs. The average productivityin terms of volume is around 7 to 8 m3 ha-1 yr-1. The productivity of eucalypts canincrease if superior genotypes are selected for growing in the suitable sites. Theshort rotation plantations are the energy forest used for biomass production whichis a fairly new concept developed in 1970s (Venturi et al., 1999). The short rotationplantations such as Eucalyptus, Populus, Salix, Casuarina, Gmelina, Leucaenaand many more tree species can grow in a wide variety of climate and soil conditions.The annual yield of biomass produced could then be as high as 20 t ha-1 yr-1 if thesoil and moisture conditions are optimal and appropriate fertilizers are used (Mosiejet al., 2012). The size of canopy in eucalypt plantation determines growth andinfluences the volume of wood production. The quantity and quality of clearwood produced by Eucalyptus species is found to be affected by its canopydynamics. Tree pruning in young stage reduces the tree growth particularly whenit is carried out prior to canopy closure and also increases the chances of wooddefects and decay. So, to increase the volume of clear wood, the suitable timeperiod and proper silvicultural interventions and judicious techniques are needed(Montagu et al., 2003).

The productivity of most plantations is less than their physiological potentialas defined by the prevailing climate, because the supply of light, water and nutrientsis less than optimal. However, the maximum growth does not equate to maximumwood value. So, silvicultural challenge is to design and use the management regimesthat achieve target growth rates and wood quality by manipulating resource supply,capture or use (Gonclaves et al., 2004). They stated that it has been and remainspossible to identify and ameliorates factors limiting growth, sometimes on a largescale by soil cultivation, management of residue, use of fertilizer, control of weeds,irrigation, coppice management, thinning and pruning practices. Therefore, some ofthese practices must be implemented to enhance the biomass and productivity foreucalypt plantations. Thus, to increase the productivity of eucalypt plantations, thesilvicultural treatments should adequately apply in the current empirical models, sothat, the process based productivity models adequately cater to pruning andthinning in eucalypt plantations to produce the better quality and quantity wood(Gonclaves et al., 2004).

Carbon sequestration potential of fast growing eucalypts plantation is 0.03 t C pertree at five years age. The carbon sequestration in fast growing eucalypt plantationwas comparatively higher (11%) than mixed tree plantations (Pragasan and Karthick,2013). Present estimate of carbon sequestration at five years age is comparable withthe 0.09 t C ha-1 at 15 year age, which was three times higher in both carbon contentand age of plantation.


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Eucalyptus and many other fast growing species are planted in farm forestryand agroforestry systems. The short rotation tree crops are considered as effectivemeans to mitigate the greenhouses effect because of their ability to accumulatesubstantial quantities of carbon in vegetation in a limited period. In addition, thewood production from plantations may relieve pressure on timber extraction fromnatural forests, thus, contribute to forest conservation (Prasad et al., 2012). There isa 630 Mha potential area for agroforestry in the world which could be able to store586 t C ha-1 yr-1 by 2040 mostly in the developing countries of the world (Watson etal., 2000). Prasad et al. (2012) estimated 34 t ha-1 C stock of eucalypt in four-year-oldplantation under farm forestry system.

Eucalyptus species may produce chemicals from leaves and litter that inhibitthe germination and/or growth of other understorey species (Shiva andBandyopadhyay, 1985). The sparse undergrowth of the eucalypt stands explains itsallelopathic effects (Kardell et al., 1986). In six-year-old eucalypt plantation, an initialexposed ground area of 66 per cent decreases rapidly as the production of vegetationand litter increases. However, in older eucalypt stands which are mature for felling,coverage by vegetation and litter is 95 per cent (Kardell et al., 1986). The large scalecultivation of eucalypt is a threat to fauna, flora and landscape scenery; thesenegative effects can be lessened, though not avoided entirely. A new tree speciescreates its own environment. Thus, the introduction of Eucalyptus species wouldcause the landscape to change within five years. Within a decade, the newenvironment would be fully developed. Eucalypt stands are of little value for thehigher fauna. There are hardly some insects which eat the leaves, consequently,there are few birds. The absence of bushes, the stand provides poor protection forwild animals (Kardell et al., 1986).

The criticism of eucalypt plantations appear to be realistic, but the evidence is notsufficient to support the conclusion that eucalypt stands are promoting desert in largeareas of the country and elsewhere. Wherever, the eucalypt plantations are located,the areas have a surplus precipitation and scarcity of fresh water except for shortperiods. This lack of water could be overcome through storage (Kardell et al., 1986).There is not much to indicate that planting of eucalypt would lower the site qualitysubstantially in the long run. However, a certain amount of erosion always occurs andit is not possible to totally exclude the probability of any future lack of soil nutrients.But the soils should be carefully managed and the abundant production of littershould be positive and valuable asset (Kardell et al., 1986).

Eucalypt is economically one of the best forest tree crops but environmentally,many other tree species have considerable advantages but they generally take 50-100 years to create forest sufficient for a sustained industrial production. However,there are many environmentalists who consider eucalypt as a valuable future crop.It is easy to understand the criticism raised against the eucalypt plantations in India

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but it is not simple to come up with realistic and practical alternatives. Growingpopulation put pressure on the environment and existing natural forests. So, due tohigh usability for people and industries, eucalypt has moved to many new locationsaround the globe.

Eucalypt has become a model forest tree for its high productivity; severalsilvicultural and genetic researches are carried out by many scientists for itsimprovement in terms of biomass production and suitability for different ecologicalregions. A lot of research has been conducted in the past 50 years leading to substantialincrease in the productivity of Eucalyptus species.

Nutrients analyses of eucalypt plantations in terms of biomass and productionat short rotation cycle in farm forestry and agroforestry systems have beendiscussed by various scientists and environmentalists in many countries. Somepeople claim that eucalypt is not depleting much nutrients and water, if they aremanaged with proper silvicultural practices. There are debates among theenvironmentalists about the eucalypt monoculture in Karnataka. The stategovernment issued a guideline for reducing/banning its large scale plantations inthe areas where the sites received above 750 mm rainfall. But in 1990, the stategovernment has completely banned its plantation except the locations whichreceived between 500 and 750 mm rainfall. However, there are several common andspecific reasons to a particular region or state for raising its large scale plantations.The most common reason is to re-clothe the denuded and barren hilly areas andreplace low value natural forest (FAO, 1979). Other reasons are based on nationalpolicies to improve the forest productivity, to generate the government revenueand to create employment to the people by replacing low productive natural foreststhrough large scale eucalypt plantations. Apart from these, eucalypt is a treewhich is easy to propagate, uses low input and is highly adaptable and productiveto varied soil conditions. Eucalyptus species can produce large amount of drymatter in the soil having low nitrogen, phosphorus and potassium. The dynamicsof nutrient fluxes in eucalypt plantations, throughout their rotation, depends onthe current rate of annual requirement of nutrients, uptake of soil nutrients, returnof nutrients through litter fall and leaching, decomposition rate of forest floor aswell as the internal translocation of nutrients within the tree species. The soilnutrient concentration decreased with plantation age, possibly as theconsequences of nutrient depletion caused by ever increasing uptake by thevegetation and the leaching of soil nutrients from the plantations (Lodhiyal andLodhiyal, 1997a, b). Trees take up large quantities of nutrients and, although muchof the absorbed nutrients are returned to the soil through litter fall, appreciableamount of nutrients are removed in harvesting. The nutrients removed fromplantations are likely to increase with more intensive utilization, as is happening inthe Tarai region of India (Lodhiyal, and Lodhiyal, 1997a, b).


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11. ConclusionIt is concluded that no indigenous species could compete with eucalypt’s versatilequalities as we need a sizeable amount of its timber for pulp industry in the country.This tree has a capacity to provide coppice crops; its plantation raising requirescomparatively low investment and produces 4-5 times more raw material than otherindigenous species. If there are some demerits about this species in terms of nutrients,water and biodiversity losses, clear cut policy should be framed keeping in view itssuitability in different states/regions, and demand for raw materials and local needs.More productive varieties and clones should be introduced which are site-specificin terms of their production as well as environment amelioration. The use of this treealong with other indigenous species will not only boost production of timber woodbut also improve the fertility, water availability and biodiversity of the region besidesreducing the growing pressure on natural forests.

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Turner, J. and Lambert, M.J. 2008. Nutrient cycling in age sequences of twoEucalyptus plantation species. Forest Ecology and Management, 225(5-6): 1701-1722.

Venturi, P.; Gigler, J.K. and Huisman, W.1999. Economical and technical comparisonbetween herbaceous (Miscanthus giganteous) and woody energy crops(Salix viminalis). Renewable Energy, 16(1-4): 1023-1026.

Vezzanni, F.M.; Tedesco, M.J. and Barros, N.F. 2001. Alteracoes dos nutrientes nosolo e nasplantas em consorcio de eucalipto e acacia negra. Revistabrasileira de Ciencia do solo, 25: 225-231.

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Vogt, K.A.; Grier, C.C.; Meier, C.E. and Edmonds, R.L. 1982. Mycorrhizal role in netprimary production and nutrient cycling in Abies annabalis ecosystems inwestern Washington. Ecology, 63(2): 370-380.

Waring, R.H. and Schlesinger, W.H. 1985. Forest ecosystems: Concepts andmanagement. New York, Academic Press. 339p.

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L.S. Lodhiyal

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1. IntroductionThe role of forests in carbon sequestration is an important part of India’s approachto the climate change mitigation. The government owned forests, spread over 20.6per cent of the nation’s geographical area, act as a sink to sequester and store135.15 Mt of CO2 every year and this annual removal by forests is enough toneutralize 9.31 per cent of the country’s total emission levels of the year 2000.Further, even if the sequestration remains stagnant at this level, the forests ofIndia would still be able to offset 4.87 per cent of the projected increased emissionsin the year 2020. A successful implementation of the National Mission for GreenIndia as a part of the National Action Plan on Climate Change, which envisagestree plantations over 6 Mha by the year 2020 would add another 66 Mt of CO2ethrough sequestration by forests (ICFRE, 2009).

The offsetting potential of the Indian forests can be significantlyenhanced by laying greater emphasis on the trees outside forests (TOF),which presently cover about 2.8 per cent of geographical area in India andhave been shown to sequester 18 Mt C by 2020. TOF consist of commercialplantations and plantations under agroforestry, which are mostly grown onprivate land using fast growing tree species such as Eucalyptus, Populus,Leucaena, Gmelina arborea, Ailanthus, etc. which have been shown togrow at a rate ranging from 10 to 40 m3 ha-1 yr-1. These high yielding plantationforests occupy more than 6 Mha, generally, fertile alluvial plains as block orboundary plantations or as intercrops with food and commercial crops.Consequently, the trees generally have access to assured irrigation, highernutrients, better upkeep and protection. Such short rotation plantations andagroforests, mostly grown outside the conventional forests, offer a much

CDM Activities in TreesOutside Forests in North-West India with a SpecialReference to EucalyptsPadam Parkash Bhojvaid andPramode Kant

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higher potential for CO2 sequestration in tropical forests. Based on publishedreports, the chapter analyzes the productivity of government plantationsand their CO2 sequestration potential. Further, the realized growth and biomassaccumulation of TOF has been compared with that in government plantations.Finally, some policy and institutional issues involved in such initiatives havebeen discussed.

2. The Present Scenario of Forestry Sector in IndiaWith about 76 Mha of land area as recorded forests (notified as forests underIndian Forest Act of 1927), forestry is the second largest land use in Indianext to agriculture. About 92 per cent of these recorded forests are stateadministered of which 27 per cent are managed under a joint forest management(JFM) regime with local communities as stakeholders. The remaining 8 percent are private forests, including farm forests on agricultural lands andplantations managed by companies and families. However, the actual forestcover in India is about 64 Mha (21% of total geographical area) with majorityof forests (41%) in open and degraded category (Table 1). Consequently, themean annual productivity is about 0.7 m3 ha-1 yr-1, which is significantly lowerthan the world average of 2.1 m3 ha-1 yr-1. The per capita availability of forestsin India is also very low at about 0.1ha, which is one sixth of the world’saverage.

Forestry and logging account for only 1.1 per cent of India’s GDP thoughmany have opined that this is an underestimation of the total economic valueof the forests as many goods and services from forests are not traded in formalmarkets. Furthermore, fuel wood forms the major portion ($17 Bn) of woodbased trade in India and employs 11M people. The forest industry consists ofmany small, medium and large units (pulp and paper, saw mills and plywoodunits), which are constrained due to financial, legal and policy issues. Projectedpotential contributions from eco-tourism and carbon sequestration in forestshave been shown to raise GDP share of Indian forestry sector from 1.1 to 2.4per cent (Verma, 2006; Midgley et al., 2007).

P.P. Bhojvaid and P. Kant

S. no. Parameter World Asia S & SE Asia India

1. Forest cover (% of land area) 31 18 33 21

2. Per capita area under forests (ha) 0.62 0.15 0.14 0.07

3. Growing stock (m3 ha-1 ) 110 82 84 65

4. Productivity (m3 ha-1 yr-1 ) 2.1 - - 0.7

Table 1. Comparison of India’s forests with respect to world, Asia, South and SouthEast Asia

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There is a wide gap between demand and supply of wood in India resultingin overexploitation of its natural forests. Supply of timber from the natural forestshas been influenced by the low productivity, priority for ecological security bythe forests, and due to the moratorium on the green felling by the Supreme Courtof India. Consequently, only a small percentage of total wood requirements ismet from the natural forests and the rest is contributed by illegal removal fromgovernment owned forests, plantations and import (Ahmed, 2008). Moreover,this demand for wood is increasing rapidly due to economic growth and resultantincrease in urbanization and associated changed consumption pattern of forestbased products. The deficit for timber for 2006 was estimated to be 39 Mm3, onlya part of which was met by imports from southeast Asian nations with most ofdemand being met from unaccounted felling.

3. Forest Types and Their RoleAn overview of the global forestry sector suggests that forests can be classifiedinto three major groups (Allan and Lanly, 1991), namely, the conservation, theproduction and the restoration forests. While, the conservation forests are thereservoirs of biodiversity ensuring ecological security; the production forests,which occupy relatively fertile lands, provide timber and other forest products.Production forests mainly consist of plantations of introduced species or, in somecases, native species, established through seeding/seedling/clonal planting mainlyfor production of wood and non-wood goods (Ahmed, 2005). Such productionforests are mainly plantations of superior genotypes and are, generally, raised asmonocultures through intensive operations such as mechanized soil working,irrigation, chemical weed control and harvesting. The plantations of clonaleucalypts in Brazil, radiata pines in New Zealand, hoop pines (Araucariacunninghamii) and its hybrids in Australia, and tropical pines in many tropicalcountries are some examples of production forests (Evans, 1992). The restorationforests aim at ecological restoration of landmasses degraded due to anthropogenicactivities such as over-irrigation, indiscriminate application of agrochemicals,mining, etc., natural calamities such as flood, erosion and drought, and day to daydependence of local people for their subsistence living (Singh, 1982). In thecontemporary management regime that gives expression to the National ForestPolicy, the demand for fuel wood, pulp, and timber in future will be met primarilyfrom the production forests and the conservation and restoration forests willcontribute very little towards this (NFAP, 1999).

4. Trees Outside ForestsOver the last two decades, concern about the world’s forests has risendramatically. Large forest areas have been converted to other land uses, or

CDM activities in trees outside forests in north-west India....

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severely degraded. At the same time, it has been increasingly recognizedthat forests and trees provide for crucial economic, environmental and socialneeds in many countries (Rawat et al., 2003). In India, due to burgeoningpopulation, rapid urbanization, rising demand for quality forest productsand limited land mass have resulted in limited options of afforestation, exceptfor wastelands. Therefore, trees on private lands have a crucial role in carbonsequestration.

The world has billions of trees that are not included in the forest resourceassessment definitions of ‘forests’ and ‘other wooded land’ (FSI, 2001). Treesoutside forests (TOF), trees and tree systems found on agricultural land, meadowsand grazing lands, unproductive lands, along canals, railways, roads and inhuman settlements have numerous, often essential, roles and functions. Theymake critical contribution to agriculture, food security and rural householdincome. They supply many products, e.g., wood for fuel and construction, fodder,fruits, bark and food; and services, e.g., biodiversity, carbon storage, habitat forwildlife, microclimate stabilization, soil and water conservation (Rawat et al.,2003).

The trees outside forests in various models of agroforestry, farm forestryand social forestry are contributing a major portion of pulp and small timberrequirements in India (FSI, 2001). The national annual requirements for fuelwood, timber and fodder are 201 M mt, 64 M m3 and 1,337 M mt, respectively.However, forest loss and forest degradation due to expansion of agriculture,indiscriminate wood extraction and other anthropogenic pressures have resultedin a net deficit of 21 M m3, 365 M mt and 86 M mt of timber, fodder and fuel wood,respectively. Moreover, the policy emphasis on restricted extraction fromconservation forests and the moratorium on green felling from forests imposedby the Supreme Court of India have further increased deficits. Therefore, manyhave opined that there is a possibility of addressing this demand-supply gapby creating a special category of ‘production forests’ that are maintained andmanaged for production of timber, fuel wood and leaf fodder with a far highermean annual increment (MAI) than the national average of 0.7 m3 ha-1 yr-1. Thiswould require planting with trees of high genetic potential on soils of highfertility, moisture content and nutrient status. Consequently, no more than 10per cent of the 78 Mha of national forests would qualify as lands suitable forsuch production forests in India. Furthermore, a significant enhancement ofproductivity would require that these forests be raised as monocultureplantations of economically important species and, rarely, a mixed forestdominated by one or two economically important species; but this would bedifficult to achieve on government forests on account of policy mandatedbiodiversity requirements.


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5. Scope of Production Forestry in Carbon SequestrationIn the succeeding paragraphs, the potential of government plantations in India forcarbon sequestration is analyzed followed by a projection on productivity ofagroforests and TOF and their potential role in C sequestration. For the purpose ofanalysis of data for the production forests, experiences from the states of Punjab,Haryana and Uttar Pradesh, located in the Indo-Gangetic plains of northern India,have been used. The section also identifies interventions, such as geneticimprovement of species leading to use of quality planting material and policy initiativessuch as provision of subsidized low cost quality planting material to farmers.

5.1. Carbon Sequestration in State Owned Plantations in India: An AnalysisA fast growing tree species, such as eucalypts under intensive management canassimilate more than 15 m3 ha-1 yr-1 of wood during its rotation, which is significantlyhigher than the observed assimilation potential of traditional timber trees such asteak (Tectona grandis) and sal (Shorea robusta). Furthermore, rotation for suchquick growing species (QGS) is much shorter (5 to 10 years) compared withtraditional timber species. Consequently, plantations of QGS species with a MAIof 15 m3 ha-1 yr-1 and with a rotation of 10 years have a potential to sequester 5 t ofC ha-1 yr-1 or about 18.35 t CO2e ha-1 yr-1. Therefore, If 40 Mha of plantations at thisaverage rate of carbon sequestration are managed on short rotations in the next 40to 50 years in India, about 73.40 Gt of CO2e yr-1 could be mitigated. However, theMAI of social forestry plantations, largely created in less productive degradedforest (government) land in India, has been estimated to be only in the range of 2to 4 m3 ha-1 (MoEF, 1999), which could be largely because of lower soil fertility,poor nursery techniques and genetic stock, and small size of scattered plantations.Furthermore, the realization of high MAI is constrained due to inadequatebudgetary provisions and trained professionals in the state forest departments toraise plantations.

It is possible to achieve a higher MAI in plantations; however, it wouldinvolve intensive management inputs such as soil working, regular irrigation,application of fertilizers and, above all, significant genetic improvement in plantingstock such as improved seed and clonal planting material. MAI between 15 and70 m3 ha-1 has been achieved in plantations by intensive management and withthe use of genetically superior material of radiata and tropical pines and eucalyptsin Australia, New Zealand and Brazil (Table 2).

5.2. Carbon Sequestration from Agroforestry Plantations in IndiaAgroforestry practices optimise production potential of land in more than onetier; i.e., both above and belowground systems. Conceptually, it is possiblewherever agriculture is practised and needs to be spread to all areas with suitable


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crop-tree combinations. Agroforestry means combining tree cultivation withagriculture crops on a spatial and/or temporal scale. This practice is not new as‘kheti’ (agriculture) always used to be with ‘bari’ (fenced tree groves) undertraditional agriculture in India. With the advent of commercial agriculture andautomation, ‘bari’ was neglected and present effort is directed to re-establish thisaspect of tree cultivation by making it remunerative to landowners. However,some of the states of India have evolved various models comprising a combinationof tree crops with traditional agriculture and horticulture crops in differentagroclimatic zones. Some of such practices that are in vogue in Punjab, Haryana,Uttarakhand and western Uttar Pradesh states of the Republic of India haveevolved in terms of higher production and income generation and, consequentlyattained national and international recognition. The timber output generated fromagroforestry substitutes timber grown in natural forests, thereby, reducing pressureon natural forests. Further, the availability of suitable raw material on a sustainedbasis has led to the establishment of forest-based industries. Today, these on-farm forestry activities have added substantially to the income of small, mediumand large farmers and created significant employment opportunities along thevalue chain (Ahmed, 2008).

Wood yields in the agroforests are significantly higher than the governmentplantations even when planted with similar species and genetic stocks. This canbe attributed to numerous factors namely, innate higher soil fertility, assuredirrigation, better post-planting care and lower weed competition in better managedagriculture/farm lands. Seedling mortality in agroforests is negligible (1 to 2%)compared to government plantations (30 to 40%) (NFAP, 1999). The introductionof clonal planting material, after systematic research and field-testing hasparticularly raised MAI in agroforestry (Fig. 1), which is in the range of 15 to40 m3 yr-1 in Haryana, Punjab and Uttar Pradesh. Clonal plantations provide uniformand better quality wood than seedling plantations (Fig. 2). This clearly shows thattrees in well-managed agroforests offer a greater potential for carbon sequestration(Table 2).

5.3. Carbon Sequestration from Agroforestry Plantations in ThreeIndian States5.3.1. PunjabTable 3 details statistics on the status of tree cover in the classified forests andoutside the notified forestland in the state of Punjab. Though the notified forestsin Punjab occupy a significantly larger area than the TOF, yet they contain amuch lower volume. The growing stock per unit area in the TOF (110.70 m3) isthree times higher than that of natural forest (35.20 m3). The average rotation ageof trees grown in TOF is shorter than in natural forests (7 vs. 35 yrs). Therefore,


273CDM activities in trees outside forests in north-west India....

Fig. 1. Diagramatic representation of increase in MAI realized in clonal eucalyptsusing silvicultural inputs in Haryana.

Fig. 2. Clonal plants of eucalypts of superior genetic material produce better qualitywood than those raised through seeds.

274 P.P. Bhojvaid and P. Kant

the trees in the small-scale agroforests assimilate 15 times more biomass eachyear, and this offers a great opportunity for carbon sequestration.

5.3.2. HaryanaA comparative account of the classified forests (government lands declared asreserved and protected forests under the various provisions of the Indian ForestAct, 1927) and tree cover outside the notified forestlands in the state of Haryanais given in Table 4. The data indicates that the trees growing outside state ownedforests contain seven times higher volume than those present in the notifiedforest areas. This higher volume is attributed to higher productivity of soils,ensured inputs of water and nutrients and a better protection and post-planting

S. no. Species MAI (m3 ha-1 y-1) Location 1. Eucalyptus 28-70 Brazil 2. Clonal Eucalyptus 8-14 Haryana, India 3. ITC Eucalyptus clones 20-30 Andhra Pradesh, India 4. ITC Eucalyptus clones 22-30 Under trials in Haryana, India 5. Pinus radiata 15-25 New Zealand 6. Pinus radiata 15-20 Australia 7. Tropical pines 15-25 Australia 8. Poplars 10-25 Haryana and Uttar Pradesh, India

Table 2. Data on MAI realized under intensively managed production plantations inIndia and elsewhere in the world

Table 3. A comparative account of classified forests and TOF in the state of PunjabParameter Classified forests TOF Total Tree cover (km2) 1,580 1,608 3,188

% of total geographical area

3.14

3.19

6.33

Growing stock (Mm3)

11.08

17.90

28.98

Growing stock (m3 ha-1)

35.20

110.70

-

Rotation age of tree species (years)

35

7

-

Mean annual increment (m3 ha-1 yr-1)

1.1

15.81

- Based on India State of the Forest Report (FSI, 2003).

Table 4. A comparative account of classified forests and TOF in the state of Haryana

Based on India State of the Forest Report (FSI, 2003).

Parameter Classified forests TOF Total Tree cover (km2) 1,517 1,415 2,932


3.43

3.20

6.63

Growing stock (Mm3)

2.37

15.36

17.33


15.3

108.5

-


30

7

-


0.5

10-12

-

275CDM activities in trees outside forests in north-west India....

care of seedlings. Consequently, the growing stock per hectare in the TOF(108.5 m3) is seven times higher than that of natural forest (15.3 m3) in Haryana(Table 4). Moreover, the average rotation age of trees grown in TOF (seven years)is less than one-fourth of that in natural forests (30 years). Thus, the trees in thesmall-scale agroforests assimilate 20 times higher biomass each year and, therefore,offer a great opportunity for carbon sequestration.

5.3.3. Uttar PradeshThe tree stock per hectare in the TOF (114 m3) is higher than that of natural forest(99 m3) (Table 5) but the difference is relatively smaller in Uttar Pradesh. In this state,large areas of TOF consist of orchards of long rotation fruit trees, consequentlyaverage rotation in TOF is relatively longer, 27 years, but clearly shorter than innatural forests, 80 years. Thus, the trees in the small-scale agroforests assimilatefive times higher biomass each year, and this offers a great opportunity for carbonsequestration.

6. High Quality Seedling: A Crucial Input to Carbon SequestrationQuality seedlings are the most important input to sustain the momentum ofagroforestry practice. Every year, between 100 to 150 M seedlings are used inthe states of Punjab, Haryana and Uttar Pradesh for raising plantations ongovernment and private farmland of which more than half of the seedlings areused by the agroforestry sector. The cost of raising trees in forest areas is aboutfive times greater (Rs. 45 per seedling) than that of raising the same trees onfarms (Rs. 10 per seedling) and resultantly, the government has been sellingthese seedlings at subsidized price through the state forest departments. Atpresent, there is a general feeling in the country that subsidies on seedlingsshould be discontinued, as they do not support economic efficiency andcompetitiveness. Such ideas, which stem from observations of internationalfinancial institutions, cannot be applied indiscriminately to agroforestry in India.In the initial stages, the seedlings which are supplied free of cost to farmers

Table 5. A comparative account of classified forests and TOF in the state of Uttar Pradesh

Based on India State of the Forest Report (FSI, 2003).

Parameter Classified forests TOF Total Tree cover (km2) 14,118 7,715 21,833


5.86

3.20

9.06

Growing stock (Mm3)

164

88

252


99

114

-


80

27

-


1.2

4-5

-

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would result in encouragement to grow more trees on farmland and to create araw material base for the industry. Once this linkage is established and stablemarket are developed for agroforestry-grown produce, it would be expected thatthis would lead to an even greater interest by landowners in planting trees ontheir farms. Moreover, the seedlings that are supplied to farmers also haveecological and economic benefits, which compensate more than their cost. Theraw material generated from the agroforestry sector has provided a substitutefor forest produce and reduced the pressure on natural forests. This would alsoresult into an additional benefit in the form of avoiding deforestation as entailedin climate change debate. At the same time, it sustains the plywood, paper,charcoal and rayon industries. The finished products are also taxable providingadditional revenue to the government which compensates the expenditureincurred in supplying free seedlings. Further, the tax receipt (though a deferredreturn) is more than the expenditure incurred in free supply of seedlings.

7. Eligibility (Legal) Aspects in CDMThree important aspects of clean development mechanism (CDM), namely, landeligibility, additionality and leakages would need to be examined closely withrespect to agroforestry situations. Only those lands are eligible for CDM forestryprojects that were neither forests in 1989 nor now. This condition is easily fulfilledin most agricultural lands. But the same is not the case with the additionalityrequirement of CDM. This condition – only those climate change mitigationactivities are eligible for earning carbon credits that would not have happened inthe absence of the benefits accruing from the carbon credits – is meant forensuring the environmental integrity of the climate change mitigation projects.Now, since in the states of Punjab, Haryana and Uttar Pradesh agroforestry haslong been practised, the normal agroforestry practices would not be eligible asCDM activities as these are clearly ‘business-as-usual’ and would not passadditionality muster.

Crossing the additonality hurdle, however, is not only possible but can bringits own rewards in terms of increased investments in productivity that would notbe economically justifiable in the absence of returns from carbon credits. This is atask which would require strategic action by the Ministry of Environment andForests, Government of India and the state forest departments. Both agenciesshould undertake and promote firstly, the techno-economic research to enhanceknowledge about the technological possibilities and cost barriers under varyingecological and socio-economic conditions and, to achieve this goal, there shouldbe vast institutional apparatus at their command to disseminate the knowledgeacross the potential stakeholders through pilot projects and capacity buildingprogrammes.


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Another important side of climate mitigation project is the leakage aspect ofemissions of greenhouse gases outside the project boundaries caused, directly orotherwise, by the project activities. These leakages/emissions are required to beadjusted against the emission reductions or sink enhancements caused by the projectwithin the project boundaries. The larger the leakages, the lower are the carbonbenefits from the project. If the project activities result in displacement of grazingand firewood collection from the project area to a forest area in the neighbourhood,then, the carbon benefits would get reduced by an equivalent amount. In anagroforestry situation, with the land belonging to the farmers, such instances areless frequent. But, if the project uses large amount of fertilizers over and above theamount that was being used in past, then, the emissions generated in manufacturingand transportation of this additional amount of fertilizers would also reduce carboncredits.

In case of leakages, the main issues are the extent and the sources of leakages,and the uncertainties involved. Since the uncertainties can affect the environmentalintegrity of the credits earned, it is usual to limit the credits earned to what is‘certain’ and thus, the broader the range of uncertainty in leakages, the lesserwould be the returns to the farmer resulting in lower attraction for the CDM projectsamong stakeholders. This can also be addressed by investment in research inleakage assessments under various socio-economic conditions and various levelsof fertilizers usages. The greater is the availability of local relevant scientific datacollected in a transparent manner, the lesser would be the need of using globaldefault data with huge uncertainties and margins of error. This obviously calls foran active leadership role by forestry research organizations and universities backedby the ministry and state forestry departments.

8. Food Security and Carbon SequestrationFoodgrain production and carbon sequestration both compete for the same landresource, which is scarce and becoming even more so with the rapid growth inpopulation. Consequently, the marginal increases due to technological innovationsin foodgrain productions become narrower. It is, therefore, imperative that thegovernment policies should strike a balance between enhancing climate benefits byincreased sequestration (remuneration) in agroforestry and the need for food securityglobally across the nations and within the nations and the regions. It has to benoted that income inequalities across the regions mean that even when food issurplus globally, its movement to the regions of demand is restricted by the capacityto pay, which differs widely. It is important, therefore, to ensure localized food securityalso till income inequalities decrease substantially. This implies that agroforestrypolicies must always ensure that the food production is not reduced significantlyanywhere.


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This is not as difficult an achievement as it may appear, as there are manyagricultural lands, which are actually lying fallow and are not contributing tofoodgrain production or are only cultivated occasionally. Also, there areagroforestry models that have been shown to enable tree cultivation without anysignificant reduction in agriculture production. The need is, for governmentpolicies, to recognize this and encourage agroforestry under such conditionsthrough fiscal incentives while discouraging choices that result in decreased foodproduction.

9. Conclusions and Road AheadAlthough the government plantations offer a large potential for carbon sequestration,its actual realization would be subject to a radical change in the management of suchplantations. These drastic changes must begin with the nurseries, which shouldfocus on production of field-tested genetically superior seedlings or clones forhigher productivity. Secondly, the management regime in terms of irrigation,fertilization and post-planting operations would need to be intensified manifolds.This is possible under the proposed public-private partnership (PPP) that has often,but long been debated by the state and union governments and civil society. However,the popular fears of taking over of public assets by private companies for profiteeringhave made any advance in this field difficult.

On the other hand, TOF in general, and agroforestry in particular, even in theirpresent form, offer a better option for carbon sequestration and subsequent carbontrading, under the CDM. The prospects of TOF under CDM can be enhanceddramatically simply by shifting to improved clonal seedlings. Moreover, the extentof area under agroforestry and TOF can be increased many times without affectingagricultural production. Furthermore, inclusion of genetically screened fast growingspecies such as eucalypts, Gmelina, Ailanthus and Melia under agroforestry toensure substitution of pulp producing species would go a long way in making TOFa viable CDM option. In addition, as a major policy initiative, supply of superiorseedlings to farmers needs attention.

ReferencesAhmed, P. 2005. Study of alternatives for meeting the demand of raw

material by wood-based industries. Indian Forester, 131(5): 609-633.

Ahmed, P. 2008. Trees outside forests (TOF): A case study of wood productionand consumption in Haryana. International Forestry Review, 10(2): 165-172.

Allan, T. and Lanly, J.P. 1991. Global overview of status and trends of world’sforests. In: Technical Workshop to Explore Options foe Global Forest


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Management, Bangkok, 1991. Proceedings, edted by D. Howlett and C.Sargent. London, IIED.

Evans, J. 1992. Plantation forestry in tropics. 2nd ed. Oxford, Clarendon Press.472p.

FSI (Forest Survey of India). 2001. India state of forest report-1999. Dehradun,FSI.

Midgley, Stephen et al. 2007. A strategy for developing market opportunities forAustralian forest products in India. Farrel, Salwood Asia Pacific Pvt. Ltd.40p.

NFAP (India. Ministry of Environment and Forests). 1999. National ForestryAction Programme-India. 2V. The author.

Rawat, J.K.; Dasgupta, S.; Rajesh Kumar; Anoop Kumar and Chauhan, K.V.S.2003. Training manual on inventory outside forests (TOF). Bangkok,F.A.O. p.1.

Singh, B. 1982. Nutrient content of standing crop and biological cycling inPinus petula ecosystem. Forest Ecology and Management, 4: 317-332.

Verma, Madhu. 2006. Forest resources accounting-recent case studies from H.Pand M.P. In: Training Workshop on Contribution of the Indian ForestrySector to the Gross Domestic Product (GDP) for Indian Forest ServiceOfficers, New Delhi, 23-24 July 2006. Lecture notes. Unpublished.


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1. IntroductionEucalypts are one of the major forest plantation species grown internationally andare of prime importance in the southern hemisphere, much of South-East Asia,southern China and the Indian subcontinent. There are more than 700 species ofEucalyptus, mostly native to Australia and very small numbers are found in adjacentareas in New Guinea and Indonesia. Eucalypts have evolved under selection pressurefrom the harsh native environmental constraints and also from their major nativepathogens and pests. Their capacity for faster growth, even on poor sites, growthhabit, yield, ease of vegetative propagation and desirable product qualities have ledto widespread establishment of eucalypt plantations in many countries outside theirnatural range of distribution, including India.

Eucalypt has a long history in India. It was first introduced around 1790 by TipuSultan, the ruler of Mysore, in his palace garden on Nandi Hills in Karnataka. Thenext significant introduction of eucalypts was in the Nilgiri Hills, Tamil Nadu, in1843, and later regular plantations of E. globulus were raised in 1856 to meet thedemands for firewood (Wilson, 1973). Since then, there were several other attemptsto introduce eucalypts in various parts of the country. Most of the eucalyptplantations in India were raised during two decades between 1960-1980. The policyof converting low value natural forests into plantations aimed at improving productivityand to generate government revenue led to raising of fast growing species includingeucalypts during the 1960s, by clear felling natural forests. A much more dynamicprogramme of converting the natural forest into plantations of fast growing specieswas advocated during 1976 and more area were planted with eucalypts. So far, morethan 1 Mha of eucalypt plantations have been established in different states, viz.,Andhra Pradesh, Bihar, Goa, Daman and Deu, Gujarat, Haryana, Karnataka, Kerala,Madhya Pradesh, Maharashtra, Punjab, Tamil Nadu, Uttar Pradesh and West Bengal.Among various species, varieties and provenances of eucalypts tried in India (Bhatia,1984), Eucalyptus hybrid, a natural hybrid of E. tereticornis x E. camaldulensis known

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as ‘Mysore gum’ is the most outstanding and favoured one. Other species ofEucalyptus grown on a large-scale are E. grandis, E. citriodora, E. globulus, and E. camaldulensis. Eucalypt plantations were also raised under various state and centrallysponsored schemes to meet the demands of local people in respect of the requirementsof firewood, small timber, poles, etc. Eucalypts were also accepted as a good farmforestry tree for planting on field bunds, canal sides and in marginal agricultural lands.

Even though, eucalypts in their native environments are hosts to a wide range offungal pathogens, the broad genetic base of individual species and their presence inheterogeneous forest communities, however, provide significant protection againstdisease epidemics. However, large-scale monoculture plantations with narrow geneticbase raised outside their natural distribution range become prone to various diseasehazards. Avoidance of major epidemics of eucalypt diseases requires an increasedawareness of the risks from pathogens and a systematic approach to disease management.A good knowledge on diseases affecting the crop at their various growth phases, possiblepredisposing factors for the disease development and spread and also available short-term and long-term strategies to contain the diseases is warranted. Based on suchknowledge, clones, provenances and Eucalyptus species can be assessed for theirsusceptibility to major pathogens and strategies can be devised for the production andprotection of eucalypt stand. This chapter on diseases of eucalypts in India is an attemptto provide information on diseases affecting the various eucalypt species in plantationsand nurseries and also provides recommendations for disease management.

2. Diseases in PlantationsIn eucalypt plantations, large number of pathogens were recorded causing foliageand stem diseases, while the root diseases were only few. Most of the seriousdiseases occur within the first three years of outplanting. A few diseases are short-lived such as Lasiodiplodia stem canker, while others continue to affect the trees tillthe end of the rotation affecting the growth considerably and consequently yield(Sharma et al., 1985a, b).

2.1. Stem Canker Diseases2.1.1. Pink diseaseThe pink disease is widespread in eucalypt plantations throughout the country withincidence varying from 5 to 75 per cent depending upon the rainfall and microclimaticconditions of the area as well as the species. E. tereticornis and E. camaldulensisare the severely affected species in the low elevated areas, while E. grandis is theimportant species affected in high ranges.2.1.1.1. SymptomsUsually the pink disease affects the two-year-old plants and above, but infection ofone-year-old plants and coppice crops is not uncommon. The pathogen possibly

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infects the main stem or branches through the lenticels. Tissues of the inner bark,including cambium are killed and show prominent browning. The first sign of theinfection is the development of cobweb stage of the fungus during the monsoon.Soon pustules, small pin head size white mycelial bodies, develope over the cobweb.The infected area becomes depressed and develop vertical splitting on the bark. Theperfect stage, characterized by the pink encrustation, develops over the infectedarea. Numerous club-shaped basidia with basidiospores, a source of inocula forfresh infection are produced. Oozing of kino from the canker also occurs in certaincases (Fig. 1). The apical shoot above the canker dies when the stem is completelygirdled. Numerous epicormic shoots develop from the healthy stem just below thecanker. The shoots also get infected and killed following wilting and drying up. Oneof these shoots usually survives and becomes a leader shoot, which does notescape the infection in the following season. Thus, infected trees, which appearbushy due to repeated infections became frail and weak. The yield and productivityof plantation reduce considerably as the trees show negative growth.

Infection of older trees (three to four-year-old) usually results in localized cankersand trees are normally not girdled. However, under conducive microclimaticconditions, multiple stem cankers occur on main stem and partial to complete girdlingof the stem occurs. The toxin produced by P. salmonicolor is possibly non-hostspecific (Sharma et al., 1985a, b). Screening of various provenances of Eucalyptusspecies, viz., E. brassiana, E. camaldulensis, E. deglupta, E. grandis, E. microcorys,E. pellita, E. resinifere, E. saligna, E. tereticornis, E. tessellaris, E. urophylla,among others, indicate that none of them, except E. brassiana, were resistant toP. salmonicolor toxins (Sharma et al., 1984a, b; 1985a, b; 1988). The non-host specifictoxins have apparently a high biochemical specificity yet little specificity betweenplant species. This way the pathogen gains full benefit from production of suchtoxins in the broadening of its potential range of hosts (Ferreira and Alfenas, 1977;Mitchell, 1984).2.1.1.2. EtiologyPhanerochaete salmonicolor (Berk. and Broome) Julich (=Corticium salmonicolorBerk and Br.) is the pathogen causing pink disease. The pathogen produces fourstages, viz., cobweb, pustule, pink encrustation (perfect stage) and necator on infectedeucalypts stem.2.1.1.3. Pink disease managementDisease management by fungicides has been an established practice in pink diseaseaffected rubber plantations in India and South-East Asia (Hilton, 1958). Laboratoryand field screening of various fungicides showed that copper fungicides andtridemorph (Calixin) are equally effective in controlling the disease (Seth et al., 1978;Kumar et al, 1979; Sharma et al., 1984a, b; 1985a, b; Mohanan, 1995a). The possiblelong-term solution for managing the pink disease in eucalypts appears to be through

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species selection and tree improvement. Eucalyptus species and progenies fromtrees, which have escaped from infection in high disease incidence areas need to beselected and clonally propagated. However, various clones developed by differentagencies in different parts of the country are not giving very promising results. Theimprovement through hybridization, though time consuming, may also be attemptedfor long-term disease control.

2.1.2. Crysoporthe stem cankerIn India, the disease was first recorded from two-year-old E. grandis plantationsfrom Wayanad Forest Division, Kerala, during 1980s (Mohanan and Sharma, 1982;Sharma et al., 1985a, b). Later the disease was recorded on three- to six-years-oldplanations of E. grandis, E. citriodora, E. deglupta, E. tereticornis, E. torelliana indifferent parts of the Kerala state (Sharma et al., 1985a, b).2.1.2.1. SymptomsThe first symptom of the disease is development of slightly sunken, elongate areasmeasuring about 15-20 cm on the trunk either at the base or above ground, just afterthe south-west monsoon. Observation showed that the tissue beneath the depressedbark (inner bark) was brown and apparently dead. As canker developed during thedry period (December-April), the bark showed vertical splitting, which increased inlength and width with age. Generally, at this time gummosis (oozing of kino) wasobserved in a few of the cankers. However, gummosis was commonly associatedwith the older cankers. The ruby coloured kino was usually washed down duringthe rainy period and imparted a distinct colour to the affected trees by which theycould be recognized easily. Often multiple stem cankers appear on trunk whichbecame confluent to form long cankerous areas. Usually the cankers developedabove the ground level and occasionally at the base. Mortality of trees occurred inE. grandis, E. citriodora and E. deglupta trees (Fig. 2). Disease was also recordedon coppice shoots from E. grandis stumps. Due to infection, the per cent stumpssprouted decreased with the increasing gummosis due to canker at the basal area.2.1.2.2. EtiologyChrysoporthe cubensis (Bruner) Gryzenh. and M.J. Wingf. (= Cryphonectria cubensis(Bruner) Hodges is the pathogen associated with the stem disease. C. cubensis wasfirst reported from Cuba (Bruner, 1917) where it caused stem canker of variouseucalypts. It was not reported again until 1970 when it was reported as Endothiahavanensis Bruner by Boerboom and Maas from Surinam. Subsequently, Hodgesand Ries (1974) also recorded it under the same name from Brazil. It was only latershowed that what was described as E. havanensis from Brazil and Surinam wasDiaporthe cubensis. Bruner and recently Hodges (1980) transferred it to genusCryphonectria. This stem canker disease is widespread and has also been recordedfrom Cuba, Florida, Hawaii, Puerto Rico, Brazil, Surinam, Western Australia, Hong


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Kong, Cameroons and Venezuela (Boerboom and Maas, 1970; Hodges and Reis,1974; Ferreira et al., 1977, 1978). The distribution of pathogen is probably determinedby the tropical humid climate needed for the growth and spread of the pathogen.

Recent phylogenetic studies based on multiple gene sequence comparisons(Gryzenhout et al., 2004) have revealed that isolates of C. cubensis group separatelyfrom other Cryphonectria species. Within the C. cubensis clade, isolates formedthree distinct subclades that include isolates mainly from South America, SouthAfrica and South-East Asia, respectively. In this study, they established a newgenus, Chrysoporthe, for this species. Chrysoporthe is characterized by superficial,blackened conidiomata, limited ascostromatic tissue and blackened perithecial necksprotruding from the orange stromatal surface (Fig. 3a & b). Although, specimens ofC. cubensis from South East Asia and South America reside in two distinctphylogenetic sub-clades, they could not be separated or distinguished from thetype specimen, originating from Cuba, based on morphological characteristics. Atpresent, these specimens are collectively transferred to Chrysoporthe as a singlespecies, Chrysoporthe cubensis (Gryzenhout et al., 2004).2.1.2.3. Disease managementThe basal cankers are known to reduce the sprouting of stumps by about 10-20 percent. In Kerala, though the frequency of basal cankers was less, about 35 per cent ofthe stumps affected with the disease (indicated by gummosis) failed to producecoppice shoots. It seems that excessive gummosis kills the tissues of the outer barkas do the cankers and thus, brings about sprouting failure. In such plantations, eventhough the mortality was less, the impact of the disease was greater on the coppicecrop. At present the level of canker disease is low, with a maximum mortality of about3 per cent, the anticipated increase in inoculum over the years in the conduciveclimate of the Kerala state could pose a serious threat to eucalypts, as in Brazil. Thelong term control in a forestry crop is possible only either by field selection or bybreeding for resistance. In Brazil, stable resistance to Crysoporthe stem canker hasalready been obtained by intensive field selection followed by clonal propagation.As a first step in this direction more than 40 eucalypts (various provenancesbelonging to different species) are being screened against C. cubensis in Kerala(Sharma et al., 1984a, b; 1985a, b). Brush on application of copper fungicide (1 percent paste) on bark and cut surface of the stumps or application of tridemorph (0.2%a.i.) can control the infection on stem and coppice growth.

2.1.3. Amphilogia stem cankerThis stem canker disease was first recorded from the four-year-old E. grandisplantations in Wayanad Forest Division, Kerala during 1980s (Mohanan and Sharma,1982). Later, it was recorded from E. gandis, E. tereticornis, E. torelliana, E. degluptaplantations in the state (Sharma et al., 1985a, b; Mohanan and Yesodharan, 2005).

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The disease caused twig, branch and main stem cankers. Death of twigs and brancheswas common but it was seldom observed for a tree, except in E. torelliana, whichappeared to be more susceptible than others species. Microthia havanensis(=Cryphonectria gyrosa) was first described as Endothia havanensis from Cuba(Bruner, 1917) on various eucalypts (E. occidentalis, E. botryoides, E. rostrata,E. mycrophylla and E. robusta). Since then, it has been reported in Japan onE. globulus (Kobayashi and Ito, 1956), in Australia on E. marginata (Davison, 1982;Davision and Tay, 1983).2.1.3.1. SymptomsThe infection usually occurs on lower part of the stem, often near the ground duringthe monsoon (June-July) and by September-October depressed areas, 30-40 cm longon the bark become visible. The tissues beneath the canker turned necrotic and getkilled. During the dry period splitting of the bark appeared on cankered areas. Thepycnidia, orange-red in colour, developed over the bark arranged in vertical linearrows or scattered during the wet period (June-September) (Fig. 4a to c). The pycnidiaproduce long orange yellow tendrils of spores during monsoon. Characteristicascomata with log beaks developed during the following dry period (December-April) on the cankered areas, either separately or interspersed with pycnidia. Deathof E. torelliana trees occurred when the cankers girdled them completely. Nogummosis was noticed on the cankers as in the case of C.cubensis canker. Infectionalso occurs on branches and twigs resulting in twig and branch die-back.2.1.3.2. EtiologyAmphilogia gyrosa (Berk. and Broome) Gryzenh., H.F. Glen, H.F. and M.J. Wingf.(= Cryphonrctria gyrosa (Berk. and Br.), Endothia havanensis (Bruner) Baur. Baar(1978) transferred E. havanensis to C. havanensis keeping along with C. parasitica,C. radicalis, C. nitschkei and C. macrospora in a group typified by C. gyrosa. Lateron Hodges (1980) considered E. havanensis as synonyms with C. gyrosa. Recentphylogenetic studies by Gryzenhout et al. (2006) on isolates of C. havanensis oneucalypts in Mexico and Hawaii (U.S.A.) revealed that the isolates resided in agenus distinct from Cryphonectria sensu stricto, and described as Microthia. Thegenera Cryphonectria and Endothia are closely related and recent DNA sequencecomparisons have shown that isolates from Elaeocarpus spp. in New Zealand,previously identified as Cryphonectria radicalis and Cryphonectria gyrosa,represent a phylogenetic group distinct from those including other species ofCryphonectria and Endothia. A new genus, Amphilogia, is described for thecollections of C. gyrosa from Sri Lanka and New Zealand (Gryzenhout et al., 2005,2006, 2009).2.1.3.3. Disease managementEven though A. gyrosa is capable of killing branches and trees, long-term fieldmonitoring revealed that A. gyrosa is a weak pathogen and often it was associated


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with C. cubensis. In more than six-year-old trees, A. gyrosa caused mild cankerswithout any apparent damage. Only E. torelliana is highly susceptible to A. gyrosacauses and causes ca. 10 per cent mortality (Sharma et al., 1985a, b). Fungicidesevaluated indicate that there are quite a few fungicides like Benlate (0.1% a.i.),Bavistin (0.1% a.i.), Bayleton (0.1% a.i.), Demosan (0.5% a.i) Dithane-M45 (0.5%a.i.), Saprol (0.1% a.i.), Tecto (0.1% a.i.) effective against A. gyrosa, which may beused in controlling the canker disease, should it spread in epidemic proportion(Sharma et al., 1985a, b). Even though, chemical control of this disease is not a long-term solution, till the time we have promising canker resistant/tolerant eucalypts,chemical control may be adopted to check its further spread.

2.1.4. Cytospora stem cankerThe disease, usually causing branch cankers occurs in young E. tereticornis,E. camaldulensis, E. torelliana and E. grandis plantations and the disease incidenceranges from 2.3 to 7.1 per cent. Severe stem infection was recorded on one-year-oldsecond rotation E. tereticornis coppice crops with a mortality rate of 75 per cent.Cytospora eucalypticola has been earlier recorded causing cankers on E. ficifolia,E. globulus and E. marginata in Australia (Gibson, 1975; Davison and Tay, 1983).C. eucalyptina and C. australis have been recorded on different species of Eucalyptusfrom Australia, Portugal, South Africa, Central and East Africa (Azevedo, 1971). Thedisease appears to be favoured by stress conditions for the host. Cytospora stemcanker disease occurs in Uganda, Malawi, Kenya, Pakistan, Myanmar and WesternAustralia (Graces, 1964).2.1.4.1. SymptomsIn the case of branch and twig cankers, infection occurred on any part of the stem.The tissues of the infected region showed pronounced browning and leaves wiltedand defoliated. Numerous black conidiomata (pycnidia) developed scattered overthe entire infected region. Complete girdling of the phloem and cambium usuallyresulted in death of the affected branches. Infection on the main stem of coppiceshoots was initially observed at the base near the stump and later, it graduallyspreads towards the apex. Girdling due to the canker at the base resulted in wiltingof the leaves and death of shoots. In severe case, the infection even spreads toroots killing the stump. Generally, all the shoots of a stump got infected and died.2.1.4.2. EtiologyCytospora eucalypticola van der Westhuzien causes main stem canker and C.eucalypti Sharma and Mohanan causes twig and branch canker. Cytospora, theanamorph of Valsa Fr., sometimes occurs with their ascomatal state, such as Valsaeucalypti and C. eucalypti, although they occur more frequently alone.2.1.4.3. Disease managementSince the disease is now of minor importance, no control measures are recommended.

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2.1.5. Lasiodiplodia stem (root collar) cankerThe disease affects one- to two-year-old E. tereticornis and E. grandis plantations.Infection occurs during the hot, dry months of November-April in Kerala when theday temperature is high (350-380C) and night temperature low (220-250C). Severefluctuations in soil temperature may have caused some injury to the saplings near thecollar region, through which the infection may have occurred. The disease can pose aserious threat in the establishment of young plantations causing as much as 20 percent mortality (Sharma et al., 1985a, b). E. tereticornis is the species most susceptibleto L. theobromae. L. theobromae is a weak parasite, and usually infects the hostthrough wounds. Termites are known to cause problems in the establishment of youngplantations, especially E. tereticornis, in Kerala. In some instances, root injury causedby termites may have acted as entry points for the pathogen.2.1.5.1. SymptomsAffected plants showed typical symptoms of physiological wilting; i.e., droopingapical shoots with flaccid leaves. Within a day or two, the wilted plants died. In allthe diseased plants the root collar region was typically constricted and compressedwith irregular crevices, where occasionally conidiomata of the pathogen wereobserved. Often, the stem above the canker was abnormally swollen (Fig. 5). Thisswelling was the result of the rupturing of the outer bark at the canker resulted ingirdling of the stem and plants died. The tissue in the canker region was brown anddead or dying. Often the infection also extended to roots, causing root decay.2.1.5.2. EtiologyLasiodiplodia theobromae (Pat.) Griffon and Maubl. (=Botriodiplodia theobromaePat.2.1.5.3. Disease managementFungicidal screening against L. theobromae indicated that Bavistin (0.5% a.i) andTecto (0.5% a.i) were most effective (Sharma et al., 1985a, b). Although, chemicalcontrol of disease of this nature in forest plantations is not an economically feasiblesolution, a soil drench of 0.5 per cent a.i. of Bavistin to plants with accidentalinjury may be useful in controlling the disease. As the canker disease ismanifested through wounds, weeding and other soil operations need to be carriedout carefully.

2.1.6. Valsa stem cankerLow incidence of canker disease was recorded in one- to four-year-old E. grandisand E. torelliana plantations in Kerala. The disease caused extensive juvenile twigand branch cankers resulting in die-back of more than 30 per cent of the plants.2.1.6.1. SymptomsGenerally, the cankers are common on twigs and branches and occasionally on mainstem (Fig. 6). Usually the infection is initiated at the base of the branch where a canker


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develops. Over the dead bark, numerous black fructifications are produced. Often morefructifications are produced on the lower surface of a branch, away from the directsunlight. The affected twigs and branches die due to complete girdling of phloem tissue.2.1.6.2. EtiologyValsa eucalypti Cook and Harness and Valsa eucalypticola Sharma, Florence andMohanan are the causal agents. V. eucalypti and V. eucalypticola are the teleomorphsof Cytospora eucalypti and C. eucalypticola, respectively reported for the firsttime from India on Eucalyptus spp. (Sharma et al., 1985a, b).2.1.6.3. Disease managementSince Valsa spp. mostly cause cankers on lower branches, which eventually die as aresult of natural pruning, it does not appear to be of serious concern.

2.1.7. Macrovalsaria stem cankerThe disease occurs in isolated patches in E. tereticornis plantations in low elevatedareas and E. grandis plantations in medium and high ranges in Kerala. All theaffected trees either die or show wilting of leaves.2.1.7.1. SymptomsGenerally the infection occurs at the basal part of the stem, characterized by a largenumber of black fructifications, scattered over the bark (Fig. 7a and b). The affectedstem develop canker and the underneath tissues show browning. When the stem iscompletely girdled, the foliage wilts and the tree slowly die. Epicormic shootsdevelopment does not occur.2.1.7.2. EtiologyMacrovalsaria megalospora (Mont.) Sivan.2.1.7.3. Disease managementSince the disease is recorded in low incidence, it appears to be of a minor importanceand no control measure is required.

2.1.8. Thyronectria stem cankerThe disease was recorded in E. tereticornis, E. camaldulensis and E. torellianaplantations in Kerala (Sharma et al., 1985a, b). Though the disease was reported tokill the trees in some plantations, it appeared to be unimportant as the incidence wasvery low (>1%). Mortality of trees was recorded mostly from E. tereticornis,E. grandis and E. camaldulensis plantations. Occasionally, branch infection wasalso reported in E. torelliana which killed the shoots outright.2.1.8.1. SymptomsInitially, the conidial state of the pathogen developed near the base of the stemwhich soon spread upwards covering a large area (Fig. 8a to c). The affected tissuesof the stem developed browning and when stem completely girdled, it broughtabout wilting and consequently death of tree. The perfect stage of the fungus was

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formed in loose clusters or scattered over the dead stem. No epicormic shootsdeveloped on the affected trees.2.1.8.2. EtiologyThyronectria pseudotricha (Schw.) Seeler2.1.8.3. Disease managementThough T. pseudotricha is considered to be a wound parasite, no injury/woundswere observed in any of the affected trees examined. The pathogen, causing branchas well as main stem cankers, is capable of killing the trees. As the disease occurs inlow intensity no control measure is required.

2.1.9. Hysterium stem cankerThe disease was reported from four-year-old E. camaldulensis plantations in Kerala(Sharma et al., 1985a, b). All the affected trees died due to girdling of stem by thecanker. H. angustatum commonly occurs on Acer, Alnus, Fagus, Fraxinus, etc., intemperate countries.2.1.9.1. SymptomsThe pathogen caused extensive cankers on branches and upper part of the stem(Fig. 9a to c). The affected tissues of the stem showed pronounced browning. Ondead stem numerous characteristic black fructifications developed, aggregated orsingly.2.1.9.2. EtiologyHysterium angustatum Alb. and Schwein2.1.9.3. Disease managementHysterium canker may be considered as a minor disease of eucalypts because ofthe localized occurrence and low incidence hence, control measure is not required.

2.1.10. Nattrassa stem cankerThe disease was reported from two- to three-year-old E. tereticornis plantations indifferent parts of Kerala (Sharma et al., 1985a, b). The incidence of disease was<1 per cent. The causal agent is a weak pathogen and is known to kill the cambialregion of wide range of plants, including eucalypts, often following injury.2.1.10.1. SymptomsGenerally, the infection appeared on the stem near the ground and later spreadupwards covering a large part of the stem. The infected area got differentiated in adepression, which later turned into a canker. Occasionally, the roots also got infectedand complete girdling of the stem resulted in death of plants. The foliage graduallywilted and defoliated. On the canker numerous minute fructifications, pycnidia, ofthe fungus developed arranged in vertical broken lines. The tissue of the affectedarea showed grayish black discoloration in which dark brown, septate, thick-walled,inter and intra-mycelia were found in abundance.


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2.1.10.2. EtiologyNattrassa toruloidea (Natrrass) Dyko and Sutton2.1.10.3. Disease managementSince the disease in plantations occurs in low incidence, no control measure isrequired.

2.2. Cylindrocladium Root RotThe disease was recorded from young 9- to 18-month-old E. tereticornis and E. grandisplantations in Kerala. The disease occurred during dry period. About 10 per cent ofthe plants were found to be affected with the disease (Sharma et al., 1985a, b).2.2.1. SymptomsThe leaves of the affected plants became flaccid and apical shoot showed drooping.The leaves turned brown and dried up. The root system of such plants was foundto be completely rotted with pronounced brown discolouration. The affected plantsfailed to survive. On dead roots, abundant mycelium and sporulation of the causalfungus could be observed.2.2.2. EtiologyCalonectria floridana Sobers and its anamorph Cylindrocladium floridanum Sobersand Seymore.2.2.3. Disease managementUnlike other species of Cylindrocladium which cause foliar diseases during the wetseason, occurrence of root rot caused by C. floridanum during the dry period isquite interesting. If the roots of the affected plants are not properly examined, thisdisease may be mistaken either for termite damage or Lasiodiplodia stem canker.Considering the low incidence of this disease, it does not appear to be a seriousproblem and no control measure is required.

2.3. Cylindrocarpon Root RotThe disease was recorded from one-to five-year-old E. tereticornis and E. grandisplantations in Kerala. Even though, the disease incidence in E. grandis plantationswas low (<1%), in E. tereticornis plantations, it was more than 20 per cent during thedry period (Sharma et al., 1985a, b).2.3.1. SymptomsIn E. grandis, the initial symptom was wilting and drying up of leaves. The roots of theaffected trees became discoloured and showed rotting. The infection generally spreadup to the collar area and produced a canker. The affected trees died within one to twomonths. In E. tereticornis, the leaves of the affected plants, especially the bottomones, turned reddish purple in colour and dried up. No wilting of foliage was observed.The plants were killed within two to three weeks after the change in colour of thefoliage was noticed. The roots of diseased trees showed browning and rotting.

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2.3.2. EtiologyCylindrocarpon lucidum Booth state of Thelonectria lucida (Hohn) P. Chaverriand C. Salgado2.3.3. Disease managementC. lucidum is considered to be a weak pathogen as usually the entry in the host isthrough injury or wounds. No control measure is suggested. However, in youngE. tereticornis plantation, the disease appeared to be a potentially serious one as itkilled more than 20 per cent plants, indicating the susceptible nature of the species.

2.4. Vascular WiltWilt disease of E. gandis was recorded during the monsoon (August-September)in one- to two-year-old plantations in Kerala (Sharma et al., 1985a, b). The incidenceof the disease ranged between 10 and 25 per cent, while large-scale mortality wasrecorded in E. grandis plantations in high ranges.2.4.1. SymptomsThe affected plants showed characteristic symptoms of wilting. Initially the lowerfoliage became flaccid and dried up. Slowly and gradually, the wilting proceededupwards eventually killing the growing shoot. The wilted plants could be easilylocated in the plantations because of their dried up leaves. The vascular tissues ofroots and stem of the diseased plants showed typical browning, abundant myceliumand spores characteristic of vascular wilt.2.4.2. EtiologyFusarium oxysporum Schlecht. F. oxysporum, which has a worldwide distribution,is a soil-borne facultative parasite on many plants. It is disseminated throughplant material and soil on implements, transplant, surface drainage, water andwind-borne spores. Infection is mainly through vascular wounds.2.4.3. Disease managementVascular wilt disease in eucalypts was recorded only from a few locations and is notwidespread and hence disease management measure is not recommended.

2.5. Cylindrocladium Shoot BlightCylindrocladium shoot blight affecting leaves and stem of eucalypts is widespreadduring and immediately after the monsoon (June-September), irrespective of age ofplants and species. Stem infection, which is more common in young plants (one- totwo-year-old) and coppice shoots, is observed only during the monsoon, whilethose of leaves is prevalent round the year, especially in humid tracts and highelevation areas such as Wayanad Platteau, Munnar, Idukki and Pamba in Keralastate (Sharma et al., 1985a, b; Mohanan, 1995a, b). Shoot infection caused by variousspecies of Cylindrocladium has been reported from eucalypts growing areas inother states (Reddy, 1973; Bakshi, 1975), Brazil (Figueiredo and Cruz, 1963; Alfenas


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et al.,1979) and elsewhere (Crous et al., 1998; Crous, 2002). Severity of infectiongenerally depended upon the microclimatic conditions, especially rainfall, humidityand also the age of the plants. Medium to severe infection was recorded in youngerplantations (one- to three-year-old) situated in high rainfall areas irrespective ofspecies of Eucalyptus, whereas in older plantations (four- to eight-year-old), theseverity was usually low. Severe infection of leaves, which caused blight, resultedin extensive premature defoliation. E. tereticornis, E. camaldulensis and E. grandisare the severely affected eucalypt species.2.5.1. SymptomsThe infection affects both stem and foliage. The stem infection, observed in coppiceshoots and branches of young trees, appeared somewhere on branches and causedcanker characterized by a dull brown depression on the stem. During high humid periods,Cylindrocladium was seen to produce profuse mycelium and conidial mass. Theportion of the branch above the canker was killed outright when completely girdled.During the rainy season numerous fructifications (teleomorph) developed on the deadstem. Stem infection coupled with severe leaf blight resulted in die-back of shoots(Fig. 10a & b). New epicormic shoots developed as a result of the die-back, also gotinfected in the subsequent monsoon. Leaves of all maturities from young and oldplants, epicormic and coppice shoots were found to be equally susceptible toCylindrocladium infection. The symptom expression mainly the colour, size and spreadof the lesions varied depending on the leaf maturity and micro- and macro-climaticconditions and Eucalyptus species. In E. grandis, the leaf infection appeared in theform of minute grayish-black spots which coalesced to form large necrotic area. Underhigh humid conditions, the initial spots were usually large grayish black patches, whichspread further at time to cover the entire leaf lamina. In mature leaves occasionally theinfection initiated either from leaf tip and spread downwards or from the margin andgradually spread towards the midrib. During the dry period, the lesions became dullpale brown. Extensive leaf infection caused blight which resulted in premature defoliation.

Cylindrocladium shoot blight occurs in major plantation grown eucalypts, viz.,E. camaldulensis, E. grandis, E. tereticornis, E. urophylla, E. torelliana,E. citriodora, E. deglupta, E. globulus, among others.2.5.2. EtiologyA total of five species of Cylindrocladium were found to be associated with shootinfection of eucalypts. Calonectria quinueseptata Figueiredo and Namekata andits anamorph Cylindrocladium quinqueseptatum Boedijn and Reitsma. Calonectriapyrochroa (Desm.) Sacc. and its anamorph Cylindrocladium ilicicola (Hawley)Boedijn and Reitsma. Calonectria indusiata (Seaver) Crous and its anamorphCylindrocladium theae (Petch) Alf. and Sob. Cylindrocladium clavatum Hodgesand May Calonectria morganii Crous, Alfenas and M.J. Wingf. and its anamorphCylindrocladium scoparium Morg.

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2.5.3. Disease managementControl of Cylindrocladium shoot blight in plantations is not economically feasible.However, the incidence and severity of infection can be brought down to low leveleither by modifying the cultural measures or by chemical application. Importance ofselection of healthy planting stocks as well as selection of appropriate planting timeand schedule according to the rainfall pattern in the planting site is stressed.Mortality in one-year-old plantations due to Cylindrocladium infection can beavoided by planting only healthy seedlings of appropriate age after the onset of pre-monsoon showers or during the first week of the arrival of monsoon. A delay in theplanting programme will facilitate Cylindrocladium infection. A prophylacticfungicidal treatment (Carbendazim 0.2% a.i) of the planting stocks before transportingto the planting site is recommended to check the disease havoc immediately after theplanting (Mohanan, 1995b). Long-term strategies to deal with the Cylindrocladiuminfection in eucalypts include broadening the genetic base of Eucalyptus throughintroduction of more provenances and species with desirable characteristics.

2.6. Phaeoseptoria Leaf SpotThe infection was recorded from eucalypt nurseries and plantations throughout Keralaon E. tereticornis, E. grandis, E. camaldulensis, E. deglupta, E. globulus andE. pellitta (Sharma et al., 1985a, b; Mohanan and Sharma, 1986). Though the diseasewas prevalent in dry season (December to May), yet it was observed even during peakmonsoon period (July-August). Severe infection caused extensive prematuredefoliation. The disease has also been reported from other states (Padaganur andHiremat, 1973) and from other eucalypt growing countries (Kobayashi, 1978).2.6.1. SymptomsThe infection first appeared on mature leaves as purple to brownish purpleamphigenous spots which were characteristically angular and marked by veins,especially on E. grandis and E. tereticornis (Fig. 11). The leaf spots graduallyprogressed upwards and late in the season, they were frequently noticed on youngerleaves. By this time generally, all the mature leaves had defoliated prematurely dueto heavy infection. When the spot turned necrotic, minute black fruiting bodies(pycnidia), generally more on the abaxial surface, developed embedded in the leaftissue. Pycnidia produced long grayish-back tendrils which appear as brownish-black wooly mass on both the leaf surfaces. Due to rain or dew, the conidia gotdispersed from the tendrils and formed a black layer over the leaf surface.2.6.2. EtiologyPhaeoseptoria eucalypti (Hansf.) Walker2.6.3. Disease managementAmong the 13 fungicides evaluated against P. eucalypti, Bavistin, Benlate and Tectowere the most effective ones as they inhibited the growth completely even at 0.1 per


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cent a.i. Field trials revealed that two applications of Bavistin (0.03% a.i) at weeklyintervals were effective in controlling the leaf infection.

2.7. Coniella Leaf BlightThe leaf disease caused extensive premature defoliation of the lower branches inE. camaldulensis, E. grandis, E. pellita, E. tereticornis, and various clones ofE. tereticornis (Sharma et al., 1985a, b; Mohanan et al., 2010) due to severe infection.Field studies in different eucalypt growing areas in Kerala state suggests that thedisease incidence and severity was greatly favoured by high humidity and moisture.Coniella fragariae is widespread in eucalypt plantations in India, Brazil and thePhilippines (Ferreira et al., 1977; Mohanan, 2010).2.7.1. SymptomsUsually the infection occurred along the leaf margins and tips during the rainy season asmore or less circular lesions with regular margins (Fig. 12). In high humid tracts (>90%r.h.), the infection also developed during dry period. Infection caused by C. fragariaemanifested in the form of circular lesions, which spread to the whole leaf and becamenecrotic and often caused foliage blight. Severe leaf blight and, thereby defoliation wasnoticed in E. camaldulensis, E. grandis and E. tereticornis plantations. Numerous paleto dark brown coloured, immersed to semi-immersed pycnidia of the fungus arrangedmore or less in concentric rings develop over the necrotic lesions. As the necrotic lesionsget enlarged, new rings of pycnidia develop. However, in the case of C. australensis,pycnidia developed irregularly over the necrotic lesions. During the wet period, pale olivegreen to pale brown conidial ooze developed which dispersed by rain splashes and theinoculum spreads to the new healthy leaves. Foliage blight due to severe infection iscommon in eucalypt nurseries and young plantations (Mohanan et al., 2005).2.7.2. EtiologyConiella australiensis Petr, C. castaneicola (Ell. and Ev.) B. Sutton, C. fragariae(Oudem) B. Sutton, C. granati (Sacc.) Petr and Syd. , C. minima B. Sutton and Thaung.2.7.3. Disease managementIn nurseries and young plantations, the disease attained a important status causingsevere premature defoliation, die-back of branches and terminal shoots. The recentfield investigation revealed that Coniella species become dominated over theCylindrocladium species, especially in eucalypt nurseries and plantations situatedin high rainfall (4,000-6,000 mm per annum) of the Kerala state (Mohanan andYesodharan, 2005; Mohanan et al., 2010). Fungicidal application (Dithane M 45(0.2% a.i) is suggested for controlling the disease (Mohanan et al., 2005).

2.8. Guignardia Leaf SpotThe disease has been noticed in E. camaldulensis, E. grandis, E. pellita, E. tereticornisplantations in low and high elevated areas in the Kerala state with a low to medium

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disease severity (Sharma et al., 1985a, b). E.camaldulenis, E. citriodora, Eucalyptusclone KFRI 15, E. deglupta, E. grandis, E. pellita, E. regnans, E. tereticornis, E. torellianaand E. urophylla are the species affected. Guignardia leaf spot disease has earlier beenreported on eucalypt species from South Africa and Malaysia (Gibson, 1975).2.8.1. SymptomsInitially the symptoms developed as minute purplish spots on the upper surface ofthe leaves. Later, they got enlarged and became purplish brown necrotic areas, 4-5mm across, angular to irregular, often lined with veins.2.8.2. EtiologyGuignardia citricarpa Kiely2.8.3. Disease managementThe leaf spot disease is of minor importance and hence, control measures are notsuggested.

2.9. Leaf Spot DiseasesLeaf spot disease caused by various pathogens have been recorded on differentspecies of Eucalyptus from various parts of the country (Sharma et al., 1985a, b).Pestalotiopsis disseminata (Thum.) Steyart, P. guepinii (Desm.) Steyart, P. neglecta(Thum.) Steyart, P. mangiferae (P. Henn.) P. Steyart, P. versicolor (Speg.) Steyart,P. macrospora (Cesati) Steyaert on E. tereticornis, E. torelliana, P. maculans (Corda)Nag Raj, P. metasequoiae (Gucsvicz) Nag Raj, P. palustris Nag Raj, P. tecomicolaNag Raj, P. uvicola (Spegazzini) Bisset (Mohanan and Yesodharan, 2005), Readeriellamirabilis H. and P. Syd. on E. tereticornis, Pestalosphaeria elaedis (Booth andRobertson) van der Aa, Alternaria alternata (Fr.) Kiessler, causing leaf spot inE. camaldulensis, E. citriodora, E. globules, E. grandis, E. pellita, E. tereticornishave been recorded in Kerala (Sharma et al., 1985a, b).

Recently, Alternaria citri Ellis and Pierce apud Pierce causing leaf spot inE. urophylla; Aulographina eucalypti (Cooke and Massee) Aex and E. Mull.causing necrotic leaf spots in E. grandis and E. tereticornis have been recordedfrom Kerala. Chaetomella raphigera Swift on E. camaldulensis, E. tereticornis(Mohanan and Yesodharan, 2005); Colletotrichum acutatum Simmonds,C. dematium (Pers. Ex Fr.) Grov., C. gloeosporioides (Penz.) Sacc., onE. tereticornis; C. crassipues (Speg.) Arz. on E. tereticornis; Cryptosporiopsiseucalypti Sankaran and Sutton, Cryptosporiopsis sp. 1 on E. camaldulensis,E. grandis, E. tereticornis (Mohanan and Yesodharan, 2005), Curvulariaeragrostidis (P. Henn.) J.A. Mayer on E. camaldulensis; Cylindrocladiumcolhounii Peerally on E. camaldulensis; Drechslera state of Cochliobolusspicifer Nelson on E. pellita, Fairmaniella leprosa (Fairm.) Petr. and Syd. onE. grandis and E. tereticornis; Fusarium acuminatum Ellis and Everhart andF. lateritium Nees, F. oxysporum Schlecht, F. moniliforme Sheldon, on E. grandis,


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E. camaldulensis. Other fungal pathogens causing leaf infection include:Mycosphaerella cryptica Cook and Hansf. on E. tereticornis (Mohanan andYesodharan, 2005), Mycotribula Nag Raj and Kendrick sp. 1, on E. camaldulensis,E. grandis and E. tereticornis (Mohanan and Yesodharan, 2005). Phomopsis eucalypticausing foliage infection on E. grandis, E. tereticornis, E. torelliana (Mohanan andSharma, 1987).2.9.1. Little leaf diseaseLittle leaf disease of eucalypts has been recorded in E. tereticornis, E. grandis andE. globulus plantations throughout Kerala state and elsewhere (Ghosh et al., 1985;Sharma et al., 1985a, b). The disease occurred with low intensity both in nurseriesand plantations. The disease is suspected to be seed-borne. Earlier Sastry et al.(1971) reported a graft transmissible little leaf disease in four- to five-year-oldE. citriodora which was stated to be caused by a virus.2.9.1.1. SymptomsThe affected plants showed prominent stunting and produced much smaller leaveswhen compared to healthy ones (Fig. 13). The new leaves showed considerablereduction in size and became thin, pale, scaly with narrow lamina. The apices of suchleaves often showed browning. The internodes became stunted and all axillary budssprouted resulting in bushy shoots with abnormal minute leaves. Affected trees becameweak due to reduction in stem girth and height growth.2.9.1.2. EtiologyThe disease is caused by phytoplasma (mycoplasma-like organism).2.9.1.3. Disease managementAs the disease is possibly insect transmitted, the plants showing little leaf diseasesymptoms should be uprooted and burnt.

2.9.2. Leaf mosaicA leaf mosaic disease of E. tereticornis was recorded in plantations as well as in nurseries.In nurseries, the disease occurred rarely, however, in plantations invariably a few treeswere always found to be affected with leaf mosaic disease. Incidence of disease wasgenerally very low (<0.1%), except in Thenmala Forest Division where it was 0.5 per cent.2.9.2.1. SymptomsAll the leaves young as well as mature, of the affected plants had mosaic symptoms;i.e., light pale to yellowish white, irregular patches. Even the new leaves showedthese symptoms. The diseased plants did not show any effect on growth, exceptthat affected leaves became leathery and thick.2.9.2.2. EtiologySuspecting that the disease could be viral in nature, standard methods of sap andgraft transmission were attempted on one-year-old seedlings of E. tereticornis butnegative results were obtained.

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2.9.2.3. Disease managementSastry et al. (1971) reported a mosaic disease of E. citriodora caused by tobaccomosaic virus (TMV) from India, which was sap transmissible. The mosaic diseaserecorded from Kerala differs considerably in symptomatology and also in that itcould not be transmitted. Though the disease is not economically important somestudies are warranted to establish the etiology.

2.10. Nursery DiseasesA large number of fungal pathogens are found associated with various diseases ineucalypt nurseries. As most of the nursery diseases are soil-borne, potentialpathogens affect the eucalypt seeds immediately after they begin to germinate.Various diseases namely, damping-off, web-blight, seedling blight, seedling wilt,root-rot and leaf spots appeared almost in succession. Occurrence of web blight,seedling blight and seedling wilt overlapped. Except for the seedling blight, theother diseases continued to affect the seedlings till they were pricked out intopolythene containers. Damping-off, web blight and seedling blight were the majorwidespread diseases in seedbed nurseries. Introduction of root trainers in forestnurseries, where soil-less or soil-free growing medium is used, has had a greaterimpact on incidence of soil-borne diseases in nurseries and also in diseasemanagement.2.10.1. Damping-offBoth pre- and post-emergence damping-off occurred in eucalypt nurseries raisedthroughout the country. Pre-emergence damping-off, though uncommon, often goesundetected because it is misidentified as failure of germination of ‘poor seeds’. Thepost-emergence damping-off occurred more commonly within a week of emergenceof seedlings. The disease spread rapidly with increasing soil moisture, often resultingfrom excessive watering of beds. Mortality of seedlings was observed for the firsttwo-to three-week only.2.10.1.1. SymptomsThe infection caused rotting of the just emerged radicle and subsequently thecotyledons inside the seed coat. The disease occurred within two to three days ofsowing (Fig. 14a). Post-emergence infection caused a collapse of the stem tissuesmarked by a water-soaked constricted area at the soil level causing the seedling tofall over, such seedlings failed to survive. The damping-off usually occurred inroughly circular patches in which the most recently dead seedlings were on theperiphery.2.10.1.2. EtiologyA large number of fungal pathogens are associated with damping-off of eucalyptseedlings. Rhizoctonia solani state of Thanatephorus cucumeris (Frank.) Donk isthe major pathogen. Pythium deliense Meurs., P. myriotilum Drechsler, P. spinosum


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Saw., Cylindrocladium quinqueseptatum Boedijn and Retsma, C. ilicicola (Hawley)Boedijn and Reisma, C. floridanum Sobers and Seymore, C. parvum Anderson,Fusarium oxysporum Schlecht are the other pathogen associated with damping offin eucalypt seedlings (Sharma et al., 1985a, b).2.10.1.3. Disease managementAs soon as the disease is noticed in seedbeds, watering of beds should be reduced toa bare minimum. Even watering can be avoided for a day or two depending upon theclimatic conditions of the area. Shade over the nursery beds need to be regulated toallow more sunlight over the beds. Fungicides like Bavistin (0.01% a.i), Dithane M 45(0.01% a.i.) should be applied as soil drench at an interval of four hours, in place ofnormal watering. After treatment, watering should be regulated to prevent build up ofexcess soil moisture.

2.10.2. Web blightSeedling web blight of eucalypts, usually occurred in irregular patches in seedbedsand was widespread. Young seedlings are killed outright but older ones remainedalive for some time before dying. The disease, generally appeared within two weeksof seedling emergence.2.10.2.1. SymptomsInitially, the mycelium of the pathogen emerging from the soil grew up on the stem andover the leaves of a few seedlings; and spread to others invading the leaf tissuerapidly (Fig. 14b). The mycelia strands, which were initially hyaline, became lightbrown and branched extensively. Leaves of the infected seedlings developed water-soaked lesions and wilted. Later, they became necrotic and dried up. The stem showedcharacteristic pale grayish-black necrotic lesions. The pathogen often produced off-white to light brown irregular sclerotia on the affected stem and leaves of older seedlings.The fungus also produced its perfect stage on the stem during the rainy season.2.10.2.2. EtiologyRhizoctonia solani Kuhn. state of Thanatephorus cucumeris (Frank.) Donk.2.10.2.3. Disease managementAs soon as the disease is noticed the watering in the seedbeds should be minimized.This will facilitate in checking the spread of the disease. Bavistin or Benlate (0.02%a.i.) can be applied as soil drench for controlling the disease.

2.10.3. Seedling blightSeedling blight usually occurred in one-month-old eucalypt seedlings. The diseaseis widespread in eucalypt nurseries and caused heavy mortality. Seedling mortalityin eucalypt nurseries due to blight disease caused by Cylindrocladium spp. is aserious problem, especially in warm-humid areas of Kerala state (Sharma et al., 1985)and also in other eucalypt growing areas (Bakshi, 1975).

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2.10.3.1. SymptomsInfection on the seedling stem near the soil level, just above the root collar region,was the cause of seedling blight. The affected area became grayish brown killing thetissues and consequently such seedlings dried up. The pathogens produced profuseconidial growth under high humid conditions which helped increasing the inoculumpotential of the pathogens with consequent rapid spread of the disease.2.10.3.2. EtiologyCylindrocladium clavatum, C. colhaunii, C. ilicicola, C. parvum, C. quinqueseptatum,Cylindrocladiella camelliae, C. scoparium are the pathogen associated with the disease.2.10.3.3. Disease managementSeedling blight of eucalypt can be effectively controlled by application of fungicide,Bavistin (0.01% a.i) as foliar and soil drench. If the disease persists due to excessivesoil moisture, another application of the same fungicide may be given.

2.10.4. Coniella seedling blightThe disease occurred in one-to two-month-old E. tereticornis and E. grandisseedlings and caused severe damage to the nursery.2.10.4.1. SymptomsInitially, the symptoms appeared on the leaf tips in the form of browning, which graduallyextended and covered the entire leaf. Numerous black dot-like fructifications of thefungus developed on the necrotic areas. From the leaf, the infection spread to theentire stem, thus killing the seedlings. Later, on the stem also abundant pycnida of thefungus developed. Occasionally, the infection was observed only of stem.2.10.4.2. EtiologyConiella granati (Sacc.) Petrak.2.10.4.3. Disease managementApplication of fungicide, Dithane M45 (0.02% a.i.) as foliar spray can control thedisease in nursery.

2.10.5. Seedling wiltSeedling wilt in eucalypt nurseries was recorded affecting 45- to 60-day-old E. grandisand E. tereticornis seedlings.2.10.5.1. SymptomsThe first sign of the disease was the formation of a white weft of mycelium at the baseof the seedling stem, spreading up to the leaves which may entangle other nearbyseedlings also (Fig. 14c and d). The physiological wilting of seedlings was accompaniedby the development of spherical, off-white sclerotia on the affected leaves and stem.The sclerotia became light brown with age. Wilted seedlings turned brown and died.Usually the infection, which caused decay of the stem and consequent wilting ofplants, was localized on stem and leaves, however, roots remained unaffected.


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2.10.5.2. EtiologySclerotium rolfsii Sacc. state of Corticium rolfsii Curzi.

2.10.6. Seedling root rotSeedling root rot was recorded from various eucalypt nurseries raised in differentlocations of the Kerala state. The disease affected two-to five-month-old E. grandisand E. tereticornis seedlings.2.10.6.1. SymptomsRoot rot caused slow wilting of seedlings in scattered patches. The first symptomwas the change of pigmentation in apical leaves from normal green to light purple.Within a week, this change in pigmentation moved downwards rapidly and by thetime all the leaves were affected, and apical portion of seedlings showed wiltingsymptoms resulting in death of seedlings. The root system of such plants wasfound to be completely damaged due to rotting. The colour of the affected roots wasdark brown instead of off-white, or pale yellowish brown, the natural colour of roots.Generally, the infection was noticed starting from the feeder roots and later proceedingto the main root system. In some of the root rot specimens even the stem was foundto be affected causing decay of the root collar zone.2.10.6.2. EtiologyCylindrocladium curvatum Boedijn and Reitsma; Sclerotium rolfsii, Rhizoctoniasolani.2.10.6.3. Disease managementThe root rot disease can be effectively managed by drenching fungicide like Bavistin(0.02% a.i) in the seedbeds. The fungicidal application need to be repeated after aweek if the disease persists.

2.10.7. Cylindrocladium leaf spotsLeaf infection, caused by Cylindrocladium spp., is one of the important andwidespread diseases in eucalypt nurseries. Usually, the disease has been recordedto appear after the onset of monsoon. Since under such conditions the pathogenproduces abundant conidia on the affected leaves, which are disseminated bysplashing of rain drops, the disease spreads very rapidly. Nurseries raised at highelevations, the disease appears even before the monsoon. Seedlings of E. grandisand E. tereticornis were highly susceptible to Cylindrocladium spp. (Sharma et al.,1985a, b). This leaf spot disease was also recorded from other parts of the country(Bakshi et al., 1972; Reddy, 1973).2.10.7.1. SymptomsLeaf spots appear first as minute, grayish-black water-soaked lesions on young aswell as older leaves. Later, smaller lesions coalesce to form large necrotic patcheswhich on drying turn brown giving typical blighted appearance. Under high humidity,

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Fig. 3. a: SEM of pycnidium of C. cubensis (385x); b: SEM of ascocarps of C. cubensiscompletely immersed in the bark (120x).

Fig. 1. Pink disease ofEucalyptus.

Fig. 2. Crysoporthe cubensis canker - a general view ofE. grandis plantation showing a dead tree in the centreand thinning of crown of other trees due to disease.


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Fig. 5. Stem (root collar) cankercaused by L. theobromae.

Fig. 6. A vertical section through ascomata ofV. eucalypticola (60x).

Fig. 4. a. SEM of long spore tendrils from a completely immersed pycnidium ofA. gyrosa (35x), b. pycnidia arranged in vertical rows over the cankered bark andc. vertical section through a pycnidium (70x).

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Fig. 9. Stem canker of eucalypts caused by H. angustatum a. SEM of ascocarp ofHysterium angustatum (45x), b. ascocarp with asci and c. ascospores (400x).

Fig. 7. Stem canker caused by M. megalospora. a. A vertical section through theperithecium showing arrangement of asci and b. ascospores.

a b

Fig. 8. Stem canker of eucalypts caused by T. pseudotricha. a. A magnified view ofconidiomata (880x), b. SEM of conidial head bearing conidia and c. ascocarp with asci.

a b c

a b c


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Fig. 10. a. Cylindrocladium leaf infection and b. conidia ofCylindrocladium on affected seedling stem.

Fig. 11. Phaeoseptorialeaf infection.

a b

Fig. 13. Little leaf disease.Fig. 12. Coniella leaf infection.

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Fig. 14. Seedling diseases of eucalypts. a. Damped-off patches in seedbeds, b. webblight of E. grandis caused by R. solani and c and d. seedling wilt caused by S. rolfsii.

a b

c d

the initial symptoms are generally large-greyish-black spots, sometimes coveringthe entire leaf; abundant conidia may also be observed on the affected areas. Severeleaf infection causes leaf blight, resulting in premature defoliation, which weakenthe seedlings.2.10.7.2. EtiologyCylindrocladiella camelliae, C. clavatum, C. colhaunii, C. ilicicola,Cylindrocladium quinqueseptatum, (Venkataram and C.S.V. Ram) Boessew.2.10.7.3. Disease managementFungicidal application (Bavistin @ 0.01% a.i.) as foliar drench is found to be highlyeffective in controlling the disease. In case of severe infection, a second treatmentmay be essential after a week interval.


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2.10.8. Seedling stem infectionSeedling stem infection, often resulting in stem canker occurred in two- to three-month-old E. grandis and E. tereticornis seedlings. The disease was found moreprevalent in E. grandis nurseries raised in high ranges.2.10.8.1. SymptomsInitially the infection developed on the lower half of the stem and later it spread toupper parts as well. The affected seedlings which primarily showed typical symptomsof physiological wilting, such as flaccidity of leaves and the apical shoot, wereeventually killed. Under high humid-warm conditions abundant conidia ofCylindrocladium were observed on the infected stem. Development of epicormicroots and shoots from the callus was frequently observed during continuous rainyperiods.2.10.8.2. EtiologyCylindrocladium clavatum, C. ilicicola, C. quinquespetatum

2.10.9. Rhizoctonia collar rotThe disease occurred in seedbeds with high seedling density under high humidityand air stagnation due to crowding of seedlings. The disease was recorded in two-to three-month-old E. grandis and E. tereticornis seedlings.2.10.9.1. SymptomsThe infection appeared just near the ground level in the form of grayish water-soaked lesions on the seedling stem. This discoloration was soon followed bysplitting of the outer bark, stem girdling and callus formation. The affected seedlings,which showed typical symptoms of physiological wilting, failed to survive.2.10.9.2. EtiologyRhizoctonia solani

2.10.10. Shoot blightThis is a common disease in eucalypt nurseries raised throughout the country. Thedisease affects most of the Eucalyptus species. In Kerala, the disease was moreprevalent in high rainfall areas than in low rainfall areas. Shoot blight has beenrecorded to cause over 50 per cent of mortality of containerized seedlings. Thisdisease also affects the root trainer nurseries (Mohanan et al., 2005).2.10.10.1. SymptomsShoot blight of eucalypt seedlings was caused due to multiple infection byCylindrocladium affecting the apical buds, stem (causing stem canker) and leaves.Generally, more than one species of Cylindrocladium were associated with thedisease. Affected seedlings, which became leafless, were killed outright.2.10.10.2. EtiologyCylindrocladium clavatum, C. ilicicola, C. quinqueseptatum

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2.10.10.3. Disease managementBavistin 0.01 per cent a.i. applied as foliar and soil drench is found to be highlyeffective in controlling the shoot blight disease. In case of severe infection, a secondtreatment may be essential after a week.

2.10.11. Phaeoseptoria leaf spotThis disease was prevalent in E. grandis, E. tereticornis nurseries during the monthsof March-May. Severe infection caused defoliation of mature leaves thus affectingthe growth of seedlings.2.10.11.1. SymptomsThe infection appeared initially on the mature leaves as purple to brownish-purpleamphigenous angular spots. The leaf spots gradually progressed upwards affectingeven the youngest leaves. In dry weather, when the spots turned necrotic, minuteblack pycnidia developed embedded in the leaf tissue. These pycnidia producedabundant conidia, usually in tendrils, which appeared as brownish-black woolymasses on both the leaf surfaces.2.10.11.2. EtiologyPhaeoseptoria eucalypti (Hansf.) Walker

2.10.12. Disease management in nurseriesThe diseases in eucalypt nurseries are caused by several pathogenic fungi and it isnot possible to control them by one fungicide or specific combined application ofdifferent fungicides. Though control measures for some of the important diseasesare given at appropriate places, experience gained during the disease survey andchemical control trials indicate that the nursery disease complex affecting eucalyptseedlings can be controlled effectively by an integrated approach; i.e., propermanagement of the nursery together with some prophylactic application of fungicides.

Proper management of nursery includes adequate shade with dispersed light,medium density of seedlings and the right quantity of water per seedbed (30-40litre a time per standard bed, 12 m x 1.2 m). The frequency of watering shouldrange from two to four times a day depending on the climatic conditions andgrowth stage of seedlings. These measures, if properly followed, will preventthe appearance of diseases to considerable extent and also check thedevelopment of disease into serious epidemic proportions. Prophylacticapplication of effective fungicides at the proper time will control the developmentof these diseases effectively.2.10.12.1. Root trainer nurseries and disease managementDuring the past few years, forest nursery practices in India have undergone atremendous modifications based on various microclimatic, edaphic and biotic factors,including host, pest and pathogen association (Mohanan, 2000a, b). Consequently,


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seedling health has been given more importance which further widened the scope ofphytosanitary problems. However, introduction of root trainers in forestry sectorand thereby the technological changes in seedling production has had a majorimpact on nursery management (Mohanan, 2003). As soil less or soil-free pottingmedia are used in root trainers, common soil-borne diseases such as damping-off,seedling blight, wilt, etc. seldom occur in root trainer nurseries. Another advantageis in root trainers, the seedlings require a maximum period of 90 days growth andhence rigorous management is possible during this comparatively short period ofmaintenance than in conventional nurseries, where seedlings have to be maintainedfor two to four months. For example, eucalypt seedlings have to be maintained in theseedbeds for three to four months and, thereafter, in polythene containers for two tothree months. In root trainer nurseries, even if foliage disease occurs, the affectedseedlings can be easily removed from the blocks and replaced with other healthyseedlings, thereby avoiding the spread of disease in nursery. Since the root trainerseedlings exhibit uniform growth performance, prophylactic fungicidal treatment, ifrequired, and maintenance of seedling quality are easier than in conventional nurserysystem (Mohanan, 2003). Exploitation of the potential of clonal forestry has resultedin increased productivity of eucalypts in countries like Brazil, South Africa andCongo (Zobel, 1993). In India, clonal forestry on a large-scale was started in AndhraPradesh state by ITC Paper Boards Ltd. during 1980s. Eucalypt plus trees wereselected from the plantations and ramets were prepared on a large-scale for raisingplantations under farm forestry and regular forestry programmes (Piare Lal, 1993). InKerala state also, clonal forestry initiated recently and many disease resistant clonesof eucalypts were identified and ramets were prepared on a large-scale (Balasundaranet al., 2000). Eucalypt seedlings and clonal plants can be conveniently grown in roottrainers. The technology offers production of uniform sized, disease free and healthyplanting stock.

3. Discussion and ConclusionDuring its short rotation period of six to eight years, eucalypt suffers from a largenumber of diseases showing its vulnerability to indigenous pathogens to which ithas never been exposed to in its natural habitat. Diseases in plantations areeconomically important as they affect wood production, both qualitatively andquantitatively. While outplanting of nursery stock to the field may be expected tobe accompanied by a decline in the variety and the impact of diseases, the conversemay also occur as the age-related changes in host morphology and physiologymake it susceptible to fresh parasites. In the plantations, effect of monoculture isfound usually more pronounced in causing serious diseases of stem, especiallycanker diseases, than of foliage. The stem cankers like pink disease, Crysoporthestem canker were the most serious ones as they either killed the affected trees or

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retarded the growth considerably. Outbreak of pink disease in E. grandis is importantas this species was earlier considered to be resistant. At present, Crysoporthe stemcanker is a potentially serious disease of eucalypts in Kerala. The disease wasalready known to be of major significance in Brazil, South Africa, etc. Though themortality of eucalypts in Kerala caused by the disease is very less (ca 3%), itsoccurrence in Kerala has to be taken seriously as it may spread in epidemic proportionas in Brazil after building up of inoculum. Although, E. grandis grown in Keraladoes not appear to be as susceptible as E. saligna in Brazil.

The other significant disease, Cytospora stem canker caused byC. eucalypticola which has caused heavy mortality in South Africa and elsewhere,was recorded in Wayanad killing about 65 per cent of the coppiced shoots ofE. tereticornis. This species has not been found to cause mortality in plains, whereE. tereticornis is the major species. However, considering its potential in killingtrees outright this disease also need surveillance. Lasiodiplodia stem canker, apotentially serious disease in young plantations is mostly related to managementpractices. If cultural practices are improved, occurrence of this disease can be avoidedconsiderably. In eucalypt plantations, Cylindrocladium leaf blight caused byCylindrocladium spp. has emerged as a major problem, especially plantations situatedin high rainfall areas. The problem was more severe in plantations with tapiocaraised as intercrop. Apparently the plants do not suffer much damage from thedefoliation as they give rise to new flush after the monsoon. However, infection ofbranches and main stem, which often killed the plants up to two-year-old and coppiceshoots, was damaging (Mohanan, 1995b). Such severe infection is facilitated byprolonged high humidity due to incessant rains for two to three months. In this way,Cylindrocladium which is a minor pathogen of eucalypts in Australia poses a seriousproblem in nurseries and plantations in Kerala.

High incidence of disease was recorded in nursery due to increased proximitybetween host units and improper nursery management practices which provideconducive microclimatic conditions (Mohanan, 2000a, b). This is evident from thefact that disease incidence declines or disappears altogether after the stock istransplanted to the field. In eucalypt nurseries, Cylindrocladium spp. are the mainserious pathogens as they caused considerable mortality of seedlings. Besides,facultative parasites like R. solani and S. rolfsii have also emerged as the seriouspathogens. It becomes clear that indigenous pathogens with wide host range, whichhave adopted the introduced eucalypts in Kerala, have attained a status of seriouspathogens. Besides the susceptibility of eucalypts to these pathogens in the newenvironment, the warm-humid climatic condition of Kerala has also played animportant role in various kinds of fungi adopting eucalypts (Mohanan, 2003; 2009;Mohanan and Sharma, 2005). Biological control of Cylindrocladium diseases in forestnurseries employing antagonistic fungi like Trichoderma harzianum and T. viride


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was also attempted (Mohanan, 2007). The recent introduction of root trainertechnology in forestry sector has a major impact on seedling production system aswell as nursery disease management (Chacko et al., 2002; Mohanan, 2000a, b). Mostof the soil-borne diseases can be avoided in root trainers as soil-less or soil-freepotting media are used in root trainer cells. Foliage diseases caused by air-bornepathogens can also be managed effectively in root trainer nurseries.

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caracteristicas culturais e patogenicidade detres species de Cylindrocladiumisoladas de manchas de folha de Eucalyptus spp. Fitopatalogia Brasileira,4: 445-459.

Azevedo, N.F. dos s de.1971. Forest tree diseases. Oeiras, Laboratorio de PatologiaFlorestal Secretaria de estado da Agricultura. pp.10-33.

Baar, M.E. 1978. The Diaporthales in North America with emphasis on Gnomoniaand its segregates. Mycologia Memoir, 7: 232.

Bakshi, B.K. 1975. Forest pathology: Principles and practices in forestry. Delhi,Controller of Publications. 400p.

Bakshi, B.K.; Reddy, M.A.R.; Puri, Y.N. and Singh, Sujan. 1972. Forest disease survey.Final technical report. Dehradun, FRI. 117p.

Balasundaran, M.; Maria Florence, E.J. and Sharma, J.K. 2000. Raising planting stockof Eucalyptus clones for the Kerala Forest Department. KFRI ResearchReport No. 180. Peechi, KFRI.

Bhatia, C.L. 1984. Eucalyptus in India - Its status and research needs. IndianForester, 110(2): 91-96.

Boerboom, J.H.A. and Mass, P.W.T. 1970. Cankers of Eucalyptus grandis andE. saligna in Surinam caused by Endothia havanensis. Turrialba, 20: 94-99.

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Crous, P.W. 2002. Taxonomy and pathology of Cylindrocladium (Calonecria) andallied genera. Minnesota, APS Press.

Crous, P.W.; Wingfield, M.J.; Mohammed, C. and Yuan, Z.Q. 1998. New foliarpathogens of Eucalyptus from Australia and Indonesia. MycologicalResearch, 102(5): 527-532.

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Davison, E.M. 1982. Endothia havanensis on jarrah. Australasian Plant Pathology,11(1): 10-11.

Davison, E.M. and Tay, F.C.S. 1983. Twig, branch and upper trunk cankers ofEucalyptus marginata. Plant Disease, 67(11): 1285-1287.

Ferreira, F.A. and Alfenas, A.C. 1977. Pink disease in Eucalyptus spp. caused by Corticiumsalmonicolor Berk. and Br. in Brazil. Fitopatalogia Brasileira, 2(2): 109-115.

Ferreira, F.A.; Alfenas, A.C. and de Freita, A.L. 1978. Determinaco da Resistencia de16 procedencias de Eucalyptus ao cancro causado por Diaporthe cubensisBruner, no Vale do Rio Docc. ReVista Arvore, 2: 119-129.

Ferreira, F.A; Reis, M.S.; Alfenas, A.C. and Hodges, C.S. 1977. Avaliacada Resistenciade Eucalyptus spp. ao cancro causado por Diaporthe cubensis Bruner.Fitopatologia Brasileira, 2: 225-241.

Figueiredo, M.B. and Cruz, B.P.M. 1963 Occurrence of Cylindrocladium ilicicolaon Eucalyptus spp. in the state of Sao Paulo. Arguivos do InstitutoBiologico, 30: 29-32.

Gibson, I.A.S. 1975. Diseases of forest trees widely planted as exotics in the tropics andsouthern Hemisphere. Part 1: Important members of Myrtaceae, Leguminosae,Verbanaceae and Meliaceae. Oxford, Commonwealth Mycological Institute. 51p.

Gosh, S.K.; Mohammed Ali, M.I. and Balasundaran, M. 1985. Light and fluorescentmicroscopic studies on little leaf disease of Eucalyptus. Journal ofPhytopathology, 110(3): 207-212.

Garces, O. 1964. Las enfermedades de los arboles forestales en la America Latina ysu impacto en la produccion forestall. In: FAO/IUFRO Symposium onInternationally Dangerous Forest Disease and Insects, Oxford, 20-30 July1964. Proceedings. The author.

Gryzenhout, M.; Myburg, H.; Hodges, C.S.; Wingfield, B.D. and Wingfield, M.J.2006. Microthia, Holocryphia and Ursicollum, three new genera onEucalyptus and Coccoloba for fungi previously known as Cryphonectria.Studies in Mycology, 55(1): 35-52.

Gryzenhout, M.; Glen, H.F.; Wingfield, B.D. and Wingfield, M.J. 2005. Amphilogiagen.nov. for Cryphonectria like fungi from Elaeocarpus spp. in NewZealand and Sri Lanka. Taxon, 54(4): 1009-1021.

Gryzenhout, M.; Myburg,H.; van der Merwe, N.A.; Wingfield, B.D. and Wingfield,M.J. 2004. Chrysoporthe, a new genus to accommodate Cryphonectriacubensis. Studies in Mycology, 50: 119-124.

Gryzenhout, M.; Wingfield, B.D. and Wingfield, M.J. 2009. Taxonomy, phylogenyand ecology of bark-inhabiting and tree-pathogenic fungi in theCryphonectriaceae. St. Paul, MN, APS Press. 136p.

Hilton, R.N. 1958. The pink disease of Hevea caused by Corticium salmonicolor Ber.and Br. Journal of the Rubber Research Institute of Malayasia, 15: 275-292.


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Eucalyptus spp. no Brasil. Brasil Florestal, 5(19): 14.Kobayashi, T. 1978. Notes on the Philippine fungi parasitic to woody plants.

Transactions of the Mycological Society of Japan, 19(4): 373-381.Kobayashi, T. and Ito, K. 1956. Notes on the genus Endothia in Japan. I. Species of

Endothia collected in Japan. Bulletin of the Government Forest ExperimentStation, Meguro, 92: 87-97.

Kumar, D.; Nair, J.M.; Thankamma, L.; Deo, A.D. and Mohanan, C. 1979. Annualreport on status of diseases and their control. Kerala, EFI Unit. 128p.

Piare Lal. 1993. Economics of mass clonal multiplication of forest trees. In: RegionalSymposium on Recent Advances in Mass Clonal Multiplication of ForestTrees for Plantation Programmes, Bogor, 1-8 December 1992. Proceedingsedited by J. Davidson. Rome, FAO. pp. 327-343.

Mitchell, R.E. 1984. The relevance of non-host specific toxin in the expression ofvirulence by pathogens. Annual Review of Phytopathology, 22: 212-245.

Mohanan, C. 2000a. Introduction of rootrainer technology in forestry - Impact ofnursery disease management. In: 4th Meeting of IUFRO Working PartyS7.03.04, Finland, 25-28 July 1999. Diseases and insects in forest nurseries.Abstracts edited by A. Lilja and J. Sutherland. pp. 49-50.

Mohanan, C. 1995a. Investigations on outbreak of pink disease in HNL 1994Eucalyptus grandis plantations in Munnar, Kerala, India. ConsultancyReport No. 1. Peechi, Kerala Forest Research Institute. 19p.

Mohanan, C. 1995b. Large-scale mortality of Eucalyptus grandis in 1994 and 1995HNL plantations in grasslands at Pamba. Consultancy Report No.2. Peechi,Kerala Forest Research Institute. 14p.

Mohanan, C. 2000b. Status of forest nursery diseases in India and emerging trendsin seedling disease management. In: 4th Meeting of IUFRO Working PartyS7.03.04, Finland, 25-28 July 1999. Diseases and insects in forest nurseries.Abstracts edited by A. Lilja and J. Sutherland. pp. 31-42.

Mohanan, C. 2003. Modernization of forest tree seedling production system in Indiaand its impact on seedling health, stand establishment and productivity.In: Conference on Nursery Production and Stand Establishment of BroadLeaves to Promote Sustainable Forest Management, 7-10 May 2001.Proceedings edited by L. Ciccarese; S. Lucci and A. Mattson. Italy, APAT.pp. 89-96.

Mohanan, C. 2007. Biological control of seedling diseases in forest nurseries inKerala. Journal of Biological Control, 21(2): 189-195.

Mohanan, C. 2009. Forest health management in India: Present scenario and futurechallenges. In: Asia and the Pacific Forest Health Workshop Forest Health

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in a Changing World, Malaysia, 1-3 December 2008. Abstracts. IUFRO WorldSeries. Vol. 24. Austria, IUFRO. pp. 45-48.

Mohanan, C. and Sharma, J.K. 1982. A serious disease of Anacardium occidentaleL. caused by Cylindrocladium camelliae and its possible control. In: 5th

Symposium on Plantation Crops, Kasaragod, 15-18 December 1982.Proceedings. Kasaragod, CPCRI. pp. 527-532.

Mohanan, C. and Sharma, J.K. 1984. Calonectria theae Loos and its anamorphCylindrocladium theae (Petch) Alf. and Sob. a new record on Eucalyptusfrom India. Current Science, 53(15): 824-825.

Mohanan, C. and Sharma, J.K. 1985. Cylindrocladium causing seedling diseases ofEucalyptus in Kerala, India. Transactions of the British MycologicalSociety, 84(3): 538-539.

Mohanan, C. and Sharma, J.K. 1986. Bipolaris spicifera and Exserohilum rostratumcausing leaf spots of Eucalyptus tereticornis - New record from India.Current Science, 55(19): 990-992.

Mohanan, C. and Sharma, J.K. 1987. Phomopsis eucalypti and Bartalinia terricola,a new pathogen records on eucalypts from India. Transactions of the BritishMycological Society, 88(1): 125-126.

Mohanan, C. and Sharma, J.K. 2005. Improvement of seedling production system inthe forestry sector India and its impact on seedling health and standestablishment. In: 5th Meeting of IUFRO Working Party S7.03.04, Peechi, 6-8 May 2003. Diseases and insects in forest nurseries: Proceedings editedby A. Lilja; J.R. Sutherland; M. Poteri and C. Mohanan. Helsinki, FinnishForest Research Institute. pp. 77-82.

Mohanan, C. and Yesodharan, K. 2005. Biodiversity of plant pathogenic fungi in theKerala part of the Western Ghats. Final report of the project No. KFRI 375/01. Peechi, Kerala Forest Research Institute. 333p.

Mohanan, C.; Rajesh Kumar, K.C. and Yesodharan, K. 2010. Coniella causing foliagediseases in forest species in Kerala, India. Indian Journal of Forestry, 33(3):355-360.

Mohanan, C.; Ratheesh, N.; Laya P. Nair, Rajesh Kumar, K.C. 2005. Disease problemsin root trainer forest nurseries in Kerala State and their management. In: 5th

Meeting of IUFRO Working Party S7.03.04, Peechi, 6-8 May 2003. Diseasesand insects in forest nurseries: Proceedings edited by A. Lilja; J.R.Sutherland; M. Poteri and C. Mohanan. Helsinki, Finnish Forest ResearchInstitute. pp. 7-12.

Padaganur, G.M. and Hiremath, P.C. 1973. Phaeoseptoria eucalypti Hansf. A newrecord to India. Mysore Journal of Agricultural Sciences, 7(2): 336-338.

Reddy, S.M. 1974. Perithecial stage of Cylindrocladium ilicicolla Boed. and Reit.Current Science, 43(2): 57-58.


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Sastry, K.S.M.; Thakur, R.N.; Gupta, J.H. and Pandotra, V.R. 1971. Three virus diseasesof Eucalyptus citriodora. Indian Phytopathology, 24; 123-126.

Seth, S.K.; Bakshi, B.K.; Reddy, M.A.R. and Singh, Sujan. 1978. Pink disease ofEucalyptus in India. European Journal of Forest Pathology, 8(4): 200-216.

Sharma, J.K.; Florence, E.J.M.; Sankaran, K.V. and Mohanan, C. 1988. Differentialphytotoxic response of cutshoots of eucalypts to culture filtrates of pinkdisease fungus, Corticium salmonicolor. Forest Ecology and Management,24(2): 97-111.

Sharma, J.K.; Mohanan, C. and Maria Florence, E.J. 1985a. Occurrence ofCryphonectria canker disease of Eucalyptus in Kerala, India. Annals ofApplied Biology, 106(2): 265-276.

Sharma, J.K.; Mohanan, C. and Florence, E.J.M. 1985b. Disease survey in nurseriesand plantations of forest tree species grown in Kerala. KFRI research reportNo. 36. Peechi, KFRI. 268p.

Sharma, J.K.; Mohanan,C. and Maria Florence, E.J. 1984a. Nursery diseases ofEucalyptus in Kerala. European Journal of Forest Pathology, 14(2): 77-89.

Sharma, J.K.; Mohanan, C. and Maria Florence, E.J. 1984b. Outbreak of pink diseasecaused by Corticium salmonicolor in Eucalyptus grandis in Kerala, India.Tropical Pest Management, 30(3): 253-255.

Wilson, J. 1973. The need for a rational utilisation of the montane temperate forestsof South India. Indian Forester, 99(12): 707-716.

Zobel, B.J. 1993. Clonal forestry in eucalypts. In: Ahuja, M.R. and Libby, N.J. Eds.Clonal forestry. Vol. 2: Conservation and application. Berlin, Springer Verlag.pp. 134-144.

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1. IntroductionCylindrocladium leaf blight (CLB) caused by Cylindrocladium quinqueseptatumBoedijn and Reitsma was the first serious disease recorded in eucalypt nurseriesand plantations in South India (Sehgal et al., 1969). Subsequently, another seriousdisease namely pink disease caused by Phanerochaete salmonicolor (Berk. andBroome) Julich (= Corticium salmonicolor), came to the forefront (Seth et al.,1978). By the end of 1970s, both the diseases had spread in epiphytotic proportionsthroughout Kerala state affecting eucalypts significantly; the disease incidencewas especially high in high rainfall areas. The pink disease caused stem cankers intwo- to four-year-old eucalypt trees resulting in significant loss in yield.Cylindrocladium leaf blight (CLB) affected the seedlings in eucalypt nurseries andcoppice shoots and foliage in young plantations. When large-scale planting ofeucalypts began during the early 1960s, apparently there was not much problemposed by CLB. However, within a few years CLB became a serious problem inraising healthy nurseries, accounting for up to almost 100 per cent seedling mortalityin seedbeds and containers in high rainfall areas during the monsoon (June-September). Thus, CLB emerged as one of the most serious diseases of eucalypt inKerala and elsewhere which required immediate attention as it affected the eucalyptat all the growth stages (Mohanan, 1995). C. quinqueseptatum causing foliardiseases of Eugenia caryophyllata , Anacardium occidentale , Acaciaauriculiformis, Hevea brasiliensis and Terminalia paniculata (Sarma and Nambiar,1978; Sharma and Mohanan, 1982; Mohanan and Sharma, 1982, 1984, 1985b, 1986;Nair and Jaysree, 1986), adopted the susceptible eucalypts in Kerala and within afew years caused epiphytotic of CLB after the initial inoculum build up. This way,C. quinqueseptatum, a pathogen of minor importance in eucalypts in Australia hasbecome the major pathogen posing serious threat to eucalypt plantationprogrammes in Kerala (Mohanan and Yesodharan, 2005). Considering the magnitudeof CLB, its control is necessary to provide healthy seedlings for the afforestationprogrammes in the state. But there is a large gap in information on various aspects

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of CLB. For adopting strategies for the control of CLB in nurseries and plantations,a clear understanding of the epidemiology of the disease is a prerequisite. Exceptfor some preliminary epidemiological studies on CLB of E. microcorys, in Australiano detailed information was available on this aspect. Varied types of symptoms ofCLB observed in seedlings, saplings and mature trees of different Eucalyptusspecies in various parts of Kerala possibly indicate the association of more thanone species of Cylindrocladium. In this situation, knowledge is necessary notonly on various species of Cylindrocladium associated but also on their geographicdistribution.

The most common method of controlling fungal diseases like CLB in forestnurseries is by chemicals. There are numerous examples to show that fungal diseasescan be effectively and economically managed by fungicides. For a chemicalmanagement strategy to be successful, especially in forest nursery, where theseedlings are intensively managed, behaviour of pathogen on host – the infectionprocess, the factors responsible for infection and subsequently its spread andvariation in virulence – should be clearly understood. This helps in applying thesuitable chemicals at appropriate time to gain the maximum benefit from the treatments.To be more effective, the strategy of chemical management should form a part of thenursery management practices. In view of the fact that nursery practices, especiallythe seed rate, watering schedule, shade, etc. for raising eucalypt seedlings are foundto vary greatly and large-scale mortality of seedlings has been recorded, there wasa need to standardize the nursery practices to suit different climatic zones (high andlow rainfall regions) in Kerala.

In plantations, where CLB causes extensive defoliation and die-back of shootsduring the initial two to five years of establishment, the most appropriate diseasemanagement strategy has to be of introducing disease resistance by way of plantingeucalypt provenances/species resistant to CLB rather than chemical managementwhich will be not only impractical but also cost prohibitive. This approach requiresthe knowledge of degree of resistance available in various eucalypt provenances/species, which can be exploited against CLB through selection or breeding. For this,a large number of eucalypt provenances/species need to be screened against theexisting population of Cylindrocladium spp. which may possess genetical variabilityas being composed of even physiological races. Beside the host resistance,appropriate cultural practices to be followed during the establishment of a plantationneed to be investigated to provide significant protection against CLB. Extensivefield survey, laboratory experiments, and nursery trials were carried out to generateinformation on epidemiology and control of CLB. Only very brief data of results ofvarious experiments and field trials are provided here. The details on materials andmethods, statistical analyses of data, results, etc. of various experiments are describedby Sharma and Mohanan (1991a).

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2. SymptomsCLB is the most serious disease prevalent in eucalypt nurseries and young plantationsaffecting growth of plants. The disease caused extensive to complete prematuredefoliation accompanied by die-back of tender shoots during peak period of monsoon(July-August). Defoliated twigs generally developed new shoots within one month.The initial symptom was appearance of minute grayish-black water-soaked lesionson the leaves of any maturity. Later, these lesions coalesced to form larger necroticareas, which, on drying, turned brown giving typical blighted appearance. In highhumid areas, the initial symptoms observed on leaves of E. grandis (Fig. 1) andE. tereticornis (Fig. 2) were large grayish-black irregular spots, sometimes coveringthe entire leaf. Such severe foliage infection caused premature defoliation.

3. Cylindrocladium Species Associated with CLBA preliminary survey conducted during 1979 indicated that CLB was responsible forserious damage in eucalypt nurseries (Fig. 3) and plantations in Kerala (Sharma andMohanan, 1982). Since, Cylindrocladium was found to be associated with a varietyof diseases affecting different plant parts in eucalypt of varying maturity, occurrenceof more than one species was suspected. To ascertain this, extensive disease surveyin eucalypt nurseries (>70 nurseries), plantations of E. grandis, E. globulus,E. tereticornis (>30 plantaions) and trial plots of E. alba, E. camaldulensis,E. citriodora, E. torelliana situated in different geographical and climatic zones ofthe Kerala state was carried out during 1979-1982. A total of 10 species ofCylindrocladium, viz., 1. C. quinqueseptatum Boedijn and Reitsma, 2. Calonectriapyrochroa (Desm.) Sacc. and its anamorph Cylindrocladium ilicicola (Hawley)Boedijn and Retsma, 3. Calonectria floridana Sobers and its anamorphCylindrocladium floridanum Sobers and Seymore, 4. Calonectria induciata (Seaver)Crous and its anamorph Cylindrocladium theae (Petch) Alf. and Sobers, 5.Cylindrocladium clavatum Hodges and May, 6. Calonectria camelliaeVenkataramani and Venkata Ram and its anamorph Cylindrocladiella camelliae(Venkataram and C.S.V. Ram) Boesw., 7. C. parvum Anderson, 8. Calonectria curvata(Boed. and Reists.) L. Lombard, M.J. Wingfield and Crous and its anamorphCylindrocladium curvatum Boedijn and Reitsma, 9. Calonectria morganii Crous,Alfenas and M.J. wingfield and its anamorph Cylindrocladium scoparium Morgan,10. C. colhaunii, were found associated with various diseases of eucalypts (Sharmaand Mohanan, 1982; Mohanan and Sharma, 1984, 1985a). In a number of instances,more than one species was recorded from the same Eucalyptus species.C. quinqueseptatum was found distributed throughout the state, irrespective ofhost species of Eucalyptus or geographical location. However, other species haddiscernible spatial distribution with narrow host range. C. ilicicola and C. theaewere localized only in high ranges. The occurrence of many Cylindrocladium species,

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some localized in a particular geographical area and their causing various diseasesof eucalypt at all growth stages is suggestive of complex problems associated withcontrol measures.

For planning disease management strategy of CLB, a clear understanding of itsepidemiology is essential. Hence, detailed investigations were undertaken to studythe conidial germination (Fig. 4), severity of CLB in eucalypt plantations in relationto intercropping with taungya and rainfall, relative susceptibility of eucalyptprovenances to CLB, cultural variation of Cylindrocladium isolates, pathogenicvariation in C. quinqueseptatum, in vitro evaluation of fungicides againstCylindrocladium species, nursery trials for managing seedling diseases of eucalypts,etc. were carried out.

4. In vitro and in vivo Conidial Germination of CylindrocladiumFor obtaining optimum conidial germination, two techniques, viz., hanging drop andcavity slide were compared. Two-month-old E. grandis seedlings were used for invivo conidial germination studies (Sharma and Mohanan, 1991a, b). Seedlings wereinoculated with the conidial suspension on adaxial and abaxial surfaces till runoff.Leaves obtained from four to six hours of incubation period were processed forscanning electron microscopy by freeze drying and gold coating under vacuum.These were observed using Hitachi S-540 SEM for the formation of infection structuresand penetration.

Results of in vitro conidial germination revealed that conidia usually produce asingle germ tube from each end cell but development of germ tubes from intercalarycells was also not uncommon and up to five germ tubes were recorded from a singleconidium. However, the growth of the terminal germ tube was more rapid than thatproduced from the intercalary cells. Within 30-45 minutes of germination, a thick walledseptum was formed adjacent to conidial wall. Elongation of the germ tube was rapidafter six hours and branching occurred within an hour. Statistical analyses of data onconidial germination showed that both the techniques (GT) gave similar results.Interaction T x GT was found to be highly significant (P<0.01). Among the three conidialconcentrations tried, germination differed significantly being the highest at lowestconcentration of 1.5 x 103m l-1. Cluster analysis indicated that hanging drop methodusing the lowest conidial concentration at 25ºC gave maximum conidial germination.Conversely, in the cavity slide technique, maximum conidial germination was obtainedat 20ºC and not at 25ºC. Temperature also influenced the germination greatly as theconidia germinated only at 20º, 25º and 30ºC and was not at 10º, 15º and 35ºC.

In vivo conidial germination details were similar to that for in vitro studiesexcept that in vivo germination of conidia began after three hours of incubation andbranching of germ tubes occurred during four to five hours of incubation (Sharmaand Mohanan, 1990, 1991a). Occasionally, fusion of germ tubes was observed on

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Fig. 1. CLB affected E. grandis plantation.


Fig. 4. Conidia of Cylindrocladium.

Fig. 2. CLB in E. tereticornis.Fig. 3. Cylindrocladium seedling blight innursery.

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the leaf surface. Growth of the germ tube was faster on younger leaves than onmature. Also, the germ tube length was significantly greater on adaxial surface thanon abaxial surface of young leaves. Appressorium formation occurred after fourhours of incubation. Stomatal penetration rarely occurred. In the case of stomatalpenetration, the appressorium was formed over the stomata covering the entirestomatal opening, while for direct penetration, appressoria were formed at any placeover the epidermal cell. The efficiency of Cylindrocladium is evident from the resultswhere each conidium produced two to four germ tubes which, subsequently, branchfurther, thus, bringing about multiple infections through one conidium.

5. Severity of CLB in Relation to Cultural Practices and RainfallInitially, CLB begins to appear on leaves of lower branches near the ground andspreads upwards to higher branches. However, in seedlings and young trees theinfection may initiate at any part. Since no information was available on the influenceof climatic conditions and cultural practices followed during the stand establishmentphase such as cultivation of tapioca (Manihot utilissima) as taungya crop on theseverity of CLB, these studies were undertaken.

High CLB severity coincided with rainfall months whereas high relative humidityalone during dry period did not seem to favour infection considerably. DuringJanuary-March of 1982 though CLB severity remained very low, it showed an upwardtrend especially after showers during March-May. After heavy rainfall during June,the severity increased rapidly and it was high during July and August. Subsequently,as the rainfall declined, the CLB severity also declined gradually to low level byDecember 1982. The cultivation of tapioca as a taungya crop in the eucalypt plantationcontributed to severity of the disease. The overall high CLB severity during 1983was possibly due to the congenial conditions such as high rainfall and greenhouseconditions by tapioca which helped to build up high inoculum potential for diseasedevelopment. Positive correlation of CLB severity with the high rainfall patternappears to have some management implications. E. tereticornis, which is highlysusceptible to CLB may not be suitable for the high rainfall areas of Kerala and it isadvisable to manipulate the present cultural practices so as to minimize the diseasehazards (Sharma and Mohanan, 1992b).

6. Relative Susceptibility of Eucalypt Provenances to CLBThe long-term solution for managing CLB is possibly to raise resistantprovenances/species of Eucalyptus. To find out potential of introducing resistanceas a strategy of CLB management, artificial inoculation tests were carried out toassess the relative susceptibility of different eucalypt provenances to threepredominant species of Cylindrocladium; i.e., C. clavatum, C. ilicicola andC. quinqueseptatum.

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Seeds of 46 provenances belonging to 16 species of Eucalyptus were obtained fromthe Commonwealth Scientific and Industrial Research Organization (CSIRO),Canberra, Australia, whereas seeds of E. grandis and E. tereticornis were obtainedfrom Tamil Nadu Forest Department for raising seedlings, and nine-month-oldseedlings were used for inoculation studies.

Quantitative assessment of relative susceptibility of eucalypt provenances tothree Cylindrocladium spp., causing CLB under identical experimental conditionsrevealed a great deal of variation. Among the three Cylindrocladium species, thevariance for C. ilicicola (CI) was the least followed by that of C. quinqueseptatum(CQ) and C. clavatum (CC). This indicated a closer relationship between thesusceptibility level of the provenances to C. ilicicola than the other two species.The percentage of provenances giving resistant reaction was highest (60) to CI,lowest to CC (19.14) and intermediate to CQ (35.41). A reverse trend was observedfor the provenances giving highly susceptible (HS) and susceptible (S) reactions. Itpossibly implies that CC is the most virulent species and CI, the least.

In general, there appeared to be no correlation between level of susceptibilityand subgenus/section of the genus Eucalyptus as the response of differentprovenances varied significantly from resistant to susceptible within a subgenus/section. The relative susceptibility of different provenances of eucalypt speciesalso varied considerably to three Cylindrocladium species. This is clearly evidentfrom the responses of provenances of E. grandis and E. tereticornis. Of the eightprovenances of E. grandis, including Local TN, three gave resistant reaction (R),two susceptible (S) and three highly susceptible (HS) to CQ. Similar varyingresponses were observed for CC and CI, the respective figures for R, MS and Sreactions being 1, 3, 2 and 2, 1, 1. The susceptibility reactions of provenances ofE. tereticornis also varied greatly depending on the Cylindrocladium spp. However,there were three provenances of E. tereticornis (12944, 13277, 13319) which gaveidentical resistant reactions to three Cylindrocladium spp. Besides, E. tessellaris12967, E. cloeziana 13278, E. urophylla 12896 and E. camaldulensis 12964 alsogave identical reactions to three Cylindrocladium spp. However, there were 15provenances which gave similar (either resistant or susceptible) reactions to at leasttwo Cylindrocladium spp. (Sharma and Mohanan, 1992c). The study revealed atotal of 17 provenances with fewer restricted necrotic lesions per unit area ascompared to those with fewer but large lesions. These are E. tessellaris 12967,E. cloesiana 12945, E. deglupta 12322, E. grandis 13022, 13025, 12970, andE. camaldulensis 12181 to CI; E. citriodora 12379, E. grandis12409 and E. urophylla13357 to CC; E. propinqua 12800 to CQ; E. tereticornis 13277 and E. brassiana13412 to CQ and CI; E. tereticornis 13319 and E. brassiana 13397 to CC and CI; andE. tereticornis 12944 and E. brassiana 13415 to CQ, CC and CI. These provenancesmay prove to be superior in the field to other resistant provenances. Control of CLB


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of eucalypts in future will be based on raising provenances/species with durablefield resistance. As a first step in this direction, this study has identified provenanceswith relatively resistant reaction which might be a good indicator of field toleranceto CLB.

7. Cultural Variation in C. quinqueseptatumDuring routine isolation of C. quinqueseptatum (CQ) from diseased Eucalyptusmaterials, collected from different parts of Kerala, a great deal of cultural variationwas observed in the isolates. This together with differences recorded in leaf blightreactions on various Eucalyptus species to field isolates gave an indication to theexistence of physiological strains in CQ. Since, sources of resistance in eucalyptsto CLB are not clearly understood, for an effective and viable tree selection programmeit is essential to assess the variation in pathogenicity and virulence of the CQpopulation.

Cultural characteristics and diameter growth of 10 isolates of CQ were studiedon nine different media, viz., Czapek dox agar (CDA), glucose asparigine agar (GAA),glucose tyrosine agar (GTA), glucose yeast extract agar (GYEA), glucose limabeanagar (GLBA), malt extract agar (MEA), potato dextrose agar (PDA), vegetable agar(V8) and yeast malt agar (YMA). Five CQ isolates, viz., 897, 947, 961, 963 and 1080having very distinct cultural and morphological characters were selected and effectof 11 carbon (C ) and 13 nitrogen (N) sources on growth and MS production werecompared (Sharma and Mohanan, 1991a, 1992a).

The results revealed that cultural characters such as radial growth, colonycharacters, sporulation and microsclerotia (MS) production form an importantcriterion for ascertaining differences among CQ isolates as they differ considerablyfrom medium to medium (Sharma and Mohanan, 1992a). Though PDA and YMAwere the best media for growth, sporulation and MS production, MEA was the bestmedium as it could discern a maximum number of six isolates as distinct from theothers. This means that not all the media are equally suitable in discerning thedifferences among the isolates. This could be due to differences in nutritionalrequirements of the isolates. Growth rate (GR), which is possibly closely related tothe ability of an isolate to utilize nutrients in a particular growth medium appears tobe of limited use in discerning the isolate differences. This is due to the fact that GRof CQ isolates was statistically significant only on four media (GYEA, MEA, PDA,GLBA). However, on GLBA all the 10 isolates were separated into three distinctgroups, indicating that this medium is better for discerning isolates on the basis oftheir GR. Overall growth of five CQ isolates was found to be better on C sourcesthan N sources, but both appear to be dependable characters in differentiating theisolates into strains. Though, statistically significant differences are found in theutilization of C and N sources, the latter is better as it helped in distinguishing four

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isolates (897, 947, 961, 1080) as compared to three (947, 963 and 1080) in the former.Better growth of most of the isolates was recorded in organic N sources, especiallythe peptide and protein than inorganic sources. Monosaccharide and disaccharidesugars seem to be preferred by most of the isolates. For the production of MS,casein hydrolysate is found to be the best N source for all the isolates. The studyrevealed that eucalypt isolates of C. quinqueseptatum show remarkable differencesin their cultural characters on a given medium and in their capacity to utilize C and Nsources. This indicates that they could be different strains which may also vary invirulence (Sharma and Mohanan, 1991a, 1992a)

8. Pathogenic Variation in C. quinqueseptatumAs sources of resistance in eucalypts to CLB are not understood, for an effectiveand viable tree selection for disease resistance it is essential to assess the variationin pathogenicity of population of CQ and also to know whether different CQ isolatespossess general or specific variance. To achieve the above objectives fivemonoconidial isolates of CQ (755, 897, 947, 968, 1080) were tested on a set of 11differential provenances of Eucalyptus selected on the basis of their susceptibilityto CLB, viz., E. tessellaris 12967, E. brassiana 13412, E. tereticornis 13398,E. urophylla 12895, E. saligna 13027, E. brassiana 13415, E. grandis TN Local andE. propinqua 12800. A cluster analysis (Calinski and Corsten, 1985) was done forthe mean leaf lesions (cm-2) for various eucalypt differential provenance (P) andisolate (I) combinations to distinguish and separate resistant (R), susceptible (S)and highly susceptible reactions (HS) (Sharma and Mohanan, 1991a, b).

Eucalyptus differential provenances showed significant differences in CLBsusceptibility ranking of different provenances isolates. Susceptibility ranking ofdifferent provenances to five isolates of CQ also differed significantly indicatingdifferential interaction which is clearly evident by the two-way ANOVA (Sharma andMohanan, 1991b). The isolates and provenances differed significantly at p=0.001 invirulence and susceptibility, respectively and the interaction between them was alsosignificant at p=0.001. This showed that relative CLB susceptibility betweenprovenances depended on the CQ isolates. Similarly, the relative virulence betweenisolates depended upon the provenances. Since the mean square of isolates wasgreater than that of provenances, it possibly indicated that disease severity is mainlygoverned by the genetically different isolates and also that the provenances have acloser genetic relationship.

Cluster analysis of mean leaf lesions of 55 combinations of isolates and differentialprovenances showed three statistically significant clusters with mean lesions of7.66, 24.25 and 56.11cm-2 representing, respectively R, S and HS combinations. In Rcluster, there were as many as 37 combinations involving all 11 provenances and fiveisolates while S cluster had only 10 combinations, all excepting one provenance; i.e.,


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E. propinqua 12800 and only three isolates (755, 897, and 1080). In HS cluster, therewere only four combinations involving isolate 13412, 13397, E. grandis 13020 andE. propinqua 12800. The latter clearly indicated that isolate 947 is the most virulent offive. It is evident from the results that the dynamics of virulence in the population ofCQ is much more complex than expected. High statistically significant isolate xprovenance (I x P) interaction clearly shows the specificity in horizontal resistance(HR) in various eucalypt provenances. It could result in positive selection pressure bythe chosen provenances on the population of the CQ strains.

9. In Vitro Evaluation of Fungicides against CylindrocladiumDespite the economic importance of eucalypt seedling blight and leaf blight noproper management measures have been worked out in a systematic manner. Inlaboratory studies, Anahosur et al. (1977) found Bavistin and Thiram as highlyeffective (ED100) in inhibiting the growth of C. quinqueseptatum in poisoned-foodtechnique. Since there are more than one species of Cylindrocladium associatedwith various diseases of eucalypts, and fungicides were not evaluated using soil-fungicide technique to confirm the inhibition of microsclerotia (MS) production bythe pathogen, these observations have little importance in controllingCylindrocladium diseases in Kerala. With the objective of affording chemicalmanagement of Cylindrocladium diseases in nurseries and plantations, variousfungicides were evaluated in vitro for their efficacy against two major species; i.e.,C. quinqueseptatum and C. ilicicola. C. camelliae,C. floridanum and C. parvumwere also included in some of the screening methods to find out fungicides, if any,equally effective against all the five species of Cylindrocladium.

A total of 22 fungicides were evaluated against various Cylindrocladium spp.following conidial germination technique (CGT), poisoned-food technique (PFT)and soil fungicide screening technique (SFT). The purpose of employing threetechniques was to ascertain the efficacy of fungicides in inhibiting conidialgermination and mycelial growth and rendering microsclerotia non-viable.

9.1. Comparison of Efficacy of FungicidesIt is evident from the results that there is a differential effect of many fungicidesdepending upon the species of Cylindrocladium. Similarly, the Ed100 of fungicidealso varied depending upon the species. However, there was a few fungicideswhich were more or less equally effective against all the Cylindrocladium spp.tested using a particular screening technique. In conidial germination technique(CGT), of the 22 fungicides tested against C. quinqueseptatum (CQ), 12 showedcent per cent conidial inhibition at 0.1 per cent a.i. For C. floridanum (CF), 10 out of15 fungicides were highly effective. But for C. ilicicola (CI) which appears to bemore tolerant than other species, only 6 out of 18 fungicides were found to be

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effective. In PFT, carbendazim, benomyl, busan-30 and sodium azide were equallyeffective against all the four species of Cylindrocladium (CQ, CI, CF, CP). However,copper oxychloride, kitazin, guazatine, terrazole are highly effective against CI butnot against CQ, CF and CP. In SFT, carbendazim stood out as the only fungicideeffective against all the three species of Cylindrocladium (CQ, CF, CI); none of theothers caused even 50 per cent inhibition in growth. On comparing the effectivefungicides for various Cylindrocladium spp., it is amply clear that carbendazim isthe only fungicide consistently effective against all the five species ofCylindrocladium (Sharma and Mohanan, 1991c).

10. Nursery Trials for Controlling Seedling Diseases of EucalyptsUnder conducive microclimatic conditions, especially in high rainfall areas (>3,500mm annual rainfall), Cylindrocladium diseases in nursery may cause even 100 percent mortality of seedlings, thus posing practical problems to foresters in meetingthe requirement of stock for raising a planned area of plantations. Chemicalmanagement of seedling diseases in nursery appears to be the only solution, becauseit can be easily integrated with other nursery management practices. With this inview, the efficacy of the fungicides evaluated in the laboratory was further tested inthe nursery trials conducted during three consecutive years at Chandhanathode,Wayanad, Kerala. E. grandis and E. tereticornis seedlings were raised and a total of32 treatments consisting of 14 non-systemic fungicides, five systemic fungicides,two soil fumigants and 9 combinations of fungicide/fumigants. Solar heatingtreatments were given in the experimental nursery (Sharma and Mohanan, 1991a).

The results of first year nursery trials indicated that even five treatments ofmost of the effective fungicides could not provide a total protection againstCylindrocladium infection. Though, fungicides in various treatments reduced thedisease incidence, yet they varied greatly in their effectiveness in controlling thedisease. The ones which survived against a heavy pathogen pressure and provideda total control were systemic fungicides: carbendazim and benomyl and a non-systemic, captafol. These results are in conformity to earlier findings of Engelhard(1971) who reported the effectiveness of benomyl against Cylindrocladium rot ofAzalia cuttings caused by C. scoparium. Fumigation with chemicals has been usedcommercially for many years to control certain plant pathogens present in the upperfew centimeters of soil. However, Cylindrocladium leaf blight could not be controlledin the present trials. It means, microsclerotia of Cylindrocladium are not affected bymethyl bromide or Di-trapex. Solar heat treatment, where mulching with polythenesheet increased the soil temperature from 370 to 43.50C, resulted in reduced damping-off and seedling blight as compared to untreated control. On comparison of efficacyof different fungicidal treatments against various diseases in nursery trials conductedin three consecutive years, carbendazim stood out as the best, as it control led


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besides CLB other diseases too. Its efficacy increased when used in combinationwith other fungicides such as MEMC, mancozeb and quintozene. During the thirdyear trials when prophylactic treatments were given just after sowing of seeds, thebest treatment where no damping-off, web blight and seedling blight appeared andother diseases were subsequently controlled effectively, is a combination of MEMC,mancozeb and carbendazim in the first application followed by second and thirdapplications of carbendazim alone. By applying the fungicides initially at pre-emergence stage, the damping-off, web blight and seedling blight caused byCylindrocladium, Rhizoctonia and Pythium were controlled. Subsequently,carbendazim treatment controlled effectively all the Cylindrocladium diseases(Sharma and Mohanan, 1991a).

11. Effect of Some Nursery Practices on Incidence and Severityof Diseases and Growth of Eucalypt SeedlingsUnder the conventional method practised in Kerala, the eucalypt seedlings are raisedin seedbed nurseries during December-January, and pricked out in polythenecontainers during February/March. These container nurseries are maintained till thetime they are out planted during June after the onset of monsoon. During thisperiod, seedlings are exposed to disease hazards and any lapse in management ofnursery may accentuate the disease situation, resulting in large-scale mortality ofseedlings (Sharma et al., 1984, 1985). Some of the important nursery practices whichappear to have direct bearing on the incidence and severity of seedling diseases areshading, watering frequency and quantity of water, and seed rate. The objectives ofthis study was to investigate the effect of different types of shading over the nursery,moisture regimes and seed rates on the incidence and severity of nursery diseasesand growth of eucalypt seedlings with a view to standardize nursery practices forraising healthy and disease-free seedlings. Experimental nursery was raised atChandhanathodu, Wayanad, Kerala. For shade treatment, besides conventionalcoconut leaf thatch (CLT), coir mat (CM) of 7mm mesh was used. Two seed rates,viz., 2.6 g m-2 (SR1) and 7.0 g m-2 (SR2) equivalent of 40 g and 100 g per standardseedbed were used. Soil moisture regimes, viz., 11 l m-2 (MR1) and 14 l m-2 (MR2) perday were regulated by appropriate frequency of watering (Sharma and Mohanan,1992b).

Microclimatic conditions under two shade treatments: Microclimatic conditionsunder coir mat (CM) and coconut leaf thatch (CLT) varied significantly. Theaverage light intensity under CLT was about 15 times less as compared to CM.Average ambient and soil temperatures were higher under CM (260 and 24.30C,respectively) than under CLT. Also the soil water potential (SWP) was generallyhigher in seedbed with low moisture regime (MR1) than in high moisture regime(MR2).

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11.1. Incidence and Severity of Seedling DiseasesIncidence and severity of web blight, damping-off and seedling blight were severelyaffected by various nursery practices. Web blight appeared and persisted for a longduration under CLT than CM; in MR1-SR1 of both the shade treatments no diseasewas recorded. Average number of foci and area under disease progress curve(AUDPC) were significantly higher for CLT shading than those of CM. High moistureregime (MR2) and high seed rate (SR2) had significantly higher disease severitythan low moisture regime and low seed rate as evidenced by average number of fociand AUDPC and the disease progress rate (Sharma and Mohanan, 1992b). Incidenceof damping-off was also affected significantly by the type of shading as it appearedfirst and persisted for a long period under CLT than CM; a similar trend was alsoobserved for MR2 and SR2 treatments. However, disease severity as expressed byAUDPC and the disease progress rate did not differ in both the shade treatments.Seedling blight was recorded first under CM and a week later in CLT but it persistedfor a longer period in the latter than in former. The disease severity was significantlyhigher in MR2 of CM than of CLT. Though high disease severity was correlated wellwith high seed rate (SR2) of all the treatments of CM and CLT, significantly higherdisease severity in MR2 than in MR1 was observed only in CM (Sharma andMohanan, 1992b).

11.2. Growth of SeedlingsSince the microclimatic conditions differed considerably under CM and CLT, thegrowth of seedlings of E. grandis also showed variation under the two shadetreatments. Development of leaves was much faster under CM than under CLT. Theshoot growth was exponential in both the shade treatments. At 105-day of emergence,the length of root and shoot was significantly higher in seedlings of both the moistureregimes under CM than CLT (Sharma and Mohanan, 1991a, 1992b).

11.3. Introduction of Root Trainer in NurseriesDuring the past few years, forest nursery practices in India have undergonetremendous modifications based on various microclimatic, edaphic and biotic factors,including host, pest and pathogen association (Mohanan, 2000a). Consequently,seedling health has been given more importance which further widened the scope ofphytosanitary problems. However, introduction of root trainers in forestry sectorand thereby the technological changes in seedling production has had a majorimpact on nursery management (Mohanan, 2000b, 2003, 2007). As soilless or soil-free potting media are used in root trainers, common soil-borne diseases damping-off, seedling blight, wilt, etc. seldom occur in root trainer nurseries. Another advantageof root trainers is that the seedlings require a maximum period of 90 days growth andhence rigorous management is possible during this comparatively short period of


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maintenance than in conventional nurseries, where seedlings have to be maintainedfor two to four months. For example, eucalypt seedlings have to be maintained in theseedbeds for three to four months and thereafter in polythene containers for two tothree months. In root trainer nurseries, even if foliage disease occurs, the affectedseedlings can be easily removed from the blocks and replaced with other healthyseedlings, thereby avoiding the spread of disease in nursery. Since, the root trainerseedlings exhibit uniform growth performance, prophylactic fungicidal treatment, ifrequired, and maintenance of seedling quality are easier than in conventional nurserysystem (Mohanan, 2003; Mohanan et al., 2005).

12. Discussion and ConclusionSince the genus Cylindrocladium was originally established for a Mucedinaceaefungus, Cylindrocladium scoparium Morgan on dead pod of honey locust(Gleditschia triacanthus L.) in Indonesia, several Cylindrocladium species havefrequently been reported as pathogenic. C. quinqueseptatum Boedijn and Reitsma,isolated in Indonesia in 1941 by W.C. Sloof from clove leaves and published byReitsma and Sloof (1950) after establishing its pathogenicity, has emerged as one ofthe serious pathogens of eucalypts in Australia, Brazil, India, Indonesia, Malaysiaand Mauritius (Bakshi et al., 1972; Peerally, 1974; Sharma et al., 1985; Ferriera, 1989;Sharma and Mohanan, 1991a). At present, 52 Cylindrocladium species and 37Calonectria species were recognized based on sexual compatibility, morphologyand phylogenetic interference from specimens collected from different plant speciesincluding Eucalyptus (Crous et al., 1998; Park et al., 2000; Crous, 2002; Old et al.,2003). Association of 10 species of Cylindrocladium with eucalypts in Keralaindicates their potential threat to susceptible eucalypts in exotic environment. Amongthe 10 species, C. ilicicola, C. quinqueseptatum and C. theae are the major pathogensaffecting eucalypts at different growth stages in nurseries and plantations. In Brazil,which has the largest area under eucalypt plantations, 13 species of Cylindrocladiumhave been recorded, the prominent species being C. crotalariae, C. ilicicola,C. quinqueseptatum and C. scoparium. However, in Australia, the home of eucalypts,only C. quinqueseptatum and C. scoparium have been reported, and only the formerspecies is known to cause severe shoot blight of E. microcorys in Queensland(Pitkethley, 1976). This variation in dominant species in different geographical areaappears to be closely related to Eucalyptus species grown and climatic conditions,and to a lesser extent, the presence of hosts other than eucalypts on which differentCylindrocladium species occur. The specialized nature of Cylindrocladium speciesis clearly evident from their distribution pattern in the Kerala state and their causingdiseases of specific plant parts. There appears to be an ecological balance betweenvarious Cylindrocladium species which governs their temporal and spatialdistribution within a geographical area.

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The present study reveals that C. quinqueseptatum has specialized intophysiological strains varying greatly in virulence to adopt eucalypts. E. tereticornis,commonly called Mysore hybrid possibly has considerable genetic variability. Thisvariability in the host may have exerted the selection pressure on C. quinqueseptatumto evolve into different physiologic strains. Origin of strains is further substantiatedby the fusion of germ tubes, originating from the same conidium or different conidiaobserved on the leaf surface. Of the five strains of C. quinqueseptatum identified, four(isolate nos. 755, 897, 947 and 1080) have specific virulence or wide variability in theirreactions which possibly means that eucalypt differential provenances may have


Cylindrocladium leaf and seedling blight(CLSB) caused by Cylindrocladiumquinqueseptatum Boedjin and Reitsma isa serious disease of eucalypt nurseries andplantations in different parts of the worldincluding India (Sharma and Mohanan,1982). The disease usually attainsepidemic proportions in high rainfallareas, especially during the monsoonseason, resulting in large scale mortality ofyoung seedlings in nurseries andextensive defoliation of young trees andyoung coppice shoots in plantations. Innurseries, the initial symptoms include leafnecrosis leading to twig and stem blightand complete defoliation followed bydeath of the affected seedlings. Inplantations, leaf and twig blight leads toepicormic branching which hampers thetree growth.

This disease has been studied in detailin south Indian states. Sharma and Mohanan(1991) reported a wide range of pathogenicvariation among the five isolatesof C. quinqueseptatum which weredistinguished as different physiologic strainson 11 differential provenances. CLSB severityof a provenance is mainly governed by thegenetically different isolates. This was thefirst evidence for the existence of physiologicstrains in C. quinqueseptatum from SouthIndia. A wide range of pathogenic variationwas observed among the isolates ofC. quinqueseptatum collected from different

Molecular Studies on Eucalyptus Leaf and Seedling Blight

Amit Pandey, Partha Sarathi Mohanty, Pooja Arya and Shikha Arora

parts. Sources of resistance in eucalypts toCylindrocladium leaf blight (CLB) are notunderstood. For an effective and viableselection programme for developingeucalypts with a long lasting resistance, it isessential to assess the variation inpathogenicity of the population ofC. quinqueseptatum and determine whetherdifferent pathogenic isolates possess generalor specific virulence (Hadley et al., 1979). Toascertain phylogenetic status, comparativemorphology, pathology, characterization ofmicrosatelite loci, identification and specieswith clavate vesicles, several workers like Crouset al. (1995, 1999, 2006), Uchida and Aragaki(1997), Henricot and Culham (2002) andLouwrance et al. (2006) have used differentmolecular techniques.

Large scale mortality due to CLSB hasattained epidemic proportion in nurseries ofPunjab, Haryana, Uttarakhand and UttarPradesh. Identifying resistant germplasm is alow cost and eco-friendly solution to theproblem. There is very little knowledge aboutthe genetic diversity of C. quinqueseptatumin north Indian states. The study of variabilityin the pathogen could enable betterunderstanding of the different genotypesinvolved in the disease development. Infuture, these pathogen genotypes can becorrelated with the severity of disease theycause after artificial inoculation and analysisof disease severity and symptoms withreference to the inoculants of different


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population lines. The most virulent isolatescan be tested on different eucalyptgermplasm and the apparently resistantsources can be DNA fingerprinted and usedin breeding programmes. Variation amongC. quinqueseptatum isolates, is not known innorthern parts of India.

1. Genetic variability in North IndianIsolates of C. quinqueseptatumPandey (2010) collected 82 isolates ofC. quinqueseptatum from three north Indianstates, viz., Punjab, Haryana and Uttarakhand,and subjected them to Random amplifiedpolymorphic DNA (RAPD) analysis forquantifying polymorphism and identifyingdifferent populations. It was done with an ideato use representative isolates from eachpopulation for artificial inoculation andscreening of resistant germplasm. Apart fromdetermining taxonomic identity by microscopicexamination of different isolates, 26 isolateswere characterised using ITS regions ofribosomal DNA and nine for beta tubulin generegions. The ITS region sequences were thenused to design species specific primers andrest of the isolates were authenticated usingthese primers.

1.1. Characterization of Isolates UsingRandom Amplified Polymorphic DNAAnalysisRandom amplified polymorphic DNA (RAPD)analysis is a fast, PCR based method ofgenetic typing based on genomicpolymorphisms. RAPD is widely used bydifferent workers to assess the variability amongthe isolates within the same geographicalregion or within the same host species.Different isolates of C. quinqueseptatumcollected from Punjab, Haryana andUttarakhand were subjected to RAPD-PCR foridentifying different population lines (Fig. 1).The pathogen repository so created will behelpful in identifying durable resistance ineucalypt germplasm by artificial inoculationwith representative isolates from eachpopulation line. These resistant sources canbe propagated and utilized by the industriesand forest managers for raising disease-freenurseries and plantations.

Mohanty et al. (2012) analysed 73isolates from north India by RAPD techniqueand identified different population lines. Thefour primers used in the study producedspecific patterns that could differentiateC. quinqueseptatum isolates according totheir geographical origin (Fig. 2). For example,85 per cent isolates in OPE 2 clusteredin accordance with their geographical

location while 15 per cent isolates clusteredirrespective of their geographical location.

Later, more isolates were included inthe study and out of 40 decamer operonprimers tested initially, only three primers,viz., OPE-2, OPE-3 and OPE-5 producedconsistent and reproducible polymorphicbands with all the fungal isolates and werefinally used for molecular variability study

Fig 1. Dendrogram of 82 isolates of C. quinqueseptatum showing majorpopulation lines based on combined RAPDbinary matrix.

331Cylindrocladium disease of eucalypts

Fig 2. Random amplified polymorphic DNA (RAPD) finger prints of isolates ofC. quinquesepatatun amplified with primer OPE-2 (Mohanty et al., 2012).

of C. quinqueseptatum. The amplifiedproduct range for OPE-2, OPE-3 and OPE-5varied from 0.192-2.198 kb, 0.362-2.3 kb,0.32-2.64 kb and 0.295-2.489 kb, respectively.The RAPD profile of 82 isolates grouped in11, 9 and 10, respectively for primers OPE-2,OPE-3 and OPE-5. A combined dendrogramof 50 per cent majority rule was constructedusing the combined binary data generatedby three primers. In combined dendrogramall the 82 isolates were grouped in 12 differentclusters, one outlier and one intraclusteroutlier. The isolates representative from eachgroup may be used to screen diseaseresistance in eucalypt germplasm.

2. Amplification and Sequencing of ITSRegion of Ribosomal DNAInternal transcribed spacers (ITS-1 and ITS-2) are non-coding region of genomic DNAfound in rDNA operon of fungi. ITS-1 regionis found between 18S rDNA and 5.8S rDNAand ITS-2 between 5.8S rDNA and 28SrDNA. These regions are variable andexploited by the researchers fordiscrimination at species level in fungi andused for establishing taxonomic relationshipamong species of particular taxon. Foramplification of this region in fungi, severaluniversal primer pairs were designed,however, ITS-1 (forward primer) and ITS-4


332 C. Mohanan

(reverse primer) are frequently used byresearchers. To determine the moleculardiversity among the north Indian isolatesof C. quinqueseptatum, ITS-1 and ITS-2along with 5.8S rDNA region of 26 isolateswere amplif ied and sequenced.Sequencing was done directly from theamplified product using primer ITS-1 atgenomic laboratory of Axygen India Pvt.Ltd., New Delhi, India (Fig. 3 and 4). All thesequences were annotated using softwareORF (Open Reading Frame) finder. A maxi-mini heuristic search with all the isolatesyielded 70 most parsimonious trees with alength of 129 (Fig. 5). The consistencyindex was 0.483871, while the retentionindex and composite index were 0.602564and 0.456631, respectively. A strictconsensus tree was calculated. Thealignment of sequences generated 490characters from which 32 were parsimonyinformative (6.53%). ITS region sequencesof 26 isolates and 9 of beta tubulin genes

regions were deposited in NCBI, GenBank,USA. The evolutionary tree divided intofive different clades on the basis of variationin ITS-1 and ITS-2 region, thus, confirmingthe existence of genetically differentiatedlineages in the north Indian isolates ofC. quinqueseptatum. This knowledge mightbe expanded for studying the epidemiologyof the disease.

3. Detection of C. quinqueseptatum byspecies specific primersPandey et al. (2010) developed PCR primersto detect C. quinqueseptatum which causeheavy seedling mortality in north Indianstates. Primers based on sequence analysisof internal transcribed spacer region 1 and5.8S of rDNA produced PCR product of 245bp. The internal transcribed spacer (ITS) ofthe ribosomal DNA (rDNA) sub unit repeatwas sequenced in 26 isolates ofC. quinqueseptatum and sequences werealigned and compared with the ITS

Fig 3. Amplification of internal transcribed spacer regions of ribosomal DNA of differentisolates of C. quinqueseptatun by universal primers ITS1 and ITS4.

Fig 4. Multiple sequence alignment of internal transcribed spacer region of rDNA showingsequence dissimilarities among the isolates of C. quinqueseptatum.

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sequences of other fungi in GenBank. Noamplification resulted from PCR reactions onfungal DNA from 6 common forest fungi, 10soil contaminates and six eucalypt pathogens.For amplifications directly from infectedtissues, a nested primer PCR was done usingtwo rounds of amplification. First, the entireITS was amplified with universal fungalprimer; a second round of amplification wascarried out with species specific primer thatamplified a 245 bp PCR product. Themethod detected leaf and seedling blight inartificially and naturally infected eucalyptplants. The pathogen was also detected fromthe soil using species specific primer. Insampling studies, C. quinqueseptatum wasdetected by PCR from artificially infectedseedlings after six days of inoculation, beforeany visible symptoms were noticed. The PCRassay and direct tissue extraction methodsprovide tools which may be used to detectC. quinqueseptatum from soil, plant cuttingsand adjoining eucalypt plantations that maybe serving as recurring source of infection.Early detection may thus, limit thetransmission and spread of new aggressivestrains of C. quinqueseptatum in eucalyptgrowing regions of India.

4. Relative Virulence of C. quinqueseptatumIsolatesFor evaluating variability in the virulence,71 C. quinqueseptatum isolates collectedfrom different parts of Punjab, Haryana andUttarakhand were screened. Supernatant ofall the isolates showed varying degree ofwilting symptoms in twigs except for fiveisolates within 15 hours of incubation. After30 hours of incubation all the isolates showedwilt symptoms. Results obtained after 45hours of incubation were evaluated todifferentiate the isolates on the basis of theirrelative virulence. From this study, it wasconcluded that Punjab and Haryana hadmost virulent isolates, hence the plantingmaterial grown in these states may beavoided for raising nurseries and plantationsof eucalypts in Uttarakhand. However, moreconclusive studies are needed. Thereappears to be correlation between thevegetative growth of pathogen isolates withtheir virulence as highly virulent isolatesshowed lesser growth rates. For screeningvirulent isolates, artificial inoculation ofseedlings with different isolates in mistchamber will provide conclusive evidencewhich could be repl icated in f ieldconditions.

5. Future ProspectsFrom DNA finger printing of 82 isolates byRAPD analysis, 14 population lines ofpathogen were identified. Representativesof the each population line needs to beutilized for identifying resistant germplasm.The isolates from Uttar Pradesh are alsobeing collected and fingerprinted to identifydifferent population lines. This will furthercontribute to a more reliable screening ofresistant host germplasm. Moleculardiagnostic kit for probing C. quinqueseptatumin soil, host tissues and adjacent species willbe helpful in early detection of the disease,thus, enabling the industry managers andfarmers to take timely remedial measures.The in vitro testing of systemic and non-systemic fungicides (nine) and antagonists(12 from four different genera) against CLBShad encouraging results. The growth of 12isolates of C. quinqueseptatum on 10 growthmedia have also helped in differentiatingthe isolates. These approaches will supportin assessing the diversity of populations aswell as evolving a management strategy forthe devastating pathogen. Host specificitytesting and safety parameters need to beevaluated before the field application ofbiological control agents.



Fig 5. Maximum parsimony tree generatedthrough MEGA4 from ITS sequences ofdifferent isolates of C. quinqueseptatum.

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ReferencesCrous, P.W.; Groenewald, J.Z.; Risède, J.M.;

Simoneau, P. and Hyde, K.D. 2006.Calonectria species and theirCylindrocladium anamorphs: Specieswith clavate vesicles. Studies inMycology, 55: 213-226.Crous, P.W.; Kang, J.C.; Schoch, C.L.and Mchau, G.R.A. 1999. Phylogeneticrelationships of Cylindrocladiumpseudogracile and Cylindrocladiumrumohrae with morphologically similartaxa, based on morphology and DNAsequences of internal transcribedspacers and β-tubulin. CanadianJournal of Botany, 77: 1813-1820.

Crous, P.W.; Krof, A. and van Zyl, W.H.1995. Nuclear DNA polymorphisms ofCylindrocladium species with 1-septateconidia and clavate vesicles.Systematic and Applied Microbiology,18(2): 224-250.

Henricot, B. and Culham, A. 2002.Cylindrocladium buxicola, a newspecies affecting Buxus spp., and itsphylogenetic status. Mycologia, 94(6):980-997.

Hadley, B.A.; Beute, M.K. and Leonard, K.J.1979. Variability of Cylindrocladiumcrotalariae response to resistant hostplant selection pressure in peanut.Phytopathology, 69: 1112-1114.

Louwrance, P.W.; Wingfield, B.D.; Crous, P.W.and Wingfield, M.J. 2006. Isolation andcharacterization of microsatellite lociin Cylindrocladium pauciramosum.

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Mohanty, P.S.; Pandey, A.; Arya, P. and HarshN.S.K. 2012. Molecular variability inNorth Indian isolates of Cylindrocladiumquinquieseptatum causing Eucalyptusleaf and seedling blight. Indian Journalof Microbiology, 52(2): 131-136.

Pandey, A. 2010. Molecular variability inCylindrocladium quinqueseptatumcausing leaf and seedling blight inEucalyptus. Project completion report.Dehradun, ICFRE.

Pandey, A.; Mohanty, P.S.; Arya, P. and Harsh,N.S.K. 2010. Development of speciesspecific primer for the early detection ofCylindrocladium quinqueseptatum causingleaf and seedling blight in Eucalyptus.Agriculture and Biology Journal ofNorth America, 1(6): 1253-1259.

Sharma, J.K. and Mohanan, C. 1982.Cylindrocladium spp. associated withvarious disease of Eucalyptus inKerala. European Journal of ForestPathology, 12(3): 129-136.

Sharma, J.K. and Mohanan, C. 1991.Epidemiology and control of diseasesof Eucalyptus caused byCylindrocladium spp. in Kerala. KFRIResearch Report; 70. Peechi, KFRI.155p.

Uchida, J.Y. and Aragaki, M. 1997.Comparative morphology andpathology of Calonectria theae and C.colhounii in Hawaii. Plant Disease,81(3): 298-300.

some common genes for resistance. The fifth strain, isolate no. 968, possesses generalor uniform virulence within the sampled population as it gave identical reactions to alleucalypt genotypes. This clearly shows that the dynamics of virulence in the populationof C. quinqueseptatum is much more complex than expected. Different eucalyptprovenances show differential susceptibility to three CLB pathogens, viz., C. ilicicola(least virulent), C. clavatum (most virulent) and C. quinqueseptatum (intermediate).Most significantly, a number of provenances possess resistance to Cylindrocladiumwhich can be exploited for the management of disease in eucalypt plantations.

Highly pathogenic nature of C. quinqueseptatum is evident from infectionstudies which show production of multiple germ tubes by a conidium, and causingmultiple infections of CLB within a short duration through direct penetration. Asexpected, due to mucilage-borne conidia which are dispersed by water drops,development and spread of CLB is rain-dependent. There is a positive correlation

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of CLB severity with high rainfall. A chemical management, though justifiable innursery, is not feasible in plantations due to prohibitive operational costs. Thestudy shows that effective control of CLB and other seedling diseases in thenursery is possible through prophylactic chemical treatment and adopting standardnursery practices. The latter should be given due importance as they can influencesignificantly the availability of desired quality of plantable seedlings. Though,there were a number of effective fungicides, only carbendazim effectively controlledthe disease in nursery trials conducted at Chandhanathodu. Managing the nurserydisease employing biological tools is innovative and environment friendly.Mohanan (2007) demonstrated the efficacy of biocontrol agents like Trichodermaspp. against Cylindrocladium spp. and Rhizoctonis solani in forest nurseries. Itis essential to ensure healthy nursery stock for a large-scale plantation programmeof eucalypts. Raising healthy seedlings depends largely on the nursery culturalpractices, besides the quality of seeds. Considering the immense pressure ofCylindrocladium spp. in Kerala, growing provenances with durable field resistanceis the only viable alternative in combating CLB in nursery and plantations.

ReferencesAnahosur, K.H.; Padaganur, G.M. and Hegde, R.K. 1977. Laboratory evaluation of

fungicides against Cylindrocladium quinqueseptatum, the causal agentof seedling blight of Eucalyptus hybrid. Pesticides, 11: 44-45.

Bakshi, B.K.; Reddy, M.A.R.; Puri, Y.N. and Singh, Sujan. 1972. Forest disease survey:Final technical report. Dehradun, FRI. 117p.

Calinski, T. and Corsten, L.C.A. 1985. Clustering means in ANOVA by simultaneoustesting. Biometrics, 41(1): 39-48.

Crous, P.W. 2002. Taxonomy and pathology of Cylindrocladium (Calonecria) andallied genera. Minnesota, APS Press. 278p.

Crous, P.W.; Wingfield, M.J.; Mohammed, C. and Yuan, Z.Q. 1998. New foliarpathogens of Eucalyptus from Australia and Indonesia. MycologicalResearch, 102(5): 527-532.

Engelhard, A.W. 1971. Efficacy of benzimidazole dips, drenches and sprays for controlof Cylindrocladium on Azalia. Plant Disease Reporter, 55(8): 679-682.

Ferriera, F.A. 1989. Patologia Florestal- Principais Doencas Florestais no Brazil. 570p.Mohanan, C. 1995. Large-scale mortality of Eucalyptus grandis in 1994 and 1995 HNL

plantations in grasslands at Pamba. Consultancy Report No.1. Peechi, KFRI.14p.

Mohanan, C. 2000a. Introduction of rootrainer technology in forestry – Impact ofnursery disease management. In: 4th Meeting of IUFRO Working Party7.03.04, Finland, 25-28 July 1999. Diseases and insects in forest nurseries:Abstracts edited by A. Lilja and J. Sutherland. pp. 49-50.


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Mohanan, C. 2000b. Status of forest nursery diseases in India and emerging trendsin seedling disease management. In: 4th Meeting of IUFRO Working Party7.03.04, Finland, 25-28 July 1999. Diseases and insects in forest nurseries.Abstracts edited by A. Lilja and J. Sutherland. pp. 31-32.

Mohanan, C. 2003. Modernization of forest tree seedling production system in Indiaand its impact on seedling health, stand establishment and productivity. In:Conference on Nursery Production and Stand Establishment of Broad Leavesto Promote Sustainable Forest Management, Italy, 7-10 May 2001. Proceedingsedited by L. Ciccarese, S. Lucci and A. Mattson. Italy, APAT. pp. 89-96.

Mohanan, C. 2007. Biological control of seedling diseases in forest nurseries inKerala. Journal of Biological Control, 21(2): 189-195.

Mohanan, C. and Sharma, J.K. 1982. A serious disease of Anacardium occidentaleL. caused by Cylindrocladium camelliae and its possible control. In: 5th

Symposium on Plantation Crops, Kasaragod, 15-18 December 1982.Proceedings. Kasaragod, CPCRI. pp. 527-532.

Mohanan, C. and Sharma, J.K. 1984. Calonectria theae Loos and its anamorphCylindrocladium theae (Petch) Alf. and Sob.: A new record on Eucalyptusfrom India. Current Science, 53 (15): 824-825.

Mohanan, C. and Sharma, J.K. 1985a. Shot-hole disease of Terminalia paniculatacaused by Cylindrocladium quiqueseptatum – a new record. EuropeanJournal of Forest Pathology, 15(3): 157-159.

Mohanan, C. and Sharma, J.K. 1985b. Cylindrocladium causing seedling diseasesof Eucalyptus in Kerala, India. Transactions of the British MycologicalSociety, 84(3): 538-539.

Mohanan, C. and Sharma, J.K. 1986. Epidemiology of Cylindrocladium diseases ofeucalypts. In: National Seminar on Eucalypts in Indian Forestry: Past, Presentand Future, Peechi, 30-31 January 1984. Eucalypts in India: Past, presentand future: Proceedings edited by J.K. Sharma, T.S. Nayar, S. Kedharnathand S.S. Kondas. Peechi, KFRI. pp. 388-394.

Mohanan, C. and Yesodharan, K. 2005. Biodiversity of plant pathogenic fungi in theKerala part of the Western Ghats. Final report of the project No. 375/01.Peechi, KFRI. 333p.

Mohanan, C.; Ratheesh, N.; Nair, Laya P. and Rajesh Kumar, K.C. 2005. Diseaseproblems in root trainer forest nurseries in Kerala state and their management.In: 5th Meeting of IUFRO Working Party S7.03.04, Peechi, 6-8 May 2003.Diseases and insects in forest nurseries: Proceedings edited by A. Lilja,J.R. Sutherland, M. Poteri and C. Mohanan. Helsinki, Finnish ForestResearch Institute. pp. 7-12.

Nair, J. Madhavan and Jaysree, M.C. 1986. Occurrence of Cylindrocladium colhouniiPeerally on eucalypts in Kerala. Current Science, 55(16): 799-800.

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Old, K.M.; Wingfield, M.J. and Yan, Z.Q. 2003. A manual of diseases of eucalypts inSouth East Asia. Jakarta, Centre for International Forestry Research. 98p.

Park, R.F.; Keane, P.J.; Wingfield, M.J. and Crous, P.W. 2000. Fungal diseases ofeucalypts foliage. In: Keane, P.J.; Kile, G.A.; Podger, F.D. and Brown, N. Eds.Diseases and pathogens of eucalypts. Australia, CSIRO Publishing. pp.153-239.

Peerally, A. 1974. Calonectria quiqueseptata. CMI Descriptions of Pathogenic Fungiand Bacteria No. 423.

Pitkethley, R.N. 1976. Cylindrocladium quinqueseptatum on Myrtaceous treeseedlings. Australian Plant Pathology Society Newsletter, 5(4): 57.

Reitsma, J. and Sloof, W.C. 1950. Leaf disease of clove seedlings caused byGloeosporium piperatum and Cylindrocladium quinqueseptatum.Contribution of the General Agricultural Research Station Bogor, 109:50-59.

Sarma, Y.R. and Nambiar, K.K.N. 1978. Cylindrocladium root rot of clove. PlantDisease Reporter, 62: 562-564.

Sehgal, H.S.; Nair, J.M.; and Jagdees, S.S. 1969. Occurrence of Cylindrocladiumquinqueseptatum Boed. and Reitsma as a parasite of Eucalyptus grandisHill ex. Maiden and E. tereticornis Sm. in India. The Southern Forest RangersCollege Magazine, 1: 62-65.

Seth, S.K.; Bakshi, B.K.; Reddy, M.A.R. and Singh, Sujan. 1978. Pink disease ofEucalyptus in India. European Journal of Forest Pathology, 8(4): 200-216.

Sharma, J.K. and Mohanan, C. 1982. Cylindrocladium spp. associated with variousdiseases of Eucalyptus in Kerala, India. European Journal of ForestPathology, 12(3): 129-136.

Sharma, J.K. and Mohanan, C. 1990. Studies on conidial germination ofCylindrocladium quiqueseptatum, causing leaf blight of Eucalyptus inIndia. European Journal of Forest Pathology, 20(1): 15-23.

Sharma, J.K. and Mohanan, C. 1991a. Epidemiology and control of diseases ofEucalyptus caused by Cylindrocladium spp. in Kerala. KFRI ResearchReport 70. 155p.

Sharma, J.K. and Mohanan, C. 1991b. Pathogenic variation in Cylindrocladiumquinqueseptatum causing leaf blight of Eucalyptus. European Journal ofForest Pathology, 21(4): 210-217.

Sharma, J.K. and Mohanan, C. 1991c. In vitro evaluation of fungicides againstCylindrocladium spp. causing diseases of Eucalyptus in Kerala, India.European Journal of Forest Pathology, 21(1): 17-26.

Sharma, J.K. and Mohanan, C. 1992a. Cultural characters and growth ofCylindrocladium quiqueseptatum isolates. European Journal of ForestPathology, 22(4): 217-226.


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Sharma, J.K. and Mohanan, C. 1992b. Effect of some nursery practices on incidenceand severity of diseases and growth of Eucalyptus grandis seedlings.European Journal of Forest Pathology, 22(3): 125-135.

Sharma, J.K. and Mohanan, C. 1992c. Relative susceptibility of Eucalyptusprovenances to Cylindrocladium leaf blight. European Journal of ForestPathology, 22(5): 257-265.

Sharma, J.K. and Mohanan, C. and Maria Florence, E.J. 1984. Nursery diseases ofEucalyptus in Kerala. European Journal of Forest Pathology, 14(2): 77-89.

Sharma, J.K.; Mohanan, C. and Florence, E.J.M. 1985. Disease survey in nurseriesand plantations of forest tree species grown in Kerala. KFRI ResearchReport No. 36. Peechi, KFRI. 268p.

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1. IntroductionEucalypt, a native of Australia, is a group of fast growing tree species that hasbeen introduced in several countries. There are over 6 Mha of eucalyptsplantations established in more than 60 countries. Brazil with an area of1.052 Mha of eucalypts plantations has the largest area under eucalypts. America,Argentina, Cameroon, Chile, China, Cuba, Cypress, Ecuador, France, India, Iraq,Israel, Italy, Japan, Kenya, New Zealand, Russia, Spain and United Kingdom aresome other countries where eucalypts have been introduced.

In India, eucalypts were introduced as early as the 18th century. Initially, afew trees were planted in the Nilgiri hills of Tamil Nadu. Around 1956, a hybrideucalypt, known as ‘Mysore gum’ became more popular in Mysore. During the19th and early 20th centuries, trial plantations were raised in several localities.Eucalyptus grandis which was first introduced in Kerala for afforesting thegrasslands of high ranges has emerged as the ‘most important’ species forpulpwood plantations in Kerala. The other Eucalyptus species that are grown inIndia are E. citriodra, E. globulus, E. grandis and E. tereticornis. However, itwas only by 1960s that large-scale planting were attempted in various statessuch as Andhra Pradesh, Bihar, Haryana, Karnataka, Kerala, Madhya Pradesh,Maharashtra, Punjab, Tamil Nadu, Uttar Pradesh and West Bengal (Chaturvedi,1976; Davidson, 1998). The total area planted under Eucalyptus in India is about7-8 lakh ha.

Apart from other desirable characteristics of eucalypts such as fast growthand adaptability to a wide range of environmental conditions, one of the mainreasons for its choice as a plantation species is its comparative freedom frommajor insect pests. However, epidemics of a gall forming exotic chalcid wasp,Leptocybe invasa Fisher and La Salle (Eulophidae), popularly known as theblue gum chalcid has been recently reported from several places in India (Fig.1-2).

Current Status and FutureTrends of Research onInsect Pests of Eucalypts inIndiaGeorge Mathew

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1. Galls developed on the leaf veins 2. Galls developed on shoots

Fig. 1-2. Eucalyptus showing infestation by Leptocyba invasa.

G. Mathew

2. Pest Problems of Eucalypts in IndiaA detailed account of insects attacking eucalypts has been given by Mathur andSingh (1959), Chatterjee et al. (1967), Singh and Singh (1975), Sen-Sarma andThakur (1983), Basu Choudhuri et al. (1986), Nair et al. (1986), Rajan (1987) andTewari (1992, 1995). Information generated on insect pests of eucalypts issummarised below.

2.1. Nursery PestsThe subterranean termites which attack the roots of seedlings and saplings arethe most serious pests during the nursery stage. Termite attack is usuallyconfined to the tap root just below the soil surface causing serious damage tothe root collar leading to seedling mortality. In trials conducted in Kerala, it wasobserved that upto 80 per cent of untreated seedlings were killed by termitesduring the first year of planting, and thereafter, no serious damage was noticed.Application of 1.5 l of chlorpyriphos in 125 l of water for 2,500 seedlings per-hectare has been recommended (Nair and Varma, 1981; Varma and Nair, 1986).White-grubs, which are also root-feeding in habits, are a problem in some localitiesalthough no large-scale mortality due to this insect has been reported. Soildrenching using a soil insecticide such as Phorate 2G may be effective in managingthe white grubs.

Cut worms and leaf webbing caterpillars are often a problem in nurseries.Agrotis ipsilon and Prodenia litura of the family Noctuidae, cut off youngseedlings and the tortricids, Archips micaceanus, Strepsicrates holotephras andS. rhothia web the leaves and feed from within. A few species of Iymantrids(Lymantria ampla and Orgyia postica) and weevils (Myllocerus spp.) also oftencause minor damage to nursery seedlings.

341Current status and future trends of research on insect pests...

2.2. Pests of SaplingsDuring the sapling stage, infestation of the mirid bug Helopeltis sp. nr. antoniileading to drying up of tender terminal shoots, was recorded in young E. grandisplantations in Kerala (Nair et al., 1986) which can be controlled by the application ofchemicals such as dimethoate (Rogor) or monocrotophos (Nuvacron, Monophos)(0.01 - 0.02%) or phosphamidon (Dimecron) (0.04%) or fenitrothion (Sumithion) (0.02%)or thiamethoxam (Actra 0.25 gl-1). Recently, application of Fusarium suspensionwas also found to give good results. In fact, this insect has been reported to causedie-back to eucalypts in several countries such as Indonesia, Papua New Guineaand the Philippines (Nair, 2000). Similarly, the sapling borer, Sahyadrassusmalabaricus attacking young plants and coppice shoots of eucalypts can cause upto 20 per cent damage in young plantations. Spot application of quinalphos (0.1%)or fenvalerate (0.08%) after removing the frass covering the borer hole gave effectivecontrol (Nair, 1982).

2.3. Pests of TreesOver 40 species of leaf-feeding insects belonging to the orders Coleoptera,Lepidoptera, Orthoptera and Phasmida have been reported on grown up trees inIndia. Of these, the most damaging is the exotic, gall forming wasp, Leptocybeinvasa (Eulophidae), popularly known as the blue gum chalcid which has beenreported from several places in India. This insect, a native of Queensland, Australia,is currently spreading to almost all eucalypts growing countries in the world. Thisinsect which has a relatively narrow host range has been reported on Eucalyptussaligna, E. botryoides, E. bridgesiana, E. camaldulensis, E. cinerea, E. dunnii,E. globulus, E. grandis, E. gunii, E. maidenii, E. nicholii, E. pulverulenta, E. robusta,E. rudis, E. tereticornis, E. urophylla, E. viminalis and various clones and hybrids(Wylie and Speight, 2012).

Adult wasps of L. invasa can spread very fast by flight and wind currents.They may also be introduced into new areas through the movement of nurserystock and international air traffic. Attacks take place within 1-2 weeks of budbreak. Eggs are laid in the epidermis of the upper sides of newly developedleaves, on both sides of the midrib, in the petioles and in the parenchyma of twigs(TPCP, 2005). White minute, legless larvae develop within the host plants leadingto excessive gall formation seriously affecting the survival of the plants. Searchfor its possible biological control agents is going on in Australia and Israel andseveral natural enemies of this pest were found in Australia which include theparasitic wasps belonging to the genera Aprostocetus, Quadrastichus (Eulophidae)and Megastigmus (Torymidae).

Other pests reported in old plantations include the geometrids Ascotis selenariaand Buzura suppressaria which are considered to be occasional pests of minor

342 George Mathew

importance. Both these species are known to attack eucalypts in several Africancountries (FAO, 1979). Several species of stem borers are also recorded from olderplantations which include the cerambycids, Batocera numitor and Celosternascabrator (Lamiidae) and the moths, Endoclita undulifer (Hepialidae) and Indarbelaquadrinotata (Indarbelidae). B. numitor, which was found to attack weak and injuredtrees in Maharashtra (Sen-Sarma and Thakur, 1983), is considered to be a secondaryinvader of sick or injured trees (Browne, 1968) and may not pose much threat toeucalypts. C. scabrator, primarily known as a borer of babul (Acacia nilotica), alsoattacks young eucalypt trees but is not considered as a serious pest. Among thehepialid borers, the bark-eating caterpillar, Indarbela quadrinotata infests Eucalyptus,but the damage is seldom serious. Spot application of Quinalphos (0.1%)or Fenvalerate (0.08%) gave best results in managing this pest (Mathew and Rugmini,1998).

Incidence of certain sap-sucking insects such as Aphis gossypii (Aphididae),1cerya purchasi (Margarodidae), and three species of Trioza (Psyllidae) has alsobeen reported on eucalypts, but none of these has acquired pest status oneucalypts.

3. Possible Trends of Future Pest Outbreaks on Eucalypts in IndiaThere are two pathways in which pest problems could originate: either the indigenousinsect pests may get adapted to the exotic eucalypts and assume pest status orexotic pests from other countries may find their way into India. In this context, it maybe appropriate to make an assessment of the potential of other exotic pests inassuming pest status in Indian plantations.

Until recently, eucalypts were considered as a successful plantation speciesthat is free from any major pest incidence in India. However, with the recent emergenceof the exotic blue gum gall insect, L. invasa, this belief has changed. Eucalyptus isno longer considered as a pest-free species; rather, it is now considered as a speciesprone to further incidence of insect pests particularly of exotic origin.

When we examine the insect pests so far recorded on eucalypts, it becomesvery clear that until recently, there were very few insect pest problems ineucalypts. Among the native insect pests, only the root-feeding termites arereported to cause any economic damage. None of the leaf-feeding, sap-suckingor stem-boring insects caused much economic concern. Since termite damage isconfined to seedlings during the planting stage, control is fairly easy usinginsecticides that can be applied to soil. Nursery pests such as the cut worms andleaf webbing caterpillars could also be controlled using contact insecticides. Inthe sapling stage, incidence of the sapling borer which is of fairly low intensitycould be controlled by pruning the affected stem above the borer hole or bylocal application of a contact insecticide.


With regard to exotic pests that got introduced to India, only a few species havebeen reported on eucalypts. In the 1970’s, the cottony cushion scale, Icerya purchasi(Margarodidae), a native of Australia was reported on E. glauca (=E. globulus).Although, this insect was reported from several states such as Andhra Pradesh,Assam, Karnataka, Kerala and Tamil Nadu, it was not found to cause any damage toeucalypts (Chatterjee et al., 1976). L. invasa has posed great threat to eucalyptplantations in the country. Nair et al. (1986) made a critical evaluation of the potentialexotic insect pests of eucalypts that could assume major pest status in India. In theirassessment, they have evaluated the potential of a number of Australian eucalyptpests such as Paropsis obsolete, Ctenarytaina eucalypti, Friococcus coriaceusand Icerya purchasii, Phoracantha spp., Gonipterus scutellatus that got accidentallyintroduced in plantations raised in other countries. Of these, Gonipterus scutellatus,known as the Eucalyptus snout beetle, Ctenarytaina eucalypti, known as theEucalyptus psyllid are now widespread, occurring in many countries. Based on thedistribution pattern, damage potential and adaptability to different ecologicalconditions, these insects have great potential to assume pest status in eucalyptplantations in India in the event of accidental immigration.

4. ConclusionsAt present, the blue gum gall insect L. invasa and the subterranean termites areperhaps the major pest problems to eucalypt plantations in India. Both these insectsseriously affect the seedlings and saplings and effective control strategies are requiredfor their management. Various attempts are underway to manage the gall insectL. invasa using various bio-control agents. Even other-wise, at many places, theinfestation is coming down probably due to the development of natural mortalityfactors. A National Workshop on Eucalyptus Gall Wasp was held at the Institute ofForest Genetics and Tree Breeding, Coimbatore on 10 June, 2013 to discuss the presentstatus of the pest and to develop future strategies of managing this insect. Termiteattack is confined only to the initial one to two years of establishment of the plantationand the seedlings can be effectively protected by simple insecticidal treatment.

At this point, it is important to exercise adequate caution to prevent further entryof exotic pests in eucalypt plantations. There are chances of other exotic pests, suchas the leaf cutting weevil, Gonipterus scutellatus and the Eucalyptus psyllid,Ctenarytaina eucalypti gaining entry into the country and assuming pest status.Strict vigilance and adoption of appropriate quarantine measures are necessary toprevent any further outbreak of new exotic pests in eucalypts plantations in India.

ReferencesBasu Choudhury, J.C.; Salar Khan, A.M. and Pankajam, S. 1986. Eucalypts- their

performance and pest problems. In: National Seminar on Eucalypts in Indian

344 George Mathew

Forestry: Past, Present and Future, Peechi, 30-31 January 1984. Eucalyptsin India: Past, present and future: Proceedings edited by J.K. Sharma, C.T.S.Nair, S. Kedharnath and S. Kondas. Peechi, KFRI. pp.336-345.

Browne, F.G. 1968. Pests and diseases of forest plantation trees. Oxford, ClarendonPress. 1330p.

Chaturvedi, A.N. 1976. Eucalyptus in India. Indian Forester, 102(1): 57-63.Chatterjee. P.N.; Singh, P. and Sivaramakrishnan 1967. Control of insect pests in

Eucalyptus nurseries and young plantations. In: All India Symposium onEucalyptus, Poplars and Willows, Dehradun, FRI and C. Papers. pp. 1-14.

Davidson, J. 1998. Domestication and breeding programme for Eucalyptus in theAsia-Pacific Region. FORTIP-UNDP/FAO Project RAS/91/104. Rome, FAO.252p.

FAO (Food and Agriculture Organisation of the United Nations). 1979. Eucalypts forplanting. Forestry Series No. 11. Rome, FAO. 677p.

Mathew, G. and Rugmini, P. 1998. Control of the bark caterpillar Indarbela quadrinotatain forest plantations of Paraserianthes falcataria. Indian Journal ofEnvironment and Toxicology, 8(1): 37-40.

Mathur, R.N. and Singh, B. 1959. A list of insect pests of forest plants in India andthe adjacent countries. Part 5 - List of insect pests of plant genera ‘D’ to ‘F(Dactyloctenium to Funtumia). Indian Forest Bulletin (New Series)Entomology, 171(4): 1-165

Nair, K.S.S. 1982. Seasonal incidence, host range and control of the teak saplingborer Sahyadraaus malabaricus. KFRI Research Report No. 16. Peechi,KFRI. 36p.

Nair, K.S.S. and Varma, R.V. 1981.Termite control in eucalypt plantations. KFRIResearch Report No.6. Peechi, KFRI. 48p.

Nair, K.S.S.; Mathew, G.; Varma, R.V. and Sudheendrakumar, V.V. 1986. Insect pests ofeucalypts in India. In: National Seminar on Eucalypts in Indian Forestry:Past, Present and Future, Peechi, 30-31 January 1984. Eucalypts in India:Past, present and future: Proceedings edited by J.K. Sharma, C.T.S. Nair., S.Kedharnath and S. Kondas. Peechi, KFRI. pp. 356-363.

Nair, K.S.S. Ed. 2000. Insect pests and diseases in Indonesian forests: An assessmentof threats, research efforts and literature. Indonesia, CIFOR. 91p.

Rajan, B.K.C. 1987. Versatile Eucalyptus. Bangalore, Diana Publications. 243p.TPCP (Tree Protection Cooperative Programme). 2005. Pest alert, blue gum Chalicid.

Tree Protection News, 10:13.Sen-Sarma, P.K. and Thakur, M. L. 1983. Insect pests of Eucalyptus and their control.

Indian Forester, 109(12): 864-881.Singh, S. and Singh, P. 1975. Eucalyptus diseases and insect pests in developing

countries. In: 2nd FAO/IUFRO World Technical Consultation on Forest


Diseases and Insects, New Delhi, 7-12 April 1975. Proceedings. Rome,FAO.

Tewari, D.N. 1992. Monograph on Eucalyptus. Dehradun, Surya Publications.361p.

Tewari, D.N. 1995. Agroforestry. Dehradun, International Book Distributors.799p.

Varma, R.V. and Nair, K.S.S. 1986. Evaluation of insecticides and application methodsagainst subterranean termites in eucalypt plantations. In: National Seminaron Eucalypts in Indian Forestry: Past, Present and Future, Peechi, 30-31January 1984. Eucalypts in India: Past, Present and Future: Proceedingsedited by J.K. Sharma, C.T.S. Nair, S. Kedharnath and S. Kondas. Peechi,KFRI. pp. 346-355.

Wylie, F.R. and Speight, M.R. 2012. Insect pests in tropical forestry. 2nd ed. Wallingford,CABI.

346

1. IntroductionEucalypt species are an important source of short fibre pulp for the production ofhigh-quality paper. The trees having rapid growth rate and short rotation times, canbe grown in coppiced production and are extraordinarily well suited for large-scaleplantation in diverse parts of the world. As the area of plantation under eucalyptshas increased worldwide, so has the number of insects utilizing them as host. Manyof these insects now pose biosecurity threats to eucalypts in regions where they aregrown as exotics. Large-scale plantings of eucalypts for a variety of purposes haveoccurred throughout Asia, from India to Indonesia, Thailand, Malaysia, Philippines,Vietnam and China. Asia has had very few introductions of Australian insects, butlarge numbers of endemic insects utilize eucalypts as hosts (Sen-Sarma and Thakur,1983). This appears to be a common theme throughout Southeast Asia whereeucalypts have been grown. Invasive gall wasp, Leptocybe invasa La Salle andFisher is the only insect of Australian origin to have been introduced in to Southand Southeast Asia and to have caused significant damage with introductionsoccurring between 2002 and 2007.

First reported from Middle East during 2000, the gall wasp wreaked havoc oneucalypt plantations throughout the world (Aytar, 2003; Mutitu, 2003; Mendel et al.,2004; Nyeko, 2005; Neser et al., 2007; Costa et al., 2008; Gaskill et al., 2009; Dhahriet al., 2010; Karunaratne et al., 2010; Aquino et al., 2011). An unconfirmed news itemreported its first occurrence in India from Karnataka during 2001 (EF, 2007). However,its definitive invasion was first reported during 2004 from Tamil Nadu whichsubsequently spread to the neighboring states of Andhra Pradesh, Karnataka andKerala (Jacob et al., 2007), Maharashtra, Goa and Gujarat (Kumar et al., 2007), MadhyaPradesh (ICFRE, 2007). Since 2009, it has spread to northern India and is causingheavy loss to nursery and plantations in Punjab, Haryana, Uttarakhand and Uttar Pradesh(FRI, Dehradun). Severe incidence of the pest both in nurseries and plantations in

Invasive Gall Wasp(Leptocybe invasa)in Eucalypt and ItsManagement

A.S. Vastrad andS.H. Ramanagouda

16

347

Orissa and on new shoots of grown up plants in Jammu and Kashmir has been observedduring 2011 (Fig. 1).

The pest causes galls on midribs, petioles and stems of new shoots of eucalypt.Heavy infestation leads to deformed leaves, shoots and reduction in growth. Infestedseedlings become unfit for planting (Fig. 2). In Karnataka, the gall wasp wasreported to be on an attacking spree and damaged 2.5 M eucalypt saplings in the

Invasive gall wasp (Leptocybe invasa) in eucalypt...

Fig 1. Distribution of L. invasa in India.

348

nurseries of two major wood based industries (West Coast Paper Mills and HariharaPolyfibres) (EF, 2007). Three lakh grown up trees were severely affected by L.invasa in Punjab. Since its wide spread outbreak during 2007, work carried out atthe University of Agricultural Sciences, Dharwad on various aspects of invasivegall wasp is presented below.

2. BiologyBiology of the eucalypt gall wasp, L. invasa was studied during winter and summerof 2009-10 (Fig. 3 a to f). During summer season, the symptoms of tissue disruption(Stage I) were first evident within 10 days while it took 10-15 days during winter andoccupied 8.66 and 12.0 days during the respective season. The characteristic bumpshaped green colored, II stage galls lasted for 45.0 and 57.4 days during summer andwinter season, respectively. Stage III galls characterized by glossy pink color lastedfor 29.6 and 30.2 days during summer and winter season. While the stage IV gallscharacterized by dull pink color occupied 20.7 days during summer and 18.8 daysduring winter. Stage V galls were noticed three to six days after stage IV duringsummer and four to six days during winter season. Total life cycle of the pest occupied100-115 (mean 109 days) days during summer and 100-143 (mean 123.6 days) daysduring winter (Table 1). Adult longevity was 4.3 days without food while those fed

Fig. 2. Gall wasp damage in nursery (above) and plantation (below).

A.S. Vastrad and S.H. Ramanagouda

349

a. Oviposition on young leaf

f. Emergence hole

Fig. 3. Sequence of gall development (a-f).c. Tissue disruption

d. Gall development

e. Adult emergenceb. Oozing after oviposition


350

on 10 per cent honey solution lived for 5.7 days. These results are in agreement withMendel et al. (2004) who reported that the mean developmental time from egg toadult emergence as 132.6 days at room temperature. According to Hesami et al.(2005), the developmental period of L. invasa was 126.2 and 138.3 days underlaboratory and field conditions, respectively.

3. Seasonal IncidenceDuring survey 30 cm shoot from 10 infested eucalypt plants were collected and theobservations on different gall stage were recorded separately from top, middle andbottom portion of the sample (10 cm each) monthly. Sample was kept separately (top,middle and bottom) for pest and parasitoid emergence in a pin holed polythenebags. Adult emergence of the pest and parasitoids was recorded daily till the cessationof adult emergence. Different parasitoids emerging from these samples were identifiedby Dr. T.C. Narendran, Trust for Insect Taxonomy, University of Calicut, Kerala.Mean and standard deviation was calculated and per cent parasitization was workedout by using the following formula (Kim et al., 2008).

No. of parasitoid adults emerged Per cent parasitization = —————————————————— X 100 Total no. of adults (gall wasps + parasitoids)

3.1. Kulwalli Plantation (2008-09)Studies on seasonal incidence indicated that the pest and its parasitoids were activethroughout the year. Gall incidence (top, middle and bottom) indicated an equalnumber of galls of second, third, fourth and fifth stage (7.8, 7.2, 7.8 and 7.3,respectively) while the number of first stage galls was lowest (4.3). This isunderstandable since the total surface area available for oviposition is considerably

Source: Ramanagouda et al. (2010).

Table 1. Biology of Eucalyptus gall wasp, L. invasa on E. tereticornis


Range (d) Mean ± SD (d) Developmental stage

Winter 2009 Summer 2010 Winter 2009 Summer 2010

Stage I 10-15 8-9 13.00±1.87 8.66±0.47

Stage II 34-89 40-46 54.75±5.49 45.00±3.74

Stage III 31-40 29-32 31.00±3.80 29.66±2.05

Stage IV 18-30 19-22 19.50±4.15 20.66±1.88

Stage V 3-9 4-6 5.00±0.70 5.00±1.41

Total 100-143 100-115 123.6±15.37 109.00±6.48

351

Fig. 4. Gall incidence, adult emergence and per cent parasitization (Kulwalli, 2008-09).

less compared to those which are either unsuitable for oviposition or were occupiedby galls of later stages. Irrespective of the gall stages, total number of galls rangedfrom a lowest of 19.2 (November 2008) to highest of 44.1 (June 2009). During remainingmonths total number of galls ranged from 29.3 (January 2009) to 40.3 (December2008). Galls of all stages were recorded throughout the year (Fig. 4). However,according to Mendel et al. (2004), after over wintering as third or fourth stage fromOctober to March, though new growth appeared in February, wasps started emergingand resumed oviposition only in April.

Adult emergence was noticed throughout the year. Three peak periods of adultemergence was noticed during December 2008 (133), April 2009 (111) and June 2009(88) separated by about 120 days. Adult emergence during remaining months rangedfrom 30 (September 2008) to 95 (January 2009). Though only females emerged fromthe galls and started laying eggs indicating thelytokous reproduction, a small numberof males were regularly encountered which could be easily identified by the absenceof characteristic ovipositor and distinctly hairy antennae.

During the survey to document the seasonal incidence and natural enemies ofthe pest, several hymenopteran parasitoids emerged from the infested eucalyptssamples collected during October 2008. These include Aprostocetus gala Walkerand Aprostocetus sp. (Eulophidae), Megastigmus sp. (Torymidae) and Parallelapterasp (Mymaridae) (Vastrad et al., 2010). Among the different parasitoids, Megastigmussp. was the most dominant (90.7 %) followed by Aprostocetus sp. (6.5 %) and A.gala (2.72 %). Among several hundred parasitoids collected, one specimen eachbelonged to Telenomus sp. and Parallelaptera sp. Combined parasitization rangedfrom 49 per cent to 74 per cent on severely infested early stage galls (2nd and 3rd).However, no parasitoids emerged from the fresh galls (1st stage), low or moderately


Num

ber

352

infested coppice and nursery seedlings. Megastigmus sp. was later described asM. dharwadicus Narendran and Vastrad (Narendran et al., 2010).

3.2. Daddikamalapur Plantation (2009-10)Gall incidence indicated that the samples contained more of first stage galls (11.8)followed by third, fourth and fifth stage. Emergence of M. dharwadicus was noticedthroughout the year except November and April and accounted for a maximum of30.7 per cent and minimum of 6.5 per cent parasitization and emergence of A. galawas maximum (26) and minimum (01) and accounted for a maximum of 15.9 per centand minimum of 0.6 per cent parasitization. Adult emergence was noticed throughoutthe year and was maximum during July (348) and minimum (63) during March andincreased thereafter (Fig. 5). Only females of L. invasa were recorded during theseasonal incidence studies, however, a small number of males were also recorded(<1%) throughout the year.

Sex ratio of the parasitoids recorded during the study was ~1:2 (male: female).Parasitoids were active throughout the year except during November. Parasitizationwas more during December to March and lowest during April. M. dharwadicus wasthe dominant among the two parasitoids encountered.

L. invasa is considered to be a pest of young seedlings and coppice preferringtender leaves and shoots for oviposition. Hence the first stage galls were more on top10 cm of the sample. Since top portion consisted of only first stage galls no adultemergence was noticed. Middle portion of the sample on the other hand contains moreof third stage galls which have reached their maximum size commensurate with thematuration of the leaf and shoot. Highest adult emergence was recorded from middleportion of the sample which incidentally also recorded highest parasitization amongdifferent samples. The bottom portion of the sample containing fully expanded leaves

Fig. 5. Gall incidence, adult emergence and per cent parasitization (Daddikamalapur,2009-10).


Num

ber

M o n th

353

and matured twigs contained more of fourth and fifth stage galls while the first stagegalls were totally absent and second stage galls were occasionally encountered. Percent parasitization was more in middle portion throughout the year. Parasitization byM. dharwadicus and Aprostocetus gala was commonly noticed on middle and bottomportion consisting of II, III and IV stage galls.

Commensurating with the preference for oviposition on the tender parts of theplant, the number of early stage galls was more on the top portion of the sample thanlate gall stages. Conversely, first stage galls were least in middle portion of thesample which harbored highest number of second stage galls followed by otherstages. First stage galls were conspicuously absent on the bottom portion of thesample characterized by tissue hardening which does not support oviposition.

4. Management of Eucalyptus Gall WaspCurrently no specific management strategies against L. invasa exist. Some of theadhoc measures include, viz., periodic monitoring of infested nurseries andplantation, mechanical removal, avoiding use of susceptible clones. When pestincidence is low, selective pruning or plucking of leaves or shoots, application ofsystemic insecticide such as dimethoate or oxydemeton methyl (2 ml l-1) or imidacloprid(1 ml l-1) at fortnightly intervals and strict quarantine have been suggested by (IFGTB,EPPO). However, the use of insecticides and botanicals to manage pest has not beenvery encouraging (Javaregowda et al., 2010). Several options available to developintegrated pest management strategies are described below (Fig. 6 a to d).

4.1. Sticky TrapsPest detection with traps has been the first line of defense against exotic pests.Colored sticky traps are used in pest management for monitoring, early detectionand possibly for control by mass trapping. In all the situations the color that maximizestrap catches is most appropriate. A strongly attractive color might draw gall waspfrom greater distances than other colors.

4.1.1. Trap colourAmong the different colored sticky traps evaluated, yellow was found effective bytrapping highest number of wasps (Table 2). Held and Boyd (2008) reported that yellowtrap was most effective against Gynaikothrips uzieli Zimmermann. Among the yellowand blue sticky traps tested against the adults of Anastrepha spp. and Ceratitis capitatayellow trap was most effective (Rodrigues and Paulo, 2002). Chen et al. (2004) foundblue sticky cards to be most effective in trapping thrips and hoverfly. Protasov et al.(2007) reported that green sticky plates were effective in trapping Ophelimus muskelli(Ashmead). The efficacy of yellow sticky traps in attracting various insects both underprotected cultivation as well as open field has been reported by various authors (Durairaj


354

Figures in the parentheses are transformed values.

Table 2. Evaluation of different coloured sticky traps against Eucalyptus gall wasp

Fig. 6. Strategies to manage gall wasp (a-d).


Trap color

Yellow

Red

Blue

Green

White

Sem ±

CD@ 5%

Admin

Stamp

Admin

Stamp

355

et al., 2006; Ramegowda et al., 2007; Affandi et al., 2008). Thus, Yellow sticky traps canbe used both for monitoring of the pest in general as well as mass trapping of the waspsto reduce the infestation both in nursery and under protected cultivation.

4.1.2. Sticky materialsThe use of host odour and chemical attractants has been reported to improve theefficiency of traps. In all the treatments addition of eucalypt oil numerically enhancedthe trap catches (Table 3). Insect gum with eucalypt oil trapped maximum number ofwasps (192/trap) and was equally effective without oil (169.3/trap), while petroleumjelly with oil (122.3/trap) was the second best treatment. Automobile grease (with orwithout eucalypts oil) trapped lowest number of wasps (54.3 to 56.3). Results indicatedthe superiority of insect gum with eucalypts oil in attracting gall wasp. Insect gumwas most effective in trapping the wasps while eucalypts oil enhanced the trapcatches in petroleum jelly and grease. Influence of host odour in attractingphytophagous insects has been reviewed by Visser (1986). While, insect gum has

Number of gall wasp/trap on different days Treatment 7th 14th 21st 28th Pooled

T1 Insect gum + eucalypts oil 28.50 (5.43)

123.50 (11.16)

21.75 (4.77)

18.25 (4.39)

192.00 (13.89)

T2 Insect gum 27.25 (5.32)

77.00 (8.33)

36.75 (6.14)

28.25 (5.41)

169.25 (13.05)

T3 Petroleum jelly + eucalypts oil 8.25 (3.04)

83.00 (9.17)

16.50 (4.18)

14.50 (3.94)

122.25 (11.1)

T4 Petroleum jelly 4.25 (2.29)

58.25 (7.7)

17.25 (4.27)

6.00 (2.65)

85.75 (9.31)

T5 Grease + eucalypts oil 4.50 (2.35)

30.00 (5.57)

13.00 (3.74)

8.75 (3.12)

56.25 (7.57)

T6 Grease without oil 7.50 (2.91)

22.50 (4.85)

16.00 (4.12)

8.25 (3.04)

54.25 (7.43)

SEm ± 0.49 0.64 0.49 0.22 0.54 CD @ 5% 1.48 1.94 1.50 0.66 1.64

Table 3. Efficacy of sticky materials in trapping Eucalyptus gall wasp


been extensively used for trapping (Rodrigues and Paulo, 2002), alternatives suchas vinyl chloride (Saito et al., 1988), 5 per cent polybutane (Rushtapakornchai et al.,1989) and grease (Protosav et al., 2007) have also been successfully tried.

4.1.3. Trap shapeLiterature throws light on use of different types of sticky traps for managing differentpest species both under field and protected cultivation. Flat trap with glue on bothsides (1,260 cm2) trapped significantly higher number of wasps followed by other


356

traps, the surface areas of which ranged from 415 (cylindrical trap) to 1,073 cm2

(sphere trap) indicating direct relationship between the surface area and number oftrap catches (Table 4).

4.2. Chemical Control in NurseryDifferent methods of insecticide application, viz., seed treatment, cutting dip andfoliar spraying were evaluated.

4.2.1. Seed treatmentThe seeds (cv. Mysore gum) were soaked for 15 minutes in three dosages of thetest insecticides which were replicated thrice. Seeds soaked in water alone formedthe control. Later, the treated seeds were shade dried and sown in polythene bags.After emergence of seedlings, observations were recorded on pest infestation(oviposition damage) at weekly intervals and converted to per cent infestation.The data was suitably transformed and analyzed using two factor RandomizedBlock Design.

Neonicotinoids, viz., thiacloprid, imidacloprid and acetamiprid were equallyeffective in preventing the infestation up to 32 days, whereas azadirachtin was leasteffective (Table 5). At 39 and 46 days after emergence the infestation levels thoughincreased drastically the test chemicals were still superior over untreated control(92.79%). Higher dosage of neonicotinoids did not affect the establishment ofseedlings. Kavitha Kumari (2009) reported acetamiprid to be the best insecticidesfollowed by imidacloprid and thiamethoxam.

Number of adult wasps trapped on difference days Shape Surface area (cm2) 7th 14th 21st 28th Pooled

Rectangular cube 947.0 158.40 (12.58)

5.20 (2.49)

22.60 (4.85)

15.20 (3.97)

67.33 (827)

Sphere 1073.0 233.20 (15.58)

8.00 (3.00)

27.20 (5.30)

16.80 (4.15)

92.27 (9.66)

Cylindrical 414.9 106.80 (10.35)

1.60 (1.61)

10.20 (3.28)

15.8 (4.03)

52.93 (7.34)

Flat both sided 1260.0 454.40 (21.23)

3.80 (2.19)

8.40 (3.05)

32.4 (5.72)

176.53 (13.32)

Flat single sided 630.0 176.20 (13.29)

6.00 (2.65)

24.00 (4.98)

27.4 (5.21)

75.07 (8.72)

SEm ± - 0.78 0.19 0.21 0.40 047 CD @ 5% - 2.34 0.59 0.64 1.20 1.41

Table 4. Evaluation of different shaped yellow sticky traps in nursery



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60

0 FS

32.6

2 (3

4.49

) 25

.75

(30.

27)

16.2

1 (2

3.13

) 24

.86

(29.

29)

46

.69

(42.

98)

44.7

4 (4

1.95

) 25

.44

(29.

87)

38.9

6 (3

8.27

)

56.9

8 (4

9.11

) 54

.44

(47.

58)

31.1

1 (3

3.76

) 47

.51

(43.

48)

Thia

clop

rid

21.7

% S

L 34

.97

(36.

21)

23.1

2 (2

8.56

) 14

.48

(22.

32)

24.1

9 (2

9.03

)

51.3

4 (4

5.79

) 35

.92

(36.

76)

26.5

8 (3

0.93

) 37

.95

(37.

83)

59

.76

(50.

64)

42.4

4 (4

0.56

) 32

.83

(34.

73)

45.0

1 (4

1.98

)

Aza

dira

chtin

0.0

3% S

L 52

.31

(46.

33)

42.1

6 (4

0.46

) 32

.09

(34.

46)

42.1

9 (4

0.42

)

65.7

7 (5

4.30

) 53

.28

(46.

86)

36.1

6 (3

6.93

) 51

.74

(46.

03)

73

.42

(59.

01)

68.5

1 (5

6.05

) 61

.82

(52.

96)

67.9

2 (5

6.01

)

Cont

rol

67.4

6 (5

5.33

) 74

.34

(59.

92)

79.5

1 (6

3.20

) 73

.77

(59.

48)

83

.84

(67.

05)

86.5

9 (6

8.77

) 77

.28

(61.

56)

78.8

8 (6

5.79

)

93.5

1 (7

7.88

) 10

0 (8

9.96

) 84

.84

(68.

59)

92.7

9 (7

8.81

)

Mea

n 43

.30

(40.

97)

39.1

2 (3

8.41

) 32

.68

(33.

79)

59.1

0 (5

0.77

) 53

.07

(47.

26)

39.5

2 (3

8.67

)

69

.49

(58.

69)

62.1

7 (5

6.50

) 48

.97

(46.

19)

For c

ompa

ring

mea

ns

of

SEm

+ C

D@

5%

SEm

+ C

D@

5%

SE

m+

CD

@ 5

%

Inse

ctic

ides

(T)

2.19

6.

24

2.

11

6.03

1.

67

4.76

Dos

age

(D)

1.69

4.

83

1.

63

4.67

1.

29

3.74

Inte

ract

ion

(T X

D)

3.79

N

S

3.66

N

S 2.

89

NS

358

4.2.2. Cutting dipCuttings used for the clonal multiplication were dipped for 15 min. in three dosagesof the test insecticides with three replications. Bavistin (2g l-1) was added to all thetreatments. Bavistin (2 g l-1) alone formed the control. Treated cuttings planted inroot trainers kept in mist chamber for rooting were first transferred to net house after30 days and finally to the open nursery. Observations were recorded on establishmentof cuttings and infestation (oviposition damage) at fortnightly intervals. The datawere suitably transformed and analyzed using two factor Randomized Block Design.

The establishment of cuttings was low (~55) during the study period due to lateseason planting. Dipping the cuttings used for clonal multiplication in neonicotinoids,viz., thiamethoxam imidacloprid, acetamiprid, and thiacloprid did not affect theestablishment of cuttings (Table 6). All the insecticides were effective in reducinggall wasp infestation compared to untreated control (Table 7). Establishments ofcuttings were as good as in untreated control. Profenophos, an organophosphorouscompound even at the lowest dosage severely affected the establishment of thecuttings (< 10 % survival). Dipping the cuttings even at higher concentrations ofneonicotinoids did not show any phytotoxic symptoms. Neonicotinoids were foundto be safe for establishment of cuttings and profenophos to be highly phytotoxic.Similarly chlorpyriphos and dimethoate were also highly phytotoxic even at thelowest dosage and severely affected the establishment of cuttings (Kavitha Kumari,2009). Vastrad et al. (2011) reported that acetamiprid at 0.4 g l-1 was the best treatmentwhich provided protection up to 35 days followed by imidacloprid and thiamethoxamand did not show any phytotoxic symptoms. The increased dosage of 4 g or ml l-1

extended the protection of treated cuttings only up to 45 days.

4.2.3. SprayingSeedlings from the earlier experiment showing best results (thiacloprid, imidaclopridand acetamiprid) were used for evaluation of insecticidal sprays. The seedlings werekept below the canopy of the infested plants to ensure infestation by the gall waspsin the second greenhouse. Spraying was taken up on seedlings at weekly intervalsdepending on the number of galls recorded. Observations were recorded onoviposition damage and gall development at weekly interval. The data was suitablytransformed and the means were separated by DMRT (p=0.05). Sprays were givenonly when the number of galls/oviposition exceeded 10/seedlings. Four sprays ofthiacloprid and imidacloprid and eight sprays of other chemicals were given.

Among different insecticides tested under nursery conditions, thiacloprid wasmost effective followed by imidacloprid, acetamiprid and thiamethoxam in reducingthe oviposition damage, gall infestation and maximum per cent establishment ofcuttings (Table 8). However, spraying is not a viable option due to repeatedapplications required to reduce gall incidence. Javaregowda et al. (2010) reported


359Ta

ble

6. E

ffec

t of

inse

ctic

ide

dip

on e

stab

lishm

ent

of c

uttin

gs

DAT

– D

ays a

fter T

reat

men

t. Fi

gure

s in

the

pare

nthe

ses a

re a

rc si

ne tr

ansf

orm

ed v

alue

s.

Invasive gall wasp (Leptocybe invasa) in eucalypt...Pe

r ce

nt e

stab

lishm

ent o

f cut

tings

15 D

AT

30 D

AT

45 D

AT

Trea

tmen

t

C

1 C

2 C

3 M

ean

C1

C2

C3

Mea

n C

1 C

2 C

3 M

ean

Imid

aclo

prid

17.

8 SL

30

.83

(33.

05)

4.17

(9

.74)

5.

00

(10.

74)

13.3

3 (1

7.84

) 29

.17

(32.

67)

1.67

(7

.42)

5.

00

(12.

92)

11.9

5 (2

0.21

) 28

.33

(31.

91)

1.67

(6

.19)

4.

17

(11.

64)

11.3

9 (1

6.58

) A

ceta

mip

rid

20 S

P 23

.67

(26.

82)

9.16

(1

6.57

) 15

.00

(22.

48)

15.9

4 (2

1.96

) 23

.33

(28.

87)

9.17

(1

7.62

) 15

.00

(22.

78)

15.8

3 (2

3.44

) 28

.33

(32.

00)

10.0

0 (1

7.84

) 10

.00

(17.

84)

16.1

1 (2

3.55

) Th

iam

etho

xam

25

WG

16

.67

(23.

08)

6.67

(1

4.47

) 15

.83

(23.

04)

13.0

6 (2

0.19

) 25

.00

(29.

99)

14.1

7 (2

2.10

) 23

.33

(28.

87)

20.8

3 (2

7.15

) 25

.00

(29.

81)

14.1

7 (2

1.43

) 23

.33

(28.

77)

20.8

3 (2

6.67

) Pr

ofen

opho

s 50

EC

4.17

(9

.31)

0.

84

(3.3

0)

0.05

(0

.40)

1.

67

(4.3

4)

5.00

(1

2.92

) 0.

84

(5.2

5)

0.01

(0

.40)

1.

95

(8.0

2)

30.3

3 (6

.41)

0.

85

(3.3

0)

0.05

(0

.80)

1.

34

(3.3

7)

Thia

clop

rid 2

1.7

SL

43.3

3 (4

1.15

) 21

.67

(26.

96)

5.84

(1

3.90

) 23

.67

(27.

34)

21.6

7 (2

1.73

) 5.

17

(13.

13)

33.3

3 (3

5.25

) 20

.06

(26.

59)

15.0

0 (2

2.58

) 5.

17

(12.

85)

33.3

3 (3

5.13

) 17

.83

(23.

52)

Cont

rol

55.0

0 (4

7.86

) 58

.33

(49.

78)

45.8

3 (4

2.58

) 53

.06

(46.

74)

55.0

0 (4

7.86

) 58

.33

(49.

70)

55.0

0 (4

7.85

) 56

.11

(48.

49)

55.0

0 (4

7.86

) 58

.33

(49.

78)

45.8

3 (4

2.58

) 53

.06

(46.

74)

Mea

n 28

.94

(30.

21)

16.8

0 (2

0.13

) 14

.59

(18.

85)

26

.52

(30.

00)

14.8

9 (1

9.22

) 21

.94

(24.

68)

30

.33

(28.

43)

15.0

3 (1

8.57

) 19

.45

(22.

73)

For

com

pari

ng

mea

ns o

f SE

m±

CD

@ 5

%

SEm

± C

D@

5%

SE

m±

CD

@ 5

%

Inse

ctic

ides

(T)

1.94

5.

50

2.55

7.

33

1.76

5.

00

Dos

age

(D)

1.37

3.

89

1.81

5.

18

1.24

3.

53

Inte

ract

ion

(TX

D)

3.36

9.

53

4.43

12

.69

3.05

8.

65

360

Tabl

e 7.

Eff

ect o

f cut

ting

dip

on in

fest

atio

n by

Euc

alyp

tus

gall

was

p

DAT

- Day

s afte

r tre

atm

ent.

Figu

res i

n th

e pa

rent

hese

s are

arc

sine

tran

sfor

med

val

ues.


Per

cent

infe

stat

ion

of c

uttin

gs

30 D

AT

45

DA

T

Tre

atm

ent

C1

C2

C3

Mea

n C

1 C

2 C

3 M

ean

Imid

aclo

prid

17

.8 S

L 9.

16

(17.

58)

6.08

(1

4.22

) 0.

83

(3.3

0)

5.36

(1

1.70

) 15

.00

(22.

58)

8.58

(1

6.90

) 2.

50

(7.4

7)

8.69

(1

5.65

)

Ace

tam

iprid

20

SP

8.33

(1

3.75

) 0.

005

(0.4

0)

0.92

(3

.45)

3.

08

(5.8

6)

15.0

0 (2

1.89

) 1.

67

(4.5

7)

4.25

(1

1.79

) 6.

95

(12.

75)

Thia

met

hoxa

m

25 W

G

20.1

2 (2

6.54

) 13

.58

(17.

88)

8.33

(1

3.86

) 14

.01

(19.

43)

15.0

0 (4

4.98

) 28

.58

(32.

24)

20.8

3 (2

6.98

) 33

.13

(3

4.73

)

Thia

clop

rid

21.7

SL

10.0

0 (1

8.04

) 0.

005

(0.4

0)

0.00

5 (0

.40)

3.

33

(6.2

8)

20.8

3 (2

7.08

) 5.

83

(11.

57)

5.00

(1

2.91

) 10

.55

(17.

19)

Con

trol

20.8

3 (2

7.02

) 35

.00

(36.

11)

41.6

6 (4

0.08

) 32

.50

(34.

41)

52.7

3 (4

6.55

) 55

.00

(47.

86)

53.3

3 (4

6.90

) 53

.68

(47.

10)

Mea

n 13

.32

(20.

59)

9.67

(1

3.81

) 8.

70

(12.

22)

29

.55

(32.

62)

18.0

9 (2

2.63

) 15

.28

(21.

21)

For

com

pari

ng m

eans

of

SEm

± C

D@

5%

SE

m±

CD

@ 5

%

Inse

ctic

ides

(T)

2.32

6.

63

1.69

4.

82

Dos

age

(D)

1.93

5.

51

1.40

4.

01

Inte

ract

ion

(TX

D)

4.02

11

.48

2.93

8.

36

361Ta

ble

8. E

ffec

t of

inse

ctic

idal

spr

ay o

n ga

ll in

cide

nce

Figu

res i

n th

e pa

rent

hese

s are

tran

sfor

med

val

ues.


Admin

Stamp

362

that foliar spray of imidacloprid 17.8 SL and spot application of carbofuran 10 G atroot zone and were effective in reducing the number of fresh galls. Vastrad et al.(2011) reported that thiacloprid 21.7 SL (1 ml l-1) was most effective followed byimidacloprid 17.8 SL (0.3 ml l-1), acetamiprid 20 SP (0.2 g l-1) and thiamethoxam 25 WG(0.2 g l-1) in reducing adult emergence in nursery.

4.3. Biological Control with Native ParasitoidsClassical biological control has been a preferred approach for management of alieninsects. Though management of invasive pest can be ideally attempted throughclassical biological control, it works well if introduced during early part of invasion asit gives the best results. However, concerns have been raised about the risks ofclassical biological control (Howarth, 1991; Samways, 1997). Further, many exoticnatural enemies have been released without considering the use of native species(van Lenteren et al., 2006). In the light of increasing evidence of non-target host useand resultant threat to native biodiversity associated with it, the classical biologicalcontrol needs to be weighed carefully (Louda et al., 2003). The literature is replete withmany examples of native parasitoids exploiting the exotic hosts (Aebi et al., 2006;Cooper and Rieske, 2007). It is reported that the recently described M. dharwadicusis an efficient parasitoid of L. invasa in India (Vastrad et al., 2010). Contrary to thisview, none of the Megastigmus spp. from Brazil, Israel, Thailand and Turkey appearsto be an efficient natural enemy of Eucalyptus gall wasp (Protasov et al., 2008; Doganlaret al., 2013; Sangtongpraow et al., 2013). However, recent studies have shown thepotential utility of native parasitoids to manage the invasive Eucalyptus gall wasp ingreen houses (Kulkarni et al., 2010). Therefore, an effort was made to utilize the nativeparasitiods for the biological control of invasive Eucalyptus gall wasp.

In release and recovery studies, along with parasitoids adults of L. invasa werealso released to maintain high gall density necessary for parasitization (Fig. 7).Hence the level of parasitization recorded in both the greenhouses where the releaseand recovery studies were made was less than expected during the initial period.Megastigmus species are generally phytophagous feeding on the seeds ofGymnosperms and Angiosperms and some develop inside fig and are believed to begall formers on eucalypts. They also develop as parasites in the galls of cynipoideaand other insects (Narendran et al., 2007). An experiment was conducted to rule outthe possibility of the M. dharwadicus and A. gala as gall inducer. No gall developmentwas noticed even after two months of exposure to the parasitoids thus ruling out thepossibility of M. dharwadicus and A. gala as gall inducers.

4.3.1. Release and recovery of parasitoids in greenhouseAfter recording the emergence of parasitoids from eucalypt samples collected duringsurvey and seasonal incidence studies, they were collected with the help of aspirator


363

a. L. invasa (female, F) b. L. invasa (male, M)

c. M. dharwadicus (F) d. M. dharwadicus (M)

e. A. gala (F) f. A. gala (M)

Fig. 7. Eucalyptus gall wasp (a and b) and its parasitoids (c to f).


Admin

Stamp

Admin

Stamp

364

Table 9. Release of parasitoids in greenhouse

and released in green house at monthly interval (Table 9). Forty days after release, 10random samples were collected at monthly interval and kept for adult emergence (pestand parasitoids) and per cent parasitization was worked out as mentioned in section 2.In control, no parasitoids were released. In the first greenhouse, a total of 777 parasitoidswere released from July 2009 to March 2010, whereas in the second greenhouse, 2,220parasitoids were released from November 2009 to May 2010.

A total of 1,131 M. dharwadicus were recovered from 10 randomly collected samplesfrom both greenhouses. Highest recovery (268) of M. dharwadicus and per cent para-sitization (57.6 %) was noticed during May, 2010. During June, 2010, 314 individuals ofM. dharwadicus were recovered accounting for 36.1 per cent parasitization. Recovery ofA. gala from both the greenhouse was 343 and parasitization ranged from 5.4 (October)to 15.4 per cent (March). Though maximum parasitoids (1979 M. dharwadicus and 241A. gala) were released in the second greenhouse, no parasitoids were recovered duringApril and May 2010. This was due to the spraying experiments conducted during Marchand April 2010. Though no parasitoids were released during April 2010 in the first green-house, recovery of M. dharwadicus was maximum during May (268) and June (314)accounting for 57.6 and 36.1 per cent parasitization. In the control plot, where parasi-toids were not recorded till April, 42 individuals of M. dharwadicus were recoveredaccounting for 8.5 per cent parasitization. The migration of the released parasitoids fromthe second greenhouse where insecticide trial was conducted may have been the causefor the parasitization recorded in the control plot (Table 10).

Greenhouse I Greenhouse II Month M. dharwadicus A. gala Total M. dharwadicus A. gala Total

2009

July 24 00 24 - - - August 42 49 91 - - - September 20 20 40 - - - October 28 01 29 - - - November 91 70 161 10 19 29 December 33 26 59 38 26 64

2010

January 18 04 22 19 13 32 February 177 39 216 93 44 137 March 128 07 135 1664 92 1756 April 00 00 00 48 19 67 May 00 00 00 107 28 135 Total 561 216 777 1979 241 2220


365

Tabl

e 10

. Rec

over

y of

par

asito

ids

from

gre

enho

uses

L- L

. inv

asa;

M- M

. dha

rwad

icus

; A- A

. gal

a.

Invasive gall wasp (Leptocybe invasa) in eucalypt...M

onth

G

reen

hous

e I

G

reen

hous

e II

Con

trol

Tota

l no.

of a

dults

em

erge

d Pe

r ce

nt p

aras

itiza

tion

To

tal n

o. o

f adu

lts

emer

ged

Per

cent

par

asiti

zatio

n

Tota

l no.

of a

dult

emer

ged

Per

cent

pa

rasi

tizat

ion

L M

A

M

A To

tal

L

M

A M

A

Tota

l

L M

A

M

A To

tal

2009

Sept

embe

r 15

9 45

-

22.0

5 -

22.0

5

- -

- -

- -

11

2 00

00

0.

00

0.00

0.

00

Oct

ober

10

5 36

06

25

.53

5.40

28

.57

-

- -

- -

-

129

00

00

0.00

0.

00

0.00

Nov

embe

r 48

7 13

7 31

21

.95

5.94

25

.64

-

- -

- -

-

225

00

00

0.00

0.

00

0.00

Dec

embe

r 40

1 14

4 40

26

.42

9.07

31

.91

31

6 85

48

21

.19

13.1

8 29

.62

13

6 00

00

0.

00

0.00

0.

00

2010

Janu

ary

26

9 76

40

22

.89

12.1

4 30

.12

25

1 61

26

19

.55

9.38

25

.73

12

5 00

00

0.

00

0.00

0.

00

Febr

uary

33

2 89

53

21

.14

13.7

6 29

.95

26

0 76

37

22

.61

12.4

5 30

.29

20

8 00

00

0.

00

0.00

0.

00

Mar

ch

176

52

32

22.8

0 15

.38

32.3

0

204

62

30

23.3

0 12

.82

31.0

8

148

00

00

0.00

0.

00

0.00

Apr

il -

- -

- -

-

155

00

00

0.00

0.

00

0.00

187

00

00

0.00

0.

00

0.00

May

19

7 26

8 00

57

.63

0.00

57

.63

29

7 00

00

0.

00

0.00

0.

00

45

5 42

00

8.

45

0.00

8.

45

June

55

5 31

4 00

36

.13

0.00

36

.13

87

4 25

00

2.

27

0.00

2.

78

-

- -

- -

-

Tota

l 2,

681

1,16

1 20

2 30

.21

7.00

33

.70

2,

357

309

141

11.5

9 5.

66

16.0

3

1,72

5 42

00

2.

37

0.00

2.

37

366

Mendel et al. (2007) reported the release and recovery of Closteroceruschamaeleon in eucalypts for the management of another gall wasp, Ophelimusmaskelli where C. chamaeleon is an efficient biological control agent in loweringthe population density by parasitizing second and third instar gall wasp. A total of210 S. kryseri adults and 670 Q. mendeli adults were liberated in three sites in thecoastal plain and the first parasitoids were recovered four months after release anda total of 99 individuals of S. kryseri and 36 individuals of Q. mendeli were recoveredfrom all three sites and found that they successfully parasitized approximately 2.2and 2.5 gall units per days, respectively (Kim et al., 2008).

Male and female M. dharwadicus lived for 2.33 and three days, respectivelywithout food, whereas with food they survived for 2.7 and 3.7, respectively. Thelongevity of male and female of S. kryseri with food was 6.4+0.7 and 6.5+0.7 days,respectively. Whereas, Q. mendeli survived for 6.0+0.6 days (Kim et al., 2008).Protasov et al. (2008) reported that female of Megastigmus sp. I survived for 3 dayswithout food and with food survival ranged from 4.5 to five days where as males ofMegastigmus sp. I survival lasted for two to three days with and without food.Males and females of A. gala survived for two and three days, respectively withoutfood and with food they lived for 2.3 and 2.7 days, respectively.

To study the pattern of parasitoid emergence from different stage galls, 50 gallscollected during August, February and May were enclosed in a perforated polythenebag. Since the different gall stages could not be separated due to overlappingoccurrence of galls they were designated as II-III, III-IV and IV-V stages. The ratio ofeach gall stage was 80:20. The adult emergence was recorded daily till the cessation ofadults and parasitization was worked out. Investigations on preferred stage forparasitization indicated that the parasitoids emerged from all gall stages except I stage.Maximum numbers of parasitoids were recorded from second-third and third-fourthstage galls (Table 11).

During release and recovery studies, 1,470 and 343 individuals ofM. dharwadicus and A. gala were, respectively recovered from 10 randomly selectedsamples. Number of branches per plant and the plant height was more in thegreenhouse where parasitoids were released than control. The methodologyadopted for the release and recovery studies may also be adopted for massmultiplication of these parasitoids.

4.3.2. Large scale field release of parasitoids for the management of gallwasp4.3.2.1. Mass multiplication: Heavily galled seedlings supplied by the West CoastPaper Mills nursery were used for the mass multiplication. Parasitoids that emergedfrom eucalypts samples collected during the routine survey were released on sixmonth old galled seedlings kept in the greenhouse for mass multiplication following


367

Tabl

e 11

. Pre

fere

nce

for

diff

eren

t st

age

galls

for

par

asiti

zatio

n

L –

L. in

vasa

; M

- M. d

harw

adic

us;

A- A

. gal

a.


Gal

l sta

ge

II-I

II

III-

IV

IV-V

No.

of a

dult

emer

ged

Per c

ent

para

sitiza

tion

N

o. o

f adu

lt

emer

ged

Per c

ent

para

sitiza

tion

N

o. o

f adu

lt

emer

ged

Per c

ent

para

sitiza

tion

Peri

od

of st

udy

L M

A

M

A

To

tal

L

M

A

M

A

Tota

l

L M

A

M

A

To

tal

Aug.

20

09

49

31

16

38.7

5 24

.61

48.9

5

56

39

09

41.0

5 13

.84

46.1

5

41

16

07

28.5

7 14

.58

35.9

3

Feb.

20

10

67

46

08

40.7

0 10

.66

44.6

2

59

41

18

41.0

0 23

.37

50.0

0

40

11

04

21.5

6 9.

09

27.2

7

May

20

10

108

204

00

65.3

8 0.

00

65.3

8

112

122

00

52.1

3 0.

00

52.1

3

99

73

00

42.4

4 0.

00

42.4

4

Mea

n 74

.66

93.6

6 08

48

.27

11.7

5 52

.98

75

.66

67.3

3 09

44

.72

12.4

0 49

.42

60

33

.33

3.66

30

.85

7.89

35

.21

368

the methodology of Kulkarni et al. (2010). A total of 2,305 M. dharwadicus and 82A. gala were released in the green house between July 2010 and February 2011(Table 12). Seedlings were kept in the green house for a minimum of 45 days beforethey were distributed in the plantation. Parasitized galled seedlings and the adultparasitoids collected from the greenhouse were used for field release. Before the

field release the extent of parasitization was ascertained from 25 randomly selectedseedlings as described by Kim et al. (2008).4.3.2.2. Field release: The release site belonging to the West Coast Paper Mills,Dandeli consisted of two to six years old clones mostly derived from E. tereticornisspread over an area of 1,000 ha in Kulwalli village (located between 15o 32’ 07.57"and 15o 34’ 06.52" N, 74o 47’ 34.04" and 74o 47’ 50.51 E). A total of 14,000 parasitisedgalled seedlings were distributed at 20 randomly selected spots betweenSeptember 2010 and March 2011. In addition, 1,400 M. dharwadicus and 300A. gala collected from the greenhouse were released in the centre of the plantationduring October and November 2010 (Table 13). The impact of field release on gallincidence and per cent parasitization was recorded over a period of nine months.Galled samples were randomly collected from four locations on the day on whichfield release were made. In each location 30 centimeter apical shoots from teneucalypts plants were randomly collected. The samples were equally dividedinto top, middle and bottom portion (10 cm each). Different gall stages wererecorded on each sample as described by Mendel et al. (2004). Based on the

Month M. dharwadicus A. gala Total

2010

July 845 00 845

August 201 00 201

September 206 00 206

October 624 00 624

November 153 39 192

December 71 26 97

2011

January 07 17 24

February 198 00 198

Total 2,305 82 2,387

Table 12. Parasitoids released in the greenhouse for mass multiplication


369

Table 13. Number of parasitized galled seedling distributed and adult parasitoidsreleased at Kulwalli during 2010-11

L- L. invasa; M- M. dharwadicus; A- A. gala.

number of gall stages recorded mean gall incidence was worked out for eachspot from 30 samples. Later, the samples were kept in pin holed polythene bagsfor pest and parasitoid emergence. Adult emergence of the pest and parasitoidswas recorded daily till the cessation of adult emergence.

During the initial period though the decline in gall incidence was negligible, thepar cent parasitization increased from 42.9 to 53.1 per cent. Among the two parasitoidsreleased, M. dharwadicus was the most dominant and mainly responsible for reductionin pest incidence. True impact of parasitoid release was clearly evident three monthsafter third release indicated by substantial reduction in the number of galls (4.6 galls/30 cm shoot) coupled with significant increase in per cent parasitisation (95.0%).Faster turnover of parasitoid generation (~ 45 days) compared to the pest (~120 days)seems to have contributed to the overwhelming of the pest by the parasitoids. By theend of June 2011, no fresh oviposition damage and gall incidence was noticed resultingin spectacular control of the pest.

Though the native parasitoids were recorded as early as 2008, their impact ongall incidence was not discernible. Despite 42.9 per cent parasitization recorded inthe beginning of the study, gall incidence still remained high (16.5 galls/30 cm shoot)three months after the first release. The augmentative biological control throughrepeated field releases of parasitoids resulted in successful control of the pest(Table 14). Post release evaluation conducted during May 2012 revealed that therewas no resurgence of the pest one year after the last field release. This is a rareexample of the native parasitoids halting the ravages of an invasion resulting insubstantial financial savings on control measures that also avoided the large scalenegative environmental impact due to use of insecticides. The present study alsohighlights the importance of considering the use of native parasitoids beforeembarking on classical biological control.

Month No. of parasitized

galled seedlings

Adult emergence from 25 randomly

selected galled seedlings

Parasitization (%) recorded on galled

seedlings before distribution

No. of parasitoids released

L M A M A Total M A

September 22, 2010 500 75 108 38 48.86 17.19 66.05 - -

October 7, 2010 12,500 17 100 04 82.64 3.30 85.94 860 250

November 6, 2010 500 19 34 31 40.47 36.90 77.37 540 50

March 7, 2011 500 41 35 65 24.82 46.09 70.91 - -

Total 14,000 152 277 138 48.85 24.33 73.19 1,400 300


370Ta

ble

14. G

all i

ncid

ence

and

per

cen

t pa

rasi

tizat

ion

befo

re a

nd a

fter

rel

ease

of

para

sito

ids

at K

ulw

alli

duri

ng 2

010-

2011

* M

eans

of 3

0 sa

mpl

es fr

om to

p, m

iddl

e an

d bo

ttom

. M

-M. d

harw

adic

us; A

-A. g

ala.

On

the

day

of fi

rst r

elea

se

(Sep

tem

ber 2

010)

Se

cond

rele

ase

(Oct

ober

201

0)

Th

ird

rele

ase

(N

ovem

ber

2010

)

Four

th re

leas

e

(M

arch

201

1)

Per c

ent

para

sitiza

tion

Per c

ent

para

sitiza

tion

Per c

ent

para

sitiza

tion

Per c

ent

para

sitiza

tion

Num

ber

of

galls

/30

cm

shoo

t M

A

To

tal

Num

ber

of

galls

/30

cm

shoo

t M

A

To

tal

Num

ber

of

galls

/30

cm sh

oot

M

A

Tota

l

Num

ber

of g

alls/

30

cm sh

o ot

M

A

To

tal

Top

port

ion

of th

e sam

ple

9.80

±1.6

6 0.

00

0.00

0.

00

13.8

0±1.

32

0.00

0.

00

0.00

9.

80±1

.66

0.00

0.

00

0.00

2.

30±1

.30

0.00

0.

00

0.00

Mid

dle p

ortio

n of

the s

ampl

e

7.80

±1.4

0 47

.61

0.00

47

.61

7.80

±1.6

0 31

.81

0.00

31

.81

7.80

±1.4

0 47

.61

0.00

47

.61

3.10

±2.1

5 90

.09

4.95

95

.04

Botto

m p

ortio

n of

the s

ampl

e

4.60

±1.3

5 35

.00

0.00

35

.00

5.20

±1.1

6 58

.33

0.00

58

.33

4.60

±1.3

5 65

.00

0.00

65

.00

1.40

±1.0

1 0.

00

0.00

0.

00

Cum

ulat

ive

16.5

0±1.

66*

42.8

6 0.

00

42.8

6 15

.40±

2.85

48

.27

0.00

48

.27

16.3

0±2.

51

53.1

2 0.

00

53.1

2 4.

55±3

.35

90.0

9 4.

95

95.0

4


371

4.4. Host Plant ResistanceAn important strategy to manage pests not amenable for insecticidal control is theexploitation of host plant resistance. With more than 800 species of eucalypts(Myrtaceae) there is ample scope to exploit resistance in host plants to manage theinvasive gall wasp. A wide array of chemical substance including inorganic chemicals,primary and intermediary metabolites and secondary substance are known to impartresistance to a wide variety of insect pests. Among the secondary plant metabolites,phenolics are the source of resistance against phytophagous insects and areubiquitous in plants (Harborne, 1994; Jacob, 2009).

Total phenol, reducing sugar and protein were estimated from a total of 48eucalypt genotypes. Total phenol was inversely related to the gall incidence whileno definite relationship between the gall incidence and reducing sugar and proteincontent was evident. Among 48 eucalypt genotypes screened, 13 were classified ashighly susceptible, two were susceptible, 22 were tolerant, two were resistant andnine were immune (Table 15).

In general, E. tereticornis and E. camaldulensis were susceptible to Eucalyptusgall wasp. Wide variation in phenol content ranging from 41.7 to 131.0 mg/g among 21genotypes of E. tereticornis was noticed. Among the 21 genotypes of E. tereticornis,two were immune (C-2N and SRO-16), one was susceptible (C-4), four were highlysusceptible (K-14, C-5, KN-13 and C-9) and remaining clones were tolerant. Phenolcontent in the genotypes of E. camaldulensis ranged from 40.67 (C-411) to 141.3mg g-1 (C-526). Varied susceptibility of genotypes is attributed to highly cross pollinatednature of eucalypt plants. Therefore, in natural vegetation within the samestand some trees were severely affected while others were totally free from gall waspdamage.

E. pellita (BP-6 and P-1) and E. urophylla clones (BC-350, EU-35 and EU-3) thoughsuitable for oviposition exhibited no further gall development. Clone Mu - 8P wasimmune with highest (133.3 mg g-1) phenol content. Amongst the 10 commercialEucalyptus hybrids, one was immune, five were tolerant and four were highly susceptible.Lowest gall incidence (0.00 to 1.00) was noticed in all the eucalypt genotypes abovetwo years. Among the six species, four were immune and two were tolerant.

4.4.1. Influence of plant age on biochemical parameters of E. tereticornisEucalyptus gall wasp is a pest of young coppice and nursery seedlings and itsincidence on trees older than two years is rare. The effect of plant age onbiochemical constituents was studied. A direct relationship between plant ageand phenol content was noticed with an exception at 30 days after new growth.Total phenol content gradually increased over a period of time from 61.0 to79.0 mg g-1 (Fig. 8). Early bud sprout recorded highest (65.0 mg g-1) reducing sugarwhich declined gradually and remained more or less constant during subsequent


372


Table 15. Biochemical parameters of eucalypt genotypes

Biochemical parameter (mg g-1) Genotype/ clone

Total phenol

Total protein

Reducing sugar

No. of galls/10 cm

terminal shoot

Rating

E. tereticornis ERK-4 82.67±1.52 92.67±1.15 25.00±1.00 2.00 Tolerant C-290 92.00±1.00 53.00±1.00 73.00±1.00 1.50 Tolerant

K-16 92.67±0.57 55.00±1.00 81.33±0.57 1.20 Tolerant C-105 92.33±0.57 97.33±0.57 24.00±1.00 1.00 Tolerant K-21 94.00±1.00 101.33±1.52 62.00±1.00 1.00 Tolerant

C-2135 96.33±0.57 93.33±0.57 34.33±0.57 1.32 Tolerant C-130 99.33±0.57 95.00±1.00 24.33±0.57 1.30 Tolerant

C-288 100.67±1.15 95.00±1.00 68.33±0.57 1.40 Tolerant C-290 102.00±1.00 87.67±0.57 24.00±1.00 2.00 Tolerant C-6 103.33±0.57 85.00±1.00 31.67±0.57 1.20 Tolerant

C-2 105.67±0.57 92.33±0.57 22.33±1.52 1.00 Tolerant C-316 105.33±0.57 91.67±1.52 112.67±0.57 1.20 Tolerant C-213 108.00±1.00 94.33±0.57 94.00±1.00 1.30 Tolerant

K-11 111.33±1.52 103.33±1.52 81.00±1.00 1.40 Tolerant C-2N 117.67±0.57 85.67±0.57 23.33±0.57 0.00 Immune

SRO-16 131.00±1.00 94.33±1.52 41.67±0.57 0.00 Immune

E. camaldulensis C-2045 115.00±2.00 87.33±1.52 34.67±1.52 2.00 Tolerant C-526 141.33±1.52 93.33±1.52 48.00±1.00 0.00 Immune

E. pellita BP-6 74.33±1.15 85.33±0.57 14.00±1.00 5.00* Resistant

P-1 93.00±1.00 86.00±1.00 23.67±1.52 3.00* Resistant Mu-8P 133.33±2.08 97.67±1.15 36.00±1.00 0.00 Immune

Hybrids E. camaldulensis x E. deglupta

72.67±1.52 79.00±1.00 13.67±1.52 1.00 Tolerant

E. camaldulensis x E. pellita

98.33±0.57 77.33±1.52 24.33±0.57 1.60 Tolerant

E. tereticornis x E. urophylla

100.67±1.15 101.00±1.00 36.33±1.52 2.20 Tolerant


373

...Contd. from previous page

Immune- no oviposition; Resistant- Oviposition observed but no gall development; Tolerant- 1 to 2 galls;Susceptible- 3 to 5 galls; Highly susceptible- >5 galls (10 cm terminal shoot).

growth stages. However, total protein (65.7 mg g-1) was significantly lower duringthe bud sprout stage which gradually increased from 65.7 to 78.3 mg g-1 with theadvancing age of the plants.

4.4.2. Biochemical parameters from different leaf portions of E. tereticornisL. invasa is considered to be a stenophagous pest of young seedlings and coppicepreferring tender leaves and shoots for oviposition. As the plant growth advances

SA – 30 110±1.00 96.67±1.15 52.67±0.57 1.00 Tolerant

C – 2306 127.33±1.52 78.33±0.57 33.00±1.00 0.00 Immune E. urograndis 133.00±1.73 115.67±0.57 56.00±1.00 2.20 Tolerant

Genotypes (grown up trees >2 years) E. tereticornis 83.67±0.57 97.67±0.57 65.00±1.00 1.00 Tolerant

Corymbia torelliana

86.67±1.52 62.00±1.00 44.00±1.00 0.00 Immune

C. citriodora 92.00±1.00 85.00±1.00 26.67±0.57 0.00 Immune E. pellita 121.00±1.00 92.67±0.57 45.33±0.57 0.00 Immune

E. grandis 122.33±1.15 118.67±0.57 52.67±0.57 1.00 Tolerant E. crebra 122.67±1.52 100.33±0.57 45.67±0.57 0.00 Immune

Fig. 8. Variation in bio-chemical parameters at different growth stages of E. tereticornis.

A-Bud sprout; B-15 days after bud sprout; C-30 days after bud sprout; D-45 days after bud sprout; E- 60 days afterbud sprout; F-days after bud sprout; G-120 days after bud sprout; H-150 days after bud sprout; I-180 days after budsprout; J-210 days after bud sprout; K-240 days after bud sprout; L-270 days after bud sprout; M-300 days after budsprout; N-330 days after bud sprout


Stage

mg/

g

374

the phenolic content also increased. Change in the morphology of the plant alsoimparts resistance against gall wasp. Phenol content within the same plant variedfrom one branch to another and the same plant suffered differential damage by thepest (Fig. 9). Tender main stem and leaf petiole recorded lowest phenol whereas, thetip and the bottom portion the highest phenol content followed by middle portion ofthe leaf (Fig. 10). Hence, gall wasp preferred to oviposit on these parts of the plantswhere the phenolic content was low, this explains the preponderance of galls onpetiole and tender shoot.

5. Future OutlookBiosecurity has emerged as one of the most important issues facing the internationalcommunity. Traditionally it has been associated with risks from infectious diseases,

Fig. 9. Different portions of the leaf used for quantification of biochemical parameters.

Fig. 10. Biochemical parameters at different portions of eucalypt leaf.

A – Tip of the leaves; B – Middle portion of the leaves; C – Bottom portion of the leaves;D – Petioles; E – Main stem


Total pheno lR educing sugarTotal p ro tein

Sam ple

mg/

g

375

living modified organisms and biological weapons, but in the very broadest senseit encompasses minimizing risk through ‘biological harm’ (Meyerson et al., 2002).Not least is the economic risk from invasive alien species (IAS) that threatenecosystem stability, producer livelihoods and consumer confidence (Cock et al.,2003). That risk is facilitated by the movement of exotic species around the worldthrough increasing international tourism and trade, and is influenced by changesin climate and land use. Several national conferences and meetings held in therecent past have recommended to enhance national capacity to monitor, warn,educate and build infrastructure and trained manpower for containment of anyeventual invasions.

Since 1990 several species of gall making wasps have established themselves oneucalypts outside Australia: Quadrastichodella nova Girault, Epichrysocharisburwelli Schauff, Ophelimus eucalypti (Gahan), O. maskelli (Ashmead), Aprostocetussp., Nambouria xanthops Berry and Withers, L. invasa Fisher and La Salle, Moonaspermophaga Kim and La Salle, Leprosa milga Kim and La Salle. Recently, a new gallwasp species described as Selitrichodes globulus La Salle and Gates joined a growinglist of invasive species which have potential to damage eucalypts around the world.With potentially hundreds of species of eulophid gall inducers on eucalypts, onecould expect more of these species to become invasive in future. India, with 80 Mha ofeucalypts plantations is a potential destination for range expansion for some of theseinvaders (Ramanagouda et al., 2010).

Biological control is the only feasible way to manage an alien pest over largeareas. In Australia, the parasitoids play a significant role in regulating the populationsof L. invasa (Kim et al., 2008). Efforts made to import these parasitoids for classicalbiological control in India have been met with partial success. The risks of releasingexotic biological control agents include possible global or local extinction of a nativespecies, large reductions in distribution and abundance of native organisms,interference in the efficacy of native enemies through intraguild interactions orcompetitive displacement and loss of biodiversity. In the light of increasing evidenceof non-target host use and resultant threat to native biodiversity associated with it,the classical biological control needs to be weighed carefully (Louda et al., 2003)since many exotic species have been released without considering the use of nativespecies (van Lenteren et al., 2006).

Native Megastigmus species are known to parasitize L. invasa in Brazil, Italy,Israel, Thailand and Turkey. It is reported that Megastigmus species was notoriginally associated with eucalypts, being a local species it has adapted to developon L. invasa. However, the question of local hosts of these Megastigmus species isstill open and needs to be ascertained.

Two species of Tetrastichinae (Hymenoptera: Eulophidae) from Australia aredescribed as parasitoids of L. invasa: Q. mendeli and Selitrichodes kryceri Kim and


376

La Salle sp. nov. These parasitoids were successfully used in Israel as part of a biologicalcontrol program to counter the severe levels of damage caused by L. invasa to eucalyptplantations (Kim et al., 2008). Recent studies have shown the potential utility of nativeparasitoids to manage the invasive Eucalyptus gall wasp (Kulkarni et al., 2010).

Another important strategy to manage pests not amenable for insecticidal controlis the exploitation of host plant resistance. With more than 800 species of eucalypts(Myrtaceae) there is ample scope to exploit resistance in host plants to manage theinvasive gall wasp. Thus, host plant resistance combined with native parasitoidsholds great potential in overcoming the menace of the pest without polluting theenvironment. Estimation of biochemical parameters may pave the way for rapidscreening technique to select eucalypt genotypes resistant to gall wasp, instead ofgoing for large scale testing under field conditions.

Very low genetic diversity among L. invasa population from different locations resultingin a single cluster indicated the possibility of a single introduction which subsequentlyspread to the other areas. Free exchange of infested planting material between variouspaper industries might be the cause for the observed phenomenon. The rapid spread of thepest within short period invariably points towards wide spread human assisted transportof infested planting material across India. Occasional appearance of the pest in nurseryfollowing recent arrival of seedlings also points towards this phenomenon. Eucalyptusgall wasp spread to North India from the South where its incidence declined after 2011, it isto be expected that the pest may reinvade South India via the same route.

Lack of diversity among the A. gala populations indicated that no other speciesof A. gala was utilizing L. invasa as a host. Similar was the case with M. dharwadicus.However, variations in the Megastigmus populations from Odisha indicate theexistence of a suit of Megastigmus species utilizing Leptocybe as a host whichneeds to be explored further. These findings also highlight the development of newcommunities around invading species.

AcknowledgementAuthors are grateful to Indian Paper Manufactures Association (IPMA), New Delhifor extending the financial assistance, and the West Coast Paper Mills Limited(WCPM), Dandeli and J.K. Paper Mills Limited, Odisha for their help in conductingthe studies.

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1. IntroductionThe pace of industrial development and requirement of enhanced agriculturalproduction has created tremendous impact on the availability of timber for variousapplications. Gap between demand and supply has resulted in large scale plantationof various species to meet the requirement of fuel wood, agricultural implements andindustrial products, including pulp and paper. Continuous increase in demand andsupply gap necessitated plantations of fast grown short rotation species, includingexotics. As a result fast growing species, including Eucalyptus, became the part ofman-made forests. India stands second only to Brazil among the countries whichhave raised large extent of eucalypt plantations.

The detailed account of the introduction of eucalypts in India has been givenby Rajan (1987) in his book ‘Versatile Eucalyptus’. Regular trials on eucalyptswere started in 1843 when Captain Cotton of the Madras Engineers successfullyintroduced E. globulus at Wellington in the Nilgiri Hills. Nanjundappa in 1957reported that during 1954-1955 herbarium specimens of some of the old trees ofeucalypts growing in Nandi Hills were sent to Australia through Forest ResearchInstitute, Dehradun for getting them identified. They were mainly E. camaldulensis,E. citriodora, E. crebra, E. decepta, E. intermedia, E. major, E. polyanthemos,E. robusta, E. tereticornis, E. tesselaris and probably hybrids betweenE. transverse and red gum, E. robusta and E. tereticornis, E. botryoides andE. tereticornis. Nandi provenance of E. tereticornis, popularly known as Mysorehybrid or Eucalyptus hybrid or Mysore gum has been the most widely used speciesfor raising plantation in the denuded and barren areas and also for replacing low-value natural crops. It was first raised on plantation scale in Karnataka in 1952 andlater in Punjab and Haryana where the area under forests is negligible. In UttarPradesh (U.P.), large scale plantation of this tree was taken up from 1962. E. grandiswas first introduced in Kerala in 1948 and has emerged as the most importantspecies for pulpwood plantations there. It was also planted in Tamil Nadu and

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Karnataka. Regular plantations of E. globulus were taken up in the Nilgiris and thePalni Hills of Tamil Nadu upto 1972. E. camaldulensis has been proved useful forafforesting semi-arid tracts. E. tessellaris (syn. E. polycarpa) and E. melanophloiahave been tried in desert area of Rajasthan. In all, more than 150 Eucalyptusspecies have been tried in India. Only few species, viz., E. camaldulensis,E. citriodora, E. globulus, E. grandis and E. tereticornis have been tried on largescale. Of these, E. tereticornis or Eucalyptus hybrid of Mysore origin (mainlyE. tereticornis) forms the bulk of plantations in India.

Being fast grown and short rotation crop, eucalypt has found application in theareas of fuel wood, agricultural implements, constructional uses and various industrialapplications including pulp and paper. Due to its steady expansion into new plantationsto meet the increasing demand for wood in India, it has drawn the attention of industryand research institutions. A major attempt has been of improving the yield per hectare,producing straight bole and disease resistant trees. The extent of variation in woodproperties has been of interest to researchers for enhancing the gains from plantations.The anatomical, chemical mechanical and physical properties of wood measure its fitnessand ability to be useful for different end uses. Being of natural origin, wood has widevariation in its properties. Variation within species may be due to age, environmentalfactors and genetic makeup. Products quality and processing of timber is greatly affectedby the material characteristics. In the wood based industry, increased forest productivitiesand refinements in the quality of wood products have become increasingly important toaccelerate gains. Substantial opportunities exist for selecting superior material havingdesired traits. Proper selection of wood traits may result in reduced requirement of timberfor production of unit pulp. This would be beneficial both from the economic as well asenvironmental points of view. Hu et al. (1999) in their study on Populus termuloidesreported that repression of lignin biosynthesis exhibited reduction to an extent of 45 percent lignin resulting in 15 per cent increase in cellulose content. The major constraint inutilization of eucalypt as solid wood was poor lumber recovery and its problematicnature in subsequent drying. Concerted efforts were, therefore, needed to developappropriate sawing and seasoning methods of this species. Studies on testing of strength,durability, wood working, carving and finishing properties and methods for improvingsurface appearance were undertaken to enhance the utilization of Eucalyptus species.

This chapter deals with the solid wood utilization research that has been carriedout in India on eucalypts for exploring its utilization potential. While summarizingthe research results, the focus was on future potential and possible areas of research.Eucalypts were primarily grown for pulp and paper which at times resulted indisappointing margins. In addition, shortage of raw material for other industries andavailability of mature trees propelled diversification of eucalypts to other products.Considerable R&D efforts by research organizations made the diversiticationpossible. The CPWD and the Civil Construction Unit of Ministry of Environment

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and Forests, Govt. of India accepted eucalypt wood for doors and windows andfurniture in government buildings. The subsequent sections provide details of theresearch work done on the subject in the country.

2. Physical and Mechanical Properties of Eucalyptus Species

2.1. Variation in Specific GravitySpecific gravity (or basic density) of the wood is a critical property and has strongcorrelation with other properties (Panshin and Zeeuw, 1980). It is considered as oneof the best indicators for assessing the quality of timber. Mechanical properties incompression parallel and perpendicular to grain, impact and static bending, sidehardness, shear parallel and tension perpendicular to grain are affected to differentproportions by specific gravity. Correlations developed between specific gravityand various strength properties gives a good indication of mechanical properties aslong as the wood is clear, straight grained and free from defects (Sekhar and Rawat,1959; Shukla and Rajput, 1989). However, specific gravity values also reflect thepresence of gums, resins, and extractives, which contribute little to mechanicalproperties. The specific gravity of Eucalyptus species of different age groups, fromdifferent locations evaluated in India is reported in Table 1. The importance of specificgravity variation was felt by Shukla and Raput (1981) who devoted considerableefforts in generating data on specific gravity from different locations in India, andstudied the effect of specific gravity on strength properties. Purkayastha et al.(1982) studied the variation of specific gravity of widely separated eight to nineyears old E. tereticornis from five different localities; namely, Dehradun, Haldwani,Shahdol, Bangalore and Coimbatore and found it to be in the range of 0.539(Dehradun) to 0.639 (Bangalore). Shukla and Rajput (1981) reported the specificgravity of Eucalyptus species from different localities and varying age group inIndia for example Eucalyptus hybrid (mainly tereticornis), E. tereticornis,E. camaldulensis, E. citriodora, E. eugenioides, E. globulus, E. pilularis,E. propinqua and E. saligna. According to them, specific gravity of Eucalyptushybrid from Mahakanam Division (Tamil Nadu) varied from 0.529 to 0.623 for agebetween four to eight years. The minimum value reported by them for Eucalyptushybrid is 0.514 for five-year-old trees from Bhira Range, South Kheri Working PlanDivision (U.P.) and the maximum value for Eucalyptus species reported is 0.785 for29 years of age from New Forest, Dehradun. Kothiyal et al. (1998) reported specificgravity of 0.802 for 30-year-old Eucalyptus hybrid from Bangalore. Shukla and Rajput(1981) also reported the specific gravity of other species (E. eugenioides from Nilgiris,Tamil Nadu: 0.671, E. globulus, Nilgiris, Tamil Nadu: 0.676, E. citriodora from Nilgirisfor nine-year-old: 0.722, E. camaldulensis from New Forest, Dehradun for 24 years:0.697). Kumar et al. (1981a) reported specific gravity of 0.639 for 17-year-old

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Table 1. Specific gravity of Eucalyptus species reported from different locations in India

V. Kothiyal

S. no.

Reference Species name Locality Age (yr)

Standard specific gravity

1. Purkayastha et al., 1982 E. tereticornis Dehradun, Haldwani, Shahdol, Bangalore, Coimbatore

8-9 0.539-0.639

Eucalyptus hybrid Mahakanam, Tamil Nadu 4-8 0.529-0.623 Eucalyptus hybrid Hoskote, Karnataka 6-7 0.622 Eucalyptus hybrid Jharakbande, Karnataka 13-14 0.721 Eucalyptus hybrid Devanahalli, Karnataka 20-21 0.713 Eucalyptus hybrid Ooty Range, Tamil Nadu 8 0.571 Eucalyptus hybrid Dangs, Gujarat 8 0.568 Eucalyptus hybrid Panchmahal, Gujarat 0.563 Eucalyptus hybrid Tanda Range, U.P. 4-6 0.515-0.560 Eucalyptus hybrid Lamachaur Rane, U.P. 4-7 0.539-0.566 Eucalyptus hybrid Mailani Range, U.P. 4-5 0.537-0.557 Eucalyptus hybrid Bhira Range, U.P. 4-5 0.514-0.522 Eucalyptus hybrid Kishanpur Range, U.P. 4 0.633 Eucalyptus hybrid T&B Plantation Div, U.P. 6-9 0.529-0.592 Eucalyptus hybrid Bilaspur Division, M.P. 5 0.530 Eucalyptus sp. New Forest, Dehradun 29 0.785 Eucalyptus sp. New Forest, Dehradun - 0.734 E. tereticornis Ootacmund, Tamil Nadu 59 0.694 E. eugeniodes Nilgiris, Tamil Nadu 47 0.671 E. globulus Nilgiris, Tamil Nadu - 0.676 E. citriodora Nilgiris, Tamil Nadu 9 0.722 E. citriodora Ooty Range, Tamil Nadu 8 0.647 E. propinqua Ootacmund, Tamil Nadu 58 0.521 E. pilularis Ootacmund, Tamil Nadu 58 0.637 E. saligna Dehradun 20 0.667

2. Shukla and Rajput, 1981

E. camaldulensis New Forest, Dehradun 24 0.697 3. Kumar et al., 1981a E. camaldulensis Gottipura, Karnataka 17 0.639 4. Kamala et al., 1995-96 E. camaldulensis Hoskote, Karnataka 10 0.748 5. Kumar et al., 2007 E. citriodora Hassan, Karnataka 20 0.766 6. Kothiyal et al., 1998 Eucalyptus hybrid Bangalore, Karnataka 30 0.802

Eucalyptus hybrid Patiala, Punjab 19 0.726 7. Rajput et al., 1992 Eucalyptus hybrid Patiala, Punjab 16 0.636 FRI-4 and FRI-5 Dehradun 4 0.558-.0591 E. tereticornis Dehradun 4 0.591

8. Gulati et al., 1984

E. camaldulensis Dehradun 4 0.575 9. Sharma et al., 2005 E. tereticornis

(coppiced and non- coppiced)

Kolar, Karnataka 10-12 0.696-0.710

10. Kothiyal et al., 2002 E. tereticornis, ITC clones 3, 4, 6, 7, 10

Cherupally, AP 4½ 0.537-0.590

11. Kothiyal et al.,, 2006 E. tereticornis, ITC clones 3, 4, 6, 7, 10

Sarapakka, AP 4½ 0.505-0.563

12. Kothiyal et al., 2011 E. tereticornis (47 selected phenotypes)

Derhadun 5 0.458-0.674

E. tereticornis Kerala 16 0.627 13. Bhat and Thulasidas, 1997 E. grandis Kerala 30 0.532

14. Benny and Bhat, 1994 E. tereticornis Kerala 14 0.748-0.750 15. Benny and Bhat, 1996 E. grandis Kerala 15 0.528-0.663

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E. camaldulensis from Gottipura Forest Experimental Station in Karnataka whereasKamala et al. (1995-96) reported specific gravity of 0.748 for 10-year-oldE. camaldulensis from Hoskote Forest Range. Benny and Bhat (1994) reported nosignificant variation in density of 14-year-old E. tereticornis from wet and drylocation in Kerala and compared the results with those of Bhat and Thulasidas(1997) from other locality in Kerala. In another study (Benny and Bhat, 1996) studiedthe specific gravity of 15-year-old E. grandis from three locations. Bhat andThulasidas (1997) reported the specific gravity of 30-year-old E. grandis (0.532) and16-year-old E. tereticornis (0.627) from Kerala. Specific gravity of E. grandis wasalso reported by Bhat (1990) from Kerala.

Kothiyal et al. (2002, 2006) studied the specific gravity of five ITC clones (3, 4,6, 7 and 10) of four to five-year-old trees from two location in Andhra Pradesh(Sarapakka and Cherupally) grown on black and red soils and concluded that specificgravity was higher at Cherupally. Kothiyal et al. (2011) reported the specific gravity(0.458-0.674) of 47 superior phenotypes of Australian seed origin raised at NewForest Campus, Dehradun. In another study, Shukla et al. (2004) studied the intra-and inter-tree variation in E. tereticornis. Coppicing is common and practised inE. tereticornis plantation. The data on the properties of coppiced and non-coppicedwood from 10 to 12-year-old trees from plantation in Kolar district in Karnataka wasreported for the first time by Sharma et al. (2005). The data on physical and mechanicalproperties suggest no significant difference in properties, implying that timber canbe used for similar purposes. In another study, Kumar et al. (2007) reported thehighest specific gravity of 0.766 for 20-year-old trees of E. citriodora from Hasandistrict in Karnataka.

In addition, a number of studies have been carried out to study variation inspecific gravity with age and in radial and axial direction (Shukla et al., 1988, 1989,1991b, 1994; Jain and Arora, 1995; Benny and Bhat, 1996; Bhat and Thulasidas, 1997;Shukla et al., 2004) for Eucalyptus hybrid, E. tereticornis, E. camaldulensis andE. grandis. This is discussed in detail under the section ‘Variation in strengthproperties of Eucalyptus species’.

2.2. Shrinkage in WoodShrinkage is associated with change in dimensions of wood with reduction in moisturecontent below fibre saturation point (FSP) from green to oven dry condition. TheFSP values determined in India is in the range of 21-25 per cent for Eucalyptushybrid. It is measured as per cent change in dimensions (radial and longitudinalreferring to perpendicular to growth rings, tangential to growth rings and parallel tograin direction, respectively) and volume (volumetric) of wood piece. Owing toanatomy of wood, the shrinkage in all the three directions is different; maximum intangential direction and minimum (negligible) in longitudinal direction (Table 2). It


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-

- -

-

- -

-

3.0

-

-

-

387Eucalypts: Solid wood utilization research in India

affects the stability of timber in use and gives rise to drying defects in timber.Generally in solid wood, the ratio of tangential to radial shrinkage is about 1.8 to 1.

In normal wood, shrinkage in longitudinal direction is negligible since it isusually not over 0.1 to 0.2 per cent in drying from green to oven dry condition.Sharma et al. (2005) recorded longitudinal shrinkage in E. tereticornis coppiced andnon-coppiced trees of 10 to 12 years age to be 0.63 and 0.48 per cent, respectively.Kumar et al. (2007), in another study, obtained longitudinal shrinkage of 3 per centin 20 years old trees of E. citriodora collected from Hasan district of Karnataka.Kothiyal et al. (2011) obtained longitudinal shrinkage of 0.222 per cent to 0.781 percent in 47 trees of five-year age of E. tereticornis from Dehradun raised from Australianseed source. Radial, tangential and volumetric shrinkage recorded in India forEucalyptus hybrid/E. tereticornis, E. citriodora and E. grandis is in the range of5.6-8.3, 7.8-10.3 and 14.1 to 18 per cent, respectively compared to 2.3, 4.8 and 6.9 forteak (Jain, 1969; Rajput et al., 1992; Kamala et al., 1995-96; Bhat and Thulasidas,1997; Kothiyal et al., 1998; Sharma et al., 2005; Kumar et al., 2007). As evident fromTable 2, E. camaldulensis recorded low radial shrinkage (4-4.9%), and high tangentialshrinkage (11.5-12%). Volumetric shrinkage was also in the lower range (15.5-15.6).E. tereticornis recorded high volumetric shrinkage. High shrinkage is undesirableas it puts uneven stresses in timber while drying due moisture gradient and alsowhile in use which is expressed in the form of strains resulting in defects in timber. Italso puts more stress on plywood (Shukla, 1995) glue line with change in moisturecontent and may cause cracks in face veneers of cross-banded panels during service.It may also result in warping unless the cross-banded panels are perfectly balanced.The high ratio of tangential to radial shrinkage is an indication of the liability tocracking, splitting and warping.

The studies on the shrinkage behaviour of Indian timbers are usuallyconfined to the collection of data mainly with respect to total shrinkage fromgreen to oven dry condition. Studies on variation in shrinkage within tree arelimited in India. Jain and Arora (1995) studied the variation in shrinkage in a 20-year-old tree of E. camaldulensis. Shrinkage followed linear pattern withspecific gravity. Average tangential shrinkage exhibited slightly lower valuesfor the top log and similar observation were found by Shukla et al. (2004) inE. tereticornis. The transverse anisotropy, calculated as the ratio of tangentialand radial shrinkage, indicates a central zone of about 75 mm radius to behighly sensitive to cracking, splitting and cupping during the process ofseasoning.

2.3. Mechanical PropertiesStrength properties along with physical properties have the final bearing on thesuitability of timber for different end uses. Variation in properties in raw material

388

affects the uniformity in the product quality and leads to rejection by the buyer.Uniform raw material quality will be a treat to product developer. Also, material withdesired traits will fetch higher price from the buyer. For tree improvement, selectionof planting material from diverse population with desired traits will improve theplantation quality in terms of higher wood volume with desired traits. The majorfocus over the years had been on the study of strength properties to evaluatetimbers from various angles; different locations, varying age, within and betweentree variations to fix rotation age for different end uses. In the clonal populations,the focus of study was on desired traits and their stability at different sites anddiverse conditions. The variation within clones has also remained in the focus of theresearchers and plant growers.

In the past, the strength properties of Eucalyptus hybrid of Mysore origin(mainly E. tereticornis), E. citriodara, E. eugenioides, E. globulus, E. grandis,E. pilularis, E. propinqua, E. saligna and E. tereitocrnis have been studied. Thestudies on E. eugenioides, E. pilularis, E. propinqua and E. saligna are of preliminarynature as not much plantation exists, however E. tereticornis have been studied forvarious end uses. Table 3(a-e) details the strength properties of eucalypt timbertested in India.

Shukla et al. (1988, 1989, 1994) studied the variation of strength properties frompith to periphery in Eucalyptus hybrid of 16 years of age from Saharanpur; variationof strength properties along the tree height in three species; namely, E. camaldulensis,E. grandis and E. tereticornis of 14 years of age from New Forest Estate, Dehradun;variation of strength along the tree height in Eucalyptus hybrid trees from Punjab.As early as 1968, Sekhar and Rajput studied the physical and mechanical propertiesof Eucalyptus hybrid of Mysore origin from two to eight years of age and positionwithin tree. In yet another study, Sekhar et al. (1968) compared the strength propertiesof Eucalyptus hybrid with those of E. eugenioides and E. globulus. Jain (1969)studied the physical and mechanical properties of Eucalyptus hybrid from threelocalities in Karnataka of three age group (6-7, 13-14 and 20-21 years). Shukla et al.(1991b) also studied the effect of age on strength of Eucalyptus hybrid for timberfrom 6 to 22 years from Nabha Range in Patiala Forest Division. Jain (1969) andShukla et al. (1991b) concluded that the maturity age for Eucalyptus hybrid for thepurpose of solid wood be 13 to 14 years. Contrary to this, timber for pulp and paperis harvested at much younger age. Shukla et al. (1981) also reported the strengthproperties of Eucalyptus hybrid (8 years), E. pilularis (58 years), E. propinqua (59years) and E. tereticornis (59 years), from Ootacamund, and E. citriodora (8 and 9years) from Ootacamund and Cheramady range of Tamil Nadu. Kumar et al. (2007)reported data on physical and mechanical properties of 20-year-old trees fromHasan district in Karnataka. Shukla and Rajput (1983) consolidated and presentedthe data on physical and mechanical properties tested till then. In the present

V. Kothiyal

389

paper, the list has been updated and Table 3(a-e) summarises the work done so faron the strength properties Eucalyptus spp. Gulati et al. (1987) carried out preliminarystudy on strength properties of FRI-4 and FRI-5 Eucalyptus hybrid of E. tereticornisand E. camaldulensis developed by FRI, Dehradun and carried out preliminarystudies on their suitability for poles (Gulati et al., 1984). Also, Rajput et al. (1992)reported testing results on physical and mechanical properties of Eucalyptushybrid from Punjab and Haryana and compared the strength properties ofE. tereticornis grown in dry and wet localities of Kerala; Bhat and Thulasidas(1997) reported the physical and mechanical properties of E. grandis andE. tereticornis from Kerala; Kothiyal et al. (1998) at the same time studied Eucalyptushybrid of 30-year age from Bangalore, Karnataka and Shukla et al. (1996) studied

Sp. gr.: specific gravity based on oven dry weight and volume at test.*1- Shukla and Rajput, 1983; 2-3: Sharma et al., 2005; 4: Gulati et al., 1987.


Table 3a. Physical and mechanical properties of E. tereticornisS. no.

Property E. tereticornis

1. Place Ootacamund, Tamil Nadu

Kolar, Karnataka

Kolar, Karnataka

Dehradun

2. Reference no.* 1 2 3 4 3. Testing condition Green Green Dry Green Dry Green 4. Age (yr) 59 10-12 10-12 4 5. No. of trees/log 5 5 5 5

6. Girth (cm) 70-80 70-80 7. Sp. gr. 0.694 0.710 0.822 0.696 0.815 0.591 8. MC (%) 47.4 56 12 59.2 12.0 83.4 9. Weight (kg m-3) 1,023 1,107 920 1,104 913 1,084

Static bending FS at EL (kg cm-2) 491 445 727 417 696 346 MOR (kg cm-2) 834 766 931 681 929 675 MOE, 103 (kg cm-2) 110.5 81.3 116.4 70.1 114 71.2

10.

W to EL (kg cm cm-3) 0.131 0.116 Compression parallel to grain 11. MCS, (kg cm-2) 389 324 631 276 575 303 Compression perpendicular to grain

12.

CS at EL (kg cm-2) 59 80.7 159.2 71.5 146.5 46 Hardness (kg) Radial 461 425 1,005 399 994 341 Tangentia l - 441 1,000 409 934 331

13.

End - 420 1,322 349 1,299 - Shear parallel to grain (kg cm-2)

Radial 84 75.6 127.2 59.7 127.1 63.7 Tangentia l 91 73.8 133 66.4 132.2 58.7 Tension parallel to grain (kg cm-2)

TS at EL - - - - - 706 MTS at EL - - - - - 1,128

14.

MOE (103) - - - - - 123.2 15. Tension perpendicular to grain

(kg cm-2)

Radial - 35.1 51.3 31.8 48.1 - Tangentia l - 35.2 44.5 34.5 44.2 -

390

Table 3b. Physical and mechanical properties of E. citriodora and E. camaldulensis

Sp. gr.: specific gravity based on oven dry weight and volume at test.*1: Kumar et al., 2007; 7: Gulati et al., 1987; 2-3,6, 8-12: Shukla and Rajput, 1983; 4: Kamala et al., 1995-96; 5: Kumar et al .,1981a.

Eucalyptus hybrid timber of same age group from Maharashtra. Among the studiesconducted later, Kothiyal et al. (2002, 2006) reported the strength properties of fiveITC Bhadrachalam clones (3, 4, 6, 7 and 10) of four to five years from two locations(Sarapakka and Cherupally) in Andhra Pradesh planted on black and red soil andconcluded that strength properties were higher at Cherupally. Kothiyal et al. (2011)reported the data on strength, shrinkage and pulp properties of 47 superiorphenotypes of Australian seed origin raised at New Forest Campus, Dehradun.

In addition to above study (Shukla et al., 1994) reported on 14-year-oldE. camaldulensis, Kumar et al. (1981a) evaluated the physical and mechanicalproperties of 17-year-old trees from Gottipura Forest Experimental Station inKarnataka. This was followed by Kamala et al. (1995-96) for 10-year-oldE. camaldulensis from Hoskote Forest Range.

The studies on strength properties of E. grandis were limited to work carriedout by Shukla et al. (1994) on 14-year-old trees from Dehradun and Benny and Bhat

V. Kothiyal

S. no.

Property E. citriodora E. camaldulensis

1. Place Hassan Ootacamund Nilgiris Hoskote Gottipura Dehradun 2. Reference no.* 1 2 3 4 5 6 4 3. Testing condition Green Dry Green Green Green Dry Green Dry Green Green 4. Age (yr) 20 - 8 9 10 - 17 - 31 4 5. No. of trees/logs 5 - 5 10 5 - 4/12 - 2 5 6. Girth (cm) 90 - - - 90 - 120 - - - 7. Sp. gr. 0.766 0.875 0.647 0.742 0.748 0.759 0.639 0.718 0.697 0.575 8. MC (%) 57 12 42.8 39.7 51 12 80.3 12 45.4 73.3 9. Weight (kg m-2) 1,199 1,082 924 1,037 1,069 877 1,104 813 1,013 996

Static bending FS at EL (kg cm-2) 604 786 488 465 462 654 438 516 356 322 MOR (kg cm-2) 848 1,100 771 866 783 870 640 759 621 586 MOE (103 kg cm-2) 132 146.2 93.5 121.2 91 127 95.3 107 70.3 55.6

10.

W to EL (kg cm cm-3) - - 0.152 0.109 - - - - 0.115 0.103 Impact bending 11. Izod strength (kg cm) - - 249 235 - - - - - - Compression parallel to grain (kg cm-2)

12.

MCS 464 582 344 439 335 540 288 428 315 263 Compression perpendicular to grain (kg cm-2)

13.

CS at EL 100 123 53 74 96 102 62 99 62 50 Hardness (kg) Radial 510 905 461 572 530 682 447 788 - 362 Tangential 512 872 - - 543 680 436 777 - 356

14.

End 567 801 - - 595 690 490 947 - - Shear parallel to grain (kg cm-2) Radial 84.6 127.4 90 122 49 60 71.8 89 95 70

15.

Tangential 90 126.1 90 124 54 57 70.3 107 109 70.2 Tension perpendicular to grain (kg cm-2)

Radial 39.9 31.2 - - 37 48 37 38 - -

16.

Tangential 42.8 32.3 - - 35 41 35 38 - - Tension parallel to grain (kg cm-2) TS at EL - - - - - - - - - 448 MTS - - - - - - - - - 704

17.

MOE (103) - - - - - - - - - 82.7

391

Tabl

e 3c

. Phy

sica

l and

mec

hani

cal p

rope

rtie

s of

Euc

alyp

tus

spec

ies

Sp. g

r.: sp

ecif

ic g

ravi

ty b

ased

on

oven

dry

wei

ght a

nd v

olum

e at

test

; *1-

5: S

hukl

a an

d R

ajpu

t, 19

83.

Eucalypts: Solid wood utilization research in IndiaS.

no

. Pr

oper

ty

E. s

alig

na

E

. eug

enio

ides

E. g

lobu

lus

E

. pilu

lari

s E

. pro

pinq

ua

1.

Plac

e D

ehra

dun

N

ilgiri

s

Nilg

iris

O

otac

amun

d 2.

R

efer

ence

no.

* 1

2

3

4

5 3.

T

estin

g co

nditi

on

Gre

en

Dry

Gre

en

Dry

Gre

en

Dry

Gre

en

Gre

en

4.

Age

(yr)

20

-

47

-

-

-

58

59

5.

No.

of t

rees

/log

2 -

5

-

2 -

5

5 5.

Sp

. gr.

0.

667

0.73

1

0.67

1 0.

762

0.

676

0.79

7

0.63

7 0.

521

6.

MC

(%)

65.8

12

78.8

12

52.4

12

64.6

78

.4

7.

Wei

ght (

kg m

-3)

1,10

6 81

9

1,20

0 85

3

1,03

0 89

3

1,04

9 92

9 St

atic

ben

ding

FS

at E

L (k

g cm

-2)

439

524

54

4 77

8

460

880

53

5 42

5 M

OR

(kg

cm-2

) 57

3 79

5

818

1,24

8

793

1,40

7

740

639

MO

E (1

03 kg

cm-2

) 82

.4

82.5

114.

7 13

8.1

14

8.3

246.

7

92.2

79

.3

8.

W to

EL

(kg

cm c

m-3

) 0.

134

0.20

9

0.14

6 0.

243

0.

082

0.17

9

0.19

4 0.

127

Impa

ct b

endi

ng

9.

Izod

str

engt

h (k

g cm

) 93

69

176

175

-

-

193

183

Com

pres

sion

par

alle

l to

grai

n

(kg

cm-2

)

10

.

MC

S 32

9 51

2

451

628

35

9 64

1

340

241

Com

pres

sion

per

pend

icul

ar to

gra

in

(kg

cm-2

)

11

.

CS

at E

L

109

147

13

3 11

7

59

91

49

43

H

ardn

ess (

kg)

Rad

ial

679

758

74

9 82

9

556

675

41

7 35

2 12

.

End

-

-

- 89

5

- 82

9

- -

Shea

r par

alle

l to

grai

n (k

g cm

-2)

Rad

ial

137

135

10

5 11

0

88

110

75

65

13

.

Tan

gent

ial

154

130

11

6 15

8

100

168

10

5 81

392

Tabl

e 3d

. Phy

sica

l and

mec

hani

cal p

rope

rtie

s of

Euc

alyp

tus

hybr

id

Con

td.

on

next

pag

e…

V. KothiyalS.

no

. Pr

oper

ty

Euc

alyp

tus

hybr

id

FR

I-4

FRI-

5

1.

Plac

e Pu

njab

H

arya

na

Kar

nata

ka

Guj

arat

Ta

mil

Nad

u K

arna

taka

Deh

radu

n 2.

R

efer

ence

no.

* 1

2 3

4 5

6 7

8 9

9

10

3.

Test

ing

cond

ition

G

reen

D

ry

Gre

en

Dry

G

reen

G

reen

G

reen

Gre

en

Gre

enG

reen

D

ry

Gre

en

Dry

Gre

en

Gre

en

4.

Age

(yr)

19

16

6-

7 13

-14

20-2

1

8 8

30

4

4 5.

N

o. o

f tre

es/lo

gs

4

6

4 6

3 3

5 10

4

5

5 6.

G

irth,

cm

11

0 -

- -

21

23

20

- -

- -

120

-

- -

7.

Sp. g

r. 0.

726

0.81

2 0.

636

0.69

3 0.

662

0.72

1 0.

713

0.56

3 0.

571

0.59

6 0.

689

0.80

2 0.

853

0.

591

0.55

8 8.

M

C (%

) 51

.2

12.0

58

.3

12.0

50

48

45

66

60

.7

83.1

12

30

.4

12

84

80

9.

W

eigh

t (kg

m-3

) 1,

098

909

1,00

7 77

6 93

6 1,

025

1,00

0 93

5 91

8 1,

091

772

1,04

6 95

8

1,08

7 1,

006

Stat

ic b

endi

ng

FS a

t EL

(kg

cm-2

) 45

2 72

4 37

4 49

6 52

7 64

0 54

3 43

6 51

1 29

1 39

0 58

8 69

6

280

332

MO

R (k

g cm

-2)

762

1,21

2 74

4 99

5 79

0 87

5 80

8 69

0 81

7 51

6 66

4 94

8 1,

064

61

5 61

1 M

OE

(103 k

g cm

-2)

85.6

13

9.5

87.2

10

6.6

76

115

116

72.6

93

.2

60.0

77

.3

149

138

57

.1

61.7

W

to E

L (k

g cm

cm

-3)

0.14

8 0.

382

0.09

5 0.

18

- -

- 0.

200

0.16

2 0.

091

0.12

5 -

-

0.07

6 0.

123

W to

ML

(kg

cm c

m-3

) 1.

00

1.48

0.

84

0.93

-

- -

- -

- -

- -

-

-

10.

TW (k

g cm

cm

-3)

1.72

2.

44

1.92

1.

75

- -

- -

- -

- -

-

- -

Impa

ct b

endi

ng

FS a

t L (k

g cm

-2)

1,03

3 1,

540

995

1,02

1 -

- -

- -

- -

- -

-

- M

ax. h

t. of

dro

p (c

m)

116

122

108

85

137

127

88

- -

- -

- -

-

- M

OE

(103 k

g cm

-2)

160.

5 19

0.1

108.

3 13

4.4

- -

- -

- -

- -

-

- -

W to

EL

(kg

cm c

m-3

) 0.

416

0.66

1 0.

514

0.43

7 -

- -

- -

- -

- -

-

-

11.

Izod

stre

ngth

(kg

cm)

217

211

172

109

- -

- 16

6 23

3 15

5 64

-

-

- -

Com

pres

sion

par

alle

l to

gr

ain

CS

at E

L (k

g cm

-2)

285

414

237

310

- -

- -

- -

- -

-

- -

MC

S (k

g cm

-2)

407

714

377

525

375

420

402

288

356

291

393

459

496

29

8 27

2

12.

MO

E (1

03 kg

cm-2

) 11

5.5

142.

3 90

.9

126

- -

- -

- -

- -

-

- -

393...

Con

td.

from

pre

viou

s pa

ge

1-2:

Raj

put e

t al.

(199

2); 3

-5: J

ain,

196

9; 6

-8: S

hukl

a an

d R

ajpu

t, 19

83;

Kot

hiya

l et a

l., 1

998.


13.

Com

pres

sion

per

pend

icul

ar

to

gra

in C

S at

EL

(kg

cm-2)

89

135

78

137

76

93

96

47

52

70

76

67.3

68

.4

50

48

14

. H

ardn

ess (

kg)

R

adia

l 69

5 1,

042

650

768

487

530

551

333

427

576

672

723

788

36

3 35

3

Tang

entia

l 72

5 1,

084

657

777

496

537

542

- -

-

786

799

36

6 34

8

End

754

1,00

0 70

2 84

9 57

6 61

9 62

8 -

- -

733

808

920

-

- 15

. Sh

ear p

aral

lel t

o gr

ain

(k

g cm

-2)

R

adia

l 94

.5

107.

2 11

0.3

131.

0 78

76

74

65

75

73

84

83

13

8

64.2

63

.2

Ta

ngen

tial

102.

3 11

3.9

119.

0 13

9.1

84

81

68

74

105

80

91

85

128

69

.3

62.6

16

. Te

nsio

n per

pend

icular

to gr

ain

(kg

cm-2

)

R

adia

l 54

.5

76.6

72

.6

77.2

51

48

53

-

- -

- 28

51

- -

Ta

ngen

tial

53.8

89

.9

74.8

77

.5

46

45

53

- -

- -

26

47

-

- 17

. Te

nsio

n pa

ralle

l to

grai

n

(kg

cm-2

)

TS

at E

L 73

2 1,

042

565

438

- -

- -

- -

- -

-

525

537

M

TS

1,12

7 1,

307

753

782

- -

- -

- -

- -

-

837

771

M

OE

(103 )

96.3

14

6.8

66.4

90

.1

- -

- -

- -

- -

-

104.

7 92

.2

18.

Tors

ion

(kg

cm-2

)

TS a

t EL

48.5

10

4.8

45.6

49

.1

- -

- -

- -

- -

-

- -

M

ax. T

S 11

9.5

185.

0 12

5.5

126.

5 -

- -

- -

- -

- -

-

-

MO

RG

(103 )

65.9

13

1.9

63.9

11

6.7

- -

- -

- -

- -

-

- -

19.

Cle

avag

e (k

g cm

) wid

th

R

adia

l 83

.6

81.1

67

.8

89.7

-

- -

- -

- -

- -

-

-

Tang

entia

l 79

.9

73.7

60

.9

81.6

-

- -

- -

- -

- -

-

- 20

. FS

P 21

.1

- 24

.6

- -

- -

- -

- -

- -

-

-

394

Tabl

e 3e

. Lim

ited

data

on

phys

ical

and

mec

hani

cal p

rope

rtie

s of

Euc

alyp

tus

spec

ies

Sp. g

r.: sp

ecif

ic g

ravi

ty b

ased

on

oven

dry

wei

ght a

nd v

olum

e at

test

.*1

-5: R

ajpu

t et a

l., 1

992,

Shu

kla

et a

l., 1

991b

; 6, 1

2, 1

6: S

hukl

a et

al.,

198

9; 7

, 13:

Bha

t and

Thu

lasi

das,

199

7; 8

-9: B

enny

and

Bha

t, 19

94; 1

0-11

: Kot

hiya

l, 20

02, 2

006;

14-

15: B

enny

and

Bha

t, 19

96.

Abb

revi

atio

n us

ed in

Tab

le 3

(a-e

):Sp

. gr.:

Spe

cific

gra

vity

; FS

at E

L: F

iber

stre

ss at

elas

tic li

mit;

MO

R: M

odul

us o

f rup

ture

; MO

E: M

odul

us o

f ela

stic

ity; W

to E

L: W

ork

to E

L; W

to M

L: W

ork

to m

axim

um lo

ad; T

W: T

otal

wor

k: Iz

od st

reng

th:

wor

k ab

sorb

ed; H

ardn

ess:

load

to em

bed

1.12

8 cm

dia

met

er b

all t

o ha

lf di

amet

er; C

S at

EL:

Com

pres

sive

stre

ss at

elas

tic li

mit;

MC

S: M

axim

um c

rush

ing

stre

ss p

aral

lel;

TS

at E

L: t

ensi

le st

ress

at e

last

ic li

mit;

MT

S: M

axim

um te

nsile

stre

ss; M

ax. T

S: M

axim

um to

rsio

nal s

tres

s; M

OR

G: M

odul

us o

f rig

idity

.

V. KothiyalS.

no

. Pr

oper

ty

Euca

lypt

us h

ybri

d

E. te

retic

orni

s

E. g

rand

is

E.

cam

ld-

ulen

sis

1.

Plac

e N

abha

Ran

ge, P

atia

la, P

unja

b

Deh

radu

nV

andi

oery

ar,

Kera

la

Triv

andr

um,

Kera

la

Puna

lur,

Kera

la

Cher

upal

ly,

AP

ITC

clon

es

Sara

pakk

a,

AP

ITC

clon

es

D

ehra

dun

Van

dioe

ryar

, K

eral

a Tr

ivan

drum

,K

eral

a M

unna

r, K

eral

a

Deh

radu

n

2.

Refe

renc

e no

.*

1 2

3 4

5

6 7

8 9

10

11

12

13

14

15

16

3.

Testi

ng c

ondi

tion

Gre

en

Gre

en

Gre

en

Gre

en

Gre

en

G

reen

D

ry

Dry

D

ry

Gre

en

Gre

en

Dry

Gre

en

Dry

D

ry

Dry

Gre

en

4.

Age

(yr)

6 10

14

19

22

14

16

14

14

4*1/

2 4*

1/2

14

30

15

15

14

5.

N

o. o

f tre

es

4 4

4 4

4

3 6

5 5

1 4

3 3

4 4

3

6.

Girt

h (c

m)

48

69

110

120

132

-

63

- -

28-3

7 34

-45

- 14

2 -

-

7.

Sp

. gr.

0.

504

0.64

3 0.

680

0.70

5 0.

680

0.

603

0.74

5 0.

748

750

0.53

7-0.

590

0.50

5-0.

563

0.53

2 0.

602

0.66

3 52

8

0.70

3 8.

M

C (%

) 10

9 80

.6

75.2

74

.7

72.8

- 13

.8

- -

49-6

2 0.

543-

0.60

2

-

18

- -

-

Stat

ic b

endi

ng

FS a

t EL

(kg

cm-2

) 29

9 38

3 48

7 48

1 48

9

- 48

0 60

1 62

2 35

6-38

9 26

7-36

6 45

7-55

8

- 42

9 48

7 49

6

- M

OR

(kg

cm-2)

533

661

809

803

811

46

9 88

.1

992

927

547-

656

475-

652

747-

875

64

8 83

6 75

6 78

2

778

MO

E (1

03 kg

cm-2)

93.0

78

.5

94.6

89

.8

84.9

49.5

98

.7

96.5

83

.8

63.2

-79.

7 56

.1-8

1.8

94.1

-146

83

.5

111.

3 88

.16

84.9

91.4

9.

W to

EL

(kg

cm cm

-3)

0.08

4 0.

120

0.15

7 0.

156

0.18

3

- -

- -

- -

-

- -

- -

-

Com

pres

sion

para

llel t

o gr

ain

10

. M

CS (k

g cm

-2)

201

312

403

429

419

25

7 42

9 53

1 50

6 24

7-29

2 21

3-28

5 25

7-33

8

312

356

478

456

39

2 Co

mpr

essio

n ?

to g

rain

11.

CS a

t EL

(kg

cm-2

) 49

80

12

2 12

6 11

6

- -

- -

32.7

-40.

9 39

.8-5

1 58

.2-6

9

- -

- -

-

Har

dnes

s (kg

)

Side

-

- -

- -

-

- -

- 30

0-35

1 23

6-26

0 30

7-43

4

- -

- -

-

12.

End

-

- -

- -

-

- -

- 37

3-41

2 32

4-39

5 44

7-63

0

- -

- -

-

Shea

r par

allel

to g

rain

Ra

dial

63

.3

83.1

10

1.0

93.2

92

.0

-

- -

- -

- -

-

- -

-

- 13

.

Tang

entia

l 76

.3

92.5

10

5.5

97.6

97

.6

-

- -

- -

- -

-

- -

-

-

395

(1996) studied air-dry strength properties of E. grandis grown in low and highaltitudinal localities in Kerala. E. grandis is normally preferred at high altitudes andE. tereticornis at low altitudes in Kerala. Their results showed no significantdifference in mechanical properties of 15-year-old E. grandis from low (Trivandrum)and high (Munnar) altitude. Density from low altitude was 26 per cent better thanthat from high altitude. Bhat and Thulasidas (1997) also compared the strengthproperties in air-dry condition of E. grandis (30 years) and E. tereticornis (16 years)from Trichur Foest Division in Kerala.

2.4. Nail and Screw Holding PowerEucalyptus species are being used more and more for construction, doors andwindows, furniture, cabinets, boat building, packing cases, crates, pallets, toolhandles, truck bodies, agricultural implements, sports goods and many other itemswhere fastening is a commonly employed technique to connect/combine woodpieces. Nails and screws of different sizes and shapes are employed dependingupon the requirement. Withdrawal resistance of nail and screw, therefore, assumessignificance in these applications of timber. Capacity with which the differentsizes of nails or screws are held in timber is known as nail/screw holding powerand is determined in terms of resistance offered to withdraw the nail or screw fromthe timber. This resistance to nail and screw is determined under three conditionsas per procedure mentioned in IS: 1708 (BIS, 1986).

Condition A: Driven in green condition and withdrawn at onceCondition B: Driven in green condition and withdrawn when it is driedCondition C: Driven in air-dry condition and withdrawn at once

A number of workers (Rajput et al., 1989b; Shukla, 1995-96; Kumar et al., 1981a;Kamala et al., 1995-96; Kothiyal et al., 1998) determined nail and screw holding powerof Eucalyptus hybrid and the same is compiled in Table 4 and Table 5 along withvalues of teak for comparison. While using eucalypts for making joints with nails aswell screws, the strength is comparable and often better than teak and mango. It isoften complained that eucalypts wood shows a tendency to split and nail bending,thereby, the holding power decreases and joints do not remain intact. To avoid splitting,pre-boring can be done before inserting the nail. Nail holding power is either more orclose to teak, however, screw holding power is less than that of teak.

2.5. Variation in Strength Properties of Eucalyptus SpeciesEucalyptus species are providing valuable timber for industries in sufficient quantityin the country. The aim of all the above referred studies was to understand thetimber from Eucalyptus species and formulate appropriate classification, gradingstandards and processing methods to obtain uniform material for utilization. Withthis aim in view, Sekhar and Rajput (1968) conducted a study on Eucalyptus hybrid


396

Table 4. Nail withdrawal power/resistance

1Rajput et al., 1992; 2Rajput et al., 1989b; 3Kothiyal et al., 1998; 4Sharma et al., 2005; 5Kumar et al., 1981a; 6Kamala et al., 1995-96; 7Kumar et al., 2007.Condition A: Nail driven in green condition and pulled out in green; Condition B: Nail driven in green condition and pulled out in dry;Condition C: Nail driven in dry condition and pulled out in dry; *Suitability indices with teak taken as 100.

of four to eight years with tree height upto 15 m. They concluded that strengthincreases significantly with the age (four to eight years) but no significant differencewas observed with height. Similar results were obtained by Shukla and Rajput (1981)in different plantations of Eucalyptus species of four to nine years age. Their resultsshowed non-significant variation in axial position. Shukla et al. (1988) extended thestudy on axial variation from pith to periphery on Eucalyptus hybrid timber from 16years of age. They found that strength increases from pith to periphery withinheartwood region but decreases in sapwood region. They also concluded thatalthough the sapwood strength is less than that of adjoining heartwood, there is nosignificant difference in the strength of ‘average’ heartwood and sapwood. Thestrength of the central portion of the log cross-section is consistently and

V. Kothiyal

Table 5. Screw withdrawal power/resistance

1Rajput et al., 1992; 2Rajput et al., 1989b; 3Kothiyal et al., 1998; 4Sharma et al., 2005; 5Kumar et al., 1981a; 6Kamala et al., 1995-96; 7Kumar et al., 2007.Condition A: Screw driven in green condition and pulled out in green; Condition B: Screw driven in green condition and pulled out indry; Condition C: Screw driven in dry condition and pulled out in dry; *Suitability indices with teak taken as 100.

Nail withdrawal resistance (kg) Condition

A Condition

B Condition

C

S. no.

Species Locality Standard specific gravity

Side End Side End Side End

Nail holding power*

1. Eucalyptus hybrid1 Shahpur (Haryana)

0.636 222 166 118 135 235 196 202

2. Eucalyptus hybrid1 Patiala (Punjab) 0.726 236 182 124 110 203 159 202 3. Eucalyptus hybrid2 Pune

(Maharashtra) 0.703 177 114 163 136 219 168 131

4. E. tereticornis3 Bangalore 0.802 137 103 - - - - - 5. E. tereticornis4

Non-coppiced 0.710 132 104 - - 156 118 95

6. E. tereticornis4

(coppiced)

Kolar (Karnataka)

0.696 125 81 - - 151 122 84

7. E. camaldulensis5 Gottipura (Karnataka)

0.639 134 101 - - 171 137 110

8. E. camaldulensis6 Hoskote (Karnataka)

0.748 129 99 140 120 163 136 104

9. E. citriodora7 Hasan (Karnataka)

0.766 134 98 72 86 125 117 81

10. Tectona grandis 0.596 124 87 72 57 89 71 100

Screw withdrawal resistance (kg) Condition

A Condition

B Condition

C

S. no.

Species Locality Standard specific gravity

Side End Side End Side End

Screw holding power

1. Eucalyptus hybrid1 Shahpur (Haryana) 0.636 303 208 325 195 408 281 77 2. Eucalyptus hybrid1 Patiala

(Punjab) 0.726 268 168 285 140 333 177 77

3. Eucalyptus hybrid2 Pune (Maharashtra) 0.703 244 133 379 179 379 208 77 4. E. tereticornis3 Bangalore 0.802 195 73 - - 257 99 50 5. E. tereticornis4

(non-coppiced) 0.710 238 189 - - 461 363 87

6. E. tereticornis4 (coppiced)

Kolar (Karnataka)

0.696 254 163 - - 461 317 86

7. E. camaldulensis5 Gottipura (Karnataka) 0.639 277 205 - - 284 205 77 8. E. camaldulensis6 Hoskote (Karnataka) 0.748 246 201 268 265 262 254 76 9. E. citriodora7 Hasan (Karnataka) 0.766 296 206 393 286 342 320 93 10. Tectona grandis - 0.596 302 201 383 257 398 294 100


significantly lower than the rest of the log. In another study, Shukla et al. (1989)studied the variation in specific gravity and strength in 14-year-old trees of threespecies (E. camaldulensis, E. grandis and E. tereticornis). It was concluded that incase of E. camaldulensis and E. tereticornis within a tree, properties do not differsignificantly with height and logs up to 12 to 15 m can be obtained having uniformstrength. In case of E. grandis, most of the properties were significantly differentwith height, however, a thorough study is required to be done. Shukla et al. (1994)took up exhaustive study on variation of strength properties with height in timbersof Eucalyptus hybrid of four different age groups (6, 10, 14 and 19 years) fromNabha Punjab and concluded that irrespective of age the variation in strengthproperties with height is non-significant. Shukla et al. (2004) obtained similar trendon 30-year-old E. tereticornis trees from Bangalore. Variation of strength propertiesof Eucalyptus hybrid with age of trees had been studied from 6 to 22 years (Shuklaet al., 1991b; Rajput et al., 1992) and it was concluded that strength increased withage from 6 to 14 years and, thereafter, the differences were not significant suggestingthat mechanical maturity is achieved at the age of 14 to 15 years. In another study onEucalyptus hybrid of age 6-7, 13-14 and 20-21 years from Karnataka, Jain (1969)observed that trees acquire strength to the maximum of 13-14 years.

The inferences from all the above studies are:• Irrespective of age, the variation in strength properties with height is non-

significant.• Strength increases from pith to periphery within heartwood region but decreases

in sapwood region. Although the sapwood strength is less than that of adjoiningheartwood, there is no significant difference in the strength of ‘average’heartwood and sapwood. The strength of the central portion of the log cross-section is consistently and significantly lower than rest of the log.

• Strength increases with age from 6 to 14 years, and thereafter, the differencesare not significant suggesting that mechanical maturity is achieved at the ageof about 14 years.

3. Suitability Indices of Eucalyptus SpeciesIt is often difficult to compare properties of one species with another without followinga common reference point and this makes it difficult to make preferred choices andgroup species for various end uses. Comparative suitability indices are derived fromthe basic strength properties data. Teak in India is regarded as average Indian timberhaving most of the desired properties for several end uses. The procedure wasdeveloped and has been well laid down by Sekhar and Gulati (1972). Suitability indicesare expressed as percentage of values for teak for various purposes. Table 6 report thesuitability indices reported by various workers for Eucalyptus species from differentlocations. From the Table 6 one can infer that:

398 V. Kothiyal

*ind

icat

ive

tent

ativ

e fig

ure

eval

uate

d w

ith sp

.gr.-

stre

ngth

rela

tions

hip;

**s

plitt

ing

coef

ficie

nt.

***1

: Kam

ala

et a

l., 1

995-

96; 2

: Kum

ar e

t al.,

198

1a; 3

-6: S

hukl

a an

d R

ajpu

t, 19

83; 7

-8: R

ajpu

t et a

l., 1

992;

9: K

othi

yal e

t al.,

199

8; 1

0: K

umar

et a

l., 2

007;

13-

14: S

harm

a et

al.,

200

5; 1

1-12

, 15-

16: R

ajpu

tan

d Sh

ukla

, 198

9.

Tabl

e 6.

Sui

tabi

lity

indi

ces

of E

ucal

yptu

s sp

ecie

s in

term

s of

teak

take

n as

100

S. no.

Property

E. camaldulensis

E. camaldulensis

E. globulus

E. Saligna

E. eugenioides

Eucalyptus hybrid

Eucalyptus hybrid

Eucalyptus hybrid

Eucalyptus hybrid

E. citriodora

E. citriodora*

E. citriodora*

E. tereticornis nc

E. tereticornis c

E. pilularis*

E. propinqua*

1.

Ref

eren

ce n

o.**

1

2 3

4 5

6 7

8 9

10

11

12

13

14

15

16

2.

Age

(yr)

10

17

-

- 45

8

19

16

30

20

8 9

- -

58

59

3.

Stre

ngth

as

beam

99

85

11

1 85

11

0 71

10

4 88

11

5 11

4 93

+ 99

+ 11

0 10

4 94

+ 79

+

4.

Stif

fnes

s as

bea

m

99

92

142

84

107

71

96

93

124

121

85+

110+

101

95

84+

72+

5.

Suita

bilit

y as

a p

ost

94

84

111

87

105

72

102

87

107

112

84+

108+

102

95

83+

65+

6.

Shoc

k re

sist

ing

abili

ty

116

76*

130

108*

10

8*

96*

138

111

130

127

- -

127

125

- -

7.

Ret

entio

n of

sha

pe

52

53

- -

- -

57

63

56

51

- -

49

47

- -

8.

Shea

r 55

83

10

7 14

5 12

2 83

10

5 12

5 10

3 10

4 95

+ 13

0+ 14

6 13

4 94

77

9.

Ref

ract

orin

ess*

**

57

53

88

76

77

68

92

109

50

71

- -

65

61

- -

10.

Har

dnes

s 11

4 99

99

13

6 14

3 96

14

0 12

4 11

8 10

1 69

+ 92

+ 13

6 12

6 63

+ 54

+

11.

Nai

l hol

ding

pow

er

104

110

114*

11

2*

113*

10

1*

202

202

- 81

-

- 95

84

-

-

12.

Scre

w h

oldi

ng p

ower

76

77

11

4*

112*

11

3*

101*

77

77

50

93

-

- 87

86

-

-

13.

Wei

ght o

r hea

vine

ss

130

121

- -

- 10

3 13

4 11

5 14

2 16

1 10

9 12

4 14

2 14

1 10

7 87


• Eucalyptus species have consistently low retention of shape and splittingcoefficient (refractoriness) indicating low dimensional stability and tendencyto split. The sawing pattern of eucalypt, therefore, becomes important parameterin its processing. Proper seasoning of timber also becomes essential beforeuse of timber

• Screw holding power of timber is also consistently low• Although nail holding power of eucalypt is more compared to teak, but it is

difficult to drive nail in timber without splitting or bending of nail. A pre-boring is suggested but with some loss in nail holding power

• The eucalypt timber is heavier as compared to teak and it may reduce itsapplication in areas where light weight timber is preferred.

4. Growth Stresses in EucalyptsThe stresses are generated in newly formed wood during cell maturation.Continuous formation of growth stresses during tree growth results in an unevendistribution of residual stresses across tree stems. When logs are sawnlongitudinally, these residual stresses are partially released and the resulting strains(deformation) cause sawing inaccuracy, spring and bow. Eucalyptus species areknown to be associated with problems during sawing as well as subsequent drying.Growth stresses are considered to be major reasons for problems during sawing.Existence of severe growth stresses in logs has been detected and the axis ofsymmetry based on distribution studies established. Due to unbalancing of growthstresses, severe, warping occurs during sawing by conventional plain sawingmethods. Chaturvedi (1983) explained that in a standing tree the outer trunk of thegreen Eucalyptus is in a state of tension along its longitudinal axis and the innerwood in a corresponding state of compression. The forces involved areconsiderable. The average stress in the outermost layers is approximately 84 kgcm-2 while the compressive stresses are often greater than 140 kg cm-2. The outertension stress is resisted by the inner layers of the stem resulting in a longitudinalstrain gradient across any diameter. The inner layers become compressed and theoutermost layers are crushed beyond the elastic ability of wood to resistlongitudinal compression. Under these severe forces the cell of the inner woodfails in the course of time. Under such condition if a log is cut lengthwisetangentially, the release of inner compression makes the inside edge of the resultingplank longer (when cut) than it was in tree and the outer wood contracts, becomingshorter out of tree (when cut) then in tree. The conversion of logs to tangentialplanks, therefore, creates problems during the process of subsequent drying anddevelops various defects, viz., collapse, warping, surface cracking, twisting, etc.Sharma et al. (1988a) measured the growth strain in green sawn diametric slab ofE. tereticornis. Aggarwal et al. (1997) measured the longitudinal growth strain in

400

E. tereticornis by strain gauge technique. Study of Aggarwal and Chauhan (2013)on five ITC clones (3, 4, 6, 7 and 10) of five-year-old trees measured meanlongitudinal growth strain in the range of 466 to 876 μm. The difference in strainswas significant among clones. A difference of 5 to 200 per cent in growth strainwas measured on the opposite side of the logs. Within a tree, the growth strainvariation with tree height was high but statistically insignificant. Other efforts inthis direction (Chauhan and Walker, 2011) were to study wood quality of artificiallyinclined one-year-old trees of E. regnans by studying tension and opposite woodproperties. Chauhan and Walker (2004) in another study examined the relationshipbetween longitudinal growth strain and some wood properties in E. nitens. In yetanother study, Chauhan et al. (2007) investigated the relationship between stresswave velocity and internal stresses.

5. Sawing and Seasoning of Eucalypts

5.1. Sawing of EucalyptsAs stated earlier, Eucalyptus species are known to be associated with problemsduring sawing as well as subsequent drying. The main problem during sawingdevelops due to release of growth stresses which manifests in the form of strains.The compressive and tensile stresses of the two plains that get released duringsawing of each plank come into play and cause unequal surface stresses thus,causing development of strains leading to splitting and warping, etc. The normalplain sawing method adopted in saw mills does not suit Eucalyptus species.The sequence of sawing is highly asymmetrical relative to the log centre aboutwhich the growth stresses are more or less symmetrically distributed and inbalance. The sequence of sawing releases the stresses, resulting in immediatewarping (bow) and spring of the timber. Tangential sawing, also known as livesawing, is the most common sawing pattern adopted by saw millers. This is theeasiest and basic of all sawing patterns. Unfortunately, the problems related togrowth stresses are more manifested in this sawing pattern and, hence,modifications were introduced later on for the species like Eucalyptus. Moreover,subsequent to sawing, the tangential planks containing centre heart split badlyduring drying. These problems can be avoided by cutting the log lengthwiseradially (Pandey et al., 1984). To overcome this problem, other sawing techniquessuch as radial sawing (Fig. 1), quarter sawing (Fig. 2), balanced tangential sawing(Fig. 3) and modified quarter sawing (Fig. 4) were recommended for Eucalyptusspecies to reduce defects in sawn timber.

5.1.1. True radial sawing (TR)The radial sawing can easily be employed in case of logs of bigger girth (approx.1 m). It is to be used for small girth logs only if narrow width planks for furniture

V. Kothiyal


making are required, otherwise, it is not recommended because of economic reasons.This was tried on an experimental basis. The planks are sawn almost at 45o angle ineach quarter of the log. Here the growth rings are expected to be oriented almostperpendicular to board faces thus reducing the problems associated with the releaseof growth stresses during sawing. Fig. 1 gives a representation of this sawing pattern.In addition, logs of smaller girth may be used as such for fence post, overheadpower and telecommunication lines after chemical treatment. But even in radial sawingplanks develops spring.

5.1.2. Quarter sawing (QS)This method has been evolved to avail the significant advantage of the fact thatquarter sawn planks suffer almost no cracking or splitting and cupping insubsequent air or kiln drying. This is of great advantage for small units whichhave to depend upon air seasoning for their timber. This method of sawing (Fig. 2)

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Stamp

402

consists in quartering the log, followed by sawing of planks for each quadrant inthe sequence indicated. There is chance of a certain amount of two-plain warpingin the quadrants during quartering of the logs. The planks may also show a certainamount of spring (longitudinal bending of the edge in the plane of the flat faces)during sawing. The spring and non-uniformity of thickness have to be correctedby subsequent edging and planing of the planks after seasoning has beencompleted. A representation of this sawing pattern is given in Fig. 2. Planks sawnby this method, air or kiln season, without cracking and suffer very little furtherwarping. It is important to remove centre heart portions appearing on the edges ofthe quarter sawn planks, which are prone to splitting in subsequent seasoning.Portion closer to the pith, i.e., less than about 50 mm should be avoided whilesawing as they spilt and crack during seasoning.

5.1.3. Balanced tangential sawingA balanced tangential sawing was evolved that minimises, but does not completelyprevent, these defects (Sharma et al., 1988b). Planks obtained by quarter sawing,particularly from small girth logs (below 1 m girth) are rather narrow in width, notexceeding the radius of the log. To obtain wide enough planks from smaller girthlogs and to minimize the appreciable warping and non-uniformity in thickness ofthe sawn planks during sawing operation, a symmetrical sawing sequence calledBTS (Fig. 3) has been developed. This is also known as cant sawing. In thismethod, planks are sawn sequentially from symmetrically located positions oneither side of a diameter till a central slab of width equal to the minimum width ofthe desired planks remains. Thereafter, this slab is again sequentially sawn fromeither side of the diameter. Sawing is stopped about 50 mm short of the pith oneither side leaving a flitch with centrally located pith.

Warping on sawn planks has been found to be appreciably minimised by thissawing procedure due to balanced sequence of cuts. The small amount of bowing stillobtained is not a drawback for end users where the planks are to be finally fixed inposition such as in case of table tops, as planks can be flattened by a small force beforefixing. Planks show some non-uniformity in thickness which is, however, considerablyless than in plain sawing or quarter sawing. Since all planks obtained by this techniqueare tangential in cut, they need greater care as regards humidity control in air or kilndrying than quarter-sawn planks. While planks obtained from outer positions in the logdo not suffer cracking or objectionable cupping, those obtained closer than 50 mmdistance from the pith split in the centre heart portions and cup along their width.

5.1.4. Modified quarter sawing (QSM)This method too was conceived to increase the yield that was restricted inactual quarter sawing. This method is an improvement on BTS. The pattern ofsawing is illustrated in Fig. 3.

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6. Seasoning of EucalyptusDrying of materials in general and wood in particular is energy intensive, primarilybecause a high amount of energy is required to evaporate water. The economics ofwood drying depend on the higher drying rates with minimal operational cost andkeeping the quality of seasoned wood as high as possible.

Eucalypt being a highly refractory timber to seasoning, and develops severecollapse, surface cracks, warping and twisting during the process of air or kilnseasoning. As a result, in spite of all the work done, its utilization as sawn timber byand large remained a failure because of its poor seasoning behaviour (Purushothamet al., 1961). Pretreatment with urea eliminated surface, and end cracking but not thecollapse and warping which are the major defects noticed in the tangentially sawnplanks (Purushotham et al., 1961). Attempts were, thus, made to eliminate the varioustypes of seasoning defects by adopting the quarter sawing (radial sawing) processof conversion of log and developing a new seasoning schedules for drying of thesawn timber. Pandey et al. (1984) introduced a new approach for seasoning eucalypttimber and it was followed by Sharma et al. (1988b). Pandey et al. (1984) end coatedthe logs with bituminous paints immediately after felling to avoid end splitting. Halfof the log was tangentially sawn into 25 mm planks and remaining half was convertedby radial sawing. It was extremely difficult to season tangential planks free of defects(collapse, end and surface crackings, and face checking) whereas radial plank didnot show any such defects in kiln seasoning. They further recommended that thelogs should be converted into radial plank as soon as possible after felling. Forseasoning of planks more than 25 mm thick, a combination of 60 to 90 days airseasoning (to bring planks to 25-30 per cent MC) with final kiln drying of six toseven days. A high initial humidity is preferred in kiln drying schedules.

Based on diffusion theory of drying, Pandey (1995) and Pandey and Kambo(1995) on the basis of their experiments on 40 mm thick planks in steam-heated kilnrecommended IS (BIS, 1993) schedule VI and VIII for seasoning for E. tereticornisand E. camaldulensis. The timber was classified as highly refractory to seasoning.

Preliminary ‘vacuum press drying’ experiments were conducted by Pandey etal. (1999) on 40 mm thick planks obtained from low girth (60-90 cm) Eucalyptushybrid and they reported defect free planks after seasoning with 40 per cent lessenergy consumption and on an average five times faster drying as compared toconventional kiln drying method. Upreti et al. (2011) attempted solar and kilnseasoning of timber and compared the results of both.

Dehumidification drying experiments were conducted on E. tereticornis in Indiaby Chauhan and Sethy (2008) for the first time although technical feasibility studywas done for such system by Pandey et al. (1995) by studying the drying rate andenergy requirement in drying of 40 mm thick teak, toon and sisso planks.Dehumidification based wood drying systems are considered to be very energy


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efficient and produces quality dried wood without much defects. Chauhan andSethy (2008) studied drying behaviour of wood, both from mature (35 years) andyoung trees (12 years). Longer dryer time was found to have significant influence onthe rate of drying above fibre saturation point with less of degrade at lower rate.Mature wood exhibited checks and end cracks whereas timber of young trees wasprone to warping and twisting.

7. Wood PreservationAlthough having very minimal penetration in terms of amount of wood being treatedin India, wood preservation research is an important area to increase the service lifeof timber through chemical treatment. Being short rotation crop, plantation timbershave more sapwood which is non-durable. A comprehensive account of the statusof wood preservation in India is given by Gairola and Aggarwal (2005) starting fromits initiation in 1854 to treat railway sleepers by Eastern Railway. Dev (1997) reviewedthe work on treatment of Eucalyptus hybrid and discussed the progress made.Dobriyal and Dev (1992) reviewed the work on treatment of eucalypts. Woodpreservation research encompasses few important elements like natural durability oftimber (heartwood durability), treatability (or refractoriness to treatments) in termsof penetration of chemicals in timber, permeability studies, development of chemicalformulations, methods of treatments like pressure, non-pressure treatments, etc.,retention of chemical on timber along with its distribution and, finally, field trials oftreated timber. Storage of logs after harvesting, transportation and storage in depotsresults in loss of about 30 to 40 per cent and, therefore, becomes the first step intimber protection. Bureau of Indian standard prescribes 13 standards related towood preservations.

A number of studies have been made on eucalypts for enhancing their durability.The first and the foremost is the permeability of timber which is defined as the easeof flow of fluids through a material under an applied pressure gradient. Gaspermeability studies on Eucalyptus hybrid using compressed nitrogen gas wasconducted by Bahri and Kumar (1982) on samples obtained from different portionsof discs (inner heartwood, middle heartwood, outer heartwood and sapwood). Itwas observed that sapwood possessed maximum permeability, followed by outer,inner and middle heartwoods which may be due to more extractive content in middleheartwood.

Outside storage of logs of E. camaldulensis obtained from Dehradun wasinvestigated for 12 months by Kumar et al. (1979) with five different prophylactictreatments (2% solution of borax (50): boric acid (50); 2% solution CCB, 2% solutionof sodium pentachlorophenate-boric acid-borax (2:1:1), 1 per cent solution ofpentachlorophenate in water and control) for decay, weight loss, chemical analysisand pulp yield and quality. Chemical protection with sodium pentachlorophenate

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not only helped in preventing wood losses but also retained strength properties.Although CCB fixes on to wood, it did not prove to be much effective. Least effectivewas boric acid borax and other preservatives, being water soluble, lose theireffectiveness beyond four months period.

Timber species are not equally receptive to preservative treatment, it is, therefore,necessary to know the extent to which the various timber species can be impregnatedwith the preservatives using different processes. Factors like tylose formation inpores of hardwoods may hinder penetration of liquid in addition to method of timberpreparation and treatment procedure followed. For refractory timbers, methods likeincision or treatment of timber in green condition by Boucherie process is suggested.Sud and Sharma (1976) carried out treatability studies on Eucalyptus hybrid,E. citriodora and some other Eucalyptus spp. obtained from different localities inUttar Pradesh by Full cell, Lowary and Open tank (hot and cold) processes withcreosote-fuel oil mixture and copper-chrome-arsenic composition (water soluble)and concluded that the timber is non-treatable with these processes. Earlier studieson Eucalyptus sp. by Purushothm et al. (1961) using diffusion process were alsonot satisfactory. Sapwood is, however, treatable.

Kohli and Kumar (1988) conducted various experiments to improve thetreatability of Eucalyptus hybrid. Gas permeability studies were similar as reportedby Bahri and Kumar (1982) earlier. Eucalyptus hybrid failed to get adequate penetrationeven up to 42 kg cm-2 treating pressure. Precompression treatment also did notimprove preservative retention/penetration behaviour. Pre-steaming in superheatedsteam for one hour improved absorption. Vacuum pressure treatment usingpentachlorophenol in an organic solvent was able to achieve a lateral penetration of2.5 mm with adequate preservative retentions in the treated shell. Such treatmentscan be used for treatment for prefinished door and window shutters, trussed rafters,purlins, etc., for which the timber is being utilised. Subsequently, some success wasachieved by Dev et al. (1988) in getting recommended dose of borax: boric acidfollowing pretreatment with ammonia vapours in Eucalyptus hybrid. In their anotherset of experiments (Dev et al., 1991) with slightly modified composition of ammonicalcopper arsenite (ACA) by simple soak treatment for eight days adequate penetration(5-8 mm) and absorption of preservative (~ 10 kg m-3) in heartwood was achieved.This was a useful development for protection of eucalypt timber in highly hazardousareas. Samples treated with 4 per cent ACA dip treatment for one week protectedunincised and incised samples up to seven years (Tripathi et al., 2005). Narayanappa(2008) studied the influence of ponding on treatability of Eucalyptus hybrid bydiffusion. Morrell et al. (1988) suggested fumigant treatment of Eucalyptus. Devand Kainth (1993) evaluated the natural durability and treatability of E. tereticornisand reported it to be moderately durable (class II) and very refractory (class ‘e’) totreatment. E. globulus is regarded as durable timber and E. camaldulensis as


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moderately durable. Dhamodaran and Gnanaharan (2004) in a separate experimentwere successful in treating green timber of E. grandis (regarded as non-durable)with boron compounds (boric acid and borax, 1:1.5) employing vacuum pressureimpregnation. Pandey et al. (2000) studied hygroscopic and shrinkage behaviour ofammonical copper arsenite treated wood.

For species like Eucalyptus, pre-steaming, prior to creosote treatment, wasfound to improve penetration in heartwood. For sawn wood products, where blackcolour of creosote is not acceptable, modified preservative formulations containingpenetrating ions have been found suitable to obtain reasonable penetration andabsorption of toxic elements (Dev et al., 1991). Sap displacement method developedby FRI and IWST has proven to be useful for treatment of eucalypt poles. Resultsof limited studies on Eucalyptus hybrid with different preservative treatmentswere not encouraging for its use in cooling tower (Tripathi and Bagga, 2008).

8. Wood Working and Finishing Qualities

8.1. Wood Working QualitiesThe most common wood working operations through which timber invariably passesduring fabrication and assembly are planing, shaping, boring, turning, mortisingand sanding which can be performed either with hand tools or mechanically. Underthese operations, timbers behave differently and a number of defects like raisedgrain, fuzzy and torn grain, tear out, crushing, etc., occur and their intensity varies.Their removal at finishing stage involves extra energy.

Eucalyptus hybrid and E. camaldulensis from New Forest, Dehradun weretested by Jaitly et al. (1983) under six wood working operations namely planing,sanding, turning, shaping, boring and mortising following the procedure prescribedin ASTM (1964) and IS 8292 (BIS, 1993) and suitably modified by Rawat et al. (1974)for the test specimen. The results obtained are presented in the Table 7. Ease ofworking was also worked out and compared with teak taken as 100. These are alsopresented in the Table 7. On the basis of both quantitative method of evaluation andvisual examination working quality index compared to teak is also presented in theTable. The working quality index which gives indication of the overall performanceof the timber compares well with teak in this respect.

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Table 7. Working qualities of Eucalyptus as compared to teak

*with cutters at 30o; * % of excellent specimen; *** expressed as % of teak.

Species Planing* Sanding* Turning* Shaping* Boring* Mortising* Working quality

index*** Teak 16 56 36 10 43 34 100 Eucalyptus hybrid 33 57 50 65 65 17 98 E. camaldulensis 5 60 40 30 94 12 88

Species

Teak E. tereticorE. camaldu


8.1.1. Eucalyptus hybridThe test results of Jaitly et al. (1983) concluded that Eucalyptus hybrid is a fairlyeasy timber to saw and machine. Being a heavy timber in sawing, the saw bladehaving tooth angle of clearance 10o and angle of hook 15o should be used for obtaininggood results. In machine planing, cutters set at 30o cutting angle give better results.In turning and shaping also, it behaved well enough. Clear bores and mortises wereobtained on worked surfaces. The defects like-raised grain, fuzzy grain, torn grain,etc. were also observed on the test specimen. However, after carefully sanding thetest specimen, all machining defects could be removed. Even after sanding, somewoolly surface with less severity was noticed.

8.1.2. E. camaldulensisThe wood of this species generally has a fine decorative appearance. It is an easytimber to saw and work. In sawing, saw blade having tooth with clearance angle of10o and hook angle of 15o is recommended for obtaining good results. In machineplanning, the cutters set at 200 cutting angle gave satisfactory results due to severeoccurrence of fuzzy and torn grain. In turning and shaping, it behaved very good. Inboring and mortising, clear acceptable bores and mortises were obtained. Aftercarefully sanding the test specimen, the machining defects like raised grain, torngrain, etc., are not observed but some fuzzy surfaces were noticed. Its workingquality index reveals that overall performance of this species is comparatively lowerthan Eucalyptus hybrid and teak.

Shukla et al. (1991a) put considerable efforts in developing methodologies to quantifythe quality of worked wood surface and developed an index for wood working andcarving quality taking teak as standard (100), so that meaningful comparison could bemade between different species. In their study, they evolved working quality index for 74species and carving quality index for 11 species which includes E. camaldulensis andE. tereticornis. The indexes for both the species are given in Table 8 and Table 9.

Species Specific gravity

Best cutting

angle* (o)

Overall performance

(CRF)

Ease of working

Working quality index

Grouping (overall

performance)

Comparative performance

(turning) Teak 0.556 25 100 100 100 I 100 E. tereticornis - 30 130 76 84 I 60 E. camaldulensis - 20 64 84 76 III 107

Table 8. Working quality index

*In planing.

Table 9. Carving quality taking teak as 100

Species Specific gravity

Overall comparative performance under

combined wood working operations

Overall comparative performance under carving operations

Carving quality index

Teak 0.556 100 100 100 E. tereticornis 0.785 130 111 105 E. camaldulensis 0.718 64 111 107

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8.2. Wood FinishingWood finishing is the final makeup on any timber product in the form of a thin film ofpaint, polish, lacquer, etc., coated on its surface or otherwise. During use, this finishmay be subjected to a number of fluctuating conditions, alternate wetting and drying,exposure to light radiations, diurnal and cyclic variations, heat, dust, etc. The timbermust, therefore, be capable of preserving its own compactness, apart from protectingthe timber from dust, shrinking and swelling (movement or working of timber), raisingof grains, decay, colour change and general weathering degrade to some degree, ifnot completely. Badoni (1987) has described the various operations of wood finishingin detail starting from sanding to polishing and the trends in finishing. Jaitly et al.(1983) studied finishing qualities of E. camaldulensis and Eucalyptus hybrid underfive polishing operations (Table 10). The results of treatment reveal that high gloss;i.e., over 70 per cent was obtained in both of the species by application of artificialfilms of polish. Both the species required comparatively less labour and fillers.Commercial glossy finishes were applied by Pandey et al. (2007) on E. tereticornisin their study for timber obtained from Punjab.

9. Recommended Uses of Solid Wood of Eucalyptus SpeciesAlthough most of the plantation of eucalypts in the country are being raised keepingin view their industrial potential as a short fibre pulpwood, their utilization for otherpurposes in solid wood form cannot be overlooked specially due to shortage ofconventional timbers for construction, etc. on one hand and availability of eucalyptwood in the market in good quantities on the other. Many researchers evaluatedvarious properties of Eucalyptus species and based on the properties, the timbershave been classified for various applications. Rajput and Tewari (1984) reviewed thework done on Eucalyptus hybrid till then in their article ‘Utilisation of Eucalyptushybrid’. Later, Rajput and Shukla (1989a) published an article ‘Properties andutilisation of Eucalyptus wood’. Meeting the wood quality requirement of industriesfrom plantation has been thoroughly discussed by Bhat (1986). Rajput et al. (1985)classified and graded the timber of various Eucalyptus species, tested till then, fromvarious localities based on minimum value reported for particular species for structuraluse. Classification given by Rajput and Tewari (1984) of Eucalyptus hybrid wasbased on eight-year-old plantation from single location (Mahakanam, Tamil Nadu).Chauhan and Aggarwal (2011) segregated some clones of E. tereticornis for solid

Table 10. Finish adaptability and gloss of Eucalyptus hybrid compared to teakPer cent gloss developed after giving surface treatments I to V Species

I II III IV V Finish adaptability

Teak 85 82 81 82 80 100 Eucalyptus hybrid 85 85 87 91 92 104 E. camaldulensis 92 95 90 90 94 116

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wood utilization based on wood properties. The present chapter reviews the workdone so far and classifies the timber accordingly. Table 11 gives the classificationbased on timber tested from different localities. Mostly the timber falls under groupB and C with an exception of timber tested from Bangalore. As it is not alwayspossible to identify exact species of Eucalyptus, the timber available can be safelyused at least as Group C timber for structural use.

On the basis of modulus of rupture of small clear specimens tested as per IS:1708 (BIS, 1986) in green condition, Eucalyptus species tested from different localitieshave been classified for wood poles (Jain et al., 1991) in different groups in Table 11.Eucalyptus hybrid (E. tereticornis) can be safely taken as group B timber on thebasis of strength properties for poles. On the basis of testing on full length poles(Rajput and Jain, 1988), E. tereticornis and E. camaldulensis have been recommendedas Group B timber as per IS: 876 (BIS, 1992). The data on other species is limited(Table 11) but based on available data, these can be used as Group B timber for woodpoles. Due to the strain in wood the Eucalyptus poles have a tendency to split. Theeffect depends upon the wood structure and fibre arrangement of different typespecies. Species with straight fibres are likely to split at the ends of the poles,particularly, if they are grown quickly. Species with interlocked grain may splitinfrequently and are preferable for the pole industry even if their rate of growth isless than some other species. The splitting can be reduced by slowing down thegrowth before harvest. Air-drying debarked poles under shade significantly reducesend splitting. End splitting can also be reduced by felling in the dormant season,


Table 11. End use classification of Eucalyptus species

*over head poles for power-telecommunication lines and scaffholding.

coating the ends with bitumen or by immersing in cold water for six weeks. On thebasis of the strength values of Eucalyptus hybrid in round form, it is suitable forscaffolding purposes in building industry as well as for ballies for erection oftemporary structures and fence posts (Rajput et al., 1980).

As handles for different types of tools and agricultural implements are veryimportant for rural folk, suitability of Eucalyptus species has also been investigated(Kumar et al., 1981b; Rajput and Gulati, 1984; Kamala et al., 1995-1996). The

S. no.

Species Age (yr)

Wood shutter

Wood frame

Dunnage pallet

Mining use

Structural utilization

Wood pile

Tool handle

Over head pole

1. Eucalyptus hybrid 6-30 - - - B-C - II A-C(B) 2. E. tereticornis 14-59 II(B) - III III C - - B 3. E. globulus - I I - B II - B 4. E. camaldulensis 10-14 - - I C - III B-C 5. E. citriodira 8-20 - - - B - - - 6. E. grandis 14 - - - C - - B 7. E. eugenioides - - - B - - B 8. E. pilularis - - - C - - B 9. E. propinqua - - - C - - B 10. E. saligna - - - C - - C

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mechanical suitability of any species for making tool handles is basically assessedby its tool handle figure (T.H.F) determined by combining various suitability figures(shock resisting ability, strength as beam, strength as a post and hardness withweightage factor of 3, 2, 2 and 1, respectively). Rajput and Gulati (1984) estimatedthat T.H.F. for Eucalyptus hybrid of specific gravity varying between 0.596 and0.744 will be in the range of 85 to 119. According to his classification, Eucalyptushybrid falls in Group II and even the worst lot is expected to fall at least in Group III.According to IS: 620 (BIS, 1975), there are five classes of handles and the species issuitable for making handles of class II to V. T.H.F of E. camaldunesis on the basis oftimber tested so far falls between 83 to 106 and can be said to fall at least in Group III.

E. tereticornis (Mysore gum) belongs to durability class III, treatability class‘e’ and classified as group A refractory timber with weight of 96 having strengthcoefficient of 81 for wood shutters is classified in group II(b) for wood shuttersapplications (Gupta et al., 1989; Rajput and Sharma, 1997). They also classifiedE. globulus as group I timber for wood frames. E. globulus has strength coefficientof 103 and belongs to durability class I, treatability class ‘e’ and classified as refractoryto seasoning (Group A). E. globulus and some other Eucalyptus spp. (mainlyE. tereticornis) were also found suitable for dunnage pallets as group I and groupIII timber, respectively (Shukla et al., 1984). E. tereticornis and E. camaldulensis arealso found suitable as group III and group I timbers, respectively for mining use(Purthi et al., 1991). Studies on the utilization of Eucalyptus hybrid for the manufactureof bobbins/weft pirns for automatic cotton looms (Jain et al., 1992) have beenconducted. On the basis of available data on physical, mechanical and woodworkingproperties, the species compares very well with the six approved timbers (Adinacardifolia, Betula spp., Mitragyna parviflora, Acer spp., Zanthoxylum rhetsa andDysoxylum malabaricum) for weft-pirn as recommended in IS: 4417-1967. Eucalyptusrequires slightly less machine speed at the grooving stage. The timber should beradial or balanced tangentially sawn and properly seasoned before undertaking thepirn manufacturing process. Difficulty associated with using Eucalyptus hybrid asmatch splint were also studied by Kumar et al. (1981b). The timber of E. globulushas been classified as group II timber for wooden piles (Purthi et al., 1989).

Jaitly et al. (1983) on the basis of the results of working qualities and finishadaptability concluded that Eucalyptus hybrid and E. camaldulensis worked tosmooth surface fairly easily and high gloss as compared to teak. Shukla et al. (1991a)reviewed the working qualities of 74 timbers species on the basis of their planing,turning, boring, mortising, shaping and sanding qualities. According to them, on thebasis of overall performance E. tereticornis falls under group I where asE. camaldulensis falls under group III. Bhat (1992) concluded that young Eucalyptustrees can give excellent furniture at 16 years of age. Rajput and Gupta (1992) classified102 timber species into 4 groups for furniture making and placed E. tereticornis in

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the last group (Group III) among the four groups referred as super group, group I,group II and group III. By the method of classification used by Rajput and Gupta(1992), Eucalyptus hybrid and E. camaldulensis also qualifies in group III for furnituremaking.

Efforts have been to make bent wood furniture of eucalypt by plasticizing withammonia vapours. Pandey et al. (1991) conducted a number of experiments for bendingeucalypt wood after plasticizing it with ammonia. Dubey et al. (2004) established thatplasticization with ammonia has no adverse affect on strength properties ofE. tereticornis although specific gravity showed significant increase. Some experimentsusing ammonia fumigation have been carried out (Badoni et al., 1990; Badoni andRajput, 1997) for improving the colour and appearance of eucalypt furniture anddecorative items. Indians are obsessed with the colour and appearance of timbers liketeak, rosewood, padauk and others. Considering this, experiments were conducted tochange the shades of eucalypt wood to dark by fumigating finished products withammonia using different time intervals in a closed chamber. Different shades arepossible suiting one’s requirement. The concept of diaper for utilising pieces of wastewood of different species having varying colours developed as artwork producinghigh value products such as decorative table top, wood box and many other articles.This technology of diaper was adopted for utilising eucalypt and very good qualitydiaper boards were developed. This was possible because wood working propertiesof eucalypt are comparable to teak and the surface of this wood take up polishes tohigh gloss levels. Its introduction for quality furniture manufacture has been possibleby evolving a simple, inexpensive and effective technique of ammonia fumigation,which brings out the latent figures and provides a walnut look suitable for high-classtimber works. By controlling fumigation intensity, thin sections of eucalypt are imparteddifferent shades of colours. These pieces of different colours are glued and used fordiaper work for making decorative tabletops, gift boxes, handicraft item, etc.

10. New Areas of ResearchAssessment of quality of wood produced is becoming extremely important with theaim to optimise utilization of raw material resources for economic gains and improvewood properties of plantation crop. Cost, time, simplicity of method adopted andaccuracy of results of analysis have become important in addition to multiplicity ofsimultaneous analysis that can be conducted through non-invasive means. Nearinfrared (NIR) spectroscopy has given such option fitting to all above criteria forestimating many wood properties. Reviews by various researchers have highlightedthe emergence of NIR spectroscopy along with its utility in the field of wood science,paper and forestry. Being indirect method, NIR spectroscopy needs calibration to beestablished between spectral data set and its known data (property of interest).Forest Research Institute, Dehradun took up the work of developing NIR


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spectroscopy based methods in the country for evaluating the chemical, physicaland mechanical properties of timber. Kothiyal and Raturi et al. (2011) proposedmethods for evaluation of specific gravity and mechanical properties of timber fromE. tereticornis having broad moisture content below fibre saturation point.Subsequently, a method for estimation of Klason lignin content was proposed(Kothiyal et al., 2012). Raturi et al. (2012) reported near infrared spectroscopy (NIRS)based models for evaluating specific gravity of E. tereticornis. In another study,Kothiyal et al. (2014) developed composite models with radial and tangential facespectra and compared them with models developed with radial and tangential facespectra alone obtained from E. tereticornis. This study has been the first report inthis direction and is reported to enhance the practical ability of NIRS for determinationof specific gravity. Introduction of NIRS in India in the field of wood science is awelcome step as more and more material will be required for evaluation at low cost,high speed and with improved accuracy in a non-invasive manner.

11. Future Research AreasEucalyptus species have been useful in bridging the shortfall between demand andsupply. Its utilisation as solid wood has been possible through scientific interventionby development and adoption of appropriate technology. However, some areas ofresearch which will require attention are:

Appropriate grading standard by incorporating characteristics associatedwith plantation timbers.Developing crop with desired traits for specific end use.Identifying trees having low ratio of tangential and radial shrinkage whichmay result in less of seasoning defects and improved dimensional stability.Negligible longitudinal shrinkage is also desirable.Controlling of growth stresses.Improvement in seasoning technology for reducing cost and time.Improvement in preservation technology.Value addition in products.

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measuring fracture toughness and using fracture mechanics - fifth report ofa special ASTM Committee. Materials Research and Standards, 4(3): 107-119.

Aggarwal, P. and Chauhan, S. 2013. Longitudinal growth strains in five clones ofEucalyptus tereticornis Sm. Journal of Forestry Research, 24(2): 339-343.

Aggarwal, P.K.; Chauhan, S.S.; Karmakar, A. and Ananthanarayana, A.K. 1997.Measurement of longitudinal growth strains in Eucalyptus tereticornisby strain gauge technique. Wood News, 7(4): 27-30

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BIS (Bureau of Indian Standards). 1975. General requirements for wooden toolhandles. IS 620: 1975. New Delhi, BIS.

BIS (Bureau of Indian Standards). 1986. Methods of testing of small clear specimensof timber. Part 3. IS 1708: 1986. New Delhi, BIS.

BIS (Bureau of Indian Standards). 1992. Wood poles for overhead power andtelecommunication lines – Specification. IS 876: 1992. New Delhi, BIS.

BIS (Bureau of Indian Standards). 1993. Evaluation of working qualities of timberunder different wood working operations – Methods of test. IS 8292: 1993.New Delhi, BIS.

BIS (Bureau of Indian Standards). 1993. Seasoning of timber – Code of practice. IS1141: 1993. New Delhi, BIS.

Badoni, S.P. 1987. Role of wood finishing on timber utilization. Journal of the TimberDevelopment Association of India, 33(1): 5-14.

Badoni, S.P.; Gupta, S.B. and Shukla, K.S. 1990. Preliminary studies on ammoniafuming of some Indian timbers. Journal of the Timber DevelopmentAssociation of India, 36(2): 24-30.

Badoni, S.P. and Rajput, S.S. 1997. Upgradation and utilization of secondary timbersfor furniture through ammonia fumigation. In: 1st All India Peoples’ Technology,Congress, Calcutta, 21-23 February 1997. Proceedings. pp. 37-39.

Bahri, S. and Kumar, S. 1982. Permeability studies on Eucalyptus hybrid. Journal ofthe Timber Development Association of India, 28(3): 32-43.

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1. IntroductionA composite can be defined as a combination of two or more elements held togetherby a matrix. By this definition, what we call ‘solid wood’ is a composite. Solid woodis a three-dimensional composite composed of cellulose, hemicelluloses and lignin(with smaller amounts of inorganics and extractives), held together by a lignin matrix.Therefore, composite wood may be described as any wood material adhesivelybonded together. Wood-based composites cover a range of products, from plywood,blockboard, particle board, fibreboard to laminated beams. Wood-based compositesare used for a number of structural and non-structural applications in product linesranging from panels for interior covering purposes to panels for exterior uses, infurniture and support structures in buildings.

The basic element for wood-based composites is the fibre, with larger particlescomposed of many fibres. Elements used in the production of wood-based compositescan be made in a variety of sizes and shapes. Typical elements include veneers,fibres, particles, flakes, laminates, or lumber. Element size and geometry largely dictatethe product manufactured and product performance.

The advantages of developing wood composites (1) use of smaller trees, (2) useof waste wood from other processing, (3) removed of defects, (4) creation of moreuniform components, (5) development of composites that are stronger than theoriginal solid wood and (6) ability to make composites of different shapes. Historically,wood was used only in its solid form as large timbers. As the availability of large-diameter trees decreased (and the price increased) the wood industry started to lookfor replacing large-timber products and solid wood with reconstituted wood productsmade from smaller diameter trees mostly of fast growing plantation species and sawand pulp mill wastes. There has been a trend away from solid wood for sometraditional applications towards smaller element sizes.

In the present era of environmental consciousness, more and more materialsare emerging in construction, furniture and other sectors as substitutes of wood.

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Wide ranges of plastics, synthetic material, metals, etc. are being used to substitutewood. However, the real wood substitution and service to environment is possibleif this material is sustainable as well as renewable. Only the lignocellulosic materialscome under this class besides a tree of forest or plantation origin. The fascinatingworld of composite wood in the form of panels and panel products is, thus, havingan edge over these other substitutions and even surpassing solid wood in somecases.

From the historical perspective, Egyptians were the first to saw a log and also toexperience the grace of veneer in figured woods obtained from peeling and slicing(Skeist and Miron, 1990). The merit of peeling/slicing over sawing was then utilizedin making commercial plywood for large tea chests and drums. The wood logs liketeak were peeled/sliced to obtain decorative veneer of quite sizable area to produceabout 50 sheets of OST (one side teak) ply from a log of one metre girth and standardlength. This example clearly highlights the value-addition level inherent to peelingand slicing, and such a ply comes under decorative class used by upper incomestrata of society.

Further, plywood makes it possible to use a large variety of tropicalhardwoods in contrast to solid wood utilization, where only a limited species liketeak, sissoo, and rosewood dominated the scene. Presently, more than 80 woodspecies are recommended for plywood manufacture using appropriate qualitycontrol measures during manufacturing of plywood (Khali et al., 2003). It isthus, interesting to note that peeling/slicing surpasses sawing in utilization ofthe material or obtaining of veneers of fascinating class from figured wood.Even today, teak, rosewood, sissoo and padauk veneers are in great demand formaking plywood of decorative class.

From the humble beginning cited above, successive advancements in panelproducts did not remain restricted to the log-based plywood panel making and,thus marched ahead targeting almost every lignocellulosic material and surpassingthe product range and variety that cannot be imagined in solid wood. Thischallenging task of fibre arrangement, alignment and layering has revolutionizedthe infrastructural processing and associated R&D to such a level that the panelsand composites of different types are continuously emerging in the trade as staplematerial for a wide range of products and, thereby, economizing the use of woodand saving a tree in true sense.

Panel products in fact appeared to be in tune with the developmental strategicparameters, which take into account the factors like comfort, convenience, stylebesides economy. The technology is high tech and the products are made withthe latest trends even though they are lignocellulosic in nature. In the case ofsolid wood products, the trends are somewhat antique or traditional. One canthus expect that composite wood panels of diverse range and class are going to

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emerge in the near future. Even the conventional solid wood wedding bed, ahumble but essential gift, is now a panel product in most of the cases.

The developments in composite wood industry in the country are mainlyattributed to the pioneering work carried out in the field of plywood, particle board,fibre board, adhesives at Forest Research Institute, Dehradun and elsewhere,involving the broader R&D areas essential to improve these products andincorporated the aspects of durability, permeability, lamination, compression andimpregnation. This chapter gives an account of work conducted on composite woodmanufacture from eucalypt wood.

2. PlywoodPlywood is made from thin sheets of veneer that are cross-laminated and gluedtogether with a hot-press. The wood veneer is literally peeled from the log as it isspun. Throughout the thickness of the panel, the grain of each layer is positionedperpendicular to the adjacent layer. There are always odd number of layers in plywoodpanels, so that, the panel is balanced around its central axis. This strategy makesplywood stable and less likely to shrink, swell, cup or warp. However, the plywoodmay be the result of combination of the same material from a log or a tree or may becontaining different species for different layers with a central symmetry. The plywood,thus, provides the entrepreneurs or researchers to try the best combinations fromthe economic angle (commercial) and from the functional angle (speciality). Suchexperimentation is more demanding for plantation species to economise the productand improve the quality.

Plywood industries in the country have been undergoing acute shortageof timber for manufacturing of plywood due to ban on green felling of naturalforest. As a result the plywood industries started looking for alternatives.Large scale plantations of poplar (Populus deltoides) and eucalypts(Eucalyptus species) have been undertaken in various part of country. Thesuitability of poplar for plywood is well established (Rajawat and Bist, 1981;Shukla et al., 1986). Efforts have been made for assessing the suitability ofeucalypts for manufacturing of plywood and eucalypts for general-purposeinterior grade plywood (Shukla and Negi, 1997). Initially, the investigations ofsuitability of Eucalyptus hybrid for making plywood were carried out during1978 at Forest Research Institute (Gupta and Chauhan, 1978). It was reportedthat Eucalyptus hybrid does not give satisfactory bond with urea formaldehyde(UF) and phenol formaldehyde (PF) resins in the ordinary course and offersdifficulties; but after modifying the resin with wetting agents and plasticisers,it is possible to obtain satisfactory bond (Gupta and Chauhan, 1978). Theeffect of extractives and additives on glue adhesion strength was also studiedand it was reported that extraction does not improve gluing in general. It was

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only in case of alcohol/benzene extraction that an improvement in bond strengthwith UF and PF resins (Gupta and Chauhan, 1978). The effect of removal ofextractives on wettability and glue bond quality of Eucalyptus hybrid wasinvestigated (Negi and Rajawat, 1984). The wettability was measured bycorrected water absorption height (CWAH) method. It was reported that gluebond strength increased with increase in CWAH values. The influence ofextractives in Eucalyptus hybrid on glue bond strength of UF bonded plywoodwas further investigated by Negi et al. (1990). It was reported that extractionwith acetone was found to be most effective as it improved the bond strengthby 26.95 per cent, followed by hot water (19.62%) and alcohol-benzene (11.48%).Gelation time of UF resin was adversely affected by acetone soluble extractivesfollowed by hot water extractives and then alcohol-benzene extractives. Amongthe different extractions tried, only hot water extraction of Eucalyptus hybridveneers or swabbing of veneer surfaces with acetone appeared to be practicableand economically viable (Negi et al., 1990). Eucalypt thus has a potential forcommercial exploitation in plywood manufacture (Fig. 1).

3. Combi PlywoodThere are difficulties in getting single species for making of plywood. Therefore, thecombi plywood may be the solution for this problem. Combi plywood is thecombination plywood made of veneers of different species. Combi plywood usingpoplar (Populus deltoides), eucalypts (Eucalyptus hybrid) and paulownia(Paulownia fortunei) were developed for general purpose (exterior grade) (Khali etal., 2004, 2006) as well as general purpose (interior grade) (Khali et al., 2005). It wasreported that combi plywood for general purpose (exterior grade) made of combinationof eucalypt – paulownia - eucalypt (EPE) and poplar – eucalypt - poplar (PopEPop)veneers meet the Indian standards specifications at all the three pressure levels,viz., 10.5 kg cm-2, 14.0 kg cm-2 and 17.5 kg cm-2 and combination of eucalypts – poplar- eucalypts (EPopE) meets the Indian standards specifications at two pressure level14.0 kg cm-2 and 17.5 kg cm-2. Combi plywood for general purpose (interior grade)made of combination of EPE, EPopE and PopEPop veneers meet the Indian standardsspecifications at all the three pressure levels, viz., 10.5 kg cm-2, 14.0 kg cm-2 and 17.5kg cm-2. Combi plywood made using poplar, eucalypt and paulownia veneers in thecombination poplar – poplar - poplar (PopPopPop); EPE; EPopE; PopEPop withwater borne preservatives CCA and CCB are described. It was observed that plywoodmade of poplar veneers and combination of EPE and PopEPop veneers after treatmentwith water borne preservatives CCA and CCB meet the Indian standards specificationsat all the three pressure levels, viz., 10.5 kg cm-2, 14.0 kg cm-2 and 17.5 kg cm-2 andcombination of EPopE meets the Indian standards specifications at two pressurelevel, viz., 14.0 kg cm-2 and 17.5 kg cm-2 (Khali et al., 2006).

425Composite wood from eucalypts

4. Particle Boards and Fibre BoardsWork on fibre building boards and particle boards in the country was initiated atForest Research Institute, Dehradun in 1950s and a large number of raw materialshave been evaluated for their suitability for making fibre building boards andparticle boards. For fibre board, suitability of unbarked Eucalyptus hybrid includinglops and tops, thinnings and twigs, was studied and it unbarked Eucalyptus hybridwas found a suitable raw material for hardboard manufacture. The standardhardboards could be prepared with additive after heat tempering and temperedboards after oil tempering (Chauhan and Bist, 1983, 1987). The suitability of

(a) Making of veneer from eucalypt logs. (b) Core wood left out after process of veneering.

(c) Process of plywood manufacture fromeucalypt veneer.

(d) Finished product ready for marketing.

Fig. 1(a-d). Process for manufacture of plywood from eucalypt wood.

426 D.P. Khali

Eucalyptus grandis bark as a raw material for manufacture of hardboards was alsostudied (Mehra, 1978). It was reported that Eucalyptus grandis bark being capableof forming good boards can be mixed with any timber species used for hardboardsin any ratio (Mehra, 1978).

Particle boards can be prepared with relatively lighter species. The heavierspecies such as eucalypts can also be used for manufacturing of particleboard at higher specific pressure. However, for manufacture of particle boardwith eucalypts at lower specific pressure, the lighter species such as poplarcan be used in mix with eucalypt. Particle boards prepared with lops and topsof eucalypt at three pressure level 17.5 kg cm-2, 21 kg cm-2 and 24.5 kg cm-2 with6 per cent, 8 per cent and 10 per cent resin content (Khali, 2011) and it wasreported that particle board can be prepared with 24.5 kg cm-2 specific pressureand 10 per cent and 12 per cent amount of resin. Particle boards with lops andtops of five poplar to eucalypt particle ratios (100:0, 75:25, 50:50, 25:75 and0:100) were also prepared at two pressure levels 17.5 kg cm-2 and 21 kg cm-2

with 6 per cent, 8 per cent and 10 per cent resin content with and withoutaddition of thermally conductive filler (Khali, 2011) and improvement ininternal bond strength, water absorption, thickness, swelling due to surfaceabsorption, length expansion and width expansion of the boards was reported.Therefore, thermally conductive filler can be used in particle boardmanufacture as a sizing material as well as for improvement of internal bondstrength (Khali, 2011).

5. Destructured Reconstituted WoodAttempts have been made to develop technologies for utilisation of woodresidues such as lops and tops of eucalypts into value-added products tosubstitute solid wood. Products like particle board and fibre board have beendeveloped. These products, though suitable for a variety of uses as sheetmaterial, lack the directional strength properties required in a product for use asstructural material.

Structural wood has been produced at Forest Research Institute from lopsand tops of eucalyptus (Shukla and Negi, 1996). In this process raw material inthe form of sticks are destructured by passing through counter – revolvingrollers in such a way that their fiber orientation is not disturbed. The reconstitutedmaterial is resin treated and consolidated under the influence of heat and pressure.Physical and mechanical properties of reconstituted products were studied andcompared with teak. Results indicate that modulus of rupture and other propertiesof the products are comparable with teak. Structural wood developed is akin tosolid wood in appearance. It can be bored, shaped, nailed, screwed with handand machine tools. It can also be painted and polished with ease.

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ReferencesChauhan, B.R.S. and Bisht, J.P.S. 1983. Hardboard from Eucalyptus hybrid. Van

Vigyan, 21(3-4): 99-101.Chauhan, B.R.S. and Bisht, J.P.S. 1987. Hardboard from unbarked Eucalyptus hybrid.

Indian Forester, 113(3): 185-190.Gupta, R.C. and Chauhan, B.R.S. 1978. Plywood from Eucalyptus hybrid.

Holzforschung und Holzverwertung, 30(3): 54-55.Khali, D.P. 2011. Development of quality wood composite from lops and tops of mixed

plantation species (FRI-460/FPD(CW)-72). Project completion report.Dehradun, ICFRE.

Khali, D.P.; Negi, Anil and Badoni, S.P. 2003. Quality control measures for plywoodand other panel products. In: 1st Seminar on Panel Industry-Wood andBeyond, New Delhi, 5th September 2003. Proceedings.

Khali, D.P.; Negi, Anil and Jain, V.K. 2004. Combi plywood of plantation species -Eucalyptus hybrid, Populus deltoides and Paulownia fortunei. In:National Seminar on Wood Substitution through Engineered Wood,Bamboo and other Lignocellusosics, Bangalore, 17th December 2004.Proceedings.

Khali, D.P.; Negi, Anil and Singh, J.P. 2005. Combi Plywood for general purpose(interior grade) of plantation species – Eucalyptus hybrid, Populusdeltoides and Paulownia fortunei. Journal of the Timber DevelopmentAssociation of India, 51(1-2): 43-50.

Khali D.P.; Negi, Anil; Singh, J.P. and Jain, V.K. 2006. Combi plywood forgeneral purpose (exterior grade) of plantation species –Eucalyptus hybrid, Populus deltoides and Paulownia fortunei.Journal of the Timber Development Association of India, 52(3-4): 70-78.

Mehra, M.L. 1978. Hardboards from Eucalyptus grandis bark. Journal of the TimberDevelopment Association of India, 24(2): 28-33.

Negi, Anil and Rajawat, M.S. 1984. A note on the effect of extractives on wettabilityand glue bond quality of Eucalyptus hybrid. Journal of the TimberDevelopment Association of India, 30(3): 33-36.

Negi, Anil; Rajawat, M.S. and Shukla, K.S. 1990. Influence of extractives in Eucalyptushybrid on glue bond strength of UF bonded plywood. Journal of the TimberDevelopment Association of India, 21(1): 13-17.

Rajawat, M.S. and Bist, B.S. 1981. Plywood from Indian timbers. Part VI. Van Vigyan,19(3): 108.

Shukla, K.S. and Negi, Anil. 1996. Reconstituted wood from Eucalyptushybrid. Journal of the Timber Development Association of India, 42(1):5-8.

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Shukla, K.S. and Negi, Anil. 1997. Gluing behaviour of Eucalyptus hybrid withUF adhesive for MR grade plywood. Journal of the Timber DevelopmentAssociation of India, 43(4): 10-18.

Shukla, K.S.; Rajawat, M.S. and Shukla, L.N. 1986. Plywood from Indian timbersPopulus deltoides. Journal of the Timber Development Association ofIndia, 32(3): 13-23.

Skeist, I. and Miron, J. 1990. Introduction to adhesives. In: Skeist, I. Ed. Handbookof adhesives. 3rd ed. New York, Van Nostrand Reinhold.

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1. IntroductionThe genus Eucalyptus L’Herit (Myrtaceae) is native to Australia and is amongst theworld’s most widely planted genera. It is reported to comprise about 800 species oftall trees and mallees that are primarily grown for timber, paper pulp and volatile oil.Besides, eucalypts also find use in folklore, arts and crafts, floriculture and amenityplanting (Ghisalberti, 1996).

From cough care to tension reliever, the woody scented oil and leathery leavesof eucalypt have found myriad uses over the centuries. Australian aborigines reliedon this native evergreen for soothing painful joints and healing skin lesions. Britishcolonists to the continent dubbed it ‘fever tree’ in recognition of its disease fightingpowers. Since ancient times, the bark and leaves of selected species have been usedto treat cold, influenza, toothaches, snakebites, fevers, diarrhea and many othercomplaints.

As evident by the number of patents filed and granted each year, eucalypt isone of the thoroughly exploited ‘natural resource’ of health promoters. Increasingly,the extracts prepared from eucalypt leaves are being formulated into healthsupplements/food additives and cosmetics (Amakura et al., 2002). Chewing gumsand toothpastes containing these extracts are marketed as anti-bacterial productsfor improving oral health and hygiene (Kenji and Hideyuki, 1998; Maeda et al.,2009). Eucalypt shampoos are claimed to improve hair quality while antioxidantcompositions containing eucalypts are used for prevention and treatment of radiationinjury and other skin disorders (Sakai and Koike, 2007). The extracts and compoundsisolated from leaves/bark of eucalypts also find use as bio-pesticides. Theformulations developed from eucalypt products have been patented as bio-controland/or pest control management agents (Kaushik, 2009).

Because the primary use of eucalypts is in forestry, there is a potential forgrowth of secondary industries to recover not only the essential oil as a by-product,but also other biologically important secondary metabolites of leaves and bark.

Chemistry of the GenusEucalyptusInder Pal Singh and Jasmeen Sidana

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Various classes of secondary metabolites have been reported from this genusincluding monoterpenes of the leaf essential oil. Emphasis has been laid on theclasses that are more or less exclusive to this genus, for example, formylatedphloroglucinol compounds, triketones, G-regulators and oleuropeic acid esters. Otherubiquitously occurring secondary metabolites like flavonoids, triterpenoids andtheir glycosides are also presented in the relevant sections.

This chapter is a non-comprehensive but coherent presentation of the occurrence,chemistry, biological activities, structure elucidation and biogenesis of the secondarymetabolites of eucalypts. Complete structure elucidation of representativecompounds of different classes is also presented.

2. Chemical Constituents of EucalyptusThe remarkable diversity of natural products obtained from eucalypts results fromthe unique biogenetic machineries evolved over time and the enormous gene poolof Eucalyptus species makes it possible to generate diverse secondary metabolites.These metabolites have significant roles like adaptation of the plant to harsh climaticconditions, protection from pathogens, insects and browsing animals, etc. Humancivilizations have exploited these secondary metabolites for therapeutic (preventiveand curative), nutritive as well as cosmetic purposes. This section discusses themajor classes of secondary metabolites isolated from the leaf, flower buds, bark andkino of different eucalypts. These compounds include phloroglucinols, flavonoidsand their glycosides, terpenes (mono-, sesqui-, tri-) and their glycosides, phenolicsand their glycosides, steroids, tannins and higher polyphenols. Almost every classof natural products find some representatives in this genus. Alkaloids are an exception,none reported from eucalypts so far. The biogenesis of the metabolites is presented,wherever reported.

2.1. Phloroglucinol CompoundsThe genus Eucalyptus is rich in acylated and/or formylated phloroglucinolcompounds, which are highly diverse but characterized by at least one fullysubstituted phenolic ring with one or two aldehyde groups, which are hydrogenbonded to phenolic hydroxy group. Formylated phloroglucinol compounds showa wide range of biological activities such as anti-fouling, anti-bacterial, HIVreverse transcriptase inhibitory, aldose reductase inhibitory, etc. In addition,they play a major ecological role in forests by acting as antifeedants againstherbivores.

These compounds are noted to be concentrated in the members of sub-genusSymphyomyrtus, occur at low concentrations in Corymbia and Blakella and absentin Monocalyptus and Idiogenes. Subgenus Eudesmia was found to be rich in atype of phloroglucinol-terpene adducts, viz., euglobals (Foley and Lassak, 2004).

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2.1.1. Monomeric phloroglucinolsAbout 15 compounds of this class have been reported from eucalypts. Theseinclude nuclearformylated as well as methylated derivatives. A C3 to C5branched alkyl chain is also present in the structure. Complete or partialmethoxylation of hydroxyl groups has also been observed in some cases.Methoxylated monomeric phloroglucinol compounds are generally very non-polar and have been isolated from foliar volatile oils. Formulated compounds ofthis class are medium polar in nature and may be purified by silica gel columnchromatography.

Jensenone (1), adiformylated monomeric phloroglucinol has been isolated fromE. jensenii of sub-genus Symphyomyrtus (Boland et al., 1992). Isolation strategiesfor this compound include 1) steam volatilization of constituents from the freshleaves followed by crystallization of pure jensenone, 2) hot/cold extraction followedby partitioning with aqueous base and 3) vacuum liquid chromatography of crudeextract using hexane/ethyl acetate as mobile phase. Hot Soxhlet extraction withacetone is the most efficient method for extraction of jensenone. The structure of 1has been established to be 4,6-diformyl-2-isopentanoylphloroglucinol byspectroscopic techniques.

The levels of 1 in the leaves of eucalypts have been related to the resistance ofbrowsing mammals and the consequent antifeedant activity. Antifeedant effects ofthis type of compounds are related to their facile binding to amino groups ofbiomolecules in the gastro-intestinal tract, leading to the loss of their metabolicfunction (Mclean et al., 2004).

Grandinol (2), isolated from E. grandis, is another widely studied monomericformylated phloroglucinol. The structure of grandinol was established byspectroscopic, X-ray and synthetic studies (Crow et al., 1977). Grandinol and itshomologue, homograndinol (3) have shown germination inhibitory activity (Bolte etal., 1985), Epstein Barr virus inhibitory activity (Takasaki et al., 1990) andphotosynthetic electron transport inhibitory activity (Yoneyama et al., 1996).Grandinol was also found to inhibit transpiration and stomatal opening (Yoneyamaet al., 1989). It exhibited anti-bacterial activity against Bacillus subtilis andStaphylococcus aureus (5 μg/mL and 25 μg/mL, respectively) (Nakayama et al.,1990).

As stated earlier, the occurrence of methoxylated monomeric phloroglucinols iscommon in eucalypts. However, methoxylation has only been witnessed in non-formylatednuclear methylated phloroglucinols. 4-O-demethyl miniatone (4) is amonomethoxylated compound isolated from E. jensenii. Further, miniatone (5)reported from E. miniata is a dimethoxylated derivative and torquatone (6) – is thetri-methoxylated monomeric phloroglucinol. Fig. 1 presents the structures ofmonomeric phloroglucinols of eucalypts.

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H O O H

OH O

R 1

R2

1: R1 = R 2 = C HO2: R1 = C HO , R2 = C H3

H O O H

OH O

C H O

H 3C

3

R 1O OC H3

OR 2 O4: R1 = R2 = H5: R1 = CH 3, R 2 = H6: R1 = R2 = C H3

Fig. 1. Monomeric phloroglucinols of the genus Eucalyptus.

2.1.1.1. Structure elucidation of monomeric phloroglucinolsThe spectroscopic characteristics of formylated and methylated/methoxylatedmonomeric phloroglucinols differ considerably. The IR spectrum offormylated compounds shows the presence of aldehydic carbonyl and hydroxylfunctionalities as prominent bands. These compounds generally give stablemolecular ions in mass spectrometry; hence presenting the molecular mass bybase peaks (For example, m/z 267 [M+H]+ for jensenone and m/z 253 [M+H]+ forgrandinol).The NMR spectrum (in CDCl3) shows the presence of formyl groupsbetween äH 9.8-10.2 and äC 190-192. The hydrogen bonded hydroxyls appear betweenäH 14-17 ppm. The ketonic carbonyl of the side chain is evidenced by the resonancenear 205 ppm in 13C NMR.

In case of methylated and methoxylated monomeric phloroglucinols, the presenceof O-C stretch (of O-CH3 group) along with ketone carbonyl and hydroxyl moiety isindicative of the structure. The nuclear methyl groups appear between äH 2.1-2.2and äC7.5-9.5, and methoxyls may be seen at äH3.7-3.8 and äC 60-62 ppm.

2.1.1.2. Complete structure elucidation of 4-O-demethyl miniatone4-O-Demethylminiatone (4) was isolated as yellow oil. It showed a molecular ionpeak at m/z 253 [M+1]+ and showed spectral features similar to those reported forarenic ketones (miniatone and torquatone) of the sub-genus Symphyomyrtus ofEucalyptus. The IR absorptions at 1,609 and 3,435 cm-1 were indicative of aromaticcarbonyl and hydroxyl groups. The chemical shifts in13C NMR signals for aromaticcarbons at äC108.5 (C-1), 158.8 (C-2), 106.5 (C-3), 161.3 (C-4), 109.2 (C-5) and 159.0 (C-6) suggested a hexasubstituted aromatic ring. The 1H NMR showed two aromaticmethyls at äH 2.11 (äC7.6) and 2.14 (äC 8.7) that correlated to C-2, -3, -4 and C-4, -5, -6,respectively in HMBC spectrum.

The 1H NMR also showed one hydrogen bonded (ä 13.44) and another non-hydrogen bonded (ä 5.27, broad singlet) hydroxyl groups. Anisovaleryl moiety [(äH

0.95 0.97 (äC22.9, C-10, -11), 2.27 (äC 25.6, C-9) and 2.96 (äC51.7, C-8)] was revealed by


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1H-1H COSY spectrum (Fig. 2). Comparison of the spectral data of this compoundwith those of torquatone andminiatone established their structural similarity.

CH3HO

H3COH

OCH3

O

1

3

5 8 10

4Fig. 2. The key HMBC ( ), COSY (—) and NOESY ( ) correlations of 4-O-demethylminiatone (4).

SCoA

O COOHSCoA

O

3

O O

O O

SCoA ClaisenCondensation

O O

O O

SAMHO OH

OH O

CH3

H3C

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CHO

R1: R = CHO2: R = CH3

O

Fig. 3. Proposed biogenetic pathway of monomeric phloroglucinols (1 and 2).


Torquatone and miniatoneare tri- and di-O-methylated derivatives whereascompound 4 is a mono-O-methylated phloroglucinol. The methoxyl group (äH 3.70,äC62.1) was located at C-2 (äC 158.8) on the basis of its HMBC and NOESY correlations.Finally, the structure was confirmed as 1-(4,6-dihydroxy-2-methoxy-3,5-dimethylphenyl-3-methyl-butan-1-one (named 4-O-demethyl miniatone) (Sidana etal., 2012).

2.1.1.3. Biogenesis of monomeric phloroglucinolsThe biogenetic origin of phloroglucinol compounds can be traced to polyketidesthat arise from polyketomethylene chains. In case of acyl phloroglucinols of eucalypts,different alkanoyl coenzyme A starter units are extended by three malonyl CoA unitsand the polyketide species, thus, generated undergoes a Claisen-type cyclizationreaction to yield precursor of acyl phloroglucinols. Monomethylation of doublyactivated carbons by S-adenosyl-methionine results in the introduction of nuclearmethyl groups. Nuclear methyl groups then undergo successive oxidation reactions(Ghisalberti, 1996). A scheme for biogenesis of jensenone (1) and grandinol (2) isgiven in Fig. 3.

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2.1.2. Dimeric phloroglucinolsDimeric phloroglucinols have been further divided into two categories, viz., 1)compounds involving a chroman ring formation by the cycloaddition between thetwo monomeric phloroglucinols and 2) compounds having a methylene bridgebetween the two monomeric units.

Till date, the representatives of the former category have been reported fromthe genus Eucalyptus only while the methylene bridged phloroglucinols are foundto be segregated in Hypericum, Dryopteris and Mallotus apart from Eucalyptus(Singh and Bharate, 2006).

Amongst the dimeric phloroglucinols reported from eucalypts, sideroxylonals A (7)and B (8) were the first to be isolated from E. sideroxylon (Satoh et al., 1992). SideroxylonalA exhibited a potent repelling activity against marine sessile organism blue mussel,Mytilus edulis galloprovincialis. The magnitude of this activity was found to becomparable to 2,5,6-tribromo-1-methylgramine (TBG), the most potent repellent known(Singh et al., 1996). Another stereoisomer of sideroxylonal A and B was isolated fromE. melliodora and was named sideroxylonal C (9) (Eschler and Foley, 1999).

These compounds have a wide range of biological effects, e.g., sideroxylonalsA and B showed anti-bacterial activity against gram positive bacteria, S. aureus andB. subtilis at 3.9 and 7.8 μg/disk, respectively (Singh and Etoh, 1997). SideroxylonalC has plasminogen activator inhibitory activity by virtue of which, it enhancesfibrinolysis and hence can alter many physiological and pathophysiological functionssuch as cell adhesion and migration (Neve et al., 1999). Sideroxylonals A and B alsoinhibited aldose reductase (IC50 1.25 and 2.47 μM, respectively) and the growth ofHeLa cells (Satoh et al., 1992). These compounds are reported to limit the consumptionof eucalypt leaves by koalas and other marsupial herbivores. They are potentmammalian antifeedants as shown by feeding experiments on common ringtail possumand brushtail possum (Lawler et al., 1999). A similar dimeric formylated phloroglucinol,loxophlebal A (10) has been reported as an anti-bacterial constituent from the leavesof E. loxophleba (Sidana et al., 2010).

Dimeric phloroglucinol derivatives with isovaleroyl side chain namely, grandinal(11) and loxophlebal B (12) have been isolated from E. grandis and E. loxophleba,respectively (Singh et al., 1997; Sidana et al., 2011). These are known to exist in threetautomeric forms as depicted in Fig. 8. Grandinal possesses anti-bacterial andattachment inhibitory activities (Singh et al., 1997).

Robustaol A (13) is a dimeric phloroglucinol formed via a methylene linkage. Itwas isolated from leaves of E. robusta Smith, a plant used in China to prepare anti-malarial medicine ‘Da Ye An’ (Xu et al., 1984). Structurally similar compounds 14 and15 have been isolated from E. saligna and E. jensenii, respectively (Mitaine-Offer etal., 2003; Sidana et al., 2012). Fig. 4 presents the structures of dimeric phloroglucinolcompounds of Eucalyptus species.


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HO

OH

OH

13: R = R1 = CH3, R2 = CH(CH3)214: R = CHO, R1 = H, R2 = CH2CH(CH3)215: R = CH3, R1 = H, R2 = CH2CH(CH3)2

CHO

O

HOR

OR1

OH

R2

O

O

CHOHO

OHCHO

OHR

HO

OHCOH

O

CHOHO

OHCHO

OHCHO

HO

OHCOH

O

CHOHO

OHCHO

OHCHO

HO

OHCOH

7: R = CHO10: R = H

8 9

O

CHOHO

OHCHO

OHR

HO

OHO11: R = CHO12: R = H

Fig. 4. Dimericphloroglucinol compounds occurring in Eucalyptus spp.

2.1.2.1. Structure elucidation of dimeric phloroglucinolsThe spectral data of the two types of dimeric phloroglucinols (viz., the compoundsformed by chroman ring formation and the compounds formed via methylene linkage)differs significantly. However, the common features include peaks of carbonyl,hydroxyl and aromatic functionalities in IR and NMR spectra.

2.1.2.2. Structure elucidation of loxophlebal BLoxophlebal B was obtained as a brown solid from the polar fractions ofchloroform-methanol (8:2) extract of leaves of E. loxophleba by recycle HPLC.The analytical HPLC chromatogram of the sub-fraction containing this compoundrevealed the presence of loxophlebal A (10 - peak C) (Sidana et al., 2010) as themajor component along with two other equilibrating peaks A and B (Fig. 5a).These two equilibrating peaks were subjected to recycle HPLC, the peak A wasredirected to the HPLC column and peak B was drained off. In the next detection,peak A again showed two peaks. This suggested that peaks A and B actuallyrepresented an equilibrating pair like that of grandinal (11) (Fig. 5b) (Sidana etal., 2010; Sidana et al., 2011).

The molecular formula of 12 was established as C25H29O9 by HRESIMS ([M+H]+

at m/z 473.1805 and [M + Na]+ at m/z 495.1621, while the other fragment peaksat m/z251, 223 and 167 in the mass spectrum indicated it to be a dimeric formylatedphloroglucinol compound. The NMR data of 12 exhibited a double set of proton andcarbon resonances as is the case with grandinal (11). Both the 1H and 13C NMR dataindicated the presence of one isopropyl and one isovaleroyl functionality in thestructure. The methyl doublets at ä 0.67 and ä 0.96 (H-12 or -13) showed HMBC


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correlations to carbon resonances at 26.5 (C-11) and 54.0 (C-10) ppm. In the HMQCspectrum, the carbon at 54.0 (C-10) showed correlations with three distinct signalsin proton NMR, the doublet at ä 2.97 (2H, H-10, keto form) and overlapped multipletsat ä 2.60 (1H, H-10a, enol form) and 2.75 ppm (1H, H-10b, enol form). All of theseprotons showed same HMBC correlations; i.e., to methyl carbons at C-12 and -13and methine carbon C-11. This was assigned to methylene at C-10 of keto and enolform of the molecule. The selected HMBC correlations of two tautomeric fragmentsof 12 are shown in Fig. 6a.

Minutes

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34

mA

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(a) (b)Fig. 5. (a) HPLC chromatogram (282 nm) of sub-fraction containing loxophlebal B(12); (b) Recycle HPLC chromatogram (282 nm) of peak A.

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ab

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13'

7 7

The HMBC correlations shown in Fig. 6b suggested the sub-structure containingan isopropyl, an oxymethine, an aromatic ring with three hydroxyls as shown. Thetwo protons (äH 2.24 and 2.72, H-7a and -7b) attached to carbon at 19.6 (C-7) ppmwere correlated with carbon resonances between ä103.5 to 104.4 (C-1). The proton atä 2.72 also correlated to a ketonic carbon at ä208.1 (C-6). These correlations supportedthe presence of tautomerism in ring A of the tricyclic core of dimericphloroglucinoland ruled out the possibility of isovaleryl side chain being present at position 3.

Based on the spectral data, three structural possibilities (Fig. 7) were drawn outfor this compound. In the mass spectrum, the structures I, II and III would present a

Fig.6. HMBC correlations ( ) of structural fragments of 12(a) Isovaleryl side chain;(b) Rings B and C.


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common molecular ion at m/z 473 [M+1]+and two daughter ions at m/z 251 [C13H14O5

+ 1]+ and 223 [C12H14O4 + 1]+. However, in MS2 studies, a fragment ion at m/z 195[C9H7O5]

+, resulting from the cleavage of side chain from diformylphloroglucinolfunctionality, could be seen as a major peak. So, the 2, 4-diformyl group was placedon one phloroglucinol monomeric unit as in structure I and structures II and III wereruled out.

O

HOC HO

OH

C HOO H

O

HO

O H

O

HO O H

C HOO H

O

HO

O H

O

HOC HO

OH

O H

O

HO

O HI I I I I I

CH O CH O

Fig. 7. The three structural possibilities of compound 12.

Fig. 8 presents the three possible tautomers of 12. Relative stereochemistrybetween H-7' and H-10' was determined by magnitude of coupling constant of H-7'present at ä 5.48 (J = 10.9 Hz) that indicated a trans relationship between these(Sidana et al., 2011).

O

O

HO

OH

CHOHO OH

CHOO H

O

OH

HO

O

CHOHO OH

CHOOH

O

OH

O

OH

CHOHO OH

CHOOH

a b

c

1

3

591112

137

7'

10'

12'

13'

1'

4'

8'

9'

A B

C

Fig. 8. The three possible isomers (a, b and c) of 12.

2.1.2.3. Biogenesis of dimeric phloroglucinolsGrandinol (2) and jensenone (1) are presumed to be the biogenetic precursors of thecompounds in this class. O-Quinone methide(16) generated from grandinol andstyrene compound (17) generated from jensenone undergo hetero Diels-Alderreaction to generate the chroman ring of grandinal. Similarly, [4+2] cycloaddition


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between O-quinonemethide (18) and styrene compound (17) generated fromjensenone gives sideroxylonals A-C (Fig. 9). It should be mentioned, however, thatnone of these intermediates have yet been isolated from eucalypts or any othernatural source. Nevertheless, biomimetic synthesis of grandinal and euglobalsutilizing Diels-Alder cyclo-addition lend support to the biogenetic theories(Ghisalberti 1996; Singh et al., 1997). The second type of dimericphloro glucinolcompounds are proposed to be formed by joining of two monomeric units via amethylene bridge. Methionine is presumed to be a source for the methylene unit(Penttila et al., 1965).

HOCHO

O

O

HOC HO

OH

C HOOH

O H

HOCHO

O

O HC

HOCHO

OH

CHOOH

O H

16

1717

18

Grand ina l (11) Sideroxylona ls A-C (7-9)

Fig. 9. Biogenesis of sideroxylonals and grandinal.

2.1.3. Phloroglucinol-terpene adductsLike dimericphloroglucinols, phloroglucinol-terpene adducts may also be categorizedinto two structural forms, viz., 1) adducts formed by the cycloaddition betweenphloroglucinol and terpenemoieties (named as euglobals) and 2) adducts formed bythe methylene linkage between phloroglucinol and terpene units (named asmacrocarpals).

2.1.3.1. EuglobalsEuglobals have been found in the leaves and flower tops of several species ofEucalyptus. These compounds have been named so because of the first isolation ofeuglobal III (19) from E. globulus Labill. (Eucalyptus globulus aldehyde) (Sawadaet al., 1980). Since the initial report of euglobal III, more than thirty similar compoundshave been isolated from different eucalypts. Eight different monoterpenes andtwo sesquiterpenes have been implicated in the structures of these closelyrelated compounds. Structurally, euglobals can be diformyl or formyl-isovalerylphloroglucinol-monoterpene or -sesquiterpene adducts. Di-isovaleryladducts have not yet been reported from any natural source, however, some ofthese compounds have been synthesized chemically. Fig. 10 shows the generalstructure of different types of euglobals.


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OH

OH

O OH

OH

Oor

R RR = H or isobutyl

T = Mono- or sesqui-terpene

TT

CHO/Isovaleryl

Isovaleryl/OHC

CHO/Isovaleryl

Isovaleryl/OHC

Fig. 10. General structures of natural and synthetic euglobals.

Euglobals have been tested and found active in a variety of pharmacologicalassays. They exhibited remarkable inhibitory activity in two-stage carcinogenesistest in skin and pulmonary tumour mouse models (Takasaki et al., 2000). Variousnatural and S-euglobals have been tested for their anti-leishmanial, anti-malarial,anti-microbial and cytotoxic activities. Euglobals G1 (20) and G2 (21) and someother analogs exhibited potent in vitro anti-leishmanial activity (IC50 2.4 to 5.5 μg/mL). Robustadials A (22) and B (23) showed a weak anti-malarial activity (IC5020 and16 μg/mL, respectively) (Bharate et al., 2006, 2008). Owing to their hyaluronidaseinhibitory activity, euglobals have also been considered health foods and/or anti-inflammatory cosmetics (Kokubo, 2010). Recently, isolated euglobal IX (24) inhib-ited the catalytic activity of CYP3A4 with an IC50 of 38.8 μM (Kawabata et al., 2011).Eucalyptus A-C (25-27) exhibited in vitro cytotoxicity against human leukemia celllines (HL-60) with IC50 values of 1.7, 6.8 and 17 μM, respectively (Yin et al., 2007). Forstructures of euglobals, see Fig. 11.

OCHO

HO

OHCOH

H

OR1

HO

R2OH H

20: R1 = COCH2CH(CH3)2, R2 = CHO21: R1 = CHO, R2 = COCH2CH(CH3)2

OCHO

HO

OHCOH

22 : 7β23 : 7α

OCHO

HO

OHCOH

OH

HO

OH

H

HO

OOH

H

25 26 27

CHOHO

OHCOH

CHOHO

OHCOH

19 : 7α24 : 7β

Fig. 11. Structures of some naturally occurring euglobals.


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These compounds exist as stereo-, regio-, or positional isomers and are conventionallyisolated/separated by repeated (or recycle) HPLC over reverse phase silicagel. Initialfractionation of euglobal-rich fraction(s) generally follows final purification by recycleHPLC. The recycle HPLC chromatogram of an enriched pool containing euglobals Ib(28) and Bl-1 (29) is shown in Fig. 12.

Fig. 12. Recycle HPLC chromatogram (275 nm) of enriched pool of euglobals Ib (28)and Bl-1 (29) (8 recycles).

2.1.3.2. Structure elucidation of euglobalsApart from the aldehydic, hydroxyl and aromatic resonances, the IR spectrumof euglobals shows specific bands for terpene structural units. In euglobal-rich fractions, the mono- and sesqui-terpene adducts can easily bedistinguished by their molecular ion peaks. The molecular ion peak ofmonoterpene adducts appears at m/z 386 and for sesquiterpene adducts, it canbe seen at m/z 454.

Further, diformyl adducts may also be distinguished from formyl-isovaleryladducts with the help of 1H NMR. If the 1H NMR of a euglobal fraction shows thehydroxyl protons in the region ä 13.36 to 13.63 ppm, the presence of diformyleuglobalscan be concluded. The hydroxyl proton signals between ä 14.0 to 15.0 ppm aretypical of formyl-isovaleryleuglobals. Apart from the signals due for formylatedphloroglucinol unit, the NMR of euglobals present signals for the terpene moiety.These signals give the idea about the terpene present in the structure. For example,olefinic protons appearing between ä5.6 to 6.1 ppm are conclusive for á/â-phellandrene adducts. Similarly, the sabinene adducts (euglobal Ib, Ic, IIa and Bl-1)show signals in the range of ä 0.3 to 0.8 ppm due to the cyclopropyl protons of thesabinene skeleton.


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2.1.3.3. Structure elucidation of sabinene adductsDue to the similarity in the structures of stereoisomeric euglobals, final structureelucidation relies on X-ray studies for the establishment of stereochemistry.However, a few NMR resonances also play a vital role in these stereochemicalassignments.This section is compiled with an aim to present a comparison ofNMR values of two isomeric sabinene adducts namely euglobal Ib (28) and euglobalBl-1 (29).

Both 28 and 29 have the same composition i.e. C23H30O5 (m/z 387 [M+H]+). The1H and 13C NMR spectrum of 29 revealed that it possessed the same planar structureas euglobal Ib, Bl-1, IIa and Ic. The major differences in the NMR spectra of thesecompounds were observed in the methylene proton signal at C-3' and the carbonsignals at C-7'. The chemical shifts of C-7' in euglobal Ic and IIa were upfield ascompared to those found in euglobal Ib and Bl-1. This was attributable to differencein configuration of the cyclopropane ring present in the structure. In case of 29, C-7' appeared at ä 36.4 and the methylene protons attached to C-3' were observed atä 0.51 and 0.84. On the basis of these observations, 29 can be confirmed as euglobalBl-1. Similar to the NMR data of 29, 28 showed C-7' at ä 38.0 (downfield wrt C-7' ofeuglobal Ic (ä 32.0) and IIa (ä 32.3). The methylene proton signals of cyclopropanering appeared at ä 0.37 and 0.76 in the proton NMR of this compound. So, the relativeconfiguration of the cyclopropane ring was assigned to be same as that of euglobalBl-1 (29) and hence, 28 can be confirmed as euglobal Ib (Fig.13) (Takasaki et al.,1994).

OCHO

HO

OHCOH

1

4

7 7'1'

5' 8'

10

3'

29

OCHO

HO

OHCOH

1

4

7 7'1'

5' 8'

10

3'

28 Fig. 13. Structures of euglobals Bl-1 (29) and Ib (28).

2.1.3.4. Biogenesis of euglobalsBiogenetically, euglobals and related compounds have been proposed to be formedvia a Diels-Alder cyclo-addition of mono-/sesqui-terpenes with O-quinone-methidegenerated after oxidation of phloroglucinol derivatives jensenone (1) and grandinol(2) (Ghisalberti, 1996) (Fig. 14).


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2.1.3.5. MacrocarpalsMacrocarpals are the phloroglucinol-terpene adducts that do not involve theformation of chroman ring as in euglobals. The first compound belonging to thisseries, macrocarpal A (30) was isolated from E. macrocarpa (Murata et al., 1990).This was followed by the isolation of several other structurally similar compoundsnamed macrocarpals (macrocarpa from E. macrocarpa and al from aldehyde groupin the structure) B (31), C (32), D (33), E (34), G (35), H (36), I (37), J (38), am-1(eucalyptone) (39), K (40), L (41) and antibiotic GR 95647X (42) (Yamakoshi et al.,1992; Singh and Etoh, 1995; Osawa and Yasuda, 1996) (Fig. 15).

A myriad of important biological activities have been exhibited by thesecompounds. They are active against gram positive bacteria, inhibited HIV reversetranscriptase (30: most effective RTase inhibitor, IC50 5.3 μM) (Nishizawa et al.,1992)and showed attachment inhibitory activity against the blue mussel, Mytilusedulis(Singh et al., 1999). More recently, the angiotensinase inhibitory and brainmodulatory activities of these compounds have been discovered (Roemer and Grothe,2008). Macrocarpal G and L have been investigated for their use in treatment/prevention of CNS disorders related to neurotransmitter reuptake (Fiorini et al.,2008; Fiorini-Puybaret and Joulia, 2009). Five similar compounds have been isolatedfrom dried leaves of E. globules and were patented as anti-cariogenic and anti-periodontopathic agents. Several patents disclosing the inventions relating tochewing gums and toothpastes containing macrocarpal-rich extracts (prepared fromeucalypt leaves) have been filed in the recent past (Kenji and Hideyuki, 1998; Maedaet al., 2009).

Unlike euglobals, macrocarpals are medium polar to polar constituents and aregenerally isolated from the chloroform extracts of eucalypt foliage. As mentionedearlier, these compounds do not involve in the formation of chroman ring likeeuglobals. Another structural difference between macrocarpals and euglobals is the

O

HOCHO

O

OH O

HOCHO

O

OH

Euglobal G1 and G2 Euglobal G3 and G4

Euglobal G1 and G2 Euglobal G3 and G4

Fig. 14. Proposed biogenesis of euglobals G1-G4.


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30 (β -isobutyl)31 (α-isobutyl)

32

OH

OHC

CHOHO

OH

H

33OH

OH

OHC

CHOHO

OH H

H OH OH

OHC

CHOHO

OH H

H

CHOHO

OHCOH

OHO

H

CHOHO

OHCOH

OH

OH

H

37, 38

CHOHO

OHCOH

OH

OH

CH3

34

OH

OHC

CHOHO

OH H

H

35 36, 40

CHOHO

OHCOH

OH

OH

HOH

39

OH

OHC

CHOHO

OHH

H

HO

42

CHOHO

OHCOH

OHH OH

H

41

O

Fig. 15. Structures of macrocarpals reported from Eucalyptus species.

terpene moiety which is a sesquiterpene unit in case of macrocarpals (isolated thusfar). However, the terpene moiety is a monoterpene in majority of the euglobals.

2.1.3.6. Structure elucidation of macrocarpalsThe structure of macrocarpals may be divided into two units, viz., anisopentyldiformylphloroglucinolchromophore and a sesquiterpene unit. Asdeduced by the mass spectrometry, the mass of macrocarpals range from 454 to490 depending on the degree of oxygenation of sesquiterpene unit. The high fieldregion of 1H and 13C NMR spectrum of macrocarpals is quite similar to that ofeuglobals because of the presence of phloroglucinol core. However, the low fieldregion is much complex due to the presence of C-15 sesquiterpene unit. Thestereochemistry of the isopentyl side chain has been assigned by making theMosher esters of the parent molecule(s).


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2.1.3.7. Structure elucidation of Macrocarpal-am-1Macrocarpal-am-1 was isolated as a brownish amorphous powder from the methanolextract of leaves of E. amplifolia. Around the same time, same compound was reportedas eucalyptone (stereochemistry defined) from E. globulus. The HR-FAB spectrumof macrocarpal am-1 presented the [M+H]+ peak at 487.2692 establishing the molecularformula to be C28H38O7. The NMR data showed a total of 28 carbons attached to 35hydrogens. Out of the 28 carbons, 10 were quaternary carbons, seven were methines,five were methylenes and six were methyl carbons.

The 1H NMR spectrum of macrocarpal am-1 showed a two proton signal at ä 10.01accounting for the two formyl groups on a benzene ring. The presence of an isopentylside chain was indicated by a double doublet at ä3.14 due to a benzylicmethine proton(H-9'), one multiplet at ä2.36 assigned to the two methylene protons (H-10') and twodoublets at ä0.75 and 0.84 for two methyl groups (H-12' and 13'). In the 13C NMRspectrum, six carbons were observed in the aromatic region and two formyl carbonson the benzene ring were seen in the high field region. The connectivity data establishedby 1H-1H COSY (H-12’, 13’ to 11’ to 10’ to 9’) and HMBC (H-12’, 13’ to C-11’, 10’; H-9’to C-1’, 5’, 6’, 4) spectra confirmed the presence of an isopentylphloroglucinol unit.

A singlet methyl (H-15) at ä 1.17 could be correlated to a quaternary carbon (C-4), a methine (C-5), another methine adjacent to the aromatic ring (C-9’) and amethylene carbon (C-3) in the HMBC spectrum. The crosspeaks of H-5 and H-2 witha carbonyl carbon (C-1) were also present in the HMBC spectrum. H-2 was furtherconnected to H-3 on the basis of a 1H -1H COSY experiment. All these data clearly ledto partial structure I.

A two proton signal at ä 0.46-0.54 (H-6 and -7) and two singlets at ä 1.01 and 1.08(H-12 and -13) in the 1H NMR spectrum, two quartet carbons at ä 16.4 and 29.2 (C-12and-13), one quaternary carbon at ä 19.3 (C-11) and two methine carbons at ä 27.3and 28.7 (C6- and -7) in the 13C NMR data suggested a cyclopropane-type structure.Each of these methyl protons showed HMBC coupling to either C-12 or -13, C-11, C-6 and C-7 and hence, established a three-membered ring bearing two germinal methylgroups (partial structure II).

A three proton singlet at ä 2.15 (H-14) and two multiplets at ä 2.50 and 2.56 (H-9) in the 1H NMR spectrum and a carbonyl carbon at ä 212.2 (C-10) and two methylenecarbons at ä45.2 (C-9) and 21.4 (C-8) in the 13C NMR, which were connected by 1H-1H COSY (H-9 to 8; H-8 to 7) and HMBC (H-14 to C-10, 9) as shown in Fig. 16 suggestCH3-CO-CH2-CH2- group (partial structure III).

Partial structures I, II and III were connected by 1H-1H COSY (H-5 to 6 and H-7to 8) as shown in the structure 39. Hence, it was deduced to be a new macracarpalwith a 1,10-secoaromadendrane skeleton coupled with a diformylphloroglucinolmoiety. Fig. 16 presents the partial structures I, II and III and the complete structureof macrocarpal am-1 (39) (Singh and Etoh, 1995).


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CHOHO

OHCOH

OHO

H

O

1'3'

5'

7'

8'

14 5

9'

11'

67

11

9 1410O

CH3

CHOHO

OHCOH

OHH2CH2C O

H

H3CCH3

CH3

H

I

H3C CH3

IIIII

39

Fig. 16. The key HMBC ( ) and COSY (—) correlations of partial structures I, II andIII of macrocarpal am-1 (39).

2.1.3.8. Biogenesis of macrocarpalsThe biogenesis of macrocarpals is proposed to involve carbocationic species (43)derivable from jensenone (1). The carbocation 43 can act as an initiator forthe cyclization of sesquiterpene precursors to give macrocarpals. Theproposed biogenesis of macrocarpal-am-1 (39) is shown in Fig. 17.Sesquiterpenebicyclogermacrene (44) can cyclize in the presence of 43 to generatemacrocarpals A/B (30/31). Macrocarpal-am-1 may be formed by the dehydrationof 30 or 31 generating a tetra-substituted double bond at C1-10 which can, then,undergo oxidative cleavage to give 39 (Ghisalberti, 1996).

OHCHO

HO

OHCOH

43 44

O H2

30 /31

OH

OHC

CHOHO

OH39

Fig. 17. Proposed biogenetic pathway of macrocarpal-am-1.

2.1.4. Cyclic polyketonesEucalypt volatile oils are a rich source of mono- and sesqui-terpenes. Apart fromthese terpenes, the oil contains cyclic polyketones, also called â-triketones. Thesecompounds differ in their oxygenation pattern, nuclear methyl groups and sidechain. Tasmanone (45) was the first â-triketone to be isolated from E. tasmanica(Birch and Elliott 1956; Bick and Horn, 1965). Another triketone, agglomerone (46)was isolated from E. agglomerate (Hellyer, 1964). Both 45 and 46 exist as mixtures oftautomericketo and enolic forms. Other â-triketones isolated from various Eucalyptusspp. are flavesone (47) (Bick et al., 1965), leptospermone (48) and isoleptospermone(49) (Boland et al., 1991). Rhodomyrtone (50) and eucalyptone G (51) have beenrecently isolated from the bark of E. globulus. Eucalyptone G displayed anti-bacterial


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activity against Bacillus subtilis, Staphylococcus aureus and Escherichia coli(Mohamed and Ibrahim, 2007). Structures of various cyclic polyketones are presentedin Fig. 18.

O

O

OHO

O OH O

O

OHO

O OH

O

O

O

50 51

O

O

O

O

O

O

O

O

O

O

O

O

O

O

O

H3CO

R

45: R = CH346: R = H

47 48 49

Fig. 18. Structures of cyclic polyketones isolated from eucalypts.

2.1.4.1. Structure elucidation of cyclic polyketonesAs mentioned earlier, cyclic polyketones are the constituents of foliar essentialoils of Eucalyptus (and other species). These compounds have been isolated byfractional distillation, crystallization of derivatives and formation of copper salts.These are then studied by gas chromatography (may be coupled with massspectrometer). Largely, these compounds exist as enolictautomers as evident bytheir spectral studies. These enolic forms are known to interchange at a negligiblerate in neutral solutions but the rate of interconversion increases in presence ofbase.

2.1.4.2. Structure elucidation of flavesoneThe UV spectrum of flavesone pointed toward a conjugated structure existing astautomericenols. The existence of enolictautomers was also supported by its IRspectrum that presented peaks for an unconjugated (1,726 cm-1), conjugated (1,672 cm-1)and conjugate-chelated (1,564 cm-1 broad band) carbonyl groups.

The 1H NMR of flavesone showed a one-proton signal between ä 18.3 to 18.5characteristic for enolic protons in a chelated system. An isobutyryl side chainwas indicated by a symmetrical heptet at ä 3.82 for methine proton and a doublet atä 1.17 for six protons of gem-dimethyl group. The four methyl groups of the ring


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could be seen as two signals of almost equal intensities at ä1.43 and 1.37. The lowfield value (ä1.37) was assigned to the pair of methyls between two carbonylgroups. The appearance of the ring methyls as two distinct signals inferred thatthe interchange of the enols (47a) and (47b) was negligible in neutral solution(Fig. 19).

The peaks for the two pairs of ring methyls merge into an averaged sharp signalat ä1.40 on addition of a mild base like ammonia. This could be the consequence ofbase-catalyzed interconversion of the two tautomers at an accelerated rate. Onaddition of a small amount of deuterodimethylsulphoxide (DMSO-d6) to the solutionof flavesone, the two ring-methyl peaks (ä1.42 and 1.38) and the enolic-proton peak(ä 18.3) were broadened and flattened. This may have resulted from the change inhydrogen bonding of the enolic proton and an increase in the rate of interconversionof the two tautomers.

The two ring methyl signals were also observed to coalesce on increase in thetemperature indicating that the positions of the signals were dependent upon therate of tautomerism. Furthermore, the structure of flavesone was confirmed bydegradation and synthetic studies. Acid hydrolysis followed by the methylation ofthe acid liberated yielded methyl isobutyrate confirming the side chain to beisobutyryl moiety. The second hydrolysis product was identified to be 1,1,3,3-tetramehtyl phloroglucinol. Chemical synthesis of flavesone was achieved by themethylation of phloroisobutyrophenone in the presence of methanolic sodiummethoxide and methyl iodide (Bick et al., 1965).

O O

O OH

O O

O

OH

a bFig. 19. The two tautomeric forms of flavesone (47a and 47b).

2.1.4.3. Biogenesis of cyclic polyketonesBiosynthetic studies with labelled (14C) precursors revealed that cyclic polyketonesare generated in a similar fashion as that of acyl phloroglucinol compounds. Thepolyketide intermediate generated undergoes methylation by S-adenosyl methionine.The gem-dimethylation at any one carbon prevents enolization of the system(Ghisalberti, 1996).


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2.1.5. G-regulatorsG-regulators or G-inhibitors (G for grandis) are plant growth regulators isolatedfrom the adult leaves of E. grandis. Till date, three such compounds (G1, G2 andG3) (52-54) having epidioxy group in their structure have been isolated. Thesecompounds aid the process of rooting in stem cuttings and also inhibitphotosynthetic electron transport chain at the site between photosystem II andplastoquinone (Crow et al., 1971; Yoshida et al., 1988). It is hypothesized that G-regulators reduce water loss and are involved in frost resistance by controllingthe active electron properties of membranes (Paton et al., 1980; Paton, 1981). Later,this activity was ascribed to 2 and 3.

O

OO

OHO

52

O

OO

OHO

53

O

OO

OHO

54

48O O

O

O O

OH

[O2]

55Fig. 20. Structures of G-regulators G1-G3 and plausible biogenesis of G3 fromleptospermone (48).

2.1.5.1. Structure elucidation of G-regulatorsThe structure elucidation of G-regulator G1 was done by X-ray crystallographicstudies. G1 (52) was crystallized from cyclohexane in a monoclinic system with fourmolecules in a unit and the structure was solved by iterative application of Sayre’sequation. The structure of G1 then served as a reference for the elucidation of G2(53) and G3 (54) from spectroscopic data.

G1 (52) and G2 (53) were found to isomerize on silica gel TLC plates and presentedidentical mass spectra. The 1,2-dioxolane unit present in the structure governed the


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fragmentation pattern through the ions A and B (Fig. 21). Fragment ion A was formedby the loss of O2 from the molecular ion. Furthermore, A fragmented to daughter ionA1 after the loss of dimethyl ketene. This pointed toward the presence of carbocyclicring in the structure.

Another prominent fragment B was formed by the cleavage of neutral CO2 fromthe molecular ion. This [M-CO2] peak could also arise by sequential loss of O followedby CO. However, the [M-O] peak was negligible and it was, therefore, inferred that[M-CO2] fragment was formed after a Bayer-Villiger type rearrangement to give lactone(B') followed by ring contraction (Fig. 21). A similar mass fragmentation pattern wasobserved in case of G3 (Crow et al., 1971).

OO

O

O

R1

R2

OH

52 : R1 = C2H5, R2 = CH353 : R1 = CH3, R2 = C2H554 : R1 = R2 = CH3

OH

O

O

R1

R2

OO OH

O

O

R1

R2

OO

O

O

R1

R2

OH

CR1

R2CO

O

A

B

A1

B'

13

5 7

9

Fig. 21. Mass fragmentation pattern of G regulators.

The 1H NMR data of all the three G regulators presented the signals for methylgroups in the upfield region (ä 1.0 to 1.5). A one proton signal was present betweenä 7.1 to 7.2 for 5-H. Another one proton broad-singlet between ä 3.8 to 4.0 (D2Oexchangeable) could be ascribed to the hydroxyl group present at C-1. Ethyl moietyat C-4 was inferred by a set of quartet at ä 1.74 (for G1) and ä 1.70 (for G2) and a tripletat ä 0.98 (for both G1 and G2). However, these signals were not seen in the spectrumof G3. All the three compounds showed a methyl singlet (between ä 0.98 to 1.07)assigned to axial 10-á-methyl on the basis of long range shielding by the anisotropic2,3-peroxide linkage (Crow et al., 1971).

2.1.5.2. Biogenesis of G-regulatorsLeptospermone (48) and isoleptospermone (49) are thought to be the plausibleprecursors of G-regulators. The reduction of acyl ketone group followed bydehydration may generate a hydroxybutadiene intermediate (55) that can interactwith oxygen to give epidioxy functionality of G-regulators (Ghisalberti, 1996). Thestructures of G-regulators G1-G3 and plausible biogenesis of G3 is given in Fig. 20.


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2.1.6. Phloroglucinol glycosidesSeveral O- and C-glycosides of phloroglucinol derivatives have been reported fromplant sources including the members of Myrtaceae. However, the reports ofoccurrence of phloroglucinol glycosides in eucalypts are scarce. A recentphytochemical screening of E. maideni resulted in the isolation of five phloroglucinolglycosides, named eucalmainosides A-E (56-60) (Tian et al., 2010). Acetophenoneglycosides, Myrciaphenone A (61) and B (62) have been reported from E. maculata.61 has exhibited an in vitro anti-leishmanial activity comparable to miltefosine againstL. donovani promastigotes. This compound has earlier been isolated as an aldosereductase and á-glucosidase inhibitor from Myrcia multiflora (Suksamrarn et al.,1997) (Fig. 22).

OHHOR2

R3R1

OHO

HOOH

O

OH

56: R1 = CH3, R2 = R3 = H57: R1 = R2 = CH3, R3 = H58: R1 = CH3, R2 = H, R3 = CHO

OHHO

OHO

HOOH

O

OHO

HOOH

OO

R

59: R = CH(CH3)CH2CH360: R = CH2CH(CH3)2

Fig. 22. Phloroglucinol glycosides of eucalypts.

2.1.6.1. Structure elucidation of phloroglucinol glycosidesPhloroglucinol glycosides present a sugar moiety along with the phloroglucinolunit in their spectral data. This sugar moiety may be a monosaccharide or adisaccharide unit and can be identified from its 1H and 13C NMR resonances.

2.1.6.2. Structure elucidation of myrciaphenone A and BMyrciaphenone A was isolated as off-white solid from the methanol extract of leavesof C. maculata. A sodiated molecular ion peak was observed at m/z 353 [M+Na]+. Afragment peak due to loss of one methyl was present at m/z 316 [C13H15O9+H]+.Another fragment peak at m/z 202 showed the presence of sodium adduct of ahexose sugar [C6H11O6Na]+. The IR absorption band at 3,368 cm-1 indicated thepresence of hydroxyl groups and the absorption band at 1,654 cm-1 was indicative ofa keto group. The signal of a quaternary carbon at ä203.4 in 13C NMR spectrumconfirmed the presence of a keto function in the molecule. 13C NMR also showedsignals due to phloroglucinol aromatic ring (between äC95-166) and an acetyl group.


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The 1H NMR spectrum presented two aromatic protons (ä 6.18, d, J = 2.0 Hz and 5.94,d, J = 2.0 Hz) meta to each other. The presence of six 13C NMR signals between ä60to 105 were attributable to an O-glycosidically linked hexose residue. The hexoseresidue was considered to be â-D-glucopyranose because the chemical shifts ofsugar carbon were in good agreement with literature data (Suksamrarn et al., 1997).The coupling constant of anomeric proton (J = 7.4 Hz) confirmed â configuration.The alternative possible structure, 2,6-dihydroxy-4-O-(â-D-glucopyranosyl)acetophenone was ruled out since the symmetrical structure of the latter compoundwould give only four aromatic carbon atoms in the 13C NMR spectrum. In fact, thespectrum indicated that C-2 and C-6 were non-equivalent; i.e., signals at ä164.8 and161.2, respectively. The H-3 (C-3) and H-5 (C-5) signals were also non-equivalent;i.e., signals at ä6.18 (100.6) and 5.94 (93.9), respectively. This compound wascharacterized as 4,6-dihydroxy-2-O-(â-D-glucopyranosyl) acetophenone ormyrciaphenone A (61) (Suksamrarn et al., 1997).

The spectral data of Myrciaphenone B (62) indicated a close structuralresemblance between the two compounds. 1H and 13C NMR showed signals forphloroacetophenone core as in myrciaphenone A. The presence of a galloyl groupin the structure of 62 was suggested by a two proton singlet at ä7.10 in 1H NMR andfour characteristic carbon signals (ä 108.8, 119.8, 145.1, 166.9) in 13C NMR spectrum.The resonances between ä 3.48 and ä 4.45 were assigned to the protons of sugarmoiety. The coupling constant of the anomeric proton (ä 5.07, d, J = 7.6 Hz) in the 1HNMR spectrum indicated â configuration and from the other chemical shifts andcoupling constants of the sugar moiety, it was clear that the sugar unit was â-D-glucopyranose.

A considerable downfield shift in the signals of H-6' (ä 4.55 and 4.45) of sugarmoiety indicated the possible placement of galloyl functionality at C-6' position.Finally, the HMBC spectrum ascertained the correlation of H-6' of the â-glucosemoiety with C-1'’ of galloyl subunit. The structure of 62 was confirmed to be 4,6-dihydroxy-2-O-[â-D-(6'’-galloyl) glucopyranosyl] acetophenone or myrciaphenoneB (Fig. 23) (Chosson et al., 1998).

1O

OHOH

HOO

OH

HOCOCH3

OH

OOH

OHHO

O

O

HOCOCH3

OH

O

OHOH

OH

35

1' 3'

6'1''

4''

61 62

Fig. 23. Structures of myrciaphenone A (61) and B (62).


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2.2. Flavonoids and Flavonoid GlycosidesEucalypts are known to be a rich source of biologically active flavonoids. Thesecompounds occur as aglycones, mono-, di-, tri-, or higher glycosides, acylatedderivatives and adducts. Flavonoids can be found in leaves, flowers, fruits or kinoof various Eucalyptus species. Flavonoidal contents, calculated as rutin, variesfrom 0.62 per cent in the flowers of E. sideroxylon, 0.45 per cent in flowers ofE. torquata, followed by 0.36 per cent in the fruits of E. torquata and 0.27 per centin the leaves of E. sideroxylon (El-Hawary et al., 2007). Aglycones commonlyfound in various Eucalyptus species arequercetin (62), luteolin (63), myricetin (64),kaempferol (65), taxifolin (66), sakuranetin (67), alpinetin (68), naringenin (69), etc.(Bick et al., 1972; Echeverri et al., 1985; Yao et al., 2004; Freitas et al., 2008).

Leaf waxes of various species of Eucalyptus are also known to containflavonoids. These include C-methylated flavones like sideroxylin (70), 8-demethylsideroxylin (71), eucalyptin (72), 8-demethyleucalyptin (73), 8-demethylkalmiatin (74) and other flavonoid aglycones like chrysin (75) and pinocembrin (76)((Lamberton, 1964; Wollenweber and Kohorst, 1981; Sarker et al., 2001). Fig. 24presents the structures of various flavonoid aglycones reported from eucalypts.

The flavonoid glycosides reported from eucalypts are known to contain â-D-glucose, â-D-galactose, â-D-xylose, á-L-rhamnose, á-D-arabinose, â-D-glucuronicacid as the glycone portion. Diglycosides, generally, occur as rutinosides andsambubiosides, etc. The details of flavonoid structure, classes, occurrence andbiogenesis have been exhaustively presented by J. B. Harborne in his compilations(Harborne and Mabry, 1975; Harborne, 1994).

OOH

R4O O

R2R5

R1

R3

62: R1 = R2 = R5 = OH, R3 = R4 = H63: R1 = R3 = R4 = H, R2 = R5 = OH,64: R1 = R2 = R3 = R5 = OH, R4 = H65: R1 = R5 = OH, R2 = R3 = R4 = H75: R1 = R2 = R3 = R4 = R5 = H

O

O

R266: R1 = R2 = R3 = R4 = R5 = OH (2R, 3R f orm)67: R1 = OMe, R2 = R4 = H, R3 = R5 = H (2R f orm)68: R1 = OH, R2 = OMe, R3 = R4 = R5 = H (2S form)69: R1 = R2 = R4 = OH, R3 = R5 = H (2S form)76: R1 = R2 = OH, R3 = R4 = R5 = H (2S form)

R1

O

R1

O

H3CO

OHH3C

R70: R = CH3, R1 = OH, R2 = H71: R = R2 = H, R1 = OH72: R = CH3, R1 = OCH3, R2 = H73: R = R2 = H, R1 = OCH374: R = H, R1 = R2 = OCH3

R3R4

R5

3

2

R2

Fig. 24. Various flavonoid aglycones occurring in the genus Eucalyptus.


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2.2.1. Structure elucidation of 8-demethyl kalmiatin8-Demethyl kalmiatin(74) was isolated as yellow needles from the non-polar fractionsof chloroform-methanol (8:2) extract of E. loxophleba foliage. The 1H and 13C NMRspectra of this compound revealed that it was a flavone, methoxylated at position 3and having hydrogen bonded 5-hydroxyl group. A one proton singlet at ä 12.75 wasnot linked to any carbon resonance in the HMQC spectrum. However, it showedcorrelations to C-6 (ä108.5) and C-10 (ä 105.7) in HMBC (Fig. 25). It was inferred to bethe hydroxyl proton at C-5. From the combined information of the spectral data, itwas possible to deduce that 74 was methoxylated at C-7 and C-4' positions alongwith C-3. Further, the high field region of the NMR spectra presented a methylfunctionality (äH 2.10,ä C 7.2) that was correlated to C-5 (ä158.2), C-6 (ä 108.5) and C-7 (ä 163.4) in HMBC (Fig. 25). In the low field region of the spectra, two doublets (äH

8.07, äC 130.1 and äH 7.01, äC 114.0, for two protons each) could be observed. Thesewere attributable to C-2'/6' and C-3'/5' of ring C of the flavonoid nucleus, respectively.The H-2'/6' showed HMBC correlations with C-2 (ä 155.6) and C-4' (ä 161.5). Likewise,H-3'/5' was correlated to C-1' (ä122.9) and C-4' (ä 161.5). A one proton singlet (äH 6.43,äC 89.1) was characteristic of an unsubstituted C-8 in ring A. Further evidence infavour of this observation was extracted from the HMBC correlations of this protonwith C-9 (ä 154.9), C-7 (ä 163.4), C-6 (ä 108.5) and C-10 (ä 105.7). Finally, the structureof this compound was deduced to be 5-hydroxy-3,7,4'-trimethoxy-6-methylflavone(8-demethyl kalmiatin).

O

OCH3

OCH3

OOH

H3CO

H3C

H

2

45

8

1'

3'

5'

Fig. 25. Selected HMBC correlations used in determining the structure of 74.

2.3. Terpenes

2.3.1. Monoterpenesand sesquiterpenesEucalypts are mainly grown for the production of essential oil whose medicinal potentialwas noted by the Europeans soon after their settlement in Australia. Boland et al intheir book ‘Eucalyptus Leaf Oils: Use, Chemistry, Distillation and Marketing’ havecompiled the composition of volatile oils from 111 species of Eucalyptus (Boland etal., 1991).


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The primary component of the medicinal oil is 1,8-cineole (77) which mayconstitute more than 90 per cent of the terpenes in some Eucalyptus species (Foleyand Lassak, 2004).The foliar concentrations of 1,8-cineole have been positivelycorrelated with the levels of sideroxylonals (dimeric formylated phloroglucinolcompounds). This correlation is found to be ecologically important because marsupialfolivores use the concentration of the cineole as a cue to the concentration offormylated phloroglucinols. It is also being widely used as a herbicidal compound.

The other mono- and sesqui-terpene components of the eucalypt oil include 3-methyl butanal (78), linalool (79), linalyl acetate (80), 4-methylpentyl-2-acetate (81),isoamylisovalerate (82), citronellyl acetate (83), â-phenylethyl butyrate (84), myrcene(85), E-â-ocimene (86), Z-â-ocimene (87), á-farnesene (88), E,E-farnesol (89),á-terpinene (90), ã-terpinene (91), terpinolene (92), á-phellandrene (93),â-phellandrene (94), limonene (95), â-elemene (96), australol (97), trans-piperitol(98), á-terpineol (99), terpinen-4-ol (100), trans-p-menth-2-en-1-ol (101), cis-p-menth-2-en-1-ol (102), trans-p-mentha-1(7), 8-dien-2-ol (103), elemol (104),phellandral (105), piperitone (106), cryptone (107), carvone (108), p-cymene (109),p-cymen-8-ol (110), carvacrol (111), cuminal (112), sabinine (113), á-pinene (114),â-pinene (115), pinocarvone (116), pinocarveol (117), bicycloelemene (118),ä-cadinene (119), á-copanene (120), á-cubebene (121), cubeban-11-ol (122),á-eudesmol (123), â-eudesmol (124), ã-eudesmol (125), á-humulene (126),bicyclogermacrene (127), â-caryophyllene (128), caryophyllene oxide (129),á-bulnesene (130), aromadendrene (131), allo-aromadendrene (132), á-gurjunene(133), virdiflorene (134), spathulenol (135), virdiflorol (136), palustrol (137), globulol(138), epiglobulol (139) and ledol (140) (Foley and Lassak, 2004) (Fig. 26 and 27).

2.3.2. Monoterpene glycosides and monoterpene-sugar estersA very few monoterpene glycosides have been reported from the genus Eucalyptus.In this type of compounds, the monoterpene functionality is found to be attached ateither or both the C1 anomeric and C6 primary hydroxyl groups of the sugar. Primarily,the sugar present in these compounds is â-(D)-glucose. Since in most of the cases,the carboxylic acid moiety of the monoterpene is found to be esterified with thehydroxyl of the sugar, these compounds may not be called as glycosides in truesense. Examples of true monoterpene glycosides occurring in eucalypts includeglobulusin A (141)(1S, 2S, 4R)-trans-2-hydroxy-1,8-cineole â-D-glucopyranoside(142) (Hasegawa et al., 2008).

Majority of the monoterpene-sugar esters contain (R or S)-oleuropeic acid as astructural unit while a few have menthiafolic acid. Froggattiside A (143) reportedfrom E. froggatii and E. cypellocarpa contains both of these monoterpene acids.Three oleuropeic acid-glucose esters named cypellocarpins A, B and C (144-146)were isolated from E. cypellocarpa. These have shown potent in vitro anti-tumour


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O78

HO

79

O

O

O

O83

O

O81

O

O

O

O84

87 88 89H H

85

OH

86

O

9590 92 949391 96

HO

101

OH

OH99

100

OH

98

OH

103

OH

97

109

O

107

CHO

105

O

106

O

108

CHO

112110OH

OH104

HO

111

O

113 116 117115114

OH

7780

82

102

OH

Fig. 26. Structures of the monoterpenes present in eucalypt oils.

promoting activity. Eucalmaidins A-C and E (147-150), isolated from the fresh fruitsof E. maideni, possess the same esterified oleuropeic acid moiety as incypellocarpins. Recently, three chromenone glucosides, named eucamaldusides A(151), B (152), and C (153), were isolated from the leaves of E. camaldulensis var.obtuse (Begum et al., 2011). Other acylated sugar-esters reported from Eucalyptusspecies include globulusinB (154), eucaglobulin (155), cuniloside B (156),6-O-[(S)-oleuropeoyl]sucrose (157), 1-O-[(S)-oleuropeoyl]-â-D-glucopyranose (158), 8-O-(â-D-glucopyranosyl)-(4S)-oleuropeic acid (159).

Compounds 141, 142, 154-156 were found to be DPPH radical scavengers,globulusin A (141) being most potent molecule with an IC50 of 3.8 μM. Globulusin A


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HH

121118

H

H

120

H

HH

133

128

131 135

124 125

136

OH

OH OH

HO

132

H

130

126

134

127

H

119

H

HO

137

HH

HO

129

HO

138OH

139

OH

140

OH122

OH

123

H

H

Fig. 27. Structures of the sesquiterpenes present in eucalypt oils.

(141) and eucaglobulin (155) also exhibited a concentration-dependent decrease inpro-inflammatory cytokines (Goodger et al., 2009; Goodger and Woodrow, 2011;Hasegawa et al., 2008). Fig. 28 presents monoterpene glycosides and sugar-estersof Eucalyptus species.

2.3.2.1. Structure elucidation of cuniloside BThe mass spectrum of cuniloside presented a sodiated molecular ion at m/z 535and fragment peaks at m/z 329 [C16H25O7]

+ and 311 [C16H25O7-H2O]+. IRabsorptions at 1700 and 1250 cm-1 in addition to 13C resonances at ä 169.2 and167.6 in 13C NMR indicated, â- unsaturated ester functionalities. A double setof ten signals corresponding to oleuropeoyl moiety could be observed in the1H and 13C NMR spectra of 156. Other signals in the NMR spectra wereunambiguously assigned to a glucopyranose moiety. On the basis of thespectral data, 156 was inferred to be glucopyranose esterified with twooleuropeoyl moieties and was identified to be O1,O6-bis-(8-hydroxymenth-1-en-7-oyl)-â-D-glucopyranose (cuniloside B). The structure was further


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146: R= (S)-oleuropeoyl, R1 = CH3, R2 = H152: R= (S)-oleuropeoyl, R1 = CH(CH3)2, R2 =H153: R= (S)-oleuropeoyl, R1 = R2 = CH3

151

O OHOH

HO

O

OROH

HO

COOH

O OHOH

HO

O

OR

O

O

HO

OH

O OHOH

HOO

OR

O

O OH

R1

R2

OOH

OHHO

O

O

O

O OH

H3C

H2C CH3

OHH3C

O

OOH

OHHO

HO

OR

OOH

OHHO

OR1

O

ORHOOC

OR

147: R= (S)-oleuropeoyl

148: R = H, R1 = (S)-oleuropeoyl149: R = CH3, R1 = (S)-oleuropeoyl

OOH

OHHO

OR2

R1O

150: R1 = R2 = (S)-oleuropeoyl156: R1 = R2 = (R)-oleuropeoyl158: R1 = (S)-oleuropeoyl,R2 = H

OOH

OHHO

OR

OO

OOH

OHHO

O

OOH

OH

OHRO

OOH

OHHO

OR

OO

HOOH

OH

141: R = gallate142: R = H

154: R = (S)-oleuropeoyl


OOH

OHHO

OR

OO

HO

143: R = (R)-oleuropeoyl 144: R =(S)-oleuropeoyl



OOH

OHHO

OH

O

O

HO

159

O

OHO

Oleuropeoyl moiety

OOH

OHHO

OR

OO

HO

HO OH

HO

Fig. 28. Structures of the monoterpene glycosides and sugar esters reported from eucalypts.

confirmed by hydrolysis. The aglycone generated after alkaline hydrolysiswas identified as oleuropeic acid methyl ester (160) on the basis of NMR data(Scheme 1) (Manns and Hartmann, 1994).

2.3.3. Triterpenoids and their glycosidesTerpenoids and their glycosides are ubiquitously occurring compounds in theplant kingdom. Several triterpenoids are reported from eucalypts. The presenceof common triterpenoids like ursolic acid (161), oleanolic acid (162), betulinic


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acid (163), maslinic acid (164), â-amyrin (165), etc. is far and wide in eucalypts(Furuya et al., 1987; Santos et al., 1997; El-Domiaty et al., 1999).

Five new triterpenoids, namely, camaldulic acid (166), camaldulensic acid (167),camaldulenic acid (168), eucalyptic acid (169) and eucalyptolic acid (170) havebeen isolated from the leaves of E. camaldulensis. Another triterpenecamaldulin(171), isolated from the same plant, showed spasmolytic activity on isolated rabbitjejunum (Begum et al., 1997; Begum et al., 2000).

Other triterpenes with ursane skeleton arerobustanic acid (172), isolated fromE. robusta (Khare et al., 2002) and loxanic acid (173) and 3-acetyl loxanic acid (174)from E. loxophleba (Sidana et al., 2011) and cladoclol (175), a pentacyclictriterpeneisolated from E. cladocalyx showed cytotoxic activity in HL-60 cells. It has displayeda cytotoxic potency with an IC50 of 42 ± 4 μM (Benyahia et al., 2005). Fig. 29 presentsthe structures of triterpenoids and their glycosides.

2.3.3.1. Structure elucidation of loxanic acidLoxanic acid (173) exhibited an [M-OH]+ fragment ion at m/z 437. Its molecularformula C30H46O3 was confirmed by an interplay of 1H and 13C NMR (DEPT). Anabsorption band at 281 nm in UV spectrum indicated conjugation in the molecule(homoannulardiene system). The 1H and 13C NMR data of loxanic acid indicated thatit is an ursane type of triterpenoid. The 1H NMR spectrum showed five tertiarymethyl signals at ä 1.33 (H-26), 1.28 (H-23), 1.22 (H-25), 1.14 (H-27) and 1.07 (H-24)and two secondary methyl signals at ä 1.01 (d, J = 6.4 Hz, H-29) and 0.95 (d, J = 6.3 Hz,H-30). A triplet for one proton at ä 3.49 indicated the presence of a hydroxyl group atC-3. The chemical shift and coupling constant (J=8.3 Hz) suggested the

O

OHO

OOH

HOHO

OO

HO

(R)

(R)

OCH3O

OH

(R)

a

156 160

Scheme 1. Alkaline hydrolysis of cuniloside B (156) to oleuropeic acid methyl ester(160). Reagents and conditions: (a) 0.01M NaOH, 5 min., RT.


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HO

COOH

161

OHCO

OO

171

COOH

HO 166

CH2OH

COOH

HO

H3CO

167

COOH

HO

HO

168

O

COOHHO

O

CHCH

H3CO

HO

O

HOO

CHCH

H3CO

HO

COOH

169

170

HO

R

162: R = COOH165: R = CH3

COOH

HO

R1

HO

172: R1 = COOH, R2 = OCH3175: R1 = OCHO, R2 = H

R2

O O

163

COOH

HO

HO

164

COOH

R

173: R = OH174: R = OCOCH3

Fig. 29. Triterpenoids of various Eucalyptus spp.


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stereochemistry of the hydroxyl group to be â . The 1H NMR showed two olefinicone-proton doublets at ä 5.79 (äC 124.5, C-12) and 5.75 (äC116.8, C-11) which wereconnected through1H-1H COSY. The correlations of H-11 with C-8, C-10 and C-13; H-12 with C-9, C-14 and C-18 in HMBC (Fig. 30) spectrum confirmed the presence of acisoiddiene at C-9 (11):12 in this compound. The quaternary carbon ä 181.2 supportedthe presence of a carboxyl moiety and was located at C-17 on the basis of comparisonof the chemical shift value with those of structurally similar triterpenes (Begum etal., 1997; Ikuta et al., 2003).

COOH

HOH

HH

H

HH 1

59

11 12

30

29

28

18

16

22

23 24

The 1H and 13C NMR values and HMBC correlations coincided with those ofeucalyptanoic acid except for the two secondary methyl groups in thespectrum (Begum et al., 2002). Thus, compound 173 was established as 3â-hydroxyursa-9(11), 12-dien-28-oic acid (named loxanic acid, Fig. 30) (Sidana etal., 2011).

2.4. Miscellaneous CompoundsEucalypt leaves and wood are known to contain simple and complex polyphenols.The spectrum of polyphenolic constituents of eucalypts ranges from simplemonomers like gallic acid to complex polymeric tannins. Simple phenols occurringwidely in eucalypt plants are gallic acid (176), ellagic acid (177), vanillin (178),syringaldehyde (179), sinapaldehyde (180), vanillic acid (181), vomifoliol (182),2,6-dimethoxy-p-benzoquinone (183) and 2,4,6-trimethoxyphenol (184) (Conde etal., 1995; Hur et al., 2003) (Fig. 31).

1,2,6-tri-O-galloyl-â-D-glucose (185) and tellimagrandin 1 (186) were isolatedfrom E. rostrata and have shown anti-oxidant activity (Okamura et al., 1993). 3-O-Methylellagic acid-4'-O-rhamnoside (187) has been isolated from E. cypellocarpa,


Fig. 30. HMBC ( ) and COSY ( ) correlations of loxanic acid (173).

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E. deglupta, E. globulus and E. regnans (Yazaki and Hillis, 1976). Four other ellagicacid rhamnosides were isolated from E. globulus. The antioxidant activity of allcompounds was evaluated by thiobarbituric acid method in rat liver microsomes andwere found to be active (Kim et al., 2001).

Globoidnan A (188), a lignan, has been isolated from E. globoidea by bioassayguided fractionation of methanol extract of buds. It was found to inhibit the activityof HIV integrase with an IC50 of 0.64 μM (Ovenden et al., 2004).

COOH

OHOH

HO

O

OOH

OHO

O

HO

HO

OH

CHO

OCH3 OCH3OH

H3CO

CHO

OCH3OH

H3CO

CHO

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176177 178 179 180

181 182 183 184

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OO

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OHHO

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O O

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185186

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OHOH

HO

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187

Fig. 31. Miscellaneous constituents of Eucalyptus.

3. The Indian EucalyptsThe genus Eucalyptus is reported to be introduced to India in the late eighteenthcentury whence about 16 different species were imported from Australia. About


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170 species, varieties and provenances of eucalypts are found in India; speciesgrown on plantation scale include E. camaldulensis, E. citriodora, E. globulus,E. grandis and E. tereticornis. Despite the wide cultivation of pure and hybrideucalypts throughout India, not many Indian scientists have worked on unveilingthe chemistry of this genus.

Primarily, the phytochemistry of eucalypts done in Indian laboratoriesincludes, the compositional analyses of crude volatile oil followed by antimicrobialactivity evaluation.Apart from the identification of components of volatile oils,the phytochemical analyses of Indian eucalypts have only resulted in theidentification and/or isolation of triterpene compounds. A new triterpenic acidnamed robustanic acid (172) has been isolated from the leaves of E. robustaalong with previously known constituents, viz., ursolic acid, ursolic acid lactone,sideroxylin and gallic acid (Khare et al., 2002). Biofungicidal potential of aEucalyptus hybrid (E. camaldulensis × E. tereticornis) has been studied usingsome plant pathogenic fungi. Ursolic acid was isolated as an antifungal principlein this study (Varshney et al., 2012).

4. Conclusions and RecommendationsOriginally native to Australia, eucalypts have come to stay in many countries aroundthe globe. In India, it meets the demand for fuel, timber and paper and helps reduce theburden on natural forests. This chapter has been written with an effort to compile theexisting information on chemistry of eucalypts. Various structural classes of compoundsnamely phloroglucinols, flavonoids, terpenes, etc. have been described in details. Thecompounds reported from this genus exhibit a vast array of biological and ecologicalactivities. Hence, eucalypts provide scope both in terms of new chemical constituentsand new activities of already known compounds.

The sustained interest in the phytochemistry of eucalypts is evident from thenumber of publications and patents describing chemical composition and biologicalprofile of different species. A few books describing the different aspects related toeucalypts volatile oils and their constituents have been published (Boland et al.,1991; Coppen and Dyer, 1993). For phloroglucinols, as a class of compounds, areview article entitled ‘Phloroglucinol compounds of natural origin’ by Singh andBharate is of interest (Singh and Bharate, 2006). Other readings on similar subjectsinclude review articles on Eucalytpus compounds and their biological activities(Singh and Etoh, 1997; Singh, 2003) and phloroglucinols (Ghisalberti, 1996).

AcknowledgementAuthors are thankful to the Director, NIPER, Prof. Monica Gulati (Senior Dean,Pharmaceutical Sciences) and Dr. Amit Mittal (Head of the Department,Pharmaceutical Sciences) for support.


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1. IntroductionPaper is one of the essential commodities for daily use and paper industry formsthe core sector of our country’s economy. Paper and paper products contribute toother sectors also such as education, communication and product packaging. Theuses and applications of paper and paper products are limitless and new specialtyproducts are continuously developing. Despite the revolution in electronic mediaand tough competition from computers and internet connectivity, the demandforecasts clearly indicate rise in requirement of paper and paper products in theyears to come. With rise in its literacy rate, per capita consumption in India isexpected to double within next 10 years (Mishra, 2011). Indian paper industry hasa tough task ahead and has to gear itself for facing the growth in demand. However,there are several bottlenecks the industry has to overcome and one of the biggesthurdles is the availability and utilization of inputs to match quality with costeffective production.

2. Current Scenario of Paper ProductionThe global consumption of paper is 400 Mt yr-1 and expected to increase itsconsumption to 500 Mt by 2020 (WWF, 2010), while in India, the consumption ofpaper and paper board is estimated to be double from 10 Mt yr-1 by 2020 (Mishra,2011). Though the softwoods and hardwoods have desirable characteristics offibres for pulp and paper making, over-exploitation of these woods for differentpurposes has resulted in continuous decline in their production from natural forests(Ashori, 2006; Sharma et al., 2013). Fig. 1 to 4 represent the global scenario ofpaper and virgin pulp production world wide and Fig. 5 represents the cost analysisof paper making (SFIF, 2011).

Cellulose and Paper Division, Forest Research Institute (FRI), Dehradun has animpressive record in conducting research and development in the field of pulp and papertechnology since 1909 when Sir William Raitt initiated studies on evolving an efficient

Eucalypts in Pulp andPaper IndustryVikas Rana, Gyanesh Joshi,S.P. Singh and P.K. Gupta

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and economic process for preparation of easy bleaching pulp from bamboo. Agriculturalwastes, grasses and hardwood forests plantations were also introduced for the productionof a variety of papers. Work on high yield pulping process, bio-degradation of lignin,beater/wet additives and development of speciality paper have been carried out in theCellulose and Paper Division of FRI, Dehradun (Singh et al., 1992).

Fig. 1. Global paper production in 2011 (Total production: 399 Mt).

Eucalypts in pulp and paper industry

Fig. 2. Global paper production of different grades of paper in 2011 (Total production: 399 Mt).

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When Indian paper industry was facing an acute shortage of quality rawmaterial, an initiative was taken by the division to explore the possibility ofpaper production from alternative sources like eucalypts, poplar and subabul,etc. During last decades, the division has done an extensive research work onsuitability of various species for pulp and paper production, technologies werealso developed which have been adopted by a number of Indian paper mills.

Fig. 3. Global pulp production by region in 2011 (Total production: 184 Mt).

Fig. 4. Global pulp production by grade in 2011 (Total production: 184 Mt).

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Fig. 5. Cost of paper manufacturing.

3. Raw Material Constraint to Paper IndustryToday there are 759 pulp and paper mills in India producing 10 Mt of paper andpaper boards which is 2.52 per cent of the total world production. Indian paperindustry is highly fragmented in terms of product wise segmentation and produces38.58 per cent printing or writing, 53.61 per cent packaging and 7.81 per centnewsprint papers. Depending upon the production capacity paper mills areclassified as large (33,000 tpa), small (7,500 tpa) and medium (between 7,500 to33,000 tpa). The paper production from small and medium mills accounts for 60 percent while 40 per cent comes from large mills. Out of 759 mills, 114 (15%) are large,342 (45%) small and 303 (40%) medium.

India has a total forest area of about 75 Mha which forms only 22.8 per centof the total geographical area (328 Mha) of the country. The productivity ofIndian forests is only 1.34 m3 ha-1 yr-1 against the world average of 2.1 m3 ha-1 yr-1.The wood based papermills in India continue to face challenges with forestbased raw material. Pulp and paper industry consumes 3 per cent of total nationalrequirement of wood. The annual pulp production is 3.03 Mt from, 10 Mt ofwood, agricultural wastes and waste paper. Nearly 20 per cent of wood is procuredfrom government sources while, 80 per cent from agroforestry sources. Thestrategy adopted by the industry to meet the ever growing demand of wood ona sustainable basis is to obtain wood from social and farm forestry plantations(Kulkarni, 2013).

The small paper mills set up in the early seventies almost exclusively useagricultural wastes as raw material for paper production whereas large mills mainly


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use forest species like bamboos, eucalypts, poplar, etc. Whereas agricultural wastessuch as rice straw, wheat straw and bagasse are relatively short cycled, regenerativeand available in abundance, the availability of forest-based raw material is ratherlimited. With the implementation of central and state government policies towardsforest protection and afforestration, the pulp and paper mills will have to reduceconsumption of forest materials and raise forest plantations. The government is alsoencouraging the industry to create plantations on degraded forest and waste land.The overall limited availability of raw materials will force the paper industry to relymore and more on imports of pulp or final paper products. To overcome the shortageof raw material, the government has liberalized its import and given concessions inexcise duty for the use of non-conventional raw materials (Schumacher and Sathaye,1999).

4. Eucalypts a Promising Source for PapermakingEucalypts are fast-growing trees, and can be made available for pulp production withinfour to five years after planting. The increasing demand for wood partly results fromthe attractive economic return from eucalypt plantations (Jawjit, 2006). The use ofeucalypts in cellulosic pulps was initially developed more than 50 years ago in Australia,where there are vast natural forests of the species. Work on developing eucalypt pulpbegan in Argentina in 1974 by Celulosa Argentina S.A. at its captain Bermudez Mill.Since then growth in the number of users of eucalypts has stimulated significantforestation in that country (Ordonez and Zilli, 1971). In India, the pulp and paperindustry was getting raw material from the plantation raised by forest departments orcorporations. However, National Forest Policy 1988 made the pulp and paper industriesto raise their own plantation to meet the demands. Clonal technology was used forincreased productivity especially for E. tereticornis (Lal et al., 1997).

Eucalypt plantations are being established to supply raw material in the leastpossible time to fill the gap of demand and supply of wood for industries. In countrieswith good environmental conditions a particular fast grown plantation is beingdeveloped with diverse genus: Populus, Salix, Pinus and Eucalyptus. Although thegenus Eucalyptus has more than 600 species and varieties, those planted oncommercial scale do not surpass the dozen. Among them one can mention E. grandis,(and its hybrids, as ‘urograndis’), E. camaldulensis, E. globulus, E. nitens, E. saligna,E. tereticornis, E. urophylla and E. viminalis, although at present, E. globulus andE. grandis are the predominant in fast grown plantations (Acosta et al., 2008).

Eucalypt plantations offer the possibility of being easily certifiable withenvironmental certification if the good practices are followed, along the productionchain and even the custody chain. Today thousands of hectares of eucalypts arecertified all over the world. These plantations of eucalypts generally have highgrowth rate, but with the advances in genetics and tree improvement in eucalypts

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and the use of productive clones, growth rates of 70 m3 ha-1 yr-1 or higher can beachieved. In Argentina, Brazil and Uruguay it is not rare to find one-year-old treessurpassing 6 meters of height (Acosta et al., 2008).

5. Status of Eucalypt Plantations for Paper Industry in IndiaAbout 170 species, varieties and provenances of Eucalyptus have been cultivatedin India (Bhatia, 1984); out of these, the most outstanding and favoured has beenthe Eucalyptus hybrid, a form of E. tereticornis known as Mysore gum. The mostimportant characteristic of Eucalyptus hybrid contributing to its popularity underIndian conditions are (Kushalappa, 1985):

• Fast growth,• capability of over topping the weeds,• fire hardy nature and• ability to adapt to a wide range of edaphoclimatic conditions.

Other species which are grown for plantation are E. camaldulensis, E. citriodora,E. globulus and E. grandis. Over 0.1 Mha of eucalypt plantations have been establishedmostly by state forest departments and forest development corporations (Sandhu,1988). There are several reasons for raising large scale eucalypt plantations in thecountry; some are common and some are specific to each state. The most importantcommon reason is to re-vegetate the denuded and barren hilly areas and replace lowvalue natural forests (FAO, 1979). The policy of converting low value natural forestsinto plantations was aimed at improving productivity and generating governmentrevenue. Some of the state governments took advantage of the centrally sponsoredscheme of raising fast growing species initiated during the 1960s, and raised eucalyptplantations by clear felling even the moist deciduous forests. The pulpwood shortageat times had created the need for quick growing species and this led to the biggestsingle urge to plant eucalypts in large scale plantations to meet the demand for woodfibre for the industry (Shiva et al., 1991). A large number of plantations programmeshave been initiated by pulp and paper mills which aim to correct the vicious circle oflow investment, low productivity and low income deeply rooted in Indian forestry.

In Brazil, eucalypt plantations grow at an average rate of 35 to 45 m3 ha-1 yr-1. Thiscorresponds to 10 to 12 t of bleached pulp ha-1 yr-1. Considering a six to seven yearscycle, an average forest stand produces 250 to 320 m3 ha-1 at the time of harvesting(www.celsofoelkel.com.br, accessed on 3/1/14). In India, most of the pulp woodrequirement at present is met from farm forestry initiated by the paper mills byutilizing marginal farm lands and their own captive plantations (Mishra, 2011).However, about 0.25 Mha land is required to meet the present demand of pulpwood. To consider the paper industry, it is projected that the gap between demandand supply of forest-based fibres will be around 18 to 20 Mt, 10 years from now.


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6. Why Paper from Eucalypts?Characteristics which make eucalypts suitable for paper making are describedhereunder:

6.1. Good Paper Making QualitiesThe short eucalypt fibres form small flocks in aqueous suspensions resulting ingood paper formation, i.e., without clouds on the paper webs (when looked at againsta source of light). Deficient formation causes variations in paper sheet basis weightand calliper. This impairs subsequent operations, such as calendaring, coating,printing, etc. When calendaring a poorly formed paper due to fibre bundle wetpressing, dark spots are formed, gloss is irregular, and often there appear transparentspots. Paper formation is one of the vital properties for some fine paper grades.Eucalypt fibres are acknowledged as very favourable to this property.

6.2. Paper BulkBulk is the inverse property to sheet density. It is connected with the capacity of acertain paper to show higher or lower volume (or thickness) at a certain basis weight.Bulky paper sheets can be obtained by using the short and rigid eucalypt fibres,especially at the initial levels of pulp stock refining. This property is closely associatedwith paper porosity. It interferes with numerous characteristics of paper use. Ahigher bulk makes it possible to reduce the basis weight. The property is also helpfulin the production of tissue papers for facial or hygienic purposes, presenting highvolume for the same paper weight or area. Papers requiring high porosity, like thosedemanding ink or resin impregnation like, decorative papers, industrial filters, cigarettepaper, etc.

6.3. Porosity/Air ResistanceThe pulp from eucalypts produces less porous paper sheet which makes it more airresistant.

6.4. Liquid Absorption by the Paper WebPaper sheets produced with eucalypt fibres have capacity to quickly absorb andretain water or inks by micro capillarity. For this reason, eucalypt fibres areextensively used in manufacture of tissue and printing papers. In such papers, theprinting ink impregnates the sheets more easily. In case of decor papers, phenol ormelamine resins also penetrate easily into the paper body.

6.5. Paper SmoothnessThe eucalypt fibres are short and narrow in their diameter which favours a bettersurface distribution of anatomical components resulting in higher surface

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smoothness. Smoothness correlates very well with the fibrous population of thepulp. Smooth papers are ideal for printing and coating as they allow savings in termsof printing ink and coatings.

6.6. Paper OpacityOpacity is strongly influenced by the high fibrous population of eucalypt pulp. Thepulp of eucalypts produces the paper having higher opacity.

6.7. Sheet PrintabilityThe combination of the properties of smoothness, liquid absorption and opacity favoursprintability of the paper sheets manufactured with eucalypt pulp fibres. Therefore,surface layer of most of the multi-layer papers are made up of eucalypt pulp.

6.8. Dimensional StabilityDimensional stability is a very important property required by printing papers. Thehigher the refining applied to the fibres, lesser will be the dimensional stability asfibrillation, swelling and the content of anionic groups (carboxyl) in the pulps increase.The requirement of refining is minimum in the case of eucalypt fibres hence, thedimensional stability of fibres is maintained. This property is excellent in papersheets manufactured with the short refined eucalypt fibres.

6.9. Tissue Paper SoftnessThe feeling of softness, or tactile softness, is one of the properties mostly desired inthe tissue grade papers. Long fibres transmit a feeling of roughness, while theunrefined or limited refined short eucalypt fibres offer an excellent tactile sensationof softness and smoothness.

6.10. Paper Surface GlossCalendaring the smooth surfaces of paper sheets manufactured with the eucalyptfibres improves the paper sheet gloss (http://www.celso-foelkel.com.br/, accessedon 3/1/14).

7. Physico-Chemical Characteristics of Eucalypts

7.1. Fibre Morphology and Wood DensityThe suitability of raw material for pulp and paper from a variety of lignocellulosicraw materials depends largely on the shape of its cells. During the early stage ofgrowth, the cell cavities contain protoplasm but soon after the cell wall is fullyformed, this disappears from the cells, which are useful for papermaking, leavingonly the hollow, tubular or quill shaped structure. These narrow, elongated plant


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Table 1. Comparison of fibre quality of Eucalyptus with other available raw materials

cells with tapering ends, resemble minute threads in shape and are known asfibres. In pulp and paper technology a cellulose fibre is any elongated cell with alength much greater than its diameter. A fibre may originate from any type of cell inthe plant source. Electron microscope study of the structure of wood fibres revealsthat the fibre wall is composed of four distinct concentric layers surrounding thecentral cavity, the lumen (Luna et al., 2004).

Eucalypts are the most valuable and widely planted forest tree species inthe world (> 20 Mha) due to its wide adaptability, extremely fast growth rate,good form and excellent wood and fibre properties. Eucalypt plantationsworldwide have expanded in the last 60 years because of the superior fibre andpulping properties of the species and the increased global demand for short-fibre pulp.

While considering wood or non-wood as a source of fibre for the production ofpulp and paper, two factors must be taken into account: the yield of fibre per givenvolume or weight of raw material (more so in the chemical processes), and the qualityof the resulting fibre. The former depends on the characteristics of the feedstockprior to pulping and the process employed in its conversion into pulp, while the lateris mainly a result of morphological features of the individual fibres and theirmodification brought about by the methods of conversion (Vaughn et al., 2003). Thefibre variables responsible for determining the physical characteristics and qualityof pulp and paper are classified under fibre morphological aspects. These variablesare fibre length, cell wall thickness, fibre coarseness, fibre strength and interfibrebonding (Haygreen and Bowyer, 1996; Sridach, 2010). Table 1 summarizes acomparative study of the morphological characteristics of E. grandis, sugarcanebaggase, bamboo and pine (Seykere, 1994; Agnihotri et al., 2010; Dutt and Tyagi,2011).

Literature also reports that the pulp of E. grandis is of superior quality thansugarcane bagasse non-wood pulp. Fibre length generally influences the tearing

V. Rana et al.

Species Source Fibre length

(L), mm

Fibre width

(D), μm

Lumen diameter (d), μm

Cell wall thickness

(w), μ

Runkel ratio

(2w/d)

Slenderness ratio (L/D)

Rigidity coefficient

(2w/D) E. grandis Bhadrachalam, India 1.1 19.2 3.2 12.2 0.5 55.2 0.3 E. grandis Saharanpur, India 0.9 20.1 2.8 14.3 0.4 52.3 0.3 E. tereticornis - 0.7 14.2 3.4 5.4 3.2 49.3 0.8 E. robusta - 1.1 19.0 12.1 3.4 0.6 56.3 0.4 Sugarcane bagasse India 1.5 21.4 6.3 7.7 2.5 70.6 0.7 Sugarcane bagasse Mexico 1.1 20.0 2.0 4.0 0.7 56.5 0.4 Bambusa vulgaris India 2.0 15.1 4.0 5.5 2.8 134.0 - B. vulgaris Philippines 2.3 17.0 4.0 7.0 3.5 137.0 - B. vulgaris Ghana 2.7 14.6 9.7 5.0 1.0 182.0 - Pinus kesiya - 2.3 40.7 34.8 5.9 0.3 56.5 0.03

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strength of paper; the greater the fibre length, the higher will be the tearing resistanceof paper (Muneri, 1997; Fardim and Duran, 2004). Paper made from fibres that are tooshort will have insufficient common bonding area between fibres, and as a resultthere will be points of weakness for stress transfer within the sheet, and the paperwill be low in strength (Haygreen and Bowyer, 1982).

Fibre diameter and wall thickness influences the fibre flexibility (Dutt andTyagi, 2011). Thick walled fibres adversely affect the bursting and breakingstrengths, and folding endurance of paper. The paper manufactured from thick-walled fibres will be bulky with coarse surface texture containing a large amount ofvoid volume. Thin-walled cells on the other hand, collapse readily to form dense,well-bonded paper, low in tear but high in other strength properties (Deniz et al.,2004).

Fibre lumen width affects the beating of pulp. The smaller the fibre lumenwidth, the poorer will be the beating of pulp because of the penetration ofliquids into empty spaces of the fibres (Mosello et al., 2010). The breakinglength and other physical properties of E. grandis pulp was far better as

compared to other raw materials, viz., bamboo and sugarcane bagasse (Table 2).The Runkel ratio of E. grandis was on the lower side as compared to bambooand sugarcane bagasse which further contributed to the positive effect onbreaking length. Different Eucalyptus species have been evaluated for theirmorphological characteristics. A detailed description of different species islisted in Table 3.

Among Eucalyptus, basic density has been correlated with paper properties(Higgins, 1970), so that different density ranges are suited to different paperproducts. Eucalypts with high density up to 600 kg m-3, have fibres with thickwalls relative to their diameter and are stiff and resistant to collapse (Higgins,


Table 2. A comparison of paper strength properties derived from sugarcane bagasse,E. grandis and bamboo

Property Sugarcane bagasse E. grandis Bamboo

Kraft pulping Beating time (min) 23 80 40 Drainage rate (oSR) 45 40 44 Tear index (mNm2g-1) 3.6 8.4 14.4 Burst index (K.Pa. m2 g-1) 5 5.3 7.1 Breaking length (km) 3.8 5.9 5.3 SodaAQ pulping Beating time (min) 20 55 40 Drainage rate (oSR) 45 40 47 Tear index (mN m2 g-1) 3.8 4.1 15.9 Burst index (K.Pa. m2 g-1) 4.7 4.7 5.5 Breaking length (km) 4.9 5.7 3.4

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Table 3. Morphological characteristics of different Eucalyptus species

Source: Dutt and Tyagi, 2011.

1978). It results in forming of bulky open sheets which are porous and morecompressible, giving better printability (Dillner, 1979; Arbuthnot, 1991). Eucalyptswith medium density up to 540 kg m-3 are considered superior raw material fortissue paper (Zobel et al., 1983; Paavilainen, 1998). Woods at the low density, aslow as 400 kg m-3, collapse more readily, forming ribbon-like shapes that havegreater surface area and, therefore, bond well together. Papers made from thesefibres have high tensile and bursting strengths but low opacity, and are bestsuited to packaging grades of paper.

Basic density is inversely related to moisture content (Higgins and Phillips,1973), although the exactness of this relationship varies (Zobel and van Buijtenen,1989). Moisture content can influence road transport costs, since state laws usuallylimit the amount of weight, that a truck can carry. Density also has direct effects onthe economics of wood chip transport, and on pulping in mills in which the capacityof the digester is a limiting factor (Paavilainen, 1998). Densities of some Eucalyptusspecies are listed in Table 4 (Hicks and Clark, 2001).

Species Tree age (yr) Basic density (kg m-3) E. badjensis 14 499 E. benthamii 14 516 E. globulus ssp. bicostata 14 569 E. kartzoffiana 14 492 E. macarthurii 14 536 E. nitens 14 553 E. smithii 14 568 E. viminalis 14 517 E. dunnii 9 513 E. cloeziana 12 644 E. pilularis 12 590 C. maculata 12 642 E. occidentalis 6 594

Table 4. Basic densities of some Eucalyptus species wood

Species Fibre length

(L), mm

Fibre width (D),

µm

Cell wall thickness (w), µm

Lumen diameter (d), µm

Runkel ratio

(2w/d)

Flexibility coefficient (d/D) x 100

Slenderness ratio (L/D)

Rigidity coefficient

(2w/D) E. grandis 1.06±0.06 19.21±1.2 3.20±0.7 12.20±3.2 0.52 0.66 55.18 0.33

E. alba 0.88±0.1 19.23±2.2 4.80±0.8 9.80±1.6 0.98 0.50 45.76 0.50

E. tereticornis 0.85±0.02 16.14±1.5 5.10±0.8 6.10±1.7 1.64 0.38 52.66 0.63

E. torrelliana 0.81±0.08 17±1.9 4.7±0.4 7.8±2.4 1.21 0.45 47.64 0.55

E. europhyllia 0.85±0.20 16±4.0 5.0±0.5 6.1±0.6 1.64 0.38 47.65 0.62

E. camaldulensis 0.80±0.21 15±3.1 4.0±0.9 7.2±0.8 1.11 0.48 53.33 0.53

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E. grandis is one of the most promising pulpwood species that merits attentionunder the intensive short rotation management. A study to evaluate the woodquality differences in terms of wood density, percentage of bark, heartwood, andfibre length of E. grandis among four age groups (three, five, seven and nine years)at three different locations was carried out by Bhat et al. (1987). This study revealedthat trees attain the minimum wood density requirement of pulp industry at the ageof three years and there was no significant increase in wood density with an increasein age from three to nine years. On the other hand, five-year-old trees produce thewood of lower density. This pattern of wood density variation with age indicatesthat, there is no significant loss in pulp yield per unit volume of wood, if three-year-old wood is pulped as against five to seven or nine-year-old wood. Increase in fibrelength and heartwood percentage and decrease in bark percentage with age fromthree to nine years was also evident. Within each age group, tree growth parameterslike height and diameter (DBH) have no marked effects on wood density, fibrelength and heartwood percentage. Bark percentage is, however, negatively correlatedwith tree growth. These results suggest that silvicultural practices aiming at fastergrowth (higher yield) will not adversely affect the wood quality.

It was further reported that there was no appreciable wood property differenceamong the three locations of E. grandis although fibre length and heartwoodpercentage are slightly greater in more rapidly grown three-and five-year-old treesat one of the locations. Fibre length increases considerably from pith to bark in allthe age groups (Bhat et al., 1987).

Numerous investigators agree with the view that wood density or specific gravityis one of the most useful parameters of measuring wood quality within the species(Zobel and Talbert, 1984). It can also be used as a predictor of yield and quality ofpulp and paper products (Dadswell and Wardrop, 1959; Barefoot et al., 1970). Anyalteration in wood density of eucalypts is, therefore, of great importance because itinfluences fibre properties and mechanical pulp qualities and consequently paperproduction (FAO, 1970). Wood density determination is also of interest to the foresterin preparing dry weight tables for prediction of productivity per unit land area (Zobeland Talbert, 1984). Wood density of E. grandis is known to be highly variable. Itvaries not only within and between the trees but also among the plots studied inSouth Africa and Zambia (Hans, 1976).

Bamber and Humphreys (1963) showed that seed source has significant effecton wood density. Fibre length plays a significant role in paper making as it influencespaper strength especially when short-fibred eucalypts are used as raw material (FAO,1970). Lower tear strength of paper made from E. grandis attributed to shorter fibresas compared to bamboo fibres (FAO, 1970).

Ferreira (1972) reported the correlation between the age and density ofE. grandis, and showed that there was a wide variation of wood density among the


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11, 12, 13, 14 and 16-year-old wood samples. With regard to the influence of growthrate, literature reveals different findings. According to Bamber et al. (1982), wooddensity and fibre length of E. grandis are independent of growth rate while a coupleof studies show that rapid growth results in longer fibres.

Santos et al. (2008) studied the effect of density in kraft cooking and papermaking from E. globulus samples collected from different locations. They alsodemonstrated the correlation between fibre length and density of sample. Resultsshowed that the pulp fibres from the lowest density wood exhibit very high wet fibreflexibility while those from the highest density wood exhibit rigid behaviour. Theseresults are helpful to understand the morphological characteristics of the E. globuluswood fibres in tree selection and genetic improvement programme for pulp and paper.

7.2. Chemical Composition of EucalyptsWood quality is critically important to the industry as, during pulp and papermanufacturing, many aspects such as pulp yield, consumption of cooking liquor,and potential for bleaching, are dependent on the chemical composition of wood.This is determined by the relative proportions of cellulose, lignin, hemicellulosesand extractives in the wood. Hardwoods show significant differences in their chemicalcomposition, structure and hence require different pulping and bleaching conditions.The wood composition and the structure of its components, namely lignin andhemicelluloses, are decisive for the wood behaviour towards the pulp productionprocesses and as well as for the quality of final pulps.

Proximate chemical analysis provide useful information for preliminarycharacterization of the fibre resources with respect to their potentiality for pulp andpaper manufacture. The various types of determination covered in conventional proximatechemical analyses include, solubility in ether, alcohol-benzene (1:1), cold water, hotwater and one percent caustic soda, and klason lignin, pentosans, holocellulose, Crossand Bevan cellulose, etc . The proximate chemical composition of Eucalyptus speciesevaluated for pulp and paper manufacture in India is given in Table 5.

Kasmani et al. (2011) studied the effect of age in the young eucalypt trees (inages of 6, 8 and 10 years) with respect to chemical compounds, for use in pulp and

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Species Ash (%) Alcohol-benzene solubility (%)

Klason lignin (%)

Holocellulose (%)

Pentosans (%)

E. grandis 2.87 3.11 29.6 59.8 11.60 E. alba 0.36 2.50 27.9 60.3 14.07 E. tereticornis 1.12 3.16 28.2 66.5 12.03 E. torrelliana 1.89 4.03 26.1 64.0 16.57 E. europhyllia 0.98 6.22 26.5 64.2 16.47 E. camaldulensis 1.26 6.19 33.2 55.6 13.00

Table 5. Proximate chemical analysis of eucalypts wood

Source: Dutt and Tyagi, 2011.

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paper industry. Hemicellulose, cellulose, lignin, extractives and ash were examinedat different age intervals. The results showed that the cellulose content wasmaximum at the 10 years age and trees of this age group can be more suitablechoice for pulp industry. It has been pointed out (Singh et al., 1987) thatdetermination of various solubilities, as represented in conventional proximatechemical analysis does not seem to be logical in eucalypts. For example, value ofether and alcohol benzene solubility may not be of much use in case of eucalypts;and instead methanol solubility gives clear cut indication of the presence ofpolyphenolic extractives which are important from pulping and papermaking pointof view. Polyphenols are also extractable with hot water and one percent causticsoda. However, this type of information on amount of polyphenols as quantifiedby methanol solubility has its limitations, because the chemical nature ofpolyphenols is equally important. The compounds usually present in thepolyphenolic extractives include ellagic acid, gallic acid and ellagitannis. Thepresence of the ellagitannis and other phenolic compounds tend to increase theconsumption of chemicals during pulping, and reduce pulp yield. Under someconditions, complexes may form between metals such as magnesium and calciumand ellagic acid (Baklien, 1960) causing hard deposits in the screens, liquorcirculation pipes, heaters, heat exchangers and spent liquor pipelines. Surfacedeposits of the ellagic acid can be removed by the use of bleach liquor in a particularpH range (Mckenzie et al., 1967). The amount of the insoluble ellagic acid metalcomplex formed during pulping increase with age of the tree and, therefore,pulpwood from younger trees is to be preferred.

Polyphenols provide additional nuclear positions for condensation reactionsduring delignification and thus create problems in viscosity of black liquor duringrecovery process. At the same solid contents, the viscosity of even the bestburning kraft liquor from mature eucalypts can be more than three times that of theliquor from pine (Smith, 1956). However, with young, fast growing material, theproblems do not arise in an acute form (Leon and Borges, 1967). A series ofinvestigations were made by Oye et al. (1972, 1973) on the viscosity of concentratedkraft black liquor from the pulping of mature wood from seven Eucalyptus speciesand on the behaviour of the liquors during evaporation and combustion. Whenthe cooking temperature was kept below 120°C for 45 minutes at the beginning ofcook, allowing decomposition of kino (group of polyphenols) withoutdelignification, the viscosity of black liquor was lowered and its combustionimproved. It appears that the high viscosity may depend upon condensationbetween polyphenols and lignin – as per the phenomenon shown by Bland andMenshun (1965). Oye et al. (1977) found an inverse correlation between blackliquor swelling volume and viscosity. Bowman and Nelson (1965) observed acorrelation between polyphenolic extractives content and brightness of kraft pulps


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of various eucalypts. The contribution of wood constituents to the colour ofeucalypts kraft and neutral sulphite pulps has been studied by Hillis (1969). Thevarious components react differently under alkaline conditions and affect thecolour intensity in the following order: ellagitannins, gallic acid, catechin, ellagicacid, lignin and stilbenes. The presence of air increases the colour considerably.The influence of polyphenolic extractives on various kraft pulps has been describedby Nelson et al. (1970).

Further, Klason lignin determination indicates apparent lignin content in wood.It has been reported that the apparent lignin content of some hardwood species,particularly eucalypts, is abnormally high when the standard method ofdetermination is applied. This is caused by the presence of ‘kinos’ in these woods.The ‘kinos’ are precipitated during the Klason lignin determination by 72 per centsulphuric acid treatment. The Klason lignin obtained is heavily contaminated andthe values are misleading. Another important point while looking at Klason ligninis to bear in mind that the value corresponds only to the acid insoluble lignin (AIL)of the sample. There is a part of lignin which goes into solution as acid solublelignin (ASL) during treatment with 72 per cent sulphuric acid. Determination ofASL should be followed as a part of Klason lignin determination, because theamount of ASL is of considerable interest. First, the total lignin content of thesample can only be known by adding the amounts of AIL and ASL. Secondly, ithas been reported that ASL is mainly derived from cell wall and AIL from middlelamella (Bland and Menshun, 1970). This fact is of great value in providingpreliminary information on limitation of high degree of delignification in combinationwith bleach ability of pulp. A pulp of higher ASL will be difficult to bleach ascompared to the pulp of lower ASL. But at the same time one has to restrict thedegree of delignification, so as not to degrade the pulp significantly for want ofremoving cell wall lignin which influences the bleachability. It has been observedthat in order to obtain pure Klason lignin, it is necessary to extract the sample with0.5 per cent sodium hydroxide, but partial dissolution of lignin during the treatmentis unavoidable (Agarwal, 1981). Instead, in a raw material the amount ofholocellulose, and pentosans give more meaningful information regarding thecarbohydrates. These determinations in conjunction with lignin are the basicrequirements for analyzing pulp quality.

7.2.1. Chemical composition of ligninIn order to elucidate the chemistry of lignin reactions during pulping andbleaching, chemical composition of eucalypts lignin has been examined by thevarious workers. Chemical characterization with respect to determination of C9

formula, and methoxyl, carboxyl and hydroxyl contents and molar ratio ofsyringyl to guaicyl units has been undertaken. It was observed that the

V. Rana et al.

485Eucalypts in pulp and paper industry

Table 6. Functional groups and S/G molar ratio of milled wood lignins of Eucalyptusspecies

properties of lignin may be fairly variable within a species of wide geographicalrange but it appears that, this variation is related to climatic conditions. Thesyringyl to guaiacyl unit ratio (S/G ratio) in E. regnans, E. oblique andE. gigenta were found to be 4.20, 3.90 and 3.90, respectively (Bland et al.,1950). The variation in S/G ratio on account of geographical range has beenreported for E. alba, E. tereticornis, E. ovata and E. camaldulensis of differentzones tropical zone 1.0, semi-tropical zone 2.5 and temperate zone 4.0.

The effect of age on chemical composition of milled wood lignin of E. grandisand E. tereticornis has been reported by Agarwal and Neelay (1986). The data onfunctional groups and S/G molar ratio are given in Table 6.

7.2.2. Composition of hemicelluloseIn the plant tissues, besides cellulose and lignin also exist the third main component,hemicelluloses. The presence of hemicelluloses invite considerable attention whenan increase in the yield of chemical pulping is in question. However, in commercialchemical processes hemicelluloses components lose their solubility during pulping.Furthermore, the inner structural divergence of hemicelluloses in every species ofEucalyptus would give in characteristic features which most clearly reveal differencein the pulps produced. The chemical composition of hemicelluloses of E. grandisand E. tereticornis are given in Table 7.

Species Xylose (%) Arabinose (%) Uronic acid (%) Methoxyl content (%)

Ash (%)

E. grandis 77.2 5.2 17.2 2.65 0.99

E. tereticornis 76.1 0.71 21.6 2.03 2.3

Table 7. Hemicellulose composition of Eucalyptus species

Hemicelluloses increase pulp yield, and their presence in pulp facilitates stockpreparation process, ensures better bonding and improves strength properties. Onthe other hand, hemicelluloses are considered undesirable components of pulp duringproduction of rayon grade pulp.

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8. Pulping, Bleaching and Physical Strength Properties of EucalyptsStudies on comparative pulping, bleaching and paper making characteristics ofE. globules, E. grandis and E. tereticornis grown in Kerala state were carried out byPant et al. (1980). The results of their investigation are given in Table 8 to 15.

The results presented in Tables 8 to 15 indicate that using 14 per cent chemicalsas Na2O at an H factor of 540, bleachable grade pulp of Kappa number 16 in a yieldof 59.6 per cent could be produced from E. globulus. From E. globulus a pulp ofKappa no. 17.60 in a yield of 52 per cent could be produced using 16 per centchemicals as Na2O and a much higher H factor of 810. E. tereticornis required 16per cent chemicals as Na2O and a much higher H factor 1,760 to produce a pulp ofKappa no. below 30, the pulp yield is 44 per cent.

For attaining the target brightness of 78 to 80 per cent as per ISO, it wasnoticed that consumption of bleaching chemicals was lowest for E. globulus pulpand highest for E. tereticornis pulp. The strength properties of unbleached andbleached pulps of E. tereticornis are much lower than those of E. globulus andE. grandis pulps. Vessel pick number is lowest for E. globulus pulp and higher forE. tereticornis pulp.

On the basis of pulping yields, bleaching, papermaking and printing studies,Pant et al. (1980) graded the three Eucalyptus species as: E. globulus is better thanE. grandis which in turn, is better than E. tereticornis. They observed that bleachablegrade pulp could be obtained from the above mentioned Eucalyptus species. The

V. Rana et al.

Table 8. Comparative kraft pulping of Eucalyptus spp.Particular E. globulus E. grandis E. tereticornis Active alkali as Na2O 14.0 16.0 16.0

Chips to liquor ratio 1:3 1:3 1:3

Sulphidity (%) 25 25 25

Cooking temperature (0C) 165 165 165

Cooking schedule Raising temperature

from room temp to 1000C (min) 30 30 30

From 1000C to 1650C (min) 105 100 105

At maximum temperature (min) 30 120 150

H factor 540 1420 1760

Screened pulp yield (%) 59.60 48.60 44.30

Screen rejects (%) 0.20 0.10 0.10

Kappa number 16.10 16.60 27.0

Black liquor analysis Total solids (% w/w) 16.1 17.2 18.5

Residual active alkali (gpl) (at 200 gpl total solids)

7.79 5.30 5.53


Species Total solids (% , w/w)

Residual active alkali (gpl at 200 gpl)

Inorganics as NaOH (% )

Swelling volume ratio

E. globulus 16.2 7.79 26.3 33 E. grandis 18.8 8.34 33.21 49 E. tereticornis 18.5 5.53 28.5 21

Table 10. Comparative properties of black liquors of Eucalyptus

pulp could be bleached to 76 to 78 per cent ISO brightness by conventional CEHHsequence. Black liquor characteristics of E. globulus, E. grandis and E. tereticornisare shown in Table 10. The data presented herein reveals that the black liquor hassignificant viscosity and burning properties.

Table 9. Bleaching characteristics of Eucalyptus kraft pulp

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Species PFI revolution CSF (ml) Tensile index (Nm g-1)

Tear index (mN m2 g-1)

E. globulus 0 585 0.57 31 1000 490 0.67 37 2000 455 0.67 42 4000 355 0.88 66 8000 180 0.94 88 E. grandis 0 570 0.63 42 2000 405 0.84 51 4000 315 1.05 88 6000 215 0.93 82 E. tereticornis 0 505 0.10 38 2000 365 0.16 45 4000 295 0.80 51 6000 230 0.77 49

Table 11. Comparative physical strength properties of bleached Eucalyptus pulp

Species Freeness CSF (ml)

Print Parker surface roughness (μm)

Vessel pick no. per 2,000 (mm)

Vessel pick

505 5.76 R R

490 5.00 R R

455 4.40 27 0.48

350 3.90 4 0.07

E. globulus

100 3.40 3 0.05

570 4.20 R R

405 3.50 57 0.98

315 3.25 6 0.28

E. grandis

215 3.20 10 0.17

305 5.00 R R

365 3.55 139 2.48

295 3.40 54 0.96

E. tereticornis

200 3.15 23 0.41

610 5.65 R R

535 4.65 70 1.73

470 4.10 30 0.44

330 3.80 3 0.07

265 3.55 2 0.04

Eucalyptus pulp (Portugal)

178 3.25 2 0.04

Table 12. Surface roughness and vessel pick tendency of hand sheets from bleachedEucalyptus pulps

R- Surface rupture during printing.

V. Rana et al.


Table 13. Physical strength characteristics of unbleached and bleachedE. globulus pulp

Table 14. Physical strength characteristics of unbleached and bleached E. grandispulp

Table 15. Physical strength characteristics of unbleached and bleachedE. tereticornis pulp

Pulp PFI revolution

CSF (ml)

Apparent density (g cm-3 )

Burst index (k Pa m2 g-1 )

Tensile index

(N mg-1 )

Tear index (m N m2 g-1 )

Fold Kohler Molin

Brightness (%)

Unbleached - 565 0.55 1.55 30.0 5.95 0.70 -

1000 475 0.66 3.80 50.5 9.85 1.82 -

2000 435 0.68 4.20 55.5 9.90 2.05 -

4000 315 0.76 5.70 71.51 1.0 2.73 -

6000 235 0.78 5.80 71.01 0.7 3.25 -

Bleached - 585 0.56 1.40 32.0 6.15 0.90 79.0

1000 490 0.63 2.70 42.0 9.15 1.61 77.4

2000 455 0.69 3.50 53.0 9.05 2.10 77.6

4000 355 0.66 4.70 64.0 8.95 2.74 77.2

6000 180 0.84 6.40 73.0 8.90 3.36 74.3

Pulp PFI revolution

CSF (ml)


Burst index

(k Pa m2 g-1 )

Tensile index

(N mg-1 )


Fold Kohler Molin

Brightness (%)

Unbleached 0 570 0.67 1.95 38.5 9.30 1.44 -

2000 430 0.76 4.75 66.0 10.7 2.58 -

4000 315 0.82 5.50 71.5 10.9 3.02 -

6000 220 0.86 5.50 79.0 10.7 3.46 -

Bleached 0 570 0.68 1.90 31.0 8.30 1.06 73.7

2000 405 0.81 3.90 53.5 10.1 2.25 71.0

4000 315 0.85 4.95 69.0 9.70 2.23 68.9

6000 215 0.87 5.05 61.0 9.50 3.28 66.2

Pulp PFI revolution

CSF (ml)


Burst index

(k Pa m2 g-1 )

Tensile index

(N mg-1 )


Fold Kohler Molin

Brightness (%)

Unbleached 0 485 0.59 1.90 33.0 6.90 1.00 -

1000 370 0.68 3.30 50.0 8.60 1.62 -

2000 305 0.71 4.10 52.5 8.70 2.10 -

4000 235 0.74 4.70 59.5 8.80 2.42 -

Bleached 0 505 0.56 1.40 27.5 6.50 0.81 75.3

2000 365 0.69 3.45 50.0 8.20 1.82 72.0

4000 295 0.76 4.00 61.5 8.25 2.10 72.6

6000 230 0.79 3.80 52.5 7.95 2.49 63.2

490

Table 16. Large scale cooking conditions and properties of the pulps obtained fromnon-extracted and xylan extracted E. grandis wood chips

V. Rana et al.

In a recent study on E. grandis, Vena (2013) reported that the alkalineextraction of hemicelluloses from hardwoods prior to pulping, for further conversionto value-added products, seems to be a promising pathway for current paper mills toincrease profit and improve sustainability. However, the amount of hemicelluloseextracted would be limited by the requirement to maintain pulp quality and pulpyield in comparison to existing pulping processes. The effects of NaOH concentration,temperature and time on hemicelluloses extraction of E. grandis were studied. Extractedwood chips were subjected to kraft pulping to evaluate the effect of the extractionon cooking chemicals, pulp quality and handsheet paper strengths. The selectivexylan recovery (12.4 per cent dry mass) from E. grandis combined with lowcooking active alkali charge and less cooking time advantaged the xylanextraction and subsequent modified kraft pulping process under the studiedconditions. Pulp viscosity, breaking strength and tensile index of handsheetswere slightly improved. The main outcomes of the study are given in Table 16.

Biopulping, the recent field in paper making, has significantly affected thepaper properties. The main biological challenge observed in biopulping, afterreviewing the studies done by various researchers on different raw materials is thatfungal hyphae could not penetrate the core of wood chips or logs, only surfacephenomenon occurred during treatment stage. In view of this there arose a need todevelop some new methods for providing large surface for more lignin removal.

Parameter Non-extracted Xylan extracted (2M NaOH, 40°C, 240 min)

Pulping conditions Active alkali (%) 18.7 - Sulfidity (%) 25 35.7 Maximum temp (°C) 170 - Time at 170°C (min) 45 30 Chips/residue (OD, g) 1000 961.0 NaOH in chips/ residue (g) 165.4 99.2 NaOH from Na2S (g) 30.2 35.5 NaOH total in cook (g) 195.6 134.7 NaSH charge (g) 42.2 49.6

Pulp evaluation Screened pulp yield (%) 53.8±3.0 51.1±2.0 Screening rejects (%) 1.7±0.4 0.6±0.5 Kappa number 20.0±2.5 20.8±1.8 Viscosity (cP)** 8.1±0.5 9.4±0.7

Carbohydrate composition of pulp Glucan (%) 83.7 73.9 Xylan (%) 22.3 19.5 Black liquor characteristics Residual alkali (g l-1) 7.5±1.5 6.2±2.0

491

Thus, an approach has been put forward to reduce the density of wood samplethereby increasing the surface area for fungal hyphae. It is presumed that destructuredsamples with large surface area and low density would allow mycelia to penetrateinto the fibre on pretreatment with fungal culture. Limited references are available onthe biopulping of eucalypts. In a recent study, Bajpai et al. (2001) demonstrated theeffect of pretreatment of eucalypt wood chips with lignin-degrading fungi and itseffect on kraft pulping. The wood chips were pretreated with Ceriporiopsissubvermispora, which preferentially attacks the lignin component of wood. Thefungus was found to be suitable for biokraft pulping of eucalypts. Fungalpretreatment reduced the pitch content in the wood chips and, during kraft pulping,reduced the active alkali requirement up to 18 per cent, the total cooking time by upto 33 per cent or the sulphidity requirement of the white liquor by up to 30 per cent.The quality of the resultant biopulps was better than that of the control (higherbrightness, better strength and improved bleachability) (Table 17). The bleachedbiopulps were easier to refine than the reference pulp. The beating time was reduced


Table 17. Biopulping of eucalypts and pulp characteristicsPulping conditions for fungal-treated chips and reference chips Active alkali (as Na2O) 17% Sulphidity 22.9% Bath ratio 3:1 Cooking temp. 1650C Time to raise the temp. from room temp.to 1650C (min.)

90

Reaction time at 1650C (min) 90 Fungal treatment conditions For two weeks; inoculum level, 5 g t-1 wood (dry weight basis),

corn steep liquor was not added during fungal treatment. a. Pulp properties Parameter Control Fungal treated Permanganate no. 14.4 14.5 Lignin (%) 1.33 1.55 Unbleached brightness (% ISO) 27.0 29.1 Unbleached pulp yield (%) 46.1 45.8 Final brightness (% ISO) 85.2 87.2 Bleach chemical consumption (kg t -1 pulp) Elemental Cl2 40.0 40.0 NaOH 18.8 18.8 NaClO (Hypo) 12.3 12.3 Chlorine dioxide 6.0 6.0 b. Strength properties

Unbleached Bleached Parameter Control Fungal treated Control Fungal treated Wetness (°SR) 17.0 18.0 35.0 35.0 Beating time (min) - - 30.0 20.0 Tensile index (Nm g-1) 42.2 48.0 75.5 82.3 Breaking length (m) 4300 4890 7700 8390 Burst index (k Pa. m2 g-1) 1.93 2.62 4.59 5.14 Tear index (mNm2 g-1) 5.66 5.48 6.92 7.20 Double fold (no.) 6 10 102 112

492

by 18 to 33 per cent in different studies. Gupta et al. (2013a) studied the influence ofmechanical operation on the biodeliginfication of E. tereticornis by Trametesversicolor. In their study, the surface area of the wood chips was increased bypassing through an impressafiner. Impressafiner compresses the chips andconverts them into spongy material. Futher the biological pretreatment ofeucalypts non-destructured (chips) and destructured samples (spongy) wascarried out by T. versicolor. It was reported that the lignin loss was approximately8.90 per cent higher in destructured samples, compared to non-destructured samples.The fungal pretreatment decreased the Kappa number of the treated destructuredsamples by as much as 10.29 points, compared to the untreated non-destructuredsamples. In another study, Gupta et al. (2013b) reported the evaluation of white rotfungi, T. versicolor induced biodelignification in E. tereticornis. The studyrevealed that T. versicolor showed 19.88 per cent lignin loss within 21 days ofincubation period at pH 5.5, temperature 25oC, moisture 60 per cent with 4 per centmolasses dose. The fungal pretreatment decreased the Kappa number from 28.92 to24.10 at 60 minutes cooking time.

In pulp and paper kraft mills, wood pulp is produced by digestion of woodchips in an aqueous solution containing sodium hydroxide and sodium sulfide- named white liquor, under high temperature and pressure. A by-product liquidstream of this digestion process known as weak black liquor, which has solidscontent of 15 to 18 per cent (w/w), needs to be concentrated to higher solidcontent for its use as fuel in the recovery boiler. To raise this concentration, atraditional multiple effect evaporators unit is used, resulting in a strong blackliquor stream, usually with solids content in the range of 65 to 75 per cent (w/w)(Andreuccetti et al., 2011). Inorganic compounds present in black liquor mainlyconsist of sodium salts and small amounts of potassium, calcium, magnesium,silicon and iron salts. Physical properties of black liquor may vary considerablydue to chemical composition associated with the type of processed wood andoperational conditions of the pulping phase. Therefore, the greater the amountof experimental data on eucalypts black liquor physical properties, the betterthe comprehension whether these properties are correlated, and in which waythey can be used to understand scale formation in evaporators, and how toprevent or even avoid this problem by accompanying the variation of theconsidered properties. Gonçalves et al. (2013) reported that the Eucalyptus(E. grandis) black liquor, emerged from different industrial units, have 63 to 69per cent (w/w) organic mater of the total solid content. The remaining 34 percent (31 to 37%) represents the amount of inorganic material contained in theliquor. Therefore, the average organic/inorganic mass ratio is 1.94. Propertiesof eucalypts black liquor of difference silvicultural patterns are given inTable 18.

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493

Technical assessment of paper making properties of E. grandis andE. tereticornis of different age groups has been made by Singh et al. (1987). Thedata on kraft pulping and bleaching of E. grandis and E. tereticornis of different agegroups are given in Table 19 to 21.

Muner et al. (1996) evaluated various sequences for bleaching of eucalyptspulp. Among the sequences evaluated for bleaching they suggested that thesequence of DZ Eop D was found the best sequence for pulp bleaching with maximumdesired brightness (Table 22).


R.A.A. - Residual active alkali.

Brookfield viscosity (cps at 80) and residual alkali at 200 g/l solids at different concentrations (%age solids)

35 45 50 55

Species Initial R.A.A. as Na2O (g l-1 at 200g l-1)

Inorganic as NaOH

(%)

Swelling volume

ratio (ml g-1 )

cps R.A.A. cps R.A.A. cps R.A.A. cps R.A.A.

E. grandis coppice

6.62

-

29

6

6.20

24

5.1

63

4.8

200

4.4

E. grandis main plantation

4.98

27.56

26

5

3.4

20

2.7

50

2.3

162

2.1

E. grandis main plantation

8.34

33.1

49

3.5

7.7

9.0

6.1

15

7.7

35

6.2

E. tereticornis main plantation

5.44

25.19

36

15

4.3

40

4.0

110

2.7

324

2.8

E. tereticornis main plantation

6.8

27.68

44

3.8

-

9

-

18

-

45

-

E. tereticornis-I coppice

6.58

28.81

38

-

-

27

-

35

-

82

-

E. tereticornis-II coppice

6.95

28.96

41

5.5

-

18

-

46

-

151

-

Table 18. Black liquor properties of Eucalyptus species

Pulp yield (%)

Screen rejects

(%)

Kappa no. Pulp yield (%)

Screen rejects

(%)

Kappa no. Species and age group

Active alkali 15% as Na2O Active alkali 16% as Na2O E. grandis (5-6 yr) 50.2 0.33 29 48.7 0.27 21.2

E. grandis (10-11yr) 55.6 0.12 28 53.1 0.15 20.5

E. grandis (14-15 yr) 53.3 0.10 21.7 - - -

E. grandis (18-19 yr) 54.4 0.34 25.2 52.4 - 20.4

Table 19. Pulping characteristics of E. grandis of different age groups

Test conditions: Chips to liquor ratio 1:3.5; Sulphidity 25%; Time 100OC (105 min), 170OC (60 min).

Pulp yield (%)

Screen rejects (%)

Kappa no.

Pulp yield (%)

Screen rejects (%)

Kappa no.

Species and age group

Active alkali 15% as Na2O Active alkali 17% as Na2O E. tereticornis (5-6 yr) 47.3 0.60 41.0 44.1 0.15 21.7 E. tereticornis (14-15 yr) 45.2 0.17 40.0 42.5 0.07 21.6

Table 20. Pulping characteristics of E. tereticornis of different age groups

*Chips to liquor ratio 1:3.5; Sulphidity 25%; Time 100OC (105 min), 170OC (60 min).

494

Sequence ClO2 (kg/adt) H2O2 (kg/adt) O2 (kg/adt) O3 (kg/adt) MgSO4 (kg/adt) Eo-D 13.7 - 5.0 - - D-Eop-D(1) 17.5 5.0 5.0 - - D-Eop-D(2) 21.3 10.0 5.0 - - D-Eop-D-Pp(1) 9.0 6.5 4.0 - 4.5 D-Eop-D-Pp(2) 9.0 6.5 4.0 - - D-Eop-D-Q-Pv 9.0 6.5 4.0 - - D-EPp-D 9.0 9.0 - - - D-Q- EPv-D 9.0 9.0 - - - P-D- Eop-D 9.0 10.5 4.0 - 5.0 Pp-D-Eop-D 9.0 10.5 4.0 - 5.0 Q-P-D- Eop-D 9.0 10.5 4.0 - 5.0 q-P-D- Eop-D 9.0 10.5 4.0 - 5.0 q-Pp-D- Eop-D 9.0 10.5 4.0 - 5.0 Q- Pp-D- Eop-D 9.0 10.5 4.0 - 5.0 Q-PO-ZD 8.8 5.0 4.0 2.9 5.0 QP-ZQ-D 6.5 5.0 - 3.0 - DZ-EOP-D 10.6 2.0 4.0 2.8 3.0 D-EOPp-D 9.0 10.0 5.0 - 5.0 Q-D- EOPp-D 9.0 10.0 5.0 - 5.0 DQ- EOPp-D 9.0 10.0 5.0 - 5.0

Table 22. Bleaching sequences of eucalypt pulp

D - chlorine dioxide stage; E/Eo/Eop/Eopp - extraction stage reinforced with oxygen (Eo); with oxygen and hydrogen peroxide; (Eop)and also in a pressurized; situation (Eop); Pp - pressurized hydrogen peroxide stage; Q - chelating stage; q - semi-chelating stage(conducted in not ideal conditions); Z - ozone stage.

Pulping and paper making characteristics of high density plantation wood (HDP)of E. tereticornis have been studied by Tiwari and Mathur (1983). The data in Table23 and 24 represent the summary of their work by suggesting that pulp derived fromyoung HDP of E. tereticornis compared well with eight-year-old plantation grownwith conventional forestry practices. The pulp also has certain advantages likebetter fibre bonding properties (at same tear index and same unbleached yield). Withthe advantages of pulp obtained from HDP more return per unit area and present gapbetween the demand and supply of raw material, HDP grown on marginal and submarginal lands owned by medium and small farmers provides good opportunities tothe farmers and the paper industry.

It has been reported by Srivastava et al. (1985) that three-year-old sampleof E. tereticornis would be more prone to freeness drop even at lower level of

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Species and age group Total chlorine applied (%)

Kappa no. Brightness ISO (%)

Bleached pulp yield (%)

E. grandis (5-6 yr) 7.6 21.2 79.1 48.6 E. grandis (10-11yr) 7.6 20.5 76.1 50.0 E. grandis (14-15 yr) 7.6 21.7 75.3 49.6 E. grandis (18-19 yr) 7.6 20.4 77.2 49.4 E. tereticornis (5-6 yr) 7.6 21.7 76.7 40.1 E. tereticornis (14-15 yr) 7.6 21.6 75.7 38.3

Table 21. Bleaching characteristics of E. grandis and E. tereticornis of different age groups


Tabl

e 23

. Pul

ping

con

ditio

ns a

nd p

hysi

cal s

tren

gth

of u

nble

ache

d pu

lps

of E

. ter

etic

orni

s w

ood

(with

out b

ark)

from

hig

h de

nsity

and

conv

entio

nal p

lant

atio

ns o

f diff

eren

t age

s at

250

ml C

SF a

nd 0

.70

appa

rent

den

sity

Hig

h de

nsity

pla

ntat

ion

C

onve

ntio

nal p

lant

atio

n Y

ear

Y

ear

Part

icul

ar

1 2

3 1

2 3

1

2 3

8 1

2 3

Act

ive

alka

li (%

) 16

15

16

14

14

14

16

16

16

16

14

14

14

Sulp

hidi

ty (%

) 25

25

25

25

25

25

25

25

25

25

25

25

25

Bat

h ra

tio

1:3

1:3

1:3

1:3

1:3

1:3

1:

3 1:

3 1:

3 1:

3 1:

3 1:

3 1:

3 M

ax. t

emp.

(o C)

165

165

165

165

165

165

16

5 16

5 16

5 16

5 16

5 16

5 16

5 H

fact

or

1101

11

01

1101

11

01

1101

11

01

11

01

1101

11

01

1101

11

01

1101

11

01

Scre

ened

pul

p yi

eld

(%)

47.4

0 47

.14

47.7

1 48

.23

47.1

0 49

.63

45

.80

46.5

5 47

.06

47.5

0 47

.00

47.6

0 45

.50

Scre

ened

reje

cts (

%)

0.60

0.

50

0.80

1.

20

0.90

1.

20

0.

65

0.84

0.

90

0.80

1.

00

1.40

1.

50

Tota

l pul

p yi

eld

(%)

48.0

0 47

.64

48.5

1 49

.43

48.0

0 50

.83

46

.45

47.3

9 47

.90

43.0

49

.00

49.0

0 50

.50

Kap

pa n

o.

26.0

8 27

.47

28.7

6 40

.38

30.8

1 32

.71

25

.00

26.1

0 28

.63

30.9

0 27

.00

28.4

0 36

.6

Res

idua

l alk

ali (

gpl)

5.7

6.6

6.6

5.4

5.9

6.6

5.

1 -

5.4

6.5

5.3

5.8

5.3

Phys

ical

stre

ngth

pro

pert

ies

at fr

eene

ss 2

50 m

l CSF

A

ppar

ent d

ensi

ty

0.69

0.

69

0.75

0.

74

0.67

0.

77

0.

79

0.79

0.

75

0.77

0.

81

0.81

0.

76

Bur

st in

dex

(K P

a m

2 g-1

) 5.

0 -

5.55

5.

70

4.75

6.

25

6.

30

6.00

6.

70

5.25

7.

00

6.66

6.

75

Tens

ile in

dex

(N m

g-1

) 77

.5

72.5

77

.5

80.5

77

.5

78.0

87.0

83

.0

94.0

69

.5

88.5

88

.5

94.0

Te

ar in

dex

(m N

m2 g

-1)

7.00

7.

46

7.00

7.

00

7.75

7.

80

6.

96

7.77

8.

47

8.80

6.

93

8.40

9.

30

Stre

tch

(%)

2.9

2.4

3.5

3.0

2.6

3.8

3.

2 3.

4 3.

0 -

3.5

3.5

4.0

Phys

ical

stre

ngth

pro

pert

ies

at 0

.70

appa

rent

den

sity

Fr

eene

ss, m

l CSF

23

0 23

0 32

5 32

5 23

0 36

0

370

350

310

- -

- 31

0 B

urst

inde

x (K

Pa

m2 g

-1)

5.10

5.

00

4.00

6.

00

6.00

5.

10

4.

25

3.70

5.

80

3.70

4.

25

4.10

6.

30

Tens

ile in

dex

(Nm

g-1

) 78

.0

72.5

67

.0

80.0

85

.0

67.0

67.5

65

.0

87.5

57

.5

60.5

65

.0

89.0

Te

ar in

dex

(m N

m2 g

-1)

7.13

7.

53

- 6.

93

7.73

7.

03

6.

23

6.80

8.

50

7.80

6.

00

6.80

8.

63

496 V. Rana et al.

Tabl

e 24

. Pul

ping

con

ditio

ns a

nd p

hysi

cal s

tren

gth

of u

nble

ache

d pu

lps o

f E. t

eret

icor

nis w

ood

(with

bar

k) fr

om h

igh

dens

ity a

ndco

nven

tiona

l pla

ntat

ions

of d

iffer

ent a

ge a

t 250

ml C

SF a

nd 0

.70

appa

rent

den

sity

Hig

h de

nsity

pla

ntat

ion

C

onve

ntio

nal p

lant

atio

n Pa

rtic

ular

Yea

r

Yea

r

1 2

3 1

2 3

1

2 3

1 2

3

Act

ive

alka

li (%

) 16

16

16

14

14

14

16

16

16

14

14

14

Sulp

hidi

ty (%

) 25

25

25

25

25

25

25

25

25

25

25

25

Bat

h ra

tio

1:3

1:3

1:3

1:3

1:3

1:3

1:

3 1:

3 1:

3 1:

3 1:

3 1:

3 M

ax. t

emp.

(o C)

165

165

165

165

165

165

16

5 16

5 16

5 16

5 16

5 16

5 H

fact

or

1,10

1 1,

101

1,10

1 1,

101

1,10

1 1,

101

1,

101

1,10

1 1,

101

1,10

1 1,

101

1,10

1 Sc

reen

ed p

ulp

yiel

d (%

) 46

.00

46.2

0 46

.80

44.8

0 47

.70

48.2

0

44.2

0 44

.92

45.0

0 45

.00

45.6

0 46

.00

Scre

ened

reje

cts (

%)

0.6

0.4

0.8

1.1

1.6

1.5

0.

4 0.

6 0.

6 1.

5 1.

4 1.

9 To

tal p

ulp

yiel

d (%

) 46

.6

46.6

47

.6

45.9

49

.3

50.7

44.0

45

.5

45.6

47

.3

48.0

48

.5

Kap

pa n

o.

28.8

8 30

.2

31.5

31

.1

32.6

33

.88

30

.32

32.5

7 33

.10

30.4

35

.4

35.6

R

esid

ual a

lkal

i (gp

l) 5.

4 6.

2 6.

7 5.

2 5.

3 5.

5

4.6

5.2

4.1

3.4

- 3.

3 Ph

ysic

al st

reng

th p

rope

rtie

s at

free

ness

250

ml C

SF

App

aren

t den

sity

0.

60

0.65

0.

67

0.64

0.

65

0.68

0.73

0.

66

0.67

0.

70

0.67

0.

61

Bur

st in

dex

(K P

a m

2 g-1

) 4.

20

5.60

4.

25

4.00

5.

20

4.50

5.00

4.

90

5.10

5.

50

5.70

4.

80

Tens

ile in

dex

(N m

g-1

) 68

.0

58.0

61

.0

64.0

80

.5

6.2

80

.5

75.5

80

.5

83.0

87

.5

93.0

Te

ar in

dex

(m N

m2 g

-1)

7.00

7.

30

6.50

6.

30

6.60

6.

10

7.

73

6.97

7.

10

6.53

7.

63

6.16

St

retc

h (%

) 2.

3 2.

8 2.

95

2.3

2.55

3.

49

2.

8 3.

3 3.

65

2.9

3.2

2.60

Ph

ysic

al st

reng

th p

rope

rtie

s at

0.7

0 ap

pare

nt d

ensi

ty

Free

ness

, ml C

SF

- 20

0 22

5 -

200

250

31

0 26

0 20

0 27

5 27

0 21

0 B

urst

inde

x (K

Pa

m2 g

-1)

5.10

5.

50

4.50

4.

60

5.30

4.

75

-

5.50

5.

57

5.40

6.

00

5.30

Te

nsile

inde

x (N

m g

-1)

67.5

72

.0

52.0

67

.5

75.0

57

.3

69

.0

77.0

83

.5

82.5

89

.0

89.5

Te

ar in

dex

(m N

m2 g

-1)

6.86

7.

30

6.66

6.

40

6.70

6.

17

7.

80

7.50

6.

86

6.03

7.

70

6.53


fibrillation due to shorter and comparatively more flexible fibres. The fibrillationin fibres of three years age samples was comparatively less at the same level offreeness (200 ml CSF) than five- and eight-year-old samples. Fibres of eight-year-old samples are comparatively thick walled and anatomically mature. Thickwalled fibres would reduce collapsibility, thereby, reducing the availablebonding area.

Anatomically mature fibres possessing well ordered cellulose molecules andhigher amount of middle lamella, would also restrict the exposure of secondary cellwall of fibres. With the increase in fibre length and wall thickness, older sampleswould impart more rigidity to the fibre and exhibit comparatively lower bondingstrength and higher tearing strength.

8.1. Rayon Grade Pulp from EucalyptsRayon, cellophane and a wide variety of fibres, films and plastics are made bychemical conversion of high purified cellulose derived principally from wood andcotton linters. Wood pulp or any other highly purified form of cellulose manufacturedfor chemical conversion into derivatives is known as dissolving pulp or rayon gradepulp.

Rayon grade pulp in satisfactory yield and of high chemical puritywas obtained from E. globulus by prehydrolysis kraft and also by acid kraftprocess. Eucalyptus hybrid has been evaluated for the preparation of rayongrade pulp by prehydrolysis sulphate process. Characteristics of rayon gradepulp.

Rayon grade pulp should have high alpha cellulose, low ash, low extractivesand other mineral matters. Rayon grade pulp may be classified in various waysaccording to their end use: textile, yarn, tyre cord, cellophane, etc. Thecharacteristic of rayon grade pulps are given in Table 25 and 26 (Bhat and Singh,1957).

8.2. Pilot Plant Trials of EucalyptsGuha and his co-workers carried out the pilot-plant experiments at ForestResearch Institute, Dehradun on pulping and papermaking characteristics ofEucalyptus species for the manufacture of wrapping, writing and printing papers(Guha and Prasad, 1961; Guha and Singh, 1963; Guha et al., 1962, 1965, 1967,1968, 1969, 1970a, b and c; 1973, 1975, 1977, 1978a, b; Guha and Kumar, 1968;Guha and Madan, 1964, 1977, 1978). The brief results of pilot plant trials aregiven in Table 27 and 28. It can be seen from the tables that all the three speciesof Eucalyptus gave satisfactory pulp yield and physical strength properties ofthe paper. The runnability of these pulps on the pilot plant paper machine wasalso good.

498

9. ConclusionIn the last few decades many new woody and agro-based biomass sources havebeen evaluated, and the suitable sources accepted which are being utilized by papermaking industry. Eucalypts have always been and will continue to receive attentionas an important fast-growing, short-rotation, renewable biomass crop for high quality

Breaking length (m)

Tear factor Burst factor

Species Total chemical

(%)

Temp. (0C)

Time (hr)

Pulp yield (%) MD CD MD CD

E. globulus 16.0 153 5.0 57.9 6810 3710 31.8 81.3 28.0 E. grandis 18.0 153 4.0 47.8 5900 3780 61.8 70.0 25.0 E. tereticornis 18.0 162 3.0 52.7 7150 4440 67.7 72.6 40.6

Table 27. Kraft pulping conditions in pilot plant for the production of wrapping paper,and pulp properties

Test conditions: Sulphidity 25%, Material to liquor ratio 1:4.

Breaking length (m)

Tear factor Burst factor

Species Total chemical

(%)

Temp. (0C)

Time (hr)

Pulp yield (%) MD CD MD CD

E. globulus 22.0 153 6.0 46.0 4780 3990 61.1 64.1 18.6 E. grandis 20.0 153 6.0 46.0 5270 2990 61.1 64.1 18.6 E. tereticornis 20.0 162 4.0 47.7 4260 2900 48.6 52.2 16.8

Table 28. Kraft pulping conditions in pilot plant for the production of writing andprinting paper and pulp properties

Test conditions: Sulphidity 25%, Material to liquor ratio 1:3.

V. Rana et al.

Description Cellophane Textile Tyre cord Alpha cellulose (%) 89.0- 92.0 81.0-91.0 94.0-96.8 Beta cellulose (%) 3.0- 5.0 5.0-7.0 2.0-3.0 Gamma cellulose (%) 3.0-6.0 3.0-5.0 2.0-4.0 Ash (%) 0.04-0.13 0.05-0.13 0.04-0.08 Ether solubility (%) 0.1-0.3 0.1-0.3 0.02-0.10 Cupramonium viscosity (cp) (ACS method) 250-700 100-200 75-175

Table 25. Characteristics of rayon grade pulp from eucalypts

Process Prehydrolysis kraft Acid sulphite Alpha cellulose (%) 96.2 93.1 Beta cellulose (%) 0.5 3.1 Gamma cellulose (%) 0.8 2.1 Ash (%) 0.19 0.08 Degree of polymerization 700 419 Brightness (%) (MgO=100) 88 92

Table 26. Analysis of E. globulus rayon grade pulp


paper production. Eucalypts grow fast and give a high pulp yield with excellentproperties which makes it suitable for manufacturing a wide range of papers. Researchreveals that eucalypts pulp has better intrinsic pulp properties (tensile/densityrelationship, etc.) as compared to other raw materials used in paper industry. Basedon pulp property analysis, the eucalypts pulp showed a very good potential forapplications in value-added paper and paperboards. Indian paper industry is facingshortage of quality fibrous raw material, and eucalypts remain as one of the importantfast growing woody biomass options, though its availability for paper making isfacing competition from other wood-based industries.

Further, the major prospects for which the research is to be focused foreucalypts wood utilization for improved paper products, are the tree harvestingage, silvicultural aspects, better clones, sustainable in its availability, costs andproductivity, management of the swelling ability of the furnish, management offines (removal or addition in controlled rates), management of fibre deformations,management of pulp blends in the furnish (incorporating different pulps withdifferent potentials) and management of wood supply to the pulp and paperindustries.

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