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Nameste

A term paper on

Afforestation on sand dunes

Presentation By

Manoj RanabhatM.Sc. Forestry

1st yearRoll No 32

Introduction

Conceptual Framework

Discussion

Conclusion

o Afforestation is the establishment of forest by artificial means on an area from which forest vegetation has always or long been absent.

o A sand dune is a mount, hill or ridge of sand built either by wind or water flow.

The valley or trough between dunes is called a slack

Large dune fields are known as ergs.

Without vegetation, wind and waves regularly change the form and location of dunes.

Dunes are not permanent structures.

Sand dunes are generally classified into three categories :

(a) small sand dunes - less than 1.5 metre in height,

(b) medium sand dunes - 1.5 metre to 3 metre in height and

(c) big sand dunes - more than 3 metre in height .

a) Locality factors The mean annual rainfall in the region varies from 100 mm to 450 mm.

a wide variation in temperature range in the desert.

The highest temperature is during May- June when mercury crosses 480 C.

The mean winter temperature varies from 140 C. to 160 C. and the lowest temperature goes below the freezing point at several places.

Wind of high velocity ranging 100 km per hour to 150 km per hour are experienced during summer.

These sand dunes have high wind erodibility , high water infiltration, low moisture capacity and very low hydraulic conductivity.

The common practice of stabilizing sand dunes consists of two steps;

(i) erecting micro windbreaks across the wind direction in parallel strips or checker board design using local available plant material and

(ii) revegetating the sand dunes by planting the seedling or sowing seeds.

Rotted cutting of 60-80 cm length are set into the sand

Deep planting protects the planting stock against deflection and secures root development in comparatively moist sand layer

afforestation in these areas calls for rapid stabilization of the drifting sand dunes, maximum moisture conservation and proper utilization, selection of suitable species and efficient planting technique

Live hedge is preferred because it protects against wind action. Euphorbia tirucalli and Jatropha curcus are often handy for live hedge.

Plantation of shelterbelt should also form a part of desert afforestation

They reduce the wind velocity and thus check the shifting of dunes in the leeward side. Windbreaks of Dalbergiasisso, Albizia lebbeck, Acaia nilotica, A. tortilis, Zizyphus mauritiana, Tamarixaculeata, Azadirachta indica, Parkinsoniaaculeata, etc. have been successful.

Tree species suitable for dunes fixation must be highly drought resistant and have a well developed root system, which is capable of deep vertical penetration to reach the lower moister layers of soil,

capable of withstanding frost as well as high temperature of both, abrasive action of moving sands

able to regenerate naturally either through suckers or coppice.

capable of producing fire-wood, charcoal, poles or posts, fodder, fibreetc.

For affoerstation of sand dunes the most successful species are Acacia tortilis and Prosopis chilensis.

The other species are:A. senegal, A. nilotica, Tecomella undulanta,Eucalyptuscamaldulensis, Parkinsonia aculeata, Zizyphus spp, Albiza lebbeck, Ailanthus excelsa, etc.

Ten to twelve months old seedlingsshould be planted in pits of 45 cm3 or 60cm3filled with weathered soil

raised nursery beds (about 22cmhigh) as is practised in high rainfall areas , sunken beds, about 30-45 cm deep from ground level, are made in arid areas

raised in planting bricks have proved very successful for sand dune

bricks are prepared with the help of a wooden or steel mould.

hardening off of seedling should begin with an exposure of an hour or two when the sun is fairly low and be gradually increased

Planting times : in the summer rainfall regions should be done after the onset of rainy season, when the sand is wet. Whereas, in the regions receiving winter rainfall, it is available to plant late in the winter after the severe wind storm.

Planting depth: On coastal sand dunes, , large-sized balled nursery stock of Acaiacyanophilla are planted deep (at least 60 cm) in the sand with only the upper 1 to 3 leaves emerging .

Spacement : Depending upon the site conditions obtaining in different countries different spacing of seedling have been adopted. For example, in India , a spacing of 5 m2 for most of the tree species and 2.5 m2 for Casuarinaequisetifolia have been suitable.

In central Asia, general practice is to plant with an inter-row and within-row spacing of 1-2 m, 1 m respectively

Fencing with five strands of barbed wire and angle iron posts spaced 3-4 m apart has proved most effective and cheaper in the long run.

Locally available thorny bushes, ie. Zizyphus nummularia are also used. This type of fencing, through cheap, is costly in the long run due to annual renewal.

Sand dunes are one of the most degraded land where vegetation is typically absent, ecologically unstable and create various environmental problems and need immediate afforestation

Sand dunes have high wind erodibility, high water infiltration, low moisture capacity and very low hydraulic conductivity

afforestation in these areas calls for rapid stabilization of the drifting sand dunes, maximum moisture conservation and proper utilization, selection of suitable species and efficient planting technique

species suitable for dunes fixation must be highly drought resistant and have a well developed root system, which is capable of deep vertical penetration to reach the lower moister layers of soil,

species must be capable of withstanding frost as well as high temperature of both, abrasive action of moving sands

also be able to regenerate naturally either through suckers or coppice

For affoerstation of sand dunes the most successful species are Acacia tortilis, Prosopis chilensis, Parkinsonia spp. Albiza lebbeck, Ailanthus excelsa etc.

Sand dunes are dominant formation in Indian desert and practiced specially in Rajasthan.

Dwivedi A.P., I.F.S.M.Sc.(Ag) AIFC(Hons). 1993, A Text Book of Silviculture

http://des.nh.gov/organization/commissioner/pip/factsheets/cp/documents/cp-02.pdf

http://en.wikipedia.org/wiki/Dune

http://www.fao.org/docrep/006/ad079e/AD079e07.htm

Khanna L.S. ,Principle and Practice of Silviculture

for your patience