Development of reforestation techniques at degraded sites in East Kalimantan, Indonesia and southern part of Thailand

Tange TakeshiThe University of Tokyo

Background

Vast area of tropical forests is degraded by human activities every year.The degraded lands are left as low productivity and low biodiversity.Lack of seed source and severe environmental conditions disturb progressing of succession.

Degradation and recovery

Climax forest with mosaic structure

Mixture of climax species and pioneer species

Degraded land

Domination of pioneer species with short life-span

Self recovery, enrichmentSelective cutting Proper shifting cultivation

Short-rotation sifting cultivation

Large-scale forest fire

Unsuccessful agricultural development

Artificial planting

Artificial planting

Purpose

Development of reforestation techniques for degraded lands with various soil conditions Development of planting techniques of dipterocarps at degraded landsImprovement of nursing techniques of planting stocks

Study sites

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Sebulu, East Kalimantan, Indonesia

Nararhiwat, Thailand

Narathiwat

Project in Sebulu, Indonesia

Reasons of degradation: forest fire(1982-83), illegal felling, shifting cultivationExperimental Forest: 3000ha of degraded landManagement: Indonesian staffs + one Japanese staffJoint Research Project (1991～2003)Ministry of Forestry, IndonesiaPT. Kutai Timber IndonesiaSumitomo Forestry Co. Ltd.The University of Tokyo

Fig. Sebulu Experimental Forest consists of developed forest dominated by dipterocarps, secondary forest damaged by fire, sifting cultivation and grass land

Nursing of dipterocarp seedlings

Raising from seeds, cuttings and wildingsInfection of ectomycorrhizaePhysical properties of potting mediaLight condition

Artificial planting of dipterocarps

Open planting Under-planting

Shorea leprosula Dryobalanops lanceolata

Fig. Artificial planting at grass land (open area planting) and secondary forest dominated by pioneer species (under-planting)

Survival and growth of planted dipterocarp seedlings

Fig. Survival rate and height growth of Shorea leprosula and S. pauciflora planted by different planting methods (Matsune et al. 2005)

solid square: 6m wide line planting hatched square: 10m wide line planting open square: 20m wide line planting open circle: open area planting solid circle: underplantingsolid triangle: 5x5m gap planting hatched triangle: 10x10m gap planting

Trial of social forestry

Making a contract with farmersAgro-forestry using fruit tree and fast growing tree

Hindrance for continuation of research project

Friction with local people concerned in social custom in right of land useDeposit of coal under the research siteChange in economic activity from self-sufficiency to a market economy systemLarge-scale forest fire (1997-98)

Project in Narathiwat, Thailand

Reasons of degradation: unsuccessful agricultural development in swamp areaProblem soil: sand, peat, acid sulfate soilJoint Research Project (1994～）Royal Forestry Department, ThailandThe University of Tokyo

Fig. Agricultural development of swamp forest at Narathiwat, southern part of Thailand (photo by K.Kojima)

Swamp forest at To-Daeng, Narathiwat

Mean tree height is 25 m and aboveground biomass is 245 t ha-1.(Suzuki 1997)

Dipterocurpus obtusifoliusforests at sand dune

D. obtusiforius is tolerant to open site conditions of sand dune. (Norisada＆Kojima2005)

Fig. Abandoned agricultural lands

Upper-right: sand dune

Upper-left: peat swamp after wild fire

Left: peat swamp dominated by Melaleuca cajuputi

Fig. Planting trial at degraded sand dune in Narathiwat, southern part of Thailand

Limiting factors of tree growth

infertile soil, drought, high temperature, seasonal flooding

Fig. Nurse tree effect on growth of dipterocarp seedlings

Fig. Survival ratio and growth of seedlings planted at sand dune (Norisada et al. 2005) ○:open area ●:mix-planting with Acacia mangium ***:p<0.01

Fig. Mitigation of high soil temperature by reforestation (Norisadaet al. 2005)

－open area－ forest floor of

Acacia mangium

Day of year

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ture

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a)

June July August

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50 soil – 1 cm

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50 soil – 3 cm

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50 soil – 5 cm

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50 soil – 10 cm

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(Photo by K.Kojima)

Fig. Improvement of nursing techniques for dipterocarp species Large-size pot nursing improved survival of planted seedlings.

Fig. Site preparation by a cultivator. It makes planting works easy and survival of planted seedlings improved (Photo by K.Kojima)

Hindrance for continuation of field studies

Political confusion concerned in Muslim peopleWild fireExpanding of oil palm plantation

Key factors for development of reforestation techniques

Selection of tolerant species for mitigation of severe environment of degraded landLight control according to eco-physiological properties of planting species and soil productivityNursing techniques for development of root systemSocial system to maintain forests for a long term