Management of Teak Plantations (2024)

Overview ofproblems in teak plantation establishment - Dr. ApichartKaosa-ard

ApichartKaosa-ard

Forest Resources Department,Chiang Mai University, Thailand

ABSTRACT

Teak plantations have been widelyestablished throughout the tropics to produce high quality timber in trees ofgood growth and stem form. Many factors affect the success of teak plantingprogrammes including site, seed supply and seed quality, management and otherbiological factors such as insects. Site is the primary factor influencingplantation growth and development. Growth and yield of plantations grown indifferent site qualities, within and outside the teak region is illustrated.With correct site selection, growth and yield can be improved more than 100 %.The composition of suitable teak sites is reviewed. Seed supply is a factorlimiting planting scale and the quality of the plantation, especially so incountries where teak is an exotic. Seed requirement in various plantationoptions is tabulated and the effect of seed sources (provenances) and improvedseed on growth and quality of plantations is demonstrated. A short termprogramme for improved seed and clonal stock production is proposed.Silvicultural management of teak plantation practices in weeding, thinning andinsect and fire protection for growth and quality improvement isreviewed.

INTRODUCTION

Teak (Tectona grandis) is oneof the most well known timbers of the world. Its timber qualities includeattractiveness in colour and grain, durability, lightness with strength, ease ofseasoning without splitting and cracking, ease of working and carving,resistance to termite, fungus, and weathering, etc. The species is native to theIndian-Burmese floristic region and found naturally in India, Myanmar, Thailandand Lao (Kaosa-ard, 1983); it is an old introduction to Indonesia (Kaosa-ard,1981). Due to its high timber qualities, market demand, ease of domesticationand cultivation, teak plantations have been widely established throughout thetropics from the 1850s (FAO, 1956, 1957). Teak has been successfully establishedas an exotic in many countries, e.g. Sri Lanka, Bangladesh and China in Asia;Ghana, Nigeria, Ivory Coast, Senegal, Togo and Benin in West Africa; Sudan andTanzania in East Africa; Trinidad, Puerto Rico and Panama in Central America;Brazil and Ecuador in South America (FAO, 1957; Keogh, 1994; Hougs, unpublisheddata). The global teak plantation area recorded in 1990 was about 1.6 million ha(Hougs, unpublished data) which comprises 75 % of the high grade tropicalhardwood plantations (Keogh, 1994). The main objective is to produce highquality timber trees with good growth.

Although teak has been ranked as ahigh priority species in many countries, its planting programme is still limitedto a small or medium scale in many countries. Keogh (1994) notes the proportionof teak to overall plantation in the tropics fell sharply from 11 % in 1980 to 5% in 1990. This is so especially where teak is grown as an exotic species. Thereare many factors limiting the success of teak plantation establishment. Thethree main factors are site quality, quality and quantity of planting materials,and silvicultural management.

SITE QUALITY

Site effects - growth ofplantations

The main objective of teakplantation establishment is to produce high quality timber in trees with good oracceptable growth rates. To achieve these objectives, the planting site must besuitable for the growth and development of teak. Teak plantations have beenestablished throughout the tropics, within and outside its natural distributionrange. This covers a wide range of climatic conditions, i.e. from the equatorialtype to the sub-tropical type with a range of rainfall and temperature of500-3,500 mm and 2°-48°C (minimum and maximum range) respectively(Kaosa-ard, 1981). Soil conditions also vary from infertile acidic to fertilealluvial. A large variation in growth and other tree characters such as stemform, mode of branching, flowering habit and wood quality of the plantationcommonly results. The mean annual volume increment (MAI) of teak plantationsover a wide range of plantation conditions varies from 2 m³/ha/yearto >15 m³/ha/year at the half rotation age of 30-40 years (FAO,1956; White, 1991; Keogh, 1994). Keogh (1994) recommended that the MAI of teakplantation should be not less than 8m³/ha/year in commercial plantingoperations. The site for teak planting should be carefully selected, e.g.through species (site matching. Within a planting zone, the effect of sitequality on plantation growth may be demonstrated through the construction ofSite Index curves. Data presented in Table 1 show the difference in diametergrowth of teak plantations grown in different site qualities, both within andoutside teak's natural distribution range. Through site selection, it is shownin the case of Indonesia that the growth of the plantation can be improved toover 116 %.

Table 1. Growth (dbh) of teakplantations grown under poor and good site qualities in selectedcountries

Sources: #1Tewari (1992); #2 Chanpaisaeng (1993); #3 Dupuy (1990); #4 modified fromMaddugoda (1993)

Site effect - woodquality

It is common knowledge among loggersthat teak from wetter site conditions, e.g. along river banks or in the lowermoist teak forest, is usually darker in wood colour than that from drier siteconditions. Teak wood colour seems to be influenced by the site. As the goldenbrown wood colour is one of teak's most attractive timber qualities, thevariation in wood colour and texture has been widely studied (Sono andSaensakul, 1959; Sandermann and Simatupang, 1966; Sunyata et al., 1992;Kaosa-ard, 1993). A study on clonal variation in wood colour and texture inThailand in a 20-year old clonal test clearly demonstrated that teak wood colourand texture is strongly controlled by the planting site (Kaosa-ard, unpublisheddata). In this test, clones of trees from different locations with differentwood colours (i.e. dark brown, golden brown, light brown colours, and woodtextures, i.e. stony-wood and waxy-wood textures (produced similar wood colourand texture when planted on the same site (< 0.5 ha plot). Similarly, resultsof 14-year old intentional provenance trials in Thailand (established within andoutside the teak bearing area) clearly showed that there is no or littlesignificant effect of provenance or seed source on wood colour (i.e., the goldenbrown colour) and wood density (Kaosa-ard, 1993). These trials consist ofprovenances from India, Thailand, Indonesia, Lao and African races. Within aprovenance, there is a marked site effect on wood colour, e.g. golden browncolour (Kaosa-ard, 1993). The proportion of trees with golden brown wood colourdecreases from a natural teak bearing site (Ngao, Lampang) to a non-teak bearingsite (Khon Kaen), i.e., from 74% to 63% (Kaosa-ard, 1993). The cause of suchvariation is still not known but is possibly due to differences in soilchemistry and moisture content in the two planting sites.

THE TEAK SITEDEFINED

It is shown that the planting sitehas a strong effect on the growth, development and wood quality of teakplantations. The productivity of a plantation can be largely improved throughthe selection of a correct site for the plantation programme. It is noted thatthe teak distribution pattern in its natural range is of discontinuous or patchytype (Troup, 1921; FAO, 1956,1958). Size, quality, density, and the form of teaktrees varies from one location to another. There are several factors whichcontrol the distribution and growth pattern of the species. The major factorsinclude the amount and distribution of rainfall and moisture, soil andlight.

Rainfall andmoisture

Teak grows naturally over a widerange of climatic condition, from the very dry (500 mm/year) to the very moist(up to 5,000 mm/year) (Seth and Khan, 1958; Kaosa-ard, 1981). Under very dryconditions, the tree is usually stunted and shrubby. Under very moistconditions, the tree is large and fluted and usually behaves like asemi-evergreen species; the wood quality is poor in terms of colour, texture anddensity. For the production of high quality wood with optimum growth, moistureconditions (as expressed by annual rainfall) should be between 1,200 and 2,500mm with a marked dry season of 3-5 months (Kaosa-ard, 1981; Keogh, 1987). Thedry season refers to a period in which the cumulative rainfall is less than 50mm per month (Keogh, 1987).

Soil

Teak grows best on deep,well-drained alluvial soils derived from limestone, schist, gneiss, shale (andsome volcanic rocks, such as basalt. Conversely, the species performs verypoorly, in terms of growth and stem form, on dry sandy soil, shallow soil (hardpan soil or lower water table soil), acidic soil (pH < 6.0) derived fromlaterite or peatbog, and on compacted or waterlogged soil (Kulkani, 1951;Kiatpraneet, 1974; Kaosa-ard, 1981; Bunyavejchewin, 1987; Srisuksai,1991).

Teak soil is relatively fertile withhigh calcium (Ca), phosphorus (P), potassium (K), nitrogen (N) and organicmatter (OM) contents (Bhatia, 1954; Seth and Yadav, 1958; Samapuddhi, 1963;Kiatpraneet, 1974; Sahunalu, 1970; Kaosa-ard, 1981; Bunyavejchewin, 1987;Srisuksai, 1991). Several studies indicate that teak requires relatively largeamounts of calcium for its growth and development, and teak has been named as acalcareous species (Seth and Yadav, 1958; Kaosa-ard, 1981; Tewari, 1992). Theamount of calcium content in the soil is also used as an indicator of teak sitequality. That is, the greater the proportion of teak to other associate species,the higher the calcium content in the forest soil (Bunyavejchewin, 1983,1987).

Soil pH is another factor limitingthe distribution and stand development of the species. Although the range ofsoil pH in teak forests is wide (5.0-8.0) (Kulkarni, 1951; Samapuddhi, 1963;Bunyavejchewin, 1983, 1987), the optimum pH range for better growth and qualityis between 6.5-7.5 (Seth and Yadav, 1959; Kaosa-ard, 1981; Tewari1992).

Light

Teak has been classified as apioneer species. Hence, it requires a high light intensity for its growth anddevelopment (Troup, 1921; Kermode, 1957; Kadambi, 1972; Kitinanda, 1969;Kwoboshi, 1974). A study conducted by Kwoboshi (1974) clearly demonstrated theeffect of light intensity on the growth and development of teak seedlings; drymatter production of teak seedlings decreases sharply with a decrease in lightintensity. In his study, the dry matter production of seedlings grown under lowlight intensity of 25% (for 8 months) was 0.6 gm as compared with 14.6 gm ofseedlings grown under high light intensity of 75% of full daylight. The optimumlight intensity for seedling growth and development is between 75-90% (Kwoboshi,1974).

Otherfactors

Apart from rainfall and moisture,soil and light intensity, other factors such as temperature and elevation alsoplay important roles in limiting the distribution and growth pattern of thespecies. It is known that teak grows well under warm and humid conditions. Aseries of studies in controlled environments indicated that the optimumtemperature for growth and development of the species is 27-36°C (Gyi,1972; Kanchanaburangura, 1976; Kaosa-ard, 1977). This range of temperature isquite normal within teak tropical range. Teak poorly tolerates cold and frostconditions during the winter period. Under frost conditions, seedlings andsaplings are severely damaged and die (Kaosa-ard, 1981), one reason why thespecies cannot grow at elevations over 700 metres.

SEED SUPPLY

Seed supply is one of the mostcritical factors limiting the teak planting programmes. This is especially so incountries where teak is grown as an exotic species and seed used is totally fromold trials or pilot plantations. Problems of seed supply, including the amountand quality of the annual seed requirement, are considered.

Seedrequirement

It is well known that teakgermination is poor and sporadic as a result of its dormancy behaviour. Undernursery conditions the germination of untreated seed is about 30-50% over agermination period of 50 days (Anon., 1956; Gartner, 1956; Suangtho, 1980;Kaosa-ard, 1986; Kumaravelu, 1993; Phengduang, 1993). This germination behaviourcauses a very low plant percentage in nursery production. Wellendorf andKaosa-ard (1988) estimated that the plant percentage in a teak nursery is only5%, or five plantable seedlings produced from 100 seeds sown in one crop year.This rate is commonly obtained in large-scale nursery operations (4-5 millionseedlings per year), where seed pre-sowing treatment is not practical for thelarge quantity of seed. The low plant percentage in nursery production is dueprimarily to poor seed germination behaviour and the growth competition of thenon transplanted seedlings in the nursery beds (Kaosa-ard, 1986). The amount ofseed required for a hectare of plantation with 4 (4 metre spacing is about 8 kg,including 25% for beating up (Wellendorf and Kaosa-ard, 1988). Estimation ofseed requirement for various options in a teak planting programme is given inTable 2. This is based on the fact in Thailand that 1 kg consists of 1,800seeds; 1 litre contains 450 seeds and the plant percentage is 5% (Kaosa-ard1986; Wellendorf and Kaosa-ard, 1988).

Table 2 shows that the requirementvaries from 8 to 34 kg/ha per plantation. Similar estimates of seed requirementare reported from India, i.e., 2.5-43 kg/ha (Sirimathi and Emmanuel, 1986). Suchlarge amounts of seed required per hectare of plantation can be reduced throughimprovement of seed germination (i.e., seed pre-sowing treatment) and nurserytechniques (sowing density, sowing, thinning and transplanting techniques,containerised seedling techniques, etc).

Table 2. Annual stumps and seedrequirement per 1,000 ha, plus 25 % for beating up

Source: Modifiedfrom Wellendorf and Kaosa-ard (1988)

Seed quality

The success of planting programmesdepends not only on the site quality but also on the genetic quality of theplanting materials. Although the growth and yield of the plantation can belargely improved through site selection, stem quality (i.e., straightness,persistence of stem axis, branching, flowering, etc.) is strongly controlled bygenetic make-up (Keiding et al., 1986; Wellendorf and Kaosa-ard, 1988;Kaosa-ard, 1993). The results of international teak provenance trials haveclearly demonstrated the effect of provenance or seed source on growth, stemquality, early flowering habit and health performance (Keiding et al.,1986). Through correct selection of provenance or seed source, growth and stemquality can be improved (from the provenance means) as high as 23% and 17%respectively (Keiding et al., 1986). In many cases, the local provenancesperformed only as well as, or even poorer, than the exotic provenances. The useof improved seed (i.e., from seed production areas, seed orchards and plustrees) is most essential in the improvement of growth, stem quality and othercharacters of the plantation. It has been estimated that by using such improvedseed, the growth and/or volume production gain of the plantation is increased(from base populations) by 5-25%, depending on types of seed source and plantingsite (Wellendorf and Kaosa-ard, 1988).

Seedproduction

The use of improved seed or plantmaterials is shown to be essential to increase the growth and quality ofplantations. To obtain such improvements, Seed production areas and/or seedorchards are required.

A Seed Production Area (SPA) is aconverted plantation or a natural stand for seed production, treated by removingall inferior trees, and SPAs seem the most practical short term option forimproved seed production programmes. An abundance of improved seed can beobtained within one year of establishment. Through the SPA option, the gain involume production of plantations is 5-15% over routine seed sources (Wellendorfand Kaosa-ard, 1986; Kaosa-ard, 1993).

The Clonal Seed Orchard (CSO) isanother option of seed source establishment. It is a plantation of mixed clonesderived from plus trees, designed, established and managed for seed productionpurposes. It is established as a propagation part of the improvement programme.Generally, the CSO starts producing seed at 10-15 years and its initial gain isabout 25% over the base population (Wellendorf and Kaosa-ard, 1986; Kaosa-ard,1993).

Seed production capacity of bothSPAs and CSOs is relatively poor, at least in the case of Thailand. Theproduction capacity in the SPA and CSO is about 10 and 70 kg/ha of teak seedrespectively (Kaosa-ard, 1979; Meekaew, 1992). Low production capacity of teakseed in the CSO is also reported from India, 0.5-1 kg per tree or approximately50-100 kg/ha (Tewari, 1992). However, a contrasting result is reported fromNigeria, where the productivity of the CSO is as high as 734 kg/ha (Egenti,1981). The needed areas of SPAs and CSOs to support a 1,000 ha annual plantingprogramme has been estimated and given in Table 3. This estimation is based onavailable information from Thailand where the seed production capacity in SPAsand CSOs is 10 and 70 kg/respectively.

Table 3. Estimated areas of SPAand CSO for various options of a 1,000 ha plantingprogramme

Source: Modifiedfrom Wellendorf and Kaosa-ard (1988)

Clonalpropagation

Apart from SPA and CSO, tissueculture is another option for mass supplying of genetically improved materialsfor the planting programme of this species. This technique of propagation hasbeen developed successfully for commercial propagation of selected plus trees(Kaosa-ard et al., 1987; Kaosa-ard and Apavatjarut, 1988, 1989). In thistechnique, shootlets are produced under laboratory condition and are thentransferred to glasshouse conditions for rooting. The rooted shootlets orplantlets are transplanted for stock production. Through this process, the costof shootlet production (as estimated in 1989) was US$5.12 per 100 shoots at 1million scale of production (Kaosa-ard, 1990). This production cost seems to bethe same level as the cost of seed production (viable seed) in the CSO(Kaosa-ard, 1990). This CSO production cost includes establishment andmaintenance of CSO for at least 10 years prior to full seed production, plus thecost of seed collection and processing.

MANAGEMENT

Apart from site and seed problems,the success of teak plantation establishment also depends largely onsilvicultural management. The common management includes spacing, weeding, fireprotection, insect and disease protection and thinning.

Plantingspacing

Initial spacing of teak plantationvaries (1.8×1.8 to 4×4 m) depending on many factors as site quality,cost of establishment, thinning regime, small wood utilization, planting system,e.g. agro-forestry, intercropping etc. However, site quality seems to be thepriority factor directing the size of spacing in the teak planting programme.Results of 12-year-old spacing trials (2×2, 3×3, 4×4, 6×6 m)in Thailand clearly demonstrated the effects of initial spacing on growth, stemquality and weed control in teak plantations of different site conditions. Underdry site conditions, where the initial growth rate of the plantation is poor(e.g. < 1.0 metre per year in height), close spacing of 2×2 m is mostsuitable. Conversely, the initial spacing can be wider up to 4×4 m, i.e.for cost reduction, under good site conditions (Kaosa-ard, 1980). Based on thisstudy, a 3×3 m spacing (1,111 trees/ha) has been recommended and used asthe routine spacing in Thailand. However, in areas where wider spacing isrequired for the application of agro-forestry systems or machine weeding, the4×2 m spacing (1,250 trees/ha) is used. Similar results of spacing trialsare reported from India where close spacing of 1.8×1.8m and wider spacingof 3.6×3.6 m are suitable for dry and good (rainfall <1,500 mm) siteconditions respectively (Tewari, 1992). Various spacings are used in teakplantation establishment under different site conditions such as 2.5×2.5 m,2.7×2.7, 3.6×1.8 m and 3.6×2.7 m in India (Tewari, 1992),2×2 m in Bangladesh (Banik, 1993), 2×3 and 3×3 m in China (Anon.,1993), 2.5×2.0 m in the Caribbean and Central America (Keogh, 1987),2.6×2.6 m in Myanmar (Gyi, 1993), 3×3 m in Sri Lanka (Maddugoda, 1993)and 3×2 m to 5×2 m in Indonesia (Anon., 1993).

Plantingtime

Planting time has marked effect onsurvival and growth in teak plantations, especially when stump planting ispractised (Kaosa-ard, 1977). A series of studies on stump storage and plantingtime in Thailand demonstrated that survival and growth in the early establishedplantations decreased sharply from May planting through June planting to Julyplanting (Kaosa-ard, 1977). The most suitable planting time for teak is soonafter the arrival of the monsoon showers or in the beginning of the rainyseason. Phenological development studies showed the importance of planting time,especially on growth (Kaosa-ard, 1982). Teak has only one growth flush periodthroughout the year (Kaosa-ard, 1982). Shoot growth, as expressed in percentageof annual growth, starts soon after the first rain shower (late April), reachesits peak in the beginning of the rainy season (May-June), thereafter declinessharply in the middle of rainy season (July-October) and ceases during the dryseason (November-April) (Kaosa-ard, 1982). Kaosa-ard (1982) also recommendedthat teak be planted just prior to, or during the growth flush period, i.e.between late April and early June, depending largely on the arrival of the firstmonsoon rain.

Weeding

Teak is a light demanding speciesand its growth and development is reduced sharply under poor light conditions.Hence, intensive weeding is very necessary during early establishment of theplantation, i.e. 1-3 years.

Thinning

The first thinning is conducted at5-10 years after planting, depending on site quality and the size of initialspacing. Generally, under good site and close spacing (1.8×1.8 m and2×2 m) the first and second thinning (mechanical thinnings) are conductedat 5 and 10 years respectively. About 25% of the trees are left for furthergrowth and development after the second thinning. In the Caribbean and CentralAmerican region, the first and second thinnings (mechanical thinnings) areconducted when the plantation height is 8 and 16 m respectively (Koegh, 1987).Times and methods of subsequent thinning however vary depending on site andeconomic considerations. Construction of Site Index tables in relation to standdensity at different stand ages is a guideline for setting a thinning regime foreach planting site.

Insectdamage

Insect damage is a serious problemin teak plantations. This is especially so where the intensive forest farmingsystem is practised, e.g. in well-irrigated plantations. The most common insectswhich cause severe damage plantations are defoliators and stemborers.

Defoliator insects cause severedefoliation and, hence, reduce growth rate, apical dominance and the seedproduction capacity of plantations, seed production areas and seed orchards. Themost important defoliators causing severe damage in teak plantations throughoutthe tropics are Hyblaea puera Cramer (Hyblaeidae) and Eutectonamachaeralis Walker (Pyralidae) (Chaiglom, 1963; Tewari, 1992). Outbreaks ofthese insects may occur 2 or 3 times during the growing season (Chaiglom, 1963).After outbreaks, especially of Hyblaea puera, the plantation growth ratemay be reduced by as much as 75% (Chaiglom, 1963). Control of outbreaks of theseinsects requires application of both chemical and biological agents, e.g.Bacillus thuringiensis or BT agents.

Stem borers cause severe damage; inyoung plantations (1-5 years old) damaged trees may die back or top breakcausing a reduction in growth rate and stem quality. The most important stemborer in young teak plantations is the red or coffee borer Zeuzeracoffeae Nietner (Cossidae). In Thailand this insect causes severe damage inprivate plantations where the planting sites were previously sugar cane andtapioca fields. In old plantations, i.e., over 10 years, the beehole borerXyleutes ceramicus is the most important stem borer. It causes severedamage to the standing trees and also reduces the value of timber, with a closerelationship between site quality and the degree of damage caused by the beeholeborer (Choldumrongkul, 1989). Plantations established on good site quality havehigher degrees of damage than those on poor site quality (Choldumrongkul, 1989).At present, there is no practical chemical and biological method for controllingoutbreaks of the beehole borer. Silvicultural treatments such as weeding,control burning, thinning, and intercropping may be the only methods which canreduce the insect populations.

CONCLUSION

Teak plantations have been widelyestablished throughout the tropics with the main objectives to produce highquality timber within a period of 40-80 years. In general, the productivity ofthe teak plantation is 8-10 m³/ha/year. Three main factors affectgrowth and quality of the plantation: site quality, seed supply andsilvicultural management.

Site quality has direct effect onthe growth and development of the plantation. The rotation age can be greatlyreduced through site selection. Teak grows well on moist sites. To produce highquality timber trees, the site should be subjected to a dry period of 3-5 monthsduration. Teak soil is deep, well- drained, and alluvial with high calcium,organic matter and other element content. The soil pH is 6.5-7.5. Teak is alight-demanding species. As a result, intensive weeding in 1-5 year-oldplantations is very important.

The supply of improved seed forplanting programmes is a major problem especially in countries where teak is anexotic. A large quantity of improved seed can be obtained through establishmentand management of Seed Production Areas and Seed Orchards. Clonal propagation bytissue culture is an option for mass production of planting stock. Thistechnique is technically and economically feasible.

Appropriate and timely silviculturalmanagement must be carried out to improve both the growth rate and quality.Initial spacing has marked effects on growth, quality and establishment cost. Inpoor site quality areas plantations should be established with close spacing.Planting time also plays an important role on initial growth and survival of theplantation. The most suitable time for teak planting is during the growth flushperiod, i.e., the beginning of rainy season. Intensive weeding should be carriedout during the first five years after establishment. The outbreak of defoliatorsand stem borers has become a serious problem; there is no practical method forcontrolling these insects. First and second thinnings are conducted at ages 5and 10 years in close spaced plantations using a simple mechanical thinningtechnique. Subsequent thinnings are carried out using relevant Site Index andStand Density Tables as thinning guidelines.

REFERENCES

Anon, 1956. India In "CountryReports on Teak Forestry" FAO, Rome 21-48 pp.

Anon, 1993. Teak in Indonesia. In"Teak In Asia" Technical Document GCP/RAS/I34/ASB, FORSPA Publication 4,FAO-RAPA 35-40 pp.

Banik, R.L. 1993. Teak inBangladesh. In "Teak In Asia" Technical Document GCP/RAS/I34/ASB, FORSPAPublication 4, FAO-RAPA 1-10 pp.

Barnes, R.D. 1984. A multiplepopulation breeding strategy for Zimbabwe. In. "Provenance and GeneticImprovement Strategies in Tropical Forest Trees". Edited by R.D. Barnes and G.L.Gibson, 619 - 632 pp.

Boonkird, S. 1964. Progress reporton the first teak tree-show in Thailand. Nat. His. Bull. Siam. Soc. 20:243-256

Brockelman, W.Y. and Baimai,V. 1993.Conservation of biodiversity and protected area anagement in Thailand. Proc. ofSkill Transfer Workshop conducted by MIDAS Agronomic Co. Ltd., for WorldBank/GEF/Pre-investment Study on Conservation Area Protection, Management andDevelopment Project, Bangkok.

Bryndum, K. and Hedegart, T. 1969.Pollination of teak (Tectona grandis Linn. f.). Silv. Genet.18:77-80pp.

Cameron, A.L. 1966. Geneticimprovement of teak in New Guinea. Aust. For. 30:76-87 pp.

Choldumrongkul, S. and C.Hutacharern 1986. The relationship between the flower development of teak andits associated insects. Jour. Nat. Res. Coun. of Thailand 18: 54-52pp.

Egenti, L.C. 1981. Aspect ofpollination ecology of teak (Tectona grandis Linn. f.) in Nigeria:Pollinators and fruit production. In "Proceedings of the Symposium on FloweringPhysiology" XVII IUFRO World Congress, Kyoto, Japan. 27-30 pp.

Egenti, L.C. 1981a. Aspect ofpollination ecology of teak (Tectona grandis Linn. f.) in Nigeria.Flowering and insect dynamics. In "Proceedings of the Symposium on FloweringPhysiology" XVII IUFRO World Congress, Kyoto, Japan. 17-20 pp.

Egenti, L.C. 1981b. Aspect ofpollination ecology of teak (Tectona grandis Linn. f.) in Nigeria.Viability of reproductive units. In "Proceedings of the Symposium on FloweringPhysiology" XVII IUFRO World Congress, Kyoto, Japan. 21-26 pp.

FAO, 1957. Report on teak growingunder exotic conditions. FAO/TSC-57/3, FAO Rome.

Gartner, I.C. 1956. Indonesia InCountry Reports on Teak forestry FAO, Rome 49-105 pp.

Gram, K. and S.C. Larsen, 1958. Theflowering of teak (Tectona grandis Linn. f.) in aspect of tree breeding.Nat. His. Bull. Siam. Soc. 19: 1-6 pp.

Gyi, K. K. 1972. An Investigation ofFactors relevant to Development of Teak Plantation in South East Asia withParticular Reference to Burma. M.Sc. Thesis, Australian National University,Canberra Australia.

Gyi, K.K 1993. Teak in Myanmar. In"Teak In Asia" Technical Document GCP/RAS/I34/ASB, FORSPA Publication 4,FAO-RAPA 51-62 pp.

Harahap, R.N. and I. Soerinegara,1977. Heritability of some characters in teak. In Proc. "The Third WorldConsultation on Forest Tree Breeding" Vol 2: IUFRO/CSIRO,Canberra.

Hardiyanto, E.B., Sunyoto, O.H.Soeseno and M. Naiem 1992. Early performance of teak (Tectona grandisLinn.f.). In "One Century of Sustainable Forest Management with SpecialReference to Teak in Java" Proc. International Symposium on Sustainable ForestManagement, Yogyakarta, Indonesia. 177-180 pp.

Hedegart, T. 1973. Pollination ofteak (Tectona grandis Linn. f.). Silv. Genet. 22 (4)

Hedegart, T. 1974. The TeakImprovement Centre: Ten years after initiation. Vanasarn 32: 342-356p.

Hedegart, T. 1976. Breeding system,variation and genetic improvement of teak (Tectona grandis Linn. f.). In"Tropical Trees" Edited by J.Burley and B.T. Styles, Linnean Soc. Symp. Ser. No.2: 109-123 pp. Academic Press, London

Kanchanaburangura, C. 1976. Teak(Tectona grandis Linn. f.) Seedlings and Provenance Variation. M.Sc.Thesis, Australian National University, Australia. 216 p.

Kaosa-ard, A. 1977. PhysiologicalStudies on Sprouting of Teak (Tectona grandis Linn. f.) Planting Stumps.Ph.D. Thesis Australian National University, Canberra Australia 370p.

Kaosa-ard, A. 1979. Summary resultsof research on teak seed production. In Teak Seed Centre, Annual Report No.2.

Kaosa-ard, A. 1981. Teak Its naturaldistribution and related factors. Nat. His. Bull. Siam. Soc. 29:55-74.

Kaosa-ard, A. 1986. Teak in ASEAN: ASurvey Report. ASEAN CANADA Forest Tree Seed Centre, p.60.

Kaosa-ard, A. 1986. Teak (Tectonagrandis Linn. f.) nursery techniques with special reference to Thailand.DANIDA Forest Seed Centre Seed Leaflet No. 4A 42 p.

Kaosa-ard, A. 1993. Teakinternational provenance trials I. Growth and stem quality. In Proceedings "50thYear of Huay Tak Teak Plantation: Teak Seminar" 113-129 pp.

Kaosa-ard, A. 1993a. Teakinternational provenance trials I. Wood production and quality. In Proceedings"50th Year of Huay Tak Teak Plantation: Teak Seminar". 294-312pp.

Kaosa-ard A., Apavatjrut, P. andParatasilpin,T. 1987. Teak tissue culture. In Proceedings of His Majesty's FifthCycle Commemorative Conference of USAID Science Research 201-206pp.

Kaosa-ard, A. and P. Apavatjrut1988. Teak tissue culture: Rooting and transplanting techniques. InBiotechnology Conference, Washington D.C.

Kaosa-ard, A. and Apavatjrut, P.1989. Teak (Tectona grandis Linn. f.) tissue culture. In RegionalSymposium on Recent Research Development in Tree Plantation for Humid andSubhumid Tropics of Asia, in Malaysia, June 5-9, 1989.

Kaosa-ard, M. 1990. Teak TissueCulture: Cost Analysis Report RFD/CMU/PSTC 1990 26 p.

Katasubrato, Y. 1992. The history ofsustainable management in Indonesia, the case of teak. In "One CenturySustainable Forest Management with Special Reference to Teak in Java" 3-39pp.

Keiding, H. 1966. Aim and prospectsof teak breeding in Thailand. Nat. His. Bull. Siam. Soc. 21(1&2).

Keiding H., H. Wellendorf and E.B.Lauridsen 1986. Evaluation of an International Teak Provenance Trials. DANIDAForest Seed Centre, p.81

Kedharnath, S. and J.D. Matthews,1962. Improvement of teak by selection and breeding. Ind. For. 88:277-284.

Kumaravelu,G. 1993. Teak in India.In "Teak In Asia" Technical Document GCP/RAS/I34/ASB, FORSPA Publication 4,FAO-RAPA 27-36 pp.

Loetsch, F. 1958. Report to theGovernment of Thailand on Forest Inventory of the Northern Teak BearingProvinces. FAO Report No. 895, Rome.

Meekaew, P. 1992. Genetic Variationin Growth, Seed Production and Foliar Nutrients of Teak. M.Sc. Thesis, Facultyof Forestry, KU, Bangkok, Thailand 73 p.

Namkoong, G., R.D. Barns and J.Burley 1980. A philosophy of breeding strategy for tropical forest trees.Tropical Tree Papers No.16, Univ. Oxford. 67 p.

Namkoong, G.; H.C. Kang and J.S.Brouard 1988. Tree Breeding Principles and Strategies. In: Monographs onTheoretical and Applied Genetics 11, Springier-Verlag 180 p.

Nair, K.R. and Mukerji, H.K. 1960. Astatistical study of the variability of physical and mechanical properties ofteak grown at different localities of India and Burma and the effects ofvariability on the choice of the sampling plan. Ind. For. Rec.1:(1)

Nikles, K.G. 1992. Conservation anduse of genetic diversity in improvement programmes with industrial forest treespecies. In. "Proc. of the Regional Symposium on Recent Advances in Mass ClonalPropagation of Forest Tree for Plantation Programmes" RAS/91/004 Field DocumentNo. 4 83-109 pp.

Person, A. 1971. Observations from aprogeny trials of at Longuza. Tanzania Silv. Res. Note, No. 24.

Phengduang, V. 1993. Teak in LaosPDR. In "Teak In Asia" Technical Document GCP/RAS/I34/ASB, FORSPA Publication 4,FAO-RAPA 41-50 pp.

RFD, 1989. Forestry Statistics ofThailand, RFD.

Siripatanadilok, S. 1974.Development of teak flower (Tectona grandis Linn. f.). For. Res. Bull.No. 31, Fac. Forestry, KU, Thailand 68 p.

Srimathi, R.A. and Emmanuel,C.J.S.K. 1986. Jour. Trop. For. 2: 256-268.

Suangtho, V. 1980. FactorsControlling teak (Tectona grandis Linn. f.) Seed Germination and TheirImportance to Thailand. M.Sc. Thesis Australian National University, Canberra,Australia.

Suksileung, P. 1975. Clonalvariation and inheritance in growth characteristics of teak (Tectonagrandis Linn.f.). M.Sc. Thesis, Fac. For. Kasetsart University, Thailand 45p.Tewari, D.N. 1992. "A Monograph on Teak (Tectona grandis Linn. f.)"Int. Nat. Book Dist. Dehra Dun, 479 p.

Wellendorf, H. and Kaosa-ard, A.1988. Teak Improvement Strategy in Thailand. Forest Tree Improvement No.21,p.43

White, K.J. 1991. Teak. Some aspectsof research and development. FAO/RAPA 1991/17.

Teakbreeding and improvement strategies - Dr. ApichartKaosa-ard

ApichartKaosa-ard

Forest Resources Department,Chiang Mai University, Thailand

Teakin situ gene conservation, Teak Improvement Center (TIC), Lampang,Thailand

ABSTRACT

Teak is one of the most valuabletimbers in the world. The species is native to South and Southeast Asia butplantations have been established throughout the world's tropics. The majorproblem in plantation establishment of this species is the supply of geneticallyimproved materials for large scale planting programmes; to overcome shortagesboth short- and long-term improvement and propagation strategies are proposed.The short-term strategy includes the establishment and management of seedproduction areas, clonal seed orchards and clone banks for seed and clonal stockproduction. The mass clonal propagation of selected trees, tissue culture incombination with a plantlet cutting technique, is recommended. Long-termimprovement strategies involve the development and management of gene resourcepopulations, breeding populations and propagation populations. Geneticstructures and functions of these three populations are discussed. In long-termbreeding populations, the formulation, establishment and management of singleand multiple breeding populations suitable for teak breeding programmes arediscussed in detail.

Key words: Tectonagrandis, Thailand, seed, seed orchards, breeding, tissue culture, genetics,research.

INTRODUCTION

Teak (Tectona grandis Linn.f.) is one of the most valuable timber tree species in the world. Its timberquality is recognised as attractiveness in color and texture, suitability forall aspects of household construction, ease of working and carving, resistanceto termites, fungi and weathering etc. The species is a member of theIndo-Burmese floristic type and occurs naturally in India, Myanmar, Thailand,and Lao (Kaosa-ard, 1983). In Indonesia, the species is a long establishedintroduction to Java (about 700 years) and neighboring islands, such as Muna,Bawean, Lombok, etc., and thereafter wildly distributed throughout the area(Kaosa-ard, 1983, 1986). The species in Indonesia has become a natural sourcewhich is isolated from the continental mainland. Due to its high timber qualityand value, plantations of this species have been widely established from theearly 1800s both within and outside its natural region (FAO, 1957). At present(1990), more than 1.6 million ha of teak plantation have been establishedthroughout the tropics (Hougs, unpublished data). However, about 90% of thisplantation is in the Asian region, especially in India, Myanmar, Thailand andIndonesia where abundant seed can be obtained for large-scale planting. Outsideits natural habitat, although its performance is very impressive in manycountries, teak planting programmes are still limited, due mostly to aninsufficiency of seed. At present teak seed supply and/or exchange, especiallyfrom natural sources, is limited to research purposes. There is no commercialseed dealer within or outside the region, and most of the teak planting agenciesor organizations have to rely on their own breeding and seed productionprogrammes. If this problem can be overcome, plantations of this species(especially outside its natural region (will be increasingly promoted.Strategies for short-term propagation and long-term breeding programmes of teakare proposed in order to increase the supply of improved genetic materialsufficient for large-scale planting programmes.

MAINELEMENTS

As many other forest treeimprovement programmes, the main elements in the teak improvement programme are:strategies, tree populations, operation and management, research anddevelopment.

Strategies

Tree improvement strategies involveplanning and execution for achieving general objectives, especially of long termbreeding, propagation and conservation in the improvement programme. Theformulation and development of an improvement strategy requires biological andtechnological knowledge including: genetic variation and gain, floweringbiology, mating system, seed production, clonal propagation, planting techniquesetc.

Populations

Tree populations in an improvementprogramme consist of genetic resources, breeding, propagation and woodproduction. The genetic structures of these four populations are the coreelements in the breeding programme. Due to the differences in their objectives,genetic structures, variabilities and long- term utilization, these fourpopulations are usually established and maintained separately. Relationshipsamong these four populations are illustrated in Figure 1.

Figure1. Over time, genetic material is progressed through the series of populationsby a process of selection and mating.

Operation/Management

Operations and management in animprovement programme are mostly concerned with the availability of humanresources, financial resources, infrastructure and organization, knowledge ofthe genetic parameters and reproductive biology of the species, information,technologies, etc.

Research andDevelopment

Research and development in animprovement programme is essential to solve certain key problems. Moreover, thedevelopment of appropriate technologies will assist and facilitate the breedingactivities (e.g. pollen extraction and storage, flowering induction, etc.) andpropagation operations (e.g. seed production, cuttings, tissue culture,etc.).

IMPROVEMENTOBJECTIVES

The general objectives in the teakimprovement programmes are broadly divided into short- and long-term objectivesas follows:

Short-term objectivesinclude:

¨ Increased volume production per unit area of theplantation through the improvement of growth rate (e.g. diameter and heightgrowth).

¨Improved stem quality of trees in terms of: stem straightness; stem - clearbole - or pruning capability; persistence of stem axis; other desirablecharacters.

¨Improved wood qualities, e.g. wood color and density.

¨Production of genetically improved seed (e.g. through the establishment ofseed production areas and seed orchards) and vegetative propagules (e.g. throughthe establishment of clone banks) sufficient for plantingprogrammes.

Long-term objectivesinclude:

¨ Establishment of long-term breeding populationsfor greater cumulative genetic gains of improved characters.

¨Manipulation and maintenance of genetic variabilities of the breedingpopulations through as many generations as possible.

¨Securing the supply of improved seed and/or planting materials of greatercumulative gain for planting programmes.

BASICASSUMPTIONS

To formulate and develop appropriatestrategies for teak improvement, the following knowledge and assumptions areconcerned particularly with the amount of seed required, and the method of itsproduction.

Seedrequirements

It is well known that thegermination of teak seed is one of the most critical problems in a plantingprogramme, especially where expensive seed from seed orchards is used.Experience gained from the teak growing region, e.g. India, Bangladesh, Myanmar,Thailand, Lao and Indonesia, indicates that the germination of teak in thenursery is very low (30-50%) and sporadic (with a germination period of 10-50days after sowing (Anon. 1956; Gartner, 1956; Suangtho, 1980; Kaosa-ard, 1986;Kumaravelu, 1993; Phengduang, 1993). This low and sporadic germination is due tothe strong dormancy behavior of teak seed, which causes a low plant percentagein nursery production.

In Thailand, for example, under alarge-scale nursery operation (4-5 million seedlings per year), the plantpercentage is markedly low, only 5 % (Kaosa-ard, 1986; Wellendorf and Kaosa-ard,1988) with only 5 plantable seedlings produced from 100 seeds sown in onegrowing season. Based on this assumption, the amount of seed required for onehectare of plantation (with spacing of 4 (4 m) is about 8 kg including 25 % forbeating up (Wellendorf and Kaosa-ard, 1988). In India, the seed requirements perhectare of plantation vary from 2.5 kg in Tamil Nadu, to 30 kg in Andhra Pradeshand to 43 kg in Gujarat (Srimathi and Emmanuel, 1986). This low germinationpercentage and the sporadic germination of the seed can be improved to a certaindegree (at least in small-scale nursery practices) through various seedpre-sowing techniques including soaking the seed in water or in a mixture of cowdung and water, alternate soaking and sun drying, heat treatment, etc. (Gyi,1972; Suangtho, 1980; Kaosa-ard, 1986; Tewari, 1992). The seed biodata, annualstump plant requirements and annual seed requirements of 1,000 ha of plantationin Thailand in various planting options are shown in Tables 2 and3.

Table 1. General figures onteak seed biodata (Thailand)

Source: Modifiedfrom Kaosa-ard (1986) and Wellendorf and Kaosa-ard (1988)

Table 2. Annual stumps and seedrequirement in a 1,000 ha planting programme (plus 25 % for beatingup)

Source: Modifiedfrom Wellendorf and Kaosa-ard (1988)

SEEDPRODUCTION

Seed Production Areas(SPA)

The most practical option in animprovement programme for the immediate supply of improved seed is in SeedProduction Areas (SPA), formed by the conversion of existing older plantationsand/or natural stands. Experience in Thailand has shown a great many benefits ofSPAs. First, a SPA can produce an abundance of good seed within a year ofestablishment whereas a Clonal Seed Orchard (CSO) starts producing seed onlyafter 10-15 years. Second, the genetic gain (in terms of growth or volumeproduction) from the SPA is very high, up to 15 %, as compared with unidentifiedor unimproved seed sources (Wellendorf and Kaosa-ard, 1986; Kaosa-ard, 1993).Through the initial/untested CSO option, the gain is estimated to be as high as25% (Wellendorf and Kaosa-ard, 1986; Kaosa-ard, 1993). The gain differencebetween a SPA and a CSO is due primarily to the difference in selectionintensity of seed or plus trees, i.e. 1:6-1:8 for the SPA and 1:100-1:1,000 forthe CSO. Finally, the cost of SPA establishment and management is much cheaperthan a CSO.

Although SPAs have many advantages,production capacity is still very low. A series of studies in Thailand show themaximum production capacity of teak seed at the Mae Huad SPA is about 10 kg perha (Kaosa-ard, 1979). This low seed production, as compared with the CSO, isprobably due to a number of factors: a) the higher tree density (160-320trees/ha); b) the smaller crown canopy; c) older trees and d) a lower proportionof insect pollinators per number of individual flowers.

Seed Orchards(SO)

Although the SPA has manyadvantages, CSOs and/or progeny seed orchards (PSO) are still essential, thecore component in a teak improvement programme. In breeding populations, theCSO/PSOs create successive new breeding and propagation populations with greatercumulative genetic gains. In propagation populations, successive CSO/PSOsproduce larger quantities of seed with greater genetic gains compared with theSPA.

Teak CSOs have long been establishedthroughout the region, e.g. Thailand in 1961 (Boonkird, 1964); India in 1962(Kedharnath and Matthews, 1962); Papua New Guinea in 1963 (Cameron, 1966);Bangladesh in 1979 (Banik, 1993); Myanmar in 1981 (Gyi, 1993), and Indonesia in1983 (Anon, 1993). Little is known about seed production capacity in the seedorchards. In Thailand, the seed production capacity in the CSO was in planningestimated at 250 kg per ha (Hedegart, 1976). When full production was reached(i.e. over 20 years old), the seed production capacity proved considerablylower, about 0.7 (0.2-1.5) kg per ramet (tree), for example 70 (20-150) kg perha during the 5-year observation period (1985-89) at the Mae Gar CSO (Meekaew,1992). Low production capacity of seed in CSOs is also reported from India(Madhya Pradesh), i.e. 0.5-1 kg per ramet (Tewari, 1992). In Nigeria, incontrast, the production capacity of the CSO is very high, i.e. 0.63-6.56 kg perramet or 244-734 (404) kg per ha (Egenti, 1981). This higher production capacityis possibly due to: a) the longer flowering period of the CSO which is about 7months per year (March-September); and b) the greater number of insectpollinators visiting the orchard during the flowering period (Egenti, 1981).Orchards in Nigeria are mostly located in high forest and savannaareas.

Areas of SO and SPArequirements

Based on available data fromThailand, the guideline for estimation of SPA and/or CSO areas for maximumproduction (10 and 70 kg per ha of SPA and CSO, respectively) of seed sufficientfor the 1,000 ha planting programme are shown in Table 3.

Table 3. SPA and CSO areasrequired for 1,000 ha of teak planting programme (Thailand)

Source: Modifiedfrom Wellendorf and Kaosa-ard (1988)

REPRODUCTIVEBIOLOGY

Knowledge of specific reproductivebiology is very important in the formulation of improvement strategies. Thisknowledge includes maturity and flowering, type of flower, flower initiation,development and structure, pollination mechanism, fruit setting, development andripening, etc.

Flowering

Teak starts flowering at 6-8 yearsafter planting. However, the first flowering may be as early as 3-4 years and aslate as 20-25 years. The first flower panicle usually initiates and develop fromthe terminal shoot of a stem axis (Gram and Larsen, 1958; Boonkird, 1964). Thisfirst flowering habit causes a development of the forked stem of this species(Boonkird, 1964). That is, early flowering trees usually have shorter stem bolesthan late flowering trees.

Table 4. Flowering and seedcollection season of teak in selected countries

Source: Kaosa-ard(1995 unpublished data)

Teak flowering starts soon after thegrowth flushing stage, i.e. in the middle of rainy season. The flowering time ofthis species, however, varies depending on the arrival of the of the rainyseason. In the continental South and Southeast Asian region, flowering timeusually starts in June-July and lasts from October-December. The floweringseason of teak within the teak-growing region is shown in Table4.

The flowers occur in a large panicleand each panicle contains 1,200 - 3,700 flowers (Bryndum and Hedegart, 1969) andmay be up to 8,000 flowers as in a case of Papua New Guinea (White, 1991). Theflower is white and small (6-8 mm in diameter) and perfect type, consisting ofsix sepals, six white petals, six stamens and a pistil (Bryndum and Hedegart,1969). The flower opens for only one day; if no pollination occurs it will dropin that evening or in the next morning (Bryndum and Hedegart,1969).

Pollinationtime

Although the flower buds startopening in the early morning, the pollination period begins in late morning andreaches a peak during midday, 11.30-13.00, and then declines thereafter (Bryndumand Hedegart, 1969; Hedegart, 1973). This is due to the light requirement forpollen ripening and receptivity. During this pollination period, the pollen isfully developed and is easily transferred by the pollinators. At the same time,a large quantity of fluid exudes on the stigma for trapping pollen (Hedegart,1973; Siripatanadilok, 1974). The flower usually opens for one day, pollenreceptivity also lasts within that day; where as the pollen viability may be upto 3 days after flowering (Egenti, 1981b). Using the vacuum desiccator storagetechnique pollen viability can be maintained for as long as 24 months and usedsuccessfully in the controlled pollination (Egenti, 1981b).

Pollinationvectors

Teak is a mainly insect-pollinatedspecies but some wind pollination also occurs (Bryndum and Hedegart, 1969;Hedegart, 1973). A series of studies in Thailand and Nigeria showed that thepercentage of fruit setting per flower panicle increases significantly with anincrease in number of visits of pollinators (Hedegart, 1973; Egenti, 1981a).Bees, flies, butterflies and ants appear to be major pollinators. A list ofthese pollinators as identified in Thailand and in Nigeria are shown in Table5.

Table 5. List of species ofteak insect pollinators

Source:Re-identified from Hedegart (1973), Egenti (1981b), Choldumrongkul andHutacharern (1986)

Crossing or selfingspecies

A series of studies on pollinationof teak in Thailand indicated that teak is a cross-pollinating species (Bryndumand Hedegart, 1969; Hedegart, 1973). Under controlled pollination, the highestpercentage of self-compatibility is only 5.5 % as compared with crossing whichis as high as 60 % (Bryndum and Hedegart, 1969; Hedegart, 1973). Moreover, theselfed seeds are smaller in size and lower in viability and germinationpercentages than the crossed seeds (Bryndum and Hedegart, 1969; Hedegart, 1973).However, when germination percentage of routine or open pollinated seed is takeninto account, the proportion of self-pollinated seed to cross pollinated seed ineach seed lot may be as high as 30% (Bryndum and Hedegart, 1969). This is due tothe lack of insects for cross pollination activity. In Papua New Guinea, Cameron(1966) reported similarly that the proportion of selfed seed from openpollinated seed orchards is expected to be very high, based on assumptions thatcross pollinated seeds will occur only through insect activity and observationsthat an early flowering isolated seed orchard tree can produce a quantity ofviable seed. Early results in isozyme studies in Thailand also indicated thatthere is a high possibility of selfing in teak seed orchards (Pers. comm.Suchitra Changtrakul). However further studies on the mating system in teak seedorchards using the isozyme marker technique are beingconducted.

Fruitsetting

Although a massive number of smallflowers occur throughout the flowering period of 4-5 months, only a smallquantity of seed can be collected from each tree. This is especially with treesin plantations, SPA and CSO/PSO where the stem density is relatively high. Aseries of studies in Thailand and Nigeria showed similar results with only 1-2 %(with a range of 0-5 %) of flowers in each panicle successfully developing intofruits (Bryndum and Hedegart, 1969; Hedegart, 1973; Egenti, 1981a). This lowfruit percentage is due primarily to: a) the low proportion of pollinators toflowers; and b) the short flowering and pollination periods of individualflowers. Based on this assumption, the production capacity and germination ofteak seed can be improved through the increase of populations of insectpollinators in the seed sources (SPA, CSO and PSO).

Controlledpollination

Controlled pollination is one of themost important activities in forest tree breeding programmes. The mainobjectives are: a) to maintain breeding populations as many generations aspossible through maintenance of pedigrees; and b) to increase gain throughselection and utilization of both additive and non-additive genetic effects fromspecific crosses. This activity is, however, considered to be a most expensiveand laborious activity. It also requires certain knowledge, equipment andtechniques such as flowering induction, pollen collection, handling and storage,flower isolation, emasculation and/or sterilization, pollination, etc. This isrequired to facilitate and/or to increase fruit setting percentage in thecontrolled pollination work.

With teak, attempts have been madeon controlled pollination, e.g. in India (Kedharnath and Matthews, 1962),Thailand (Keiding, 1966; Bryndum and Hedegart, 1969; Hedegart, 1973), andNigeria (Egenti, 1981a, 1981b). However, full-sib progeny trials of this studyhave yet to be established and/or reported. There are several factors whichlimit the development of controlled pollination technique of this species.Firstly, teak flower is only a day life and its pollination period is also veryshort (2-3 hours a day). Secondly, the emasculation and pollen brushingtechniques as used in Thailand may damage the flower stigma. Low and unreliablefruit setting commonly result. Thirdly, proper techniques for mass pollencollection and storage are urgently required. Finally, proper isolation and/oremasculation techniques of either individual flowers or a whole flower panicleare also required to prevent contamination from both, within and outsideflowers.

GENETICVARIATION

Provenancevariation

Teak occurs naturally in India,Myanmar, Thailand and Lao (along the northern Thai-Lao border) (Kaosa-ard, 1977,1981). In Indonesia (in central and eastern Java and its neighboring islands),the species was long time (>700 years) introduced and through manygenerations of succession and distribution, it has been accepted as one of thenatural sources (Kaosa-ard, 1981, 1986). Due to its wide range of distribution,three main natural populations, i.e. the Indian, the Burmese-Thai-Lao and theinsular (Indonesian) populations, have been grouped according to theirgeographical differences (Hedegart, 1976). Within each population, a number ofsub-populations are also divided such as the "dry interior", the "moist westcoast" and the "semi-moist east coast" sub-populations of the Indian population(Keiding et al., 1986). Apart from natural populations, the species hasbeen introduced since the 1800s and is well acclimatized in many countries inthe tropics (FAO, 1957). Two main "land race" populations, i.e. the "Africanland races" and the "Central American land races", have been grouped in thetesting programmes (Keiding et al., 1986).

Provenance variations in woodquality, growth rate, stem form, seed morphology and germination and othercharacters are substantially reported (Nair and Mukerji, 1960; Hedegart, 1974;Keiding, 1973; Kanchanaburangura, 1976; Keiding et al., 1986; Kaosa-ard,1993, 1993a). A series of international provenance trials (75 provenances and 48field trials) established in the early 1970s clearly demonstrated effects ofprovenances or seed source on growth, stem quality and health of this species(Keiding et al., 1986). It was also shown that local provenances are notalways superior to imported provenances and are mostly at provenance meanlevels. In some cases they are even inferior to the imported provenances(Keiding et al., 1986). Through the provenance (region analysis, theIndonesian provenance is the most attractive provenance in growth and healthperformance. Conversely, the "African land race" performs very poor especiallyin stem quality in all teak planting regions (Keiding et al., 1986). Theprovenance (region matching or breeding zone as recommended by Keiding etal. (1986) is shown in Table 6.

Table 6. Provenance x plantingregion matching of teak

Source: Modifiedfrom Keiding et al. (1986)

Heritability values ofcertain characters at provenance level have been estimated to understand teakgenetic parameters. Among the observed characters, diameter growth (dbh) andstem straightness and clear bole, persistence of stem axis and flowering habit(early and/or late flowering) are strongly inherited (i.e. h² (0.70)in this species (Harahap and Soerinegara, 1977; Keiding et al., 1986;Kaosa-ard, 1993). Based on this information, it is clearly indicated that gainsof these characters can be largely improved through provenanceselection.

Progeny/clonalvariations

Although teak breeding programmeshave operated in many countries, little information about genetic variations atprogeny/clonal levels is available. This is due to a lack of progeny and clonaltests at the initial stage of the programme. The oldest teak open pollinatedprogeny test with 21 families was established in 1966 in Tanzania (Person,1971). At 21 year age, the trial showed that diameter growth (dbh) is the onlycharacter which can be detected for genetic variation (Madoffe, 1984) inWellendorf and Kaosa-ard (1986). Similarly, an early result of open pollinatedprogeny test (125 families) in Indonesia indicated significant variation only indiameter growth (dbh) (with h² = 0.36) of the species (Hardiyantoet al., 1992). Based on the Tanzanian information, Wellendorf andKaosa-ard (1986) demonstrated that a gain in volume production of the plantationcan be improved by 15 % through the 25 % backward or familyselection.

In contrast to results of progenytests, height growth variation is found to be very significant in clonal tests(Suksileung, 1974; Wellendorf and Kaosa-ard, 1986). Wellendorf and Kaosa-ard(1986) showed an overall clone mean heritability value over two tested sites("moist" and "dry" sites) in Thailand for height growth of 0.65. There is nostrong clone (site interaction within these two different sites. It was alsodemonstrated that a gain in height growth can be improved by 5 % if 25 % of thebest clones are selected for the clonal planting programme (Wellendorf andKaosa-ard, 1986).

CLONALPROPAGATION

Clonal propagation is very essentialin the teak breeding and propagation programme. Soon after selection, plus treesare propagated for the establishment of breeding and propagation populations,e.g. clonal test, breeding orchard, clone bank, clonal seed orchard. The mostpractical technique for propagation of mature teak trees is budding (e.g. stumpbudding). Under favorable time and nursery conditions, the success of buddingcan be as high as 100 %. Although teak budding can be done throughout the year,the most suitable time is during the bud break period which is in March-April inthe continental regions. With skilled workers, about 100 plants can bepropagated per man day. One major disadvantage of using the budding technique isthat there are two genotypes (stock and scion) in one plant. Hence, within clonevariation in certain characters such as growth and flowering, as shown in clonaltests may be due largely to rootstock and/or rootstock (scion (clone) effects.Moreover a few percentages of stock scion incompatibility in budded plants havebeen observed in 20-25 year old teak clonal seed orchards inThailand.

To avoid such problems, tissueculture (shoot tip culture) production is another option for mass clonalpropagation of teak plus trees or clones. This technique has been developed andcommercially used in Thailand (Kaosa-ard et al., 1987; Kaosa-ard andApavatjarut, 1989). The cost of plantlet production from this technique is notas high as that from improved seed (CSO) (Kaosa-ard, 1990). This is especiallyso when the cost of improved seed (which includes cost of CSO establishment andmaintenance, first flowering and seed production age, seed production capacityand seed production period) and nursery production (e.g. plant percentage) aretaken into account. The tissue culture technique for teak clonal propagation hasbeen described elsewhere (Kaosa-ard et al., 1987; Kaosa-ard andApavatjarut, 1988, 1989).

OPTIONS IN TEAKIMPROVEMENT

It is seen that the key elements ofa tree improvement are the gene resource population, breeding population,propagation population and wood production population. Roles, structures andfunctions of these populations in the teak improvement programme arediscussed.

Gene resourcepopulations

Three main types of teak generesource populations are classified, according to their genetic structures, inthis section. These types are: a) natural populations; b) plantation populations(within the teak region); and c) "land race" or exoticpopulations.

Naturalpopulations

A natural population is the mostdiverse type of gene resource population. This type must be kept and maintainedfor its genetic diversity as long as possible. As mentioned previously, thereare three identified main regional populations of natural teak. These regionalpopulations include the Indian peninsular population, the continental SoutheastAsian (Myanmar-Thai-Laos) population and the insular (Indonesian) population(Hedegart, 1976). Within each regional population, a number of sub-regionalpopulations (Table 7) and local populations (provenances) are also identified,e.g. through international and local provenance testingprogrammes.

Table 7. Proposed regional andsub-regional populations of natural teak

Sources: Modifiedfrom Hedegart (1976) and Keiding et al. (1986)

Although natural populations arevery important in the improvement programme these populations are in theendangered stage throughout the teak bearing region. The population sizes (e.g.the teak forest areas) are decreasing rapidly. This is due to several factorssuch as encroachment of landless farmers, land settlement allocation, road anddam constructions, etc. Genetic structures of the remaining populations are alsodegraded and fragmented, mostly due to uncontrolled logging. In Thailand forexample the teak forest area decreased almost 50 % during the period 1956-1982.That is from 20,000 km² in 1956 (Loetsch, 1958) to 11,000km² in 1982 (Royal Forest Department, 1989) at the rate of 350km² per year. This estimate is based on the fact that about 44 % ofthe mixed deciduous forest (MDF) in the North is teak forest (Loetsch, 1958). In1989, the Government policy on imposing a logging ban was implemented. As aresult, a small part of the teak forest, i.e. 1,700 km² (which isequivalent to 3,940 km² of the MDF area), was allocated in protectedareas such as national parks and wildlife sanctuaries (Brockelman and Baimai,1993). The major part of this forest area, which has been left withoutmanagement, is being degraded and encroached. In Indonesia, which is anothercase, most of natural teak forests have been managed and converted into purestands and plantations (Kaosa-ard, 1986; Katasubrato, 1992). As a result, thegenetic structure of this population must be more uniform (e.g. throughselection and thinning) than the Indian and the continentalpopulations.

Regional and sub-regional insitu gene conservation populations are urgently need protection andmaintenance for long term breeding, securing valuable genetic diversity andfunctions.

Plantationpopulations

While the natural populations arebeing depleted throughout the region, the plantation population is converselyincreasing steadily. This is especially so in India, Indonesia and Thailandwhere teak is a high priority planting species. These populations have become tobe major gene resource populations in the improvement programme. In provenancestudies, it is clearly shown that plantation sources (provenances) performbetter, especially in growth, than natural sources (Keiding et al., 1986;Kaosa-ard, 1993). Among regional and sub-regional provenances, Indonesianprovenances from plantations grow faster than other provenances, especiallywhere the provenance x region matching is concerned (Keiding et al.,1986). Within the Thai sub-region, it is also clearly shown that plantation seedsource is, in all cases, superior to natural seed sources (Keiding etal., 1986; Kaosa-ard, 1993). The superiority of these plantationpopulations, especially in growth and stem quality, is possibly due to selectionand domestication, e.g. selective thinning. Although plantation populationscontribute higher gain at the initial stage of selection, natural populationsare however very important for long term breeding and selection programme. Thearea of teak plantation within which populations within the region are listed inTable 8.

Table 8. Regional andsub-regional plantation populations to be used as gene resourcepopulations

Land racepopulation

A "land race" population is onemostly developed from a small quantity of seed or from a small sample of trees,e.g. pilot plantation, provenance trial and species trial. As a result thispopulation is the least genetically diverse population among the gene resourcepopulations.

Teak has been successfullyintroduced in countries since the 1800s (FAO, 1957). Through many generations ofdomestication, teak has adapted e.g. at least for survival, and developed into a"land race" species in the regions and/or sub-regions (Table 9) for example, theCentral American and the African land races. Due to successive generations andselections these "land race" populations have become major sources of geneticmaterial in the regional and sub-regional breeding programmes.

Breedingpopulation

The breeding population is a set ofindividuals (plus trees or clones) of desirable commercial characters. At theinitial stage, these individuals are selected from the gene resource populationswhereas, in the advanced generations stage they are mostly selected from theexisting breeding populations. The breeding population is established mainly tocreate new individuals of better gain for new breeding and propagationpopulations. Generally, a set of breeding populations consists of breedingorchard, clonal test and progeny test.

Table 9. Regional andsub-regional teak growing as exotic and/or land racespecies

(Area greater than 500 ha asreported in 1990)

Source: * FAO(1957) and Kaosa-ard (1986), **Hougs (unpublished)

Although several breeding methodshave been developed, i.e. to maximize gain and to maintain genetic variabilityof the breeding population, few methods are being used in the teak programme,e.g. simple recurrent selection (SRS), simple mass selection (SMS), simplerecurrent selection for general combining ability (SRS-GCA) see Figures 2 and 3and selection and mass vegetative propagation (MVP). These methods may beoperated for a short term seed production or propagation programme or for a longterm breeding and propagation programme. In a long term programme, it may beoperated as a basic single population programme or as a multiple populationsprogramme (Wellendorf and Kaosa-ard, 1986). However, these teak breeding systemsare managed and operated based on the assumption that: a) there is no controlledpollination; b) an open pollinated progeny test at the initial stage is notfeasible; and c) mass clonal propagation, i.e. through tissue culture andseedling cutting is applicable.

Figure2. Simple recurrent selection in a teak improvementprogramme

It is well accepted that controlledpollination is the most difficulty part in the breeding programme. As for teak,the pollination technique, at this stage, is still not feasible for a full-sibprogeny testing programme. It has been estimated that the maximum capacity ofcontrolled pollination, as developed in Thailand, is 80 flowers per man day(Hedegart, 1976). Of this, only 16 flowers successfully develop into fruits forprogeny testing. This is based on the success of hand pollination of 20 %(Hedegart, 1973). This controlled pollination technique consists ofemasculation, isolation, pollen collection and hand pollination of individualflowers. Secondly, the amount of seed collected from a plus tree is generallytoo small and mostly not sufficient for progeny testing. This is especially inthe Indian and Continental Southeast Asian Region. Finally, the seed germinationcapacity is low and, hence, the plant percentage in nursery is very low, i.e.5-10 %. Based on these biological constraints, it has been estimated that about100 seedlings can be obtained from 5,000 hand pollinated flowers for thefull-sib progeny test.

Single breedingpopulation

Simple Recurrent Selection (SRS). ASRS, which is the simplest and cheapest breeding method, is widely practised ina short term seed production programme, e.g. in Thailand, India and Indonesia.It involves only selection and establishment of a seed production population,e.g. SPA and CSO (Figure 2). The SPA is a converted natural stand or plantationfor seed production purpose. In this conversion, all phenotypically inferiortrees are removed and the area is managed for seed collection. The CSO is aclonal plantation which is designed and managed for seed production purpose.Clones used are from budding of plus trees. Hence, the major difference betweenSPA and CSO is that selection intensity of seed trees in the SPA is lower thanplus trees (clones) in the CSO, i.e. 1:6-1:10 for SPA and 1:100-1:1,000 for CSO.In this method, clonal and progeny tests are not essential. This method is mostsuitable for short term seed production programme.

Figure3. Recurrent selection for general combining ability in the teak breedingprogramme

Recurrent Selections for GeneralCombining Ability (GCA)

This method is a modified SRS. Ineach breeding or planting zone, it includes a set of CSO, a set of clonal test(CT) of similar clones to the CSO and a set of open pollinated progeny test(OP-PT) if plus tree seed is adequate for the testing programme (Figure3).

The result of this testing programmeis used as a guideline for the following operations:

1. Selection of bestclones (e.g. for 25 %) for clonal planting programmes, i.e. through the tissueculture propagation technique;

2. Thinning of CSO and leaving about50 % of best clones, which have shown higher breeding values in the CT, for seedproduction;

3. Selection of best individualsfrom both within and among families in OP-PT for a new breeding population;and

4.

An initial clone set used in thisprogramme is 50-100 clones for the establishment of CT and CSO. Similarly,progenies of these clones are allocated in the OP-PT programme. After the first(clonal) thinning, about 25-50 best clones are left for seed production. Seedfrom these clones are also used for OP-PT in the new breedingpopulation.

Multiple breedingpopulations

The main purpose of a long termbreeding programme is to generate cumulatively improved plant material as wellas to create genetic diversity of the breeding population for as manygenerations as possible. Multiple breeding populations, designed to managelarger breeding populations, i.e. for larger genetic diversity and gain, havebeen widely developed. In this programme, a large breeding population(consisting of 200-500 individuals or clones) are divided into a number ofsmaller breeding populations (e.g. sub-lines or sub-populations) for thebreeding operation. There are many breeding systems which have been developedfor this multiple breeding populations, such as sub-line breeding system,replicate population breeding system, multiple population breeding system etc.(Namkoong et al., 1980, 1988; Barns, 1984; Wellendorf and Kaosa-ard,1986; Nikles, 1992). The multiple population breeding system, which seems to bevery popular in tropical tree breeding (Barns, 1984; Wellendorf and Kaosa-ard,1986; Nikles, 1992) has been recommended and used in the teak breeding programme(Wellendorf and Kaosa-ard, 1986).

Multiple population breedingsystem

A concept of multiple populationbreeding system is to divide a large breeding population into a number ofsub-populations for different breeding directions and objectives, such as fordifferent breeding/planting zones, environmental adaptability and differentproducts (growth, stem quality and wood quality) (Namkoong et al., 1980,1988).

With teak, the multiple populationbreeding system has been proposed and operated in Thailand (Wellendorf andKaosa-ard, 1986). Apart from genetic gain and variability, the main objective ofthis breeding system is to create the improved material (clones and seed) fordifferent potential planting zones, e.g. from dry to moist plantingzones.

In this system, a number ofsub-populations are created in each planting zone. The number of sub-populationsvaries depending on availability of resources, genetic diversity, environmentalcondition and product utilization. In Thailand, for example, 5 sub-populationsand 3 breeding and planting zones (i.e. dry, medium and moist zones) have beenproposed in the system (Wellendorf and Kaosa-ard, 1986). Each sub-populationconsists of 100 individuals (clones) and, hence, 500 initial plus trees (clones)are required in this programme. The sub-populations are managed separately foras many generations as possible. These sub-populations may be managed atdifferent breeding directions at the beginning, e.g. for wood quality, for broadrange of environmental condition, etc. If inbreeding occurs, the inbredsub-populations will be enriched by adding and/or replacing with some new clonesselected from the backup gene resources.

Within each breeding sub-population,a breeding orchard (BO), a clonal test (CT) and a open pollinated progeny test(OP-PT) (if available) of the same set of 100 clones are established (Figure 4and Figure 5). A production clonal seed orchard (CSO) of these clones is alsoestablished in the propagation population section. Clonal and progeny tests arefirst evaluated at 10-12 years. Their results, e.g. parent offspring regressionfrom the clonal/progeny tests or clonal performance alone from the clonal test,are used as the guide for clonal thinning (e.g. 50 % thinning) in the BO (andalso in the production CSO). Remaining clones (e.g. 50 clones) which are higherin breeding values are left for random mating. Thereafter, their OP-PT of 50families is created as a part of the new generation breedingsub-population.

The clonal and progeny tests arere-evaluated (i.e. 10-12 years after the first evaluation), the best clones inthe CT and best parents (clones) in the CSO are selected for mass clonal andseed propagation. Wellendorf and Kaosa-ard (1986) estimated that if 25 bestparents are left for seed production, the genetic value of plant materialsproduced from this 25 clone orchard will be 15 % higher than the average geneticvalue of the initial 100 clones.

Figure 4. Structural diagram of a sub-population in the teak multiplepopulation breeding system

Figure 5. Outline procedure of an evaluation, selection and propagation in asub-population of teak multiple population breeding system

Propagationpopulation

The propagation population isestablished and managed for mass production of seed and propagules (e.g. buds,shoots, coppice, meristems). This population is strictly established by usingselected plus trees and/or clones from the gene resource populations or derivedfrom the breeding populations, e.g. progeny and clonal trials. In the long termbreeding programme, new plus trees of better genetic combination and gain arecreated throughout the successive generations of the breeding populations. Thepropagation populations are therefore considerably of short term and dynamicprogrammes.

A teak propagation populationincludes seed production areas and seed orchards for seed production, clone bankand stock plants for propagule or clonal production e.g. scions, buds andshoots.

RESEARCH ANDDEVELOPMENT

The major constraints in teakimprovement strategies are low seed production, low plant percentage in nurseryproduction and difficulty in controlled pollination. Supportive research anddevelopment in these areas are really required.

Research on seedproduction

Priority research on seed productionshould be as follows:

• Effects of environmental factors, e.g. climate prior to and during flowering period, soil fertility and fertilizer application, stand age and density, etc., on flowering and fruit setting.
• Flowering biology in relation to seed production, e.g. flower initiation and development, pollination ecology, fruit growth and development, etc.
• Effects of leaf defoliators, e.g. Hyblaea puera, on flowering and seed productivity.
• Effects of insects feeding on flowers and young fruits, such as Pagyda salvalis on seed production.
• Effects of hormones and other related substances on flowering induction and seed production.
• Effects of pollination insects on seed production.

Research on nurseryproduction

Research and development prioritieson nursery production:

• Physiological dormancy of teak seed.
• All existing seed pre-sowing treatment techniques are revised and/or retested. Promising techniques be further developed for large scale operation programme, e.g. 0.5 ton of seed per treatment lot.
• Nursery techniques, as transplanting and lining techniques, i.e. to reduce growth competition and to improve uniformity of nursery seedlings.

Research onpollination

The main objectives are to operatecontrolled pollination and to expedite generations of breeding population forbetter cumulative gain. Research priorities are:

• Pollen collection, handling and storage.
• Mass isolation and emasculation techniques.
• Flowering induction techniques, e.g. application of gibberellic acid (GA), growth retardants such as Paclobutrazole and fertilizers such as mono-potassium sulphate (0-52-34), etc.
• Development of in-house breeding orchard techniques to facilitate breeding operation, e.g. controlled pollination.

The strong current interest invegetative propagation is justified by the outlined difficulties with seed andnursery production. An effective application of tissue culture and/orsprout-cutting of seedlings will support testing and selection in the breedingpopulations and may be an option for mass clonal propagation for the clonalplanting programme. The possibility of mass production of tested individualclones will generally lift the possible performance level of material reachingplantation forestry in the form of clone mixtures in sets of, say 25clones.

Other research urgently needed inassociation with the teak improvement programme is of wood quality studies.Environmental as well as genetic investigations into variation in those woodproperties which are of economic interest should be initiated. Based on thesefindings it will then be possible to judge if specific wood properties should beincluded among the breeding objectives.

REFERENCES

Anon. 1956. India In "CountryReports on Teak Forestry" FAO, Rome 21-48 pp.

Anon. 1993. Teak in Indonesia. In"Teak in Asia" Technical Document 1, GCP/RAS/I34/ASB, FORSPA Publication 4,FAO-RAPA 35-40 pp.

Banik, R.L. 1993. Teak inBangladesh. In "Teak in Asia" Technical Document GCP/RAS/I34/ASB, FORSPAPublication 4 FAO-RAPA 1-10 pp.

Barnes, R.D. 1984. A multiplepopulation breeding strategy for Zimbabwe. In. "Provenance and GeneticImprovement Strategies in Tropical Forest Trees". Edited by R.D. Barnes and G.L.Gibson, 619-632 pp.

Boonkird, S. 1964. Progress reporton the first teak tree-show in Thailand. Nat. His. Bull. Siam. Soc. 20:243-256.

Brockelman, W.Y. and V. Baimai 1993.Conservation of bio-diversity and protected area management in Thailand. Proc.of Skill Transfer Workshop conducted by MIDAS Agronomic Co. Ltd., for WorldBank/GEF/Pre-investment Study on Conservation Area Protection, Management andDevelopment Project, Bangkok.

Bryndum, K. and T. Hedegart, 1969.Pollination of teak (Tectona grandis Linn. f.). Silv. Genet. 18: 77-80pp.

Cameron, A.L. 1966. Geneticimprovement of teak in New Guinea. Aust. For. 30:76-87 pp.

Choldumrongkul, S. and C.Hutacharern 1986. The relationship between the flower development of teak andits associated insects. Jour. Nat. Res. Coun. of Thailand 18: 54-52pp.

Egenti, L.C. 1981. Aspect ofpollination ecology of teak (Tectona grandis Linn. f.) in Nigeria:Pollinators and fruit production. In "Proceedings of the Symposium on FloweringPhysiology" XVII IUFRO World Congress, Kyoto, Japan. 27-30 pp.

Egenti, L.C. 1981a. Aspect ofpollination ecology of teak (Tectona grandis Linn. f.) in Nigeria:Flowering and insect dynamics. In "Proceedings of the Symposium on FloweringPhysiology" XVII IUFRO World Congress, Kyoto, Japan. 17-20 pp.

Egenti, L.C. 1981b. Aspect ofpollination ecology of teak (Tectona grandis Linn. f.) in Nigeria:Viability of reproductive units. In "Proceedings of the Symposium on FloweringPhysiology" XVII IUFRO World Congress, Kyoto, Japan. 21-26 pp.

FAO 1957. Report on teak growingunder exotic conditions. FAO/TSC-57/3, FAO Rome.

Gartner, I.C. 1956. Indonesia InCountry Reports on Teak forestry FAO, Rome 49-105 pp.

Gram, K. and S.C. Larsen, 1958. Theflowering of teak (Tectona grandis Linn. f.) in aspects of tree breeding.Nat. His. Bull. Siam. Soc. 19: 1-6 pp.

Gyi, K.K. 1972. An Investigation ofFactors relevant to Development of Teak Plantation in South East Asia withParticular Reference to Burma. M.Sc. Thesis, Australian National University,Canberra Australia.

Gyi, K.K. 1993. Teak in Myanmar. In"Teak in Asia" Technical Document GCP/RAS/I34/ASB, FORSPA Publication 4,FAO-RAPA, 51-62 pp.

Harahap, R.N. and I. Soerinegara,1977. Heritability of some characters in teak. In Proc. "The Third WorldConsultation on Forest Tree Breeding" Vol 2: IUFRO/CSIRO,Canberra.

Hardiyanto, E.B., Sunyoto, O.H.Soeseno and M. Naiem 1992. Early performance of teak (Tectona grandisLinn. f.). In "One Century of Sustainable Forest Management with SpecialReference to Teak in Java". Proc. International Symposium on Sustainable ForestManagement, Yogyakarta, Indonesia. 177-180 pp.

Hedegart, T. 1973. Pollination ofteak (Tectona grandis Linn. f.). Silv. Genet. 22 (4)

Hedegart, T. 1974. The TeakImprovement Centre: Ten years after initiation. Vanasarn 32:34-356pp.

Hedegart, T. 1976. Breeding system,variation and genetic improvement of teak (Tectona grandis Linn. f.). In"Tropical Trees" Edited by J. Burley and B.T. Styles, Linnean Soc. Symp. Ser.No. 2: 109-123 pp. Academic Press, London.

Kanchanaburangura, C. 1976. Teak(Tectona grandis Linn. f.) Seedlings and Provenance Variation M.Sc.Thesis, Australian National University, Australia. 216 p.

Kaosa-ard, A. 1977. PhysiologicalStudies on Sprouting of Teak (Tectona grandis Linn. f.) Planting Stumps.Ph.D. Thesis Australian National University, Canberra Australia 370p.

Kaosa-ard, A. 1979. Summary resultsof research on teak seed production. In Teak Seed Centre, Annual Report No.2.

Kaosa-ard, A. 1981. Teak Its naturaldistribution and related factors. Nat. His. Bull. Siam. Soc. 29:55-74.

Kaosa-ard, A. 1986. Teak in ASEAN: ASurvey Report. ASEAN CANADA Forest Tree Seed Centre, p.60.

Kaosa-ard, A. 1986. Teak (Tectonagrandis Linn. f.) nursery with special reference to Thailand. DANIDA ForestSeed Centre Seed Leaflet No. 4A 42 p.

Kaosa-ard, A. 1993. Teakinternational provenance trials I. Growth and stem quality. In Proceedings "50thYear of Huay Tak Teak Plantation: Teak Seminar" 113-129 pp.

Kaosa-ard, A. 1993a. Teakinternational provenance trials I. Wood production and quality. In Proceedings"50th Year of Huay Tak Teak Plantation: Teak Seminar". 294-312pp.

Kaosa-ard, A., P. Apavatjrut and T.Paratasilpin 1987 Teak tissue culture. In Proceedings of His Majesty's FifthCycle Commemorative Conference of USAID Science Research 201-206pp.

Kaosa-ard, A. and Apavatjrut, P.1988. Teak tissue culture: Rooting and transplanting techniques. InBiotechnology Conference, Washington D.C.

Kaosa-ard, A. and Apavatjrut, P.1989. Teak (Tectona grandis Linn. f.) tissue culture. In RegionalSymposium on Recent Research Development in Tree Plantation for Humid and Subhumid Tropics of Asia, in Malaysia, June 5-9, 1989.

Kaosa-ard, M. 1990. Teak TissueCulture: Cost Analysis Report RFD/CMU/PSTC 1990 26p.

Katasubrato, Y. 1992. The history ofsustainable management in Indonesia, the case of teak. In "One Century ofSustainable Forest Management with Special Reference to Teak in Java" 3-39pp.

Keiding, H. 1966. Aim and prospectsof teak breeding in Thailand. Nat. His. Bull. Siam. Soc. 21(1&2).

Keiding, H., H. Wellendorf and E.B.Lauridsen 1986. Evaluation of an International Teak Provenance Trials. DANIDAForest Seed Centre, p. 81.

Kedharnath, S. and J.D. Matthews,1962. Improvement of teak by selection and breeding. Ind. For. 88:277-284.

Kumaravelu, G. 1993. Teak in India.In "Teak in Asia" Technical Document GCP/RAS/134/ASB, FORSPA Publication 4,FAO/RAPA 51-62 pp.

Loetsch, F. 1958. Report to theGovernment of Thailand on Forest Inventory of the Northern Teak BearingProvinces. FAO Report No. 895, Rome.

Meekaew, P. 1992. Genetic Variationin Growth, Seed Production and Foliar Nutrients of Teak. M.Sc. Thesis, Facultyof Forestry, Kasesart University, Bangkok, Thailand 73p.

Namkoong, G., R.D. Barns and J.Burley 1980. A philosophy of breeding strategy for tropical forest trees.Tropical Tree Papers No.16, Univ. Oxford. 67 p.

Namkoong, G.; Kang, H.C., andBrouard, J.S. 1988. Tree Breeding Principles and Strategies. In Monographs onTheoretical and Applied Genetics 11, Springier-Verlag 180p.

Nair, K.R. and Mukerji, H.K. 1960. Astatistical study of the variability of physical and mechanical properties ofteak grown at different localities of India and Burma and the effects ofvariability on the choice of sampling plan. Ind. For. Rec.1:(1).

Nikles, K.G. 1992. Conservation anduse of genetic diversity in improvement programmes with industrial forest treespecies. In "Proc. of the Regional Symposium on Recent Advances in Mass ClonalPropagation of Forest Tree for Plantation Programmes" RAS/91/004 Field DocumentNo. 4 83-109 pp.

Person, A. 1971. Observations from aprogeny trials of at Longuza. Tanzania Silv. Res. Note, No. 24.

Phengduang, V. 1993. Teak in LaosPDR. In "Teak in Asia" Technical Document GCP/RAS/I34/ASB, FORSPA Publication 4,FAO-RAPA 41-50 pp.

Royal Forest Department (RFD), 1989.Forestry Statistics of Thailand.

Siripatanadilok, S. 1974.Development of teak flower (Tectona grandis Linn. f.). For. Res.Bull. No. 31, Fac. Forestry, KU, Thailand 68p.

Srimathi, R.A. and C.J.S.K. Emmanuel1986. Jour. Trop. For. 2: 256-268.

Suangtho, V. 1980. FactorsControlling teak (Tectona grandis Linn. f.) Seed Germination and TheirImportance to Thailand. M.S. Thesis Australian National University, Canberra,Australia.

Suksileung, P. 1975. Clonalvariation and inheritance in growth characteristics of teak (Tectonagrandis Linn. f.). M.Sc. Thesis, Fac. Forestry, Kasetsart University,Thailand 45p.

Tewari, D.N. 1992. A Monograph onTeak (Tectona grandis Linn. f.), Int. Nat. Book Dist. Dehra Dun,479p.

Wellendorf, H. and A. Kaosa-ard,1988. Teak Improvement Strategy in Thailand. Forest Tree Improvement No.21,p.43.

White, K.J. 1991. Teak: Some aspectsof research and development. FAO/RAPA 1991/17 Bangkok.

Commercialmicropropagation of teak in Thailand - Dr. PaiboolyaGavinlertvatana

PaiboolyaGavinlertvatana

Thai Orchids Lab Co., Ltd.,Bangkok

Agenetically superior teak (plus tree) is carefully preserved. Lampang,Thailand.

ABSTRACT

Elite clones of teak were selectedby the Royal Forest Department. Meristematic tissues from these plus trees wereexcised from the mother trees, surface sterilized and cultured onto definedaseptic medium. When the tissues multiplied to a desirable quantity, they weresuccessfully transplanted into a soil mix medium and after 2-3 months weretransferred to the field. Growth of tissue cultured plants appeared to be fasterand more uniform than those from seed or stumps derived from seeds. Tissuecultured plants furthermore have fewer branches and side shoots than seed basedplants. Over 500,000 tissue cultured plants have been field established in thepast four years. Some planted nine years ago have shown very satisfactorygrowth. Volume and income projections of tissue cultured plantations arecalculated.

Key words: Tectonagrandis, Thailand, clones, micropropagation, commercial tissueculture.

INTRODUCTION

Teak (Tectona grandis) isindigenous to continental Asia and is confined to the moist and dry mixeddeciduous forest below 1,000 m altitude in India, Myanmar, Thailand and Lao(FAO, 1991). The teak forest has been diminishing year after year. For example,Thailand had nearly 100 million rai (16 million ha) of teak forest before, butnow has less than 1 million rai (160,000 ha). Teak wood was the main export item35-50 years ago, but now Thailand has become a major importer of teak. The rapiddecline of teak forest elsewhere has been very obvious due to the high demand ofteak wood which is reflected in the ever increasing price. Teak is widelyplanted between the latitudes of 28°N and 18°S in Asia and the PacificRegion, as well as in Africa and Latin America. Indonesia has established teakplantations over 1,000,000 hectares. Planting teak in the tropical evergreenforest zones is getting popular, where teak does not naturallyexist.

TEAKPLANTATIONS

Teak has been artificiallyregenerated by: direct sowing of seed, seed broadcasting, seedling transplantand stumps (derived from seed). Traditionally, seed was collected from plustrees, but unfortunately these plus trees have become rare due to heavy fellingpractices in the past. Though seed orchards have been promoted recently, theamount of seed produced is still below demand. Consequently, seed has beencollected from genetically inferior parent trees, and this guides the increaseof poor quality teak in plantations.

Clone planting was not common up tothe recent past because clonal cultivation materials were very difficult toobtain. Budding, grafting and cutting techniques have been successfullydeveloped but applied only to a limited extent. These methods have been employedto multiply plus trees for seed orchards. The successful development oflarge-scale commercial tissue culturing of teak in Thailand in the past 3-4years has opened up new horizons for clonal plantations of teak in theRegion.

MICROPROPAGATION (Tissueculture)

Laboratories in India, Indonesia andThailand have reported tissue culturing of teak with various degrees of success.Gupta, et al. (1979) reported multiple shoot formation from excisedseedling explants and from 100-year old trees. Small quantities of some 50plants were obtained from tissues excised from mature trees. Noerhadi andWirjodarmodjo (1980) reported research on teak tissue culture in Indonesia.Kaosa-ard (1990) reported successful development of teak tissue culture inThailand.

Field planting has also beenreported, but to a limited extent. Mascarenhus et al. (1988) observedfield data from teak tissue cultured plants in India, while Kaosa-ard observedsatisfactory field data from tissue cultured plants planted in 1986. ThaiOrchids Lab Co., Ltd. in cooperation with the Royal Forest Department andChiangmai University has successfully developed tissue culture techniques frommature teak trees at a commercial scale.

COMMERCIALMICROPROPAGATION

Selection of elite clones:The Royal Forest Department, Thailand, has made selections of elite clonesfrom various forests over the country in the past 30 years. Selection criteria,locations of the trees and their characteristics were systematically recorded.Clones of selected trees were made by grafting and these were planted in germplasm plots; to the present, 480 elite teak clones have been selected. Table 1illustrates examples of those elite trees.

Table 1. Examples of elite teakclones in Thailand

Source:Royal Forest Department, Thailand

Tissue cultureprocedure: Shoot tips and lateral buds of mature selected trees areexcised, surface sterilized and cultured onto the defined aseptic medium (Photo1). After explants are free of microorganisms and become established, tissueswere then cultured on a multiplier medium to speed up the multiplication rate(Photo 2). Shoots are excised and rooted on the rooting medium and thentransplanted into a soil mix medium in the nursery (Photo 3). Plantlets grown toa height of 25-30 cms (Photo 4) are ready for field planting.

PERFORMANCE OF TISSUE CULTUREDPLANTS

Field planting: Tissuecultured plants are planted in the traditional manner of transplantingseedlings. A hole of 30-50 cm square, filled with compost and topsoil isrecommended. The spacing (2 to 4 meters between rows and between plants (isnormally practiced in Thailand. Trees are planted in the early rainy season(late April) with irrigation supplement during the dry season (October toFebruary). Fertilizer is given 1-2 times a year. Pest management and weedcontrol are applied when necessary (Photo 5).

Growth: Tissuecultured plants grow rapidly and uniformly in suitable conditions, the girthgrowth is around 15 cm (gbh) annually. Photo 6 shows plants 4.5 months old;Photo 7 plants are 9 months old with notable uniformity; Photo 8 shows 1 yearold plants of average 15 cm gbh. Photo 9 shows plants 1 year and 5 months oldwith average gbh 21 cm and the uniformity is almost perfect; Photo 10 shows 3.6years old tissue cultured teak of average 39 cm gbh; Photo 11 shows 5 year oldtrees and Photo 12 is 9 years old. The 5 and 9 years old trees are of limitednumber and are in natural environment. Their growth rates are 50 cm and 68 cmgbh respectively which are quite acceptable, but still slower compared with wellmanaged plantations.

PROSPECTS OF COMMERCIAL SCALETEAK MICROPROPAGATION

Teak plants from tissue cultureselect parent trees have been proven on the average to grow faster and be moreuniform than those from seed. They clearly show, and demonstrate commercialvalues, of at least two advantages:

Yield benefit: It isestimated that at least 25-30 % higher yield is be obtained by using selectparent tissue cultured plants. At 15 years rotation, a simple comparison betweenplants from select tissue culture parents and plants from seed is shown in Table2.

Table 2. Comparison of expectedyields and incomes: tissue culture versus seed

The expected income at 15 yearsusing tissue cultured plants is US$168,000 per hectare whereas the income ofplants from seed is US$79,800 (50,400 + 29,400), a difference of US$ 88,200. Inother words, the economic gain using tissue cultured plants over those fromseeds is US$88,200 per hectare, while the investment costs of clonal materialsis only US$315 more than from seed plants.

Management benefit:Tissue cultured plants grow straight with fewer branches and require less labourfor pruning. In addition, as tissue cultured plants grow uniformly, plantationmanagement is easier.

REFERENCES

Mascarenhus A.F., Khuspe, S.S.,Gupta, R.S. and Khan, B.M. 1988. Potential of Cell Culture in PlantationForestry Programmes. In: Genetic Manipulation of Woody Plants. Plenum Press, NewYork.

Noerhadi, E. and Wirjodarmodjo.1980. Vegetative Propagation of Tectona grandis and Pinus merkusii Using TissueCulture. Duta Ramba 6 (42) Inst. of Technology, Bandung,Indonesia.

Kaosa-ard, A. 1991. Country Reportof Teak in Thailand. China/ESCAP/FAO Regional Seminar on Teak. Guangzhou,China.

White, K.J. 1991. Teak: Some Aspectsof Research and Development. RAPA Publication 1991/17. FAO, Regional Office forAsia and the Pacific, FAO, Bangkok.

Photo1. Shoot tips from mature elite clones of teak cultured onto a defined asepticmedium.

Photo2. Multiplying stage of tissue cultured teak.

Photo3. Tissue cultured plantlets were transplanted into a soil-mixmedium

Photo4. Tissue cultured teak plants, 25-30 cm tall.

Photo5. Field planting of tissue cultured teak plants, Thailand

Photo6. Tissue cultured teak plants, 4.5 months old.

Photo7. Tissue cultured plants, 9 months old.

Photo8. Tissue cultured plants, 1 year old.

Photo9. Tissue cultured plants, 1 year and 5 months old.

Photo10. Tissue cultured plants, 3 years and 6 months old.

Photo11. Tissue cultured plants, 5 years old.

Photo12. Tissue cultured plants, 9 years old.

Silvicultural problems in management of teak plantations - Mr. K.C.Chacko

K.C.Chacko

Kerala Forest ResearchInstitute

Peechi 680 653,India

Alarge scale teak plantation on a hill in West Bengal State,India

ABSTRACT

Teak is the most preferred hardwoodspecies in tropical plantation forestry. Teak plantation technology under lowinput is well-known; however, a system of quality control is lacking. At thesame time, performance of plantations under high input management remainsunder-investigated. The scarcity of superior propagules, delayed planting, andsub-optimal after-care have adversely affected the productivity of plantationsin the government sector in India. On the other hand, overenthusiasm for highinputs in terms of fertilization and irrigation, especially in the privatesector, might lead to increased damage by pests and diseases, and low prices.The fundamental principles guiding site selection are often ignored especiallyin the private commercial sector. The information on underplanting and mixedplanting is not adequate or encouraging enough to provide guidelines forestablishment of polyculture teak plantations. The paper attempts to discussvarious issues involved in teak plantation management and suggests alternativesfor ensuring quality.

Key words: Tectonagrandis, India, plantations, quality control, inspection,research.

INTRODUCTION

Teak (Tectona grandisLinn.f.), an important timber species of worldwide reputation (Banik, 1993)has indigenous distribution in Peninsular India, Myanmar, Thailand and Laos. Itis believed to be an early introduction in Java (White, 1991). Outside itsnatural habitat, it is cultivated in South and South-East Asia, the Pacific,Africa, the Caribbean Islands, South America and Central America (Tewari, 1992),accounting for 14% of tropical forestry plantations (Evans,1982).

Although systematic planting andmanagement of teak dates back to the 1840s, a number of problems have beenidentified in maintenance and improvement of productivity in plantations. Thecommercial interest in shortening rotation may complicate management practicesfor want of enough growth data under high fertilizer and irrigation inputs.Apart from this, the impact of intensive high input forestry on sustainableproduction is also not clear.

This paper reviews the traditionalplantation techniques and highlights various issues associated with managementand productivity of teak in plantations.

TRADITIONAL PLANTATIONTECHNIQUE

Teak forests are regeneratedartificially, except in the dry teak forests, which are worked under a coppicesystem, or for the moister forests where the advance growth is cut back to formthe new crop. The common practice is to raise new crops using root-shootcuttings (stumps). This procedure has been going on for over a century in India.Various techniques of artificial regeneration have been more or lessstandardised, although there is scope for further improvement. More thanknowledge about correct technique, a correct programme of work and its executionaccording to schedule is critical (Tewari, 1992).

Seed collection andnursery

Seed collection, storage andpre-sowing treatment

'Seeds' (technically fruits) arecollected from the ground as and when they fall during January and February. Thebladder-like calyx is removed by vigorously rubbing it inside a gunny bag. Theseeds are then cleaned by winnowing. Seeds store well in gunny bags or sealedtins for 2-3 years.

The stony hard pericarp poses aproblem for quick and uniform germination. In order to hasten germination,various pre-sowing treatments have been developed.

Some of the beneficial treatmentsinclude: 1) alternate soaking in water and drying for 24 hours each for twoweeks; 2) immersing the seed in water for a number of days; 3) soaking the seedin a mixture of cowdung for a period up to one week; 4) putting the seeds inalternate layers of seed and sand in a pit with daily watering for 7 days, andthen drying and storing till time of sowing; and 5) spreading the seed in a 10cm layer in the sun on a mat or cement platform and watering constantly untilcommencement of germination.

Nursery site, preparation ofbeds, and seed rate

Well-drained sandy loam with gentlysloping terrain is recommended for preparing nurseries.

Each bed is of 1.2 m (12 m size,spaced at 0.3 m to 0.6 m between beds and 0.6 m to 1.6 m between rows of beds.Each bed produces about 400-800 plantable stumps. The ground is ploughed and thearea of the bed is dug out to a depth of 0.3 m. Roots, stumps and stones areremoved. The clods of earth are broken fine. The soil is allowed to weather forabout a month and then filled into the nursery bed with sand and organic matter.However, when temporary nurseries are established in forest areas rich innutrients, no additional manurial inputs are necessary.

In moist localities the beds areraised to a height of 30 cm from ground level to prevent water logging. In dryzones, beds are made flush with the ground level. In very dry localities, with amean annual rainfall of 750 mm or less, slightly sunken beds give betterresults.

The seed rate per standard bed of 12m (1.2 m varies from 3 kg to 12 kg. At Nilambur in Kerala, about 5kg of seedsare commonly used.

Method of sowing of seed inseed bed and maintenance

Both broadcast sowing and linesowing or dibbling 5-10 cm apart are practiced. Line sowing or dibblings havegreater seed economy and better survival and growth. Beds normally do not needany overhead shade. Irrigation is not provided except in very dry areas. Bedsare maintained free of weeds.

Plantationestablishment

Selection ofsite

The site for planting may be eitherplain or gently sloping with excellent drainage. Soils derived from gneisses,schists and trap are good for teak. Alluvial sites are superior for teak growthwhile laterite or lateritic gravel as well as clays, black cotton, sandy andgravely soils derived from sandstone are not good for teakplantations.

Preparation of plantingsite

After removal of saleable material,the site is given a burn to dispose of the slash and improve access andfertility. A study conducted by the Kerala Forest Research Institute (KFRI)indicates that slash-burning does not help to improve the growth of teak beyondthe first year (Chacko et al., 1991).

Method of raisingplantations

Stump (a root-shoot cutting)planting is the popular method of raising plantations. Stumps with a 1-2 cmdiameter (at the thickest part, referred to as 'stump thickness') prepared outof one-year-old seedlings are planted in holes made with a crowbar. In drylocalities, where rainfall is less than 900 mm, pre-sprouted stumps raised inpolythene containers a few months in advance give satisfactory results. Directsowing and transplanting of bare-root seedlings, though practiced in some areas,do not give satisfactory results.

Method of planting andspacing

Stumps are planted in crowbar holesand generally buried up to the collar. In drier localities stumps are plantedflush to the ground. In hard soil, it is practiced to plant stumps in pits of 30cm deep and 15 cm diameter.

Although spacings of 1.8 m (1.8 m to3.6 m (3.6 m are practiced in different regions, 2 m (2 m is the mostcommon.

Weeding

Weeds, especially grasses, retardteak growth and therefore are managed below the level of competition either byfork weeding, scrape weeding, uprooting or knife cutting at ground level. Thenumber and intensity of weedings vary with the intensity of weedgrowth.

Intercropping

Intercropping in teak plantations(termed as 'taungya') during the initial two years of planting is a commonpractice where there is a demand for cultivatable land. Once the plantation areais leased out, the cleaning of the site, burning, staking and planting are doneby the lease holders. The common intercrops are paddy, chillies, maize, wheat,sesame and various vegetables. Crops such as sugarcane, wet rice, plantain,jute, cotton, or creeping vegetables such as pumpkin and cucumber are notallowed. During the growth of the field crop, the weeding and tending of teakare done by the lease-holding farmers. However, in certain regions the practiceof 'taungya' has been discontinued for reasons of soil degradation andsuppression of teak (Alexander et al., 1980).

Plantationmaintenance

Weeding andcleaning

Generally two to four weedings ayear are required in plantations during the first three years. Scrape weedingscan effectively control weeds. Cleaning is done in areas where bamboo forms themain understorey.

Thinning

Thinning prescriptions vary from onelocality to another. Unfortunately, it is often governed by revenue rather thansilvicultural considerations. In a good quality plantation, managed on a 50 yearrotation, the thinnings are carried out at the fourth, eighth, 12th, 18th, 26thand 35th years. Thinning schedule varies with site quality. In betterplantations the thinnings are done early as compared to poor plantations. Thefirst two thinnings in plantations with an initial spacing of 1.8 m (1.8 m or 2m (2 m are mechanical wherein 50 % of stock is removed in each thinning.Alternate diagonals in the first thinning, and alternate rows in the next arethinned. Climber cutting and cutting back of overtopping bamboos and otherspecies are done during the early thinnings.

KEY SILVICULTURAL ISSUES INPLANTATION MANAGEMENT

Site qualitychanges

Data from ideal teak growing tractsshows that yields obtained in plantations are far below expectation (KFRI,1979). Site deterioration in teak plantations has been reported by Champion(1932), FRI&C (1929, 1934, 1941), Seth and Yadav (1959), and Jose and Koshy(1972), and also widely observed in the field. Usually the site quality for teakplantations is assessed by the height (technically 'top height') of trees(Chaturvedi and Khanna, 1994), but this alone does not necessarily reflect thesoil conditions. Site deterioration is attributed to several factors, such as:1) a lack of efficient technical supervision because of a rapid expansion ofplantation areas; 2) the soil deterioration caused by intensive commercialtaungya cultivation; 3) delayed planting; and 4) poor after-care. A survey onteak plantations in Kerala of all age groups up to 60 years indicated a declineof site quality with age (Jayaraman, 1995). It could be argued that this is areflection of decrease in site quality within a rotation. The compound annualrate of decline works out to 1.6% (K. Jayaraman, pers. commn.).

Scarcity of plantingmaterial

The quality of teak stumps(root-shoot cuttings) recommended for planting is specified by its diameter atthe thickest part (1-2 cm), referred to as 'stump thickness', and their length(15-20 cm). The stumps should be relatively straight and prepared fromone-year-old seedlings. A recent survey of 36 nurseries in Kerala carried out bythe author and colleagues revealed that the number of standard plantable stumpsproduced per nursery bed varies between 74 and 808 (most of the beds gave around300) as against the expected number of 1000 per bed. Tewari (1992) reports afigure of 600-800 from Andhra Pradesh. Important reasons for such low figuresare poor site selection and nursery preparation, the use of poor seed, anddelayed nursery operations combined with pest and disease problems. The qualityof seeds used in nurseries is of utmost importance (FAO, 1985).

Delayed tendingoperations

Important management operations,such as weeding, cleaning and thinnings, are often delayed because of theunavailability of funds in time and a lack of interest among officers, who arenot payed well for carrying out these tasks. Occasionally, thinning operationsare delayed deliberately in order to harvest larger poles at a later stage,ignoring possible setbacks in the future. Moreover, field operations are oftenconstrained by the high authority that pays attension only to financial auditbut does not give credit to the quality of the plantations raised (Chundamannil,1993).

Insufficiency of fieldinspections and plantation monitoring system

Field inspections, which had greatlycontributed to the quality of plantations in earlier days, have been mostlyconfined to office inspections (Madhava Menon et al., 1986). The periodicmonitoring of plantation performance is a necessary activity for guidingplantation forestry on a sustained yield basis. At present, however, there is nomechanism to ensure systematic and regular plantation monitoring, through whichthe productivity of plantations are measured and recorded.

Lack of adequate silviculturalresearch

An analysis of 626 pieces ofliterature that have appeared in Forestry Abstracts, IndianForester, Myforest, Forest Ecology and Management, IndianJournal of Forestry and the bibliography in Tewari (1992) during the 10years from 1985 to 1994 indicates that only 13.7% of the papers deal with thesilviculture of teak (Table 1).

Also, the same survey indicates thatnearly half of them are on seed and nursery (Table 2). It is obvious that othersilvicultural subjects, such as planting methods, spacing, thinning andpolycultures, have received much less attention.

Table 1. Analysis of theliterature on teak published during 1985-94

(Total number =626)

Table 2. Analysis of theliterature on teak silviculture published during 1985-94

(Total number =86)

APPROACH TO ISSUES IN PLANTATIONMANAGEMENT

Quality control for plantingmaterials

Seeds used in nurseries should bequality-tested, size-graded and certified. A seed certification scheme should beevolved for this purpose. In order to produce good seeds, enough seed standsshould be designated and maintained. Clonal seed orchards using scion from plustrees should be expanded. A certification programme for the stumps to be plantedwill also improve plantation quality.

Emphasis on fieldinspections

Experiences in the past clearlyindicate the importance of field inspections by senior technical officers. Thereis an urgent need to reemphasise it. A written report of each inspection may beprepared and forwarded to the officer in charge of the plantation and thetechnical head for implementation of recommendations. A format for reportinginspections is suggested in Appendix 1. Such technical reports are all the moreimportant in recent contexts where working plan reports have mostly becomedefunct documents (Chundamannil, 1993). The frequency of field inspections couldvary depending on the age of the crop, with more frequent inspections in youngerplantations.

Continuous monitoringsystem

A continuous monitoring system toassess the condition of the crop, especially the site quality at differentpoints of time, will help in scheduling tending operations according torequirements. A central monitoring unit can carry out this task with localassistance. Interim thinning, final felling and other tending operations shouldbe made on this basis.

Timely implementation of tendingoperations

The investment requirements for teakplantations are generally low in relation to the revenue realised throughthinnings and final harvest (FAO, 1985; Chudamannil, 1986). Therefore,expenditure on proper maintenance of plantations is fully justified in the longterm. Hence adequate funds should be made available in time for tendingoperations.

The problem of inadequate wage ratesapproved in the government sector could be solved in two ways. Firstly, thereshould be some freedom vested with the controlling officer to revise wage ratesto match the prevailing local rates. An alternative is to award the work bycompetitive bidding, in which case the contractors will make the initialinvestment and be reimbursed on satisfactory completion of work, as is done inother government departments.

Strengthen silviculturalresearch

Silvicultural knowledge, especiallyin less investigated areas such as thinning, pruning and fertilization, needsupdating. Information on mixtures is also inadequate. Our experience withmixtures of Ailanthus tryphysa and Evodia lunuankenda are notencouraging (FAO, 1985). Bambusa arundinacea grows well in teakplantations but replaces teak in the long run. Interplanting teak withhorticultural crops such as cocoa and pepper also did not yield encouragingresults. Therefore, more research needs to be carried out on these importantaspects. Comprehensive guidelines for site selection and optimum input use fordifferent regions will be helpful. Many of the scientific publications orreports are not in a form readily usable at the field level. There should be amechanism by which such information can be collated, simplified, and madeavailable for field use.

Long term silvicultural experimentsneed to be taken up by research institutions in collaboration with forestdepartments.

CONCLUSIONS

Most of the traditional plantationtechniques hold good even now; however, scarcity of good planting materials, aswell as non-availability of funds in time, are problems. Lack of a properquality control and monitoring system leads to poor establishment andmaintenance. Site deterioration between and within rotations poses a threat topotential yields. Adequate measures such as quality control in plantingmaterials and post-planting care have to be taken. Field inspections andcentralised monitoring systems can help in assessment of the condition of theplantation and facilitate timely management decisions. Silvicultural research,especially on thinning, optimum inputs, and polycultures needs strengthening.The involvement of both user agencies and research organisations in long termfield trials is suggested.

ACKNOWLEDGEMENT

The author gratefully acknowledgesFORSPA (FAO), Bangkok, for providing financial support, Dr. C.T.S. Nair, SeniorProgramme Advisor, FORSPA, for suggesting the investigation of this problem, andDr. K.S.S. Nair, Director, KFRI for encouragement in preparing thepaper.

REFERENCES

Alexander, T.G. Sobhana, K.,Balagopalan, M. and Mary, M.V. 1980. Taungya in relation to soil properties,soil erosion and soil management. KFRI, Peechi.

Banik, R.L. 1993. Teak inBangladesh. In: Wood, H. 1993. Teak in Asia. Proceedings of the China/ESCAP/FAORegional Seminar on Research and Development of Teak, 1991, pp 1-10, FAO,Bangkok.

Chacko, K.C., Sankar, S., Pandalai,R.C., and Nandakumar, U.N. 1991. Effects of slash-burning on soil properties andgrowth of teak. Indian Forester 117:237-248.

Champion, H.G. 1932. The problem ofpure teak plantations. Forest Bulletin No. 78, Silviculture Series, Governmentof India Press, Calcutta.

Chaturvedi, A.N. and Khanna, L.S.1994. Forest mensuration (2nd ed.). International Book Distributors, Dehra Dun,India.

Chundamannil, M. 1986. Pattern ofinvestments in forestry and its implications on sustained yield management inKerala. M.Phil dissertation, Centre for Development Studies,Trivandrum.

Chundamannil, M. 1993. History offorest management in Kerala. Kerala Forest Research Institute,Peechi.

Evans, J. 1982. Plantation forestryin the tropics. Clarendon Press, Oxford.

FAO. 1985. Intensive multiple-useforest management in the tropics. FAO Forestry Paper 55, FAO,Rome.

FRI&C. 1929. Proceedings of theThird Silvicultural Conference. Government of India Press,Calcutta.

FRI&C. 1934. Proceedings of theFourth Silvicultural Conference. Government of India Press,Simla.

FRI&C. 1941. Proceedings of theFifth Silvicultural Conference. Government of India Press, DehraDun.

Jayaraman, K. 1995. Structuraldynamics of teak stands in Kerala. Final Report (draft) of Research Project KFRI147/92.

Jose, A.I. and Koshy, M.M. 1972. Astudy of the morphological, physical and chemical characteristics of soils asinfluenced by teak vegetation. Indian Forester 98:338-348.

KFRI. 1979. Yields from teakplantations in Kerala. Kerala Forest Research Institute,Peechi.

Madhava Menon, T., Hari Singh,Sharma, Y.M.L., Nair, K.K., Nair, C.T.S., Hassankutty, A. and Sivarajan, M.1986. Forest policy and management in Kerala. Report of the High Level ExpertCommittee. Government of Kerala, Trivandrum.

Seth, S.K. and Yadav, J.S.P. 1959.Teak soils. In: Proceedings of All India Teak Study Tour and Symposium, DehraDun, PP. 121-138.

Tewari, D.N. 1992. A monograph onteak (Tectona grandis) Linn.f. International Book Distributors, Dehra Dun,India.

White, K.J. 1991. Teak: Some aspectsof research and development. FAO, Bangkok.

Appendix 1 - INSPECTION REPORTON PLANTATION

1. Species:

2. Name and year ofplanting:

3. Location ofplantation:

4. Source ofseed/stump:

5. Area (ha):

6. Date of last inspection and nameof inspector:

7. Condition of the crop i)Survival/Stocking % (no/ha): ii) Growth: Mean gbh (cm): Mean height(m):

8. State whether plantation journalis maintained with up-to-date details:

9. Pending operations (indicatingreasons for delay):

10. Operations (with suggested timeframe):

11. Overall rating:Excellent/Good/Average/Poor

12. Other remarks:

SpeciesImprovement Network for Teak - Mr. Vichien Sumantakul

VichienSumantakul

Silvicultural ResearchDivision

Royal Forest Department, Bangkok,Thailand

ABSTRACT

A Regional Workshop on SpeciesImprovement Networks (SPIN), held in Chiang Mai, Thailand, during July 1994,selected seventeen priority species networks under FORTIP. The Workshopconcluded the following: all networks should be decentralised; activities shouldbe jointly initiated and organised by the co-ordinating center and FORTIP;networks should seek support from and work closely with related projects orinstitutions; FORTIP would support networks from its budget; clear commitmentsof member networks to establish, maintain and assess provenance trials areneeded; public or private sector resources will be required for sustainablenetworking. The Workshop selected one priority species group for eachco-ordinating center/country. To facilitate fast action, the FORTIP Secretariatlisted activities for immediate action (e.g. seed and propagule exchange is anactivity for early implementation); Participants should respond to proposedactivities as soon as possible. Tables show the Co-ordinating Centre withpriority species and a Timetable and Work Plan for Tectonagrandis.

Key words: Tectonagrandis, network, SPIN, Thailand, improvement, FORTIP.

INTRODUCTION

Following the first two years of itsoperation, the UNDP/FAO Regional Project on Improved Productivity of Man-MadeForests Through Application of Technological Advances in Tree Breeding andPropagation (FORTIP (RAS/91/004) has laid the basis for regional activities inforest tree improvement by setting up an efficient Regional Network among tenmember countries in South and Southeast Asia. At the same time, NationalNetworks in each country have been promoted for the success of the RegionalNetwork. In order to further boost the regional activities, the Project AdvisoryCommittee in its second meeting during 24-29 October 1993 in Manila, decided toestablish the Species Improvement Networks (SPINs) of 17 priority species orspecies groups which were previously selected by member countries of FORTIP. ARegional Workshop on Species Improvement Networks (SPINs) was held during 25-30July 1994 in Chieng Mai, Thailand, jointly organized by the Royal ForestDepartment of Thailand (RFD) and FORTIP. It aimed to operationalise the SPINidea, to reach a consensus on activities to be launched, and to initiatepractical work.

Nine representatives from FORTIPmember countries attended the Workshop: Bangladesh, Bhutan, India, Indonesia,Malaysia, Nepal, Philippines, Sri Lanka and Thailand. Participants and resourcepersons from the following agencies and projects also joined the Workshop: ASEANForest Tree Seed Centre (AFTSC), the CSIRO Division of Forestry - AustralianTree Seed Centre (ATSC), the International Network for Bamboo and Rattan(INBAR), the International Plant Genetic Resources Institute (IPGRI), the OxfordForestry Institute (OFI), the Regional Community Forestry Training Centre(RECOFTC), the Universiti Pertanian Malaysia (UPM), the Center for InternationalForestry Research (CIFOR), the Royal Forest Department of Thailand (RFD),members of FORTIP's National Network in Thailand, and a representative of theForestry Department of the Food and Agriculture Organization (FAO),Rome.

Experiences in Forest TreeImprovement and Networking were shared and discussed among the more than 30participants in the Workshop. Action plans were made up by two working groupsduring technical sessions for most of the 17 priority species or species groups.The plans were discussed and approved at the final session.

OUTPUT OF THEWORKSHOP

The main output of this workshop wasthe formation of 17 species networks of priority species selected by FORTIPmember countries. The main expected outputs and activities of these networkswere discussed in two working groups in which the main outputs and activitieswere defined for each species or species group; an activities timetable wasprepared; and participating countries, a co-ordinating centre, and possiblecollaborating institutes were identified. During the final plenary session theseoutputs and activities were approved. The FORTIP secretariat was authorized toincorporate the results of the discussions in the conclusions andrecommendations at the plenary session.

During a general discussion onorganizational aspects of the Species Networks, the following conclusions andrecommendations were approved:

1. The organization ofall species networks will be decentralized during the installation period.Participation of the countries in network activities will be on a voluntarybasis. The interest of the concerned countries in regional co-ordinatedactivities is the principal motivation for the establishment of SPINs. Thisattitude will contribute to the sustainability of the networks.

2. The activities will be jointlyinitiated and organized by a co-ordinating centre and the FORTIP Secretariat.The FORTIP Secretariat will be involved in the co-ordination of all activitiesuntil the termination of the project. Responsibility for network activities willbe shared by the co-ordinating centre and the FORTIP Secretariat. To ensure thesustainability of the networks, responsibility will be gradually transferred tothe co-ordinating centre prior to termination of FORTIP.

3. The proposed networks should seeksupport from and work closely together with related projects or institutions.The list of possible collaborating agencies/countries attached to each speciesdoes not necessarily indicate experience with the FORTIPnetworks.

4. The activities will be reviewedat the next Project Advisory (PAC) Meeting of FORTIP, scheduled for December,1994, in Sri Lanka. Necessary modifications or refinements of organizationalaspects, prioritization of species and activities, etc., will be discussed atthis meeting.

Finance

Regarding financial aspects of theproposed networks, the following was agreed:

1. FORTIP will initiallysupport the proposed SPINs from its regular budget, e.g. by providing funds forseed exchange activities, workshops, study tours andpublications.

2. For most of the proposednetworks, clear commitments of resources by individual network members, e.g. thecommitment to establish, maintain and assess a provenance trial, are needed.Additional funding will also become necessary for some networks in order toaccomplish all proposed medium and long term activities. The co-ordinatingcentre and the FORTIP Secretariat will prepare proposals to attract additionalfunding from outside sources and discuss the proposals with all participatingcountries.

3. Public or private sectorresources will be required for sustainable networking. FORTIP should survey theprospects for more private sector involvement in the SPINs.

4. A round table discussion withparticipants from all FORTIP countries and possible donor agencies is regardedas useful to attract external assistance. It is tentatively scheduled for1995.

Priorities

The number of proposed networks wasregarded as being too large to initiate work simultaneously. Thus, it was agreedto prioritize one species group for each co-ordinating centre/country. Consensuswas reached on prioritisation as shown in Table 1.

Training

A specific recommendation was madeby the Workshop regarding the FORTIP training programme. Basic tree improvementactivities are often hampered by difficulties in seed collection. Seedcollection in Paraserianthes spp. was mentioned as an example. FORTIPshould promote practical training for seed collectors, e.g. by organizing andsponsoring a training course. The Gesellschaft fur Technische Zusammenarbeit(GTZ, Germany), DANIDA Forest Seed Centre (DFSC), Australian Tree Seed Centre(ATSC) and ASEAN Forest Tree Seed Centre (AFTSC) were mentioned as a possiblepartners for these activities.

Fast implementation ofactivities

This is regarded as essential forthe success of the proposed SPINs. Exchange of information will be the mainactivity in most networks. This implies both exchange of views among scientistsas well as exchange of genetic information via shipment of seeds andpropagules.

In order to facilitate fast action,the FORTIP secretariat has listed activities for immediate action in a separatetable for each species and species group (an example on teak follows). Exchangeof genetic material via seeds and propagules is among the activities which canand should be initiated soon in order to "make the network work". Allparticipating countries should respond to the proposed activities, (i.e. theproposed exchange of materials) as soon as possible, giving details both on thekind of material they can provide and what they would like to receive from thenetwork. If applicable, countries should also mention assistance required forthese activities.

Specific remarks: with regardto Output/Activity of Tables 2:

1. The assessment shouldfollow the standardized procedure of Kieding, H., Willendorf, H. and Lauridsen,E.B.: Evaluation of an international Series of Teak Provenance Trials. DANIDAForest Seed Centre.

2. Provenance selection should bebased on an evaluation of growth and yield, stem form, and woodquality.

3. The use of results of provenancetests for the production of high quality planting material must bepromoted.

Generalremarks:

The proposed Species ImprovementNetwork for Teak is an opportunity to revitalise the activities of the TeakNetwork. The improvement work will be co-ordinated with any future activities ofthis Network. Thailand qualifies as a co-ordinating centre due to its longexperience in growing and breeding teak.

Co-ordinating centre:Thailand

Participating countries:Bangladesh (BGD), Bhutan (BHU), India (IND), Indonesia (INS), Malaysia(MAL), Nepal (NEP), Philippines (PHI), Sri Lanka (SRL), Thailand(THA).

Immediate actions byCo-ordinating Centre, participating Countries, FORTIPSecretariat:

Activity Acting PartiesAction

THA, FORTIP: consult DANIDAregarding the evaluation of international provenance tests.

THA, FORTIP: prepare and distributeguidelines for the establishment and maintenance of SPAs and plus tree selectionof teak.

BGD, BHU: explore the feasibility ofseed collection and regional seed exchange among member countries, givingdetails about the kind and quantity of material available for dispatch from eachcountry and the interest of each country in regional seed exchange (i.e. whichmaterial would the country like to receive?). If applicable, state the earliesttime of seed dispatch and the kind of assistance required for exchangeactivities. Inform the co-ordinating centre and the secretariat as soon aspossible on any matters regarding the exchange of geneticmaterial.

THA, FORTIP: identify collaboratingagencies and possible donors for a study on teak in natural populations, seedproduction areas, and seed orchards and genetic variation patterns in naturalpopulations and plantations. Collect information on ongoing or completed work onrelevant subjects. Discuss a project proposal with membercountries.

Table 1. Co-ordinating centresand priority species groups

Table 2. Output/Activity -Species: Tectona grandis

PA.C's = Participatingcountries; C.A.C's = Collaborating Agencies and countries; IND = India, INS =Indonesia, LAO = Lao PDR, THA = Thailand; MYA = Myanmar; GER = Germany, SWD =Sweden, DEN = Denmark

It was recommended at the ThirdProject Advisory Committee Meeting in Colombo, Sri Lanka 13-18 December 1994,that work plans for each species be drawn up. The Species Improvement Networkfor teak will continue according to the work plan endorsed.