Annual Report: CIRAD 2007

The market value of teak is continuing to rise as this wood is treasured for its resistance to degradation agents, along with its aesthetic and technological features. Natural teak forests in Myanmar, India, Laos and Thailand from which this species originated are disappearing or are now protected. Marketed teak therefore mainly comes from plantations covering an area of 3-4 million ha in Asia (Indonesia, India) and West Africa (Ivory Coast, Togo, Benin, Ghana), where the species was successfully introduced. Private companies have also recently set up intensive teak plantations in Latin America (Brazil, Colombia, Ecuador, Costa Rica), East Africa (Tanzania) and Australia.

CIRAD began research on teak genetics in Ivory Coast through provenance and silviculture trials. This led to the introduction of many teak provenances, while describing the behaviour of teak in plantation growing conditions and generating the first improved varieties. This research was aimed at gaining insight into how the environment affects teak tree growth, architecture and wood quality. The ultimate goal was to be able to provide growers with planting material—seeds or clones—to suit their specific needs. The studies were focused on teak stands and wood specimens from Ivory Coast, Ghana, Togo, and more recently from Sabah, Malaysia. A few specimens from Myanmar, Brazil, Tanzaniaand Colombia were also analysed.

Expansion of teak clonal plantations

The first step was to assess tree variability in original teak stands on the basis of high economic impact criteria and to select individual trees that had all of the traits that are sought for seed propagation oriented teak breeding programmes. In addition, clonal plantations have been developed through propagation from cuttings and commercial microcuttings in collaboration with the Malaysian group Yayasan Sabah. These plantations are currently booming and replacing ordinary seed-propagated plantations that have a very low germination rate andare especially heterogeneous.

Teak growers are striving to maximize the return on investment of these clonal plantations by focusing on enhancing teak volume yields and wood quality. New criteria, such as wood physicochemical characteristics, have recently been added to standard criteria to refine the initial selection of individual trees. A study is under way to assess the impact of environmental conditions on the technological properties of teak wood. This should ultimately give rise to new top quality varieties, some of which should be sufficiently versatile to be suitable for planting under various environmental conditions.

Wood durability—an essential quality feature

Teak is being logged at an increasingly younger age in plantations, and the wood quality is highly variable in terms of the proportion of sapwood and heartwood, colour, technological properties and resistance to degradation agents. For instance, according to European standards concerning resistance to wood-eating fungi, wood from natural forests are generally ranked in durability class 1 (highly durable) or 2 (durable), whereas it ranges from 1 to 4 (slightly durable) for plantation wood. The natural durability of wood, which is closely linked with the nature of some of its chemical constituents, depends on the age of the tree, the growing environment and its genome. Hundreds of teak samples from 5-40 year old trees and different origins were tested by CIRAD’s wood preservation laboratory. The resulting database can be tapped to determine the natural durability classificationof teak specimens using near-infrared spectrometry.

Other studies on growth modelling for yield estimation and molecular genetics studies, etc, have also been carried out in recent years in collaboration with partners in Ivory Coast, Togo and Ghana. The latter studies have already led to the development of a microsatellite marker library that should ultimately help to determine the geographical origins of teak trees on the basis of their DNA. Further studies are also planned on genetic marking for quality control during propagation, clonal identification with respect to commercial features, assessment of gene flows in seed plots and genetic control of target traits.

CIRAD has established many partnerships throughout the sector in several different countries and has gained expertise on teak genetic resources, so it is ideally qualified to conduct research on a broad range of topics concerning top quality teak wood production.

Contacts

Gilles Chaix, E-mail , Genetic Diversity and Breeding of Forest Species (UPR)
Olivier Monteuuis, Plant Development and Genetic Improvement (UMR Dap)
Nadine Amusant, Production and Processing of Tropical Woods (UPR)

Partenaires

• Forestry Research Institute of Ghana (FRIG, Ghana)
• Société de développement forestier (SODEFOR, Ivory Coast)
• University of Lomé (Togo)
• Yayasan Sabah Group (Malaysia)

For further information

• Chaix G., Goh D.K.S., Baillères H., Boutahar N., Monteuuis O., 2007. New techniques for upgrading the selection of teak genotypes and their clonal propagation. In : Processing and marketing of teak wood products of planted forests, 25-28 septembre 2007, Peechi, Inde.
• Goh D.K.S., Chaix G., Baillères H., Monteuuis O., 2007. Mass production and quality control of teak clones for tropical plantations: the Yayasan Sabah Group and CIRAD joint project as a case study. Bois et forêts des tropiques, 293 : 65-77.