J Wood Sci (2011) 57:171–178 © The Japan Wood Research Society 2011 DOI 10.1007/s10086-010-1164-8 ORIGINAL ARTICLE Isabel Miranda · Vicelina Sousa · Helena Pereira Wood properties of teak (Tectona grandis) from a mature unmanaged stand in East Timor Received: May 5, 2010 / Accepted: November 5, 2010 / Published online: March 17, 2011 Abstract The wood quality from 50- to 70-year-old Tectona carpentry. Teak wood is moderately hard and heavy, seasons grandis trees from an unmanaged forest in East Timor was rapidly, kiln dries well, and has overall good machining prop- assessed. The aim was to evaluate teak in mature stands that erties. It is prized mostly for its natural durability and high had undergone uncontrolled disturbances, e.g., fi re and local dimensional stability in association with pleasant aesthetics. community usage. Heartwood represented 91% of the tree Some end-user requirements include high heartwood content radius at a height of 1.7 m, and sapwood contained on average (at least 85%) and wood density (> 675 kg/m3) and suffi cient nine rings. The mean ring width showed within-tree and strength [modulus of rupture (MOR) > 135 N/mm2].1 between-tree variability. The chemical compositions of heart- Teak grows naturally in Southeast Asia and was intro- wood and sapwood were similar. Within-tree chemical varia- duced into other tropical and subtropical regions in Austra- tion occurred only in terms of extractives, which increased lia, Africa, and Latin America. Teak is now one of the most from the pith (8.3%) to the heartwood–sapwood transition important species for tropical plantation forestry, mostly (12.7%) and decreased in the sapwood (9.2%). Overall, the under intensive short rotation management with 20–30 year wood properties of teak from a unmanaged forest in East rotations.2 Teak is also present in East Timor, an island in Timor were comparable to those reported for plantation Southeast Asia, characterized by tropical and subtropical teaks of other origin: 607 kg/m3 basic density, 3.5% and 5.2% moist mountain forests totaling 507 000 ha that represent radial and tangential shrinkage, 141 N/mm2 modulus of 34.3% of the land area.3 East Timor, an independent country rupture, 10 684 N/mm2 modulus of elasticity, and 50 N/mm2 since 2002, is fi ghting for its economic development, and maximum crushing strength in compression parallel to the forests are considered one of the strong drivers, since they grain. Disturbances on individual tree growth arising from include some valuable timber species, particularly teak. the unmanaged status of the stand were evidenced by higher In young plantations, teak wood quality is a matter of within-tree variability of ring width. However, the longitudi- research, and some studies have been carried out using teak nal and radial variations of wood density and mechanical from different origins, e.g., India,4 Togo,5,6 Costa Rica,7–9 properties were of low magnitude and in a degree that did Ivory Coast,10 and Panama.11–13 However, teak wood is also not negatively impact on timber quality. provided to a large extent from natural or unmanaged mature forests for which very little information exists in the Key words Tectona grandis · Chemical composition · Wood literature regarding wood quality. This is the case in East properties · East Timor · Unmanaged stands Timor, where no data exists on teak wood quality. At present, and due to past political and developmental con- straints in East Timor, forests have not been under silvicul- Introduction tural management and have rather evolved under several natural or human-derived disturbances, e.g., fi res, illegal Teak (Tectona grandis L.f.) is one of the most valuable and logging, and pruning and thinning for local community best known tropical timber species and is highly valued for usage. Additionally, although numerous studies have dealt use in shipbuilding, outdoor equipment, furniture, and general with teak wood quality, relatively little is known on its chemical composition and within-tree variation. The present study aims to clarify some of these less I. Miranda (*) · V. Sousa · H. Pereira researched teak wood properties, namely the chemical com- Centro de Estudos Florestais, Instituto Superior de Agronomia, position and the axial and radial variations of properties. A Universidade Técnica de Lisboa, Tapada da Ajuda, 1349-017 Lisboa, teak plantation established in the period 1940–1950 and Portugal Tel. +351-21-369-3378; Fax +351-21-365-3338 then left without forest management and thus subject to e-mail: [email protected] fi res, felling for local community use, and illegal timber 172 exploitation was used as a case study to exemplify within- the absence of apparent defects. The harvested trees had and between-tree variation of wood properties in mature BH diameters of 40.5, 37.9, and 43.5 cm and heights of 25.0, trees, i.e., heartwood content, chemical composition, basic 22.7, and 29.7 m, respectively. density, shrinkage, and mechanical properties. The trees were cross-sectioned at three heights, corre- sponding to the lower, medium, and upper part of the stem. For determination of ring width, heartwood proportion, and Material and methods chemical composition, stem disks 5 cm thick were collected at heights of 1.7, 9.5, and 18.7 m. For determination of physi- Sampling cal properties, 45-cm-long stem sections were cut immedi- ately below these levels and test samples were prepared from Wood samples were collected from a pure teak stand located a central board 5 cm thick sawn from these stem sections. in the northeast of East Timor in the Lautem district between Los Palos and Fuiloro (08º30′S, 126º59′E, altitude 380 m). The climate is tropical with distinct wet and dry Ring width and heartwood seasons determined by monsoon infl uence; data for the Los Palos region is available only for the period 1953–1974 Cores were mounted in wooden blocks and cross sections (unpublished data), indicating a 23.8ºC mean annual tem- were manually polished with progressively fi ner grades of perature and 1924 mm mean annual rainfall. August, Sep- sandpaper (fi nishing with P400) until ring boundaries and tember, and October are the driest months (mean monthly vessels were macroscopically visible. Disks were polished rainfall less than 32 mm), and July and November are tran- using a mechanical belt sanding machine. Ring width mea- sition months (125 and 94 mm respectively). The site has a surement and ring counting were done using image analysis declivity of less than 5% and soils of medium texture with software (Leica QWin Standard). pH 7.2. The distinction between heartwood and sapwood was The stand is a pure teak plantation with an area of performed macroscopically by color difference, and heart- approximately 4 ha that was established by the Portuguese wood radius and sapwood width were measured. The heart- regional forest services in the period 1940–1950 with 4 m × wood percentage by radius and the number of growth rings 2 m spacing. The seed source is unknown. The stand was in sapwood were determined. unmanaged until sampling, and the present mean tree density is 165 trees/ha. Records on eventual fi rst thinning Chemical composition prior to 1974 (the end of the Portuguese administration) are not available, but fi eld observations clearly showed that the The delimitation of heartwood was made visually on each tree density reduction to the present value was the result of wood disk, and samples were taken at different positions unplanned disturbances leading to tree distribution hetero- evenly distributed along the radius from pith to bark: three geneity. Common disturbances in East Timor forests are samples in the heartwood (inner, middle, and outer posi- related to the occurrence of mostly manmade fi res, erosion, tions) and two samples in the sapwood. and community use, e.g., illegal logging, fi rewood collection, Wood samples were ground and sieved, and the 40–60 and uncontrolled grazing and agricultural use. 2 mesh fraction was kept for analysis. Standardized Technical Four circular 1000-m permanent plots were established Association of the Pulp and Paper Industry (TAPPI) in June 2002 and tree biometric data were collected: mean 2 2 methods were used. Total extractives were determined in a basal area 2.34 m (ranging from 2.06 to 2.59 m ), mean tree Soxhlet apparatus using a solvent sequence of dichloro- height 25.0 m (mean height ranged from 22.0 to 25.6 m), methane, ethanol, and water (TAPPI 204 um 88). Klason dominant tree height 29.1 m (ranging from 26.2 to 32.9 m), lignin was determined on extractive-free material as the and mean tree diameter at breast height (1.3 m, BH) 42.5 cm solid residue after total acid hydrolysis (TAPPI 222 om-02; (ranging from 37.5 to 43.1 cm). At the time of measurement, TAPPI). The polysaccharide content was calculated based trees had no leaves and so the crown diameter could not be on the amount of neutral sugar monomers released by total measured. The height of the crown ranged from 7.0 to hydrolysis (xylose, glucose, rhamnose, mannose, arabinose, 13.7 m. Sampling was done after plot measurement. and galactose) after derivatization as alditol acetates. Inosi- Cores were collected at BH from three trees (two cores tol was introduced as an internal standard before derivatiza- per tree in opposite directions) in each plot selected as tion. Separation was made by gas chromatography and follows: one tree with a diameter approximately equal to quantifi cation used a previous calibration with pure mono- the average plot diameter, and the other two trees corre- saccharides (TAPPI 249 cm-85; ASTM D 1915).