Wood property assessment of teak (Tectona grandis Linn. F) plantation of different ages grown in Lao PDR

© 2011 Phongxiong WannengThe research presented in this thesis aimed to assess the wood properties of teak (Tectona grandis Linn.F) plantations of different ages grown in Luangprabang Province, a world heritage listed area in the northern part of Laos. Specifically, the research focused upon the assessment of physical and mechanical properties of 10, 15, 20, and 25 years old teak: wood dimensional stability, density and specific gravity, static bending (modulus of elasticity and modulus of rupture), compression parallel to the grain and shear strength. The premise underlying this study was to determine an optimal age of teak plantation rotation in Laos and compare the results with the data obtained in other countries. The methodology of this study was based upon Australian methods for mechanically testing small clear specimens of timber. Nine trees from the four age groups were selected for the test. The sample trees were measured for diameter, heartwood and sapwood proportions, bole length and total height. Specimens were cut and tested according to the requirements of the relevant test method and data obtained from each wood property test was applied to analysis of variance (ANOVA) of statistical analysis (SPSS) software. Analysis of the data obtained from the tests showed consistently that, in average there was similar values between wood properties of plantation teak of different age groups (10, 15, 20 and 25 year old plantations) for both physical and mechanical wood properties (Table 52). However, the results of ANOVA showed that some values were significantly different at statistic (α=0.05) (Table 51). In average value, it did not show a relationship between the wood properties and the age of sample trees. This suggests that other factors may influence the wood properties of plantation grown teak trees (Chapter 6). The results indicated that the wood properties of younger Teak plantations (10 and 15 years old) were not inferior compared to the older plantation (20 and 25 years old), and when compared to the wood properties of mature plantation teak obtained from overseas studies. It can therefore be concluded that 10 and 15 year old teak would be acceptable for a variety of wood products for both outdoor and indoor service conditions for domestic and international markets. However, it is critical that proper processing and manufacturing procedures are applied to allow the products to meet international quality requirements, products standards and specifications. Based upon the wood property results obtained from this study, plantation rotation age between 10 and 15 years would be suitable for timber harvesting. This shorter rotation cycle would also provide economic benefits to the country as it would reduce the cost of forest management and it would increase the plantation timber yield by replacement of the harvested plantation with another in the same area