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XXI IUFRO World Congress 2000, 7-12 August 2000

XXI IUFRO World Congress 2000, 7-12 August 2000

Alik Duju & Takashi Nakai Mechanical properties of Acacia mangium planted in Sarawak, Malaysia
Ten trees of 13-year old Acacia mangium were sampled and fifty-four small clear specimens were tested. The British Standard (BS 373.1957) method on testing small clear specimens of timber was adopted to obtain the strength properties of the species. It was found that the mean values of modulus of rupture, modulus of elasticity and compressive strength tested at green condition were 86.4 MPa, 10.9 GPa and 36.8 MPa respectively. The average moisture content was 114 % and their basic density was 0.51 g/cm3. Based on their compressive strength, the timber was classified under Strength Group C by Burgess's grouping. It was revealed that the strength properties and basic density were higher at outer portion compared to the inner portion of the wood.

Andrew Tukau Salang and Tomoyuki Fujii Physical and Anatomical Characteristics of Acacia mangium Willd planted in Sarawak, Malaysia
The average thickness of the sapwood is 11 mm, whitish in colour and the heartwood is slightly pale brownish to purplish brown. The timber is slightly interlocked with smooth and even texture. It is a strong timber with an average oven-dried density of 471 kg/m3, that it is suitable for interior structural timber and furniture. The density variation amongst trees is about 11%. The density increases from the pith towards the heartwood and decreases at the sapwood. Mostly solitary vessels, multiple vessels are also common especially radial multiple of 2, medium size, moderately numerous, evenly distributed, deposit and tyloses present. Vessel diameter also increases from the pith towards the sapwood. Vessel element length is short and it increases in length from pith towards the heartwood and slightly decreasing at the sapwood. The wood fibre is small with very thin wall and long that it is suitable for pulp and papermaking. The fibre diameter is larger with higher variation at the pith compared to the heartwood and sapwood, which is almost similar in size. Fiber wall thickness showed slight increases from the pith towards heartwood and sapwood. Fibre length variation is also higher at the pith compared to the heartwood and sapwood that showed almost similar in length. Fibre length also increases from the pith towards the heartwood and slight decrease at sapwood. The variation in the parameters of the vessels and fibres are found to be higher at the pith compared to the heartwood and sapwood. The variation in the characteristics of vessel and fibre is higher within trees compared to between tree in Acacia mangium. The core wood that includes the pith consisted of juvenile wood is about 10%, and utilisable wood that consists of heartwood and sapwood is 90%.

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