Ong (1985) reported the shrinkage, density, strength and hardness of wood from 12-year-old trees. There were considerable variations between and within trees. Scharai-Rad and Budiarso (1988) classified this as a species of medium strength properties. According to them its bending strength is 83.5 N/mm2, crushing strength is 37.0 N/mm2 and modulus of elasticity (MOE) is 10.6 kN/mm2. The wood is reported to be moderately strong with an average bending strength value of 65 N/mm2 in green condition (Sattar et al. 1993). An investigation of the variation of wood density, fibre length and shrinkage within and between trees as well as between 3 provenances of 8-year-old A. mangium in Sabah by Sining (1989) showed that basic density ranged from 430 to 500 kg/m3. The variations of wood properties among provenances and among trees were less significant than within trees. Basic density and fibre length increased from pith to bark, shrinkage increased as basic density increased from pith to bark. However, among parameters, the shrinkage decreased as the basic density increased. Wu and Wang (1988) compared the wood properties of A. mangium with A. auriculiformis. They found that its shrinkage and variation were generally less, and strength properties were greater in A. auriculiformis.
Utilization of wood
A. mangium wood makes attractive furniture and cabinets, molding, door and window components (Mergen et al. 1983). The wood is also suitable for light structural works, agricultural implements, boxes and crates (Awang and Taylor 1993).
A. mangium is generally regarded as non-durable timber (Razali and Mohd 1993). It is quite amenable to preservative treatment (Mergen et al. 1983). The treated wood may not give good performance in ground contact. It has a relatively narrow sapwood band and is not a suitable species to be used for exterior and outdoor purposes. The wood seasons fairly rapidly without serious defects. Warping, end splitting and surface checking are negligible. The timber kiln-dries well and fairly rapidly, without serious defects when suitable kiln schedules are used (Awang and Taylor 1993).
It has high incidence of knots, which causes good-quality sawn timber to be unobtainable in significant quantities. Knots can be eliminated through proper pruning regimes. The presence of flutes and incidence of rots and termite attack all detract from both quality and quantity of sawn timber (Razali and Mohd 1993).
Peh et al. (1982) and Peh and Khoo (1984) reported the suitability of A .mangium for pulping with high yields, quality of kraft, NSSC pulps and produced paper with good optical, physical and surface properties (Logan 1987). A. mangium has the highest pulp yield and required the least cooking chemicals when compared with other species like Eucalyptus deglupta and Gmelina arborea (Becker 1987). So, it is currently being grown with the primary use for pulp and paper in Sumatra, Sabah and Vietnam.
A. mangium timber is reported to be easily peeled and the green veneers of tight, smooth and acceptable quality were obtained (Chai 1989). The timber is also suitable for the production of decorative veneers.
Wood of A. mangium has been successfully utilized for the manufacture of particle boards (Mergen et al. 1983). It is reported to be suitable for many re-constituted wood products, such as being medium density fibre board (MDF) (Tomimura et al. 1987). The calorific value of the timber is also relatively high, 4,800-4,900 k cal per kg, so the wood can make good biofuel, reasonably good quality charcoal, charcoal briquettes and activated carbon (Awang and Taylor 1993). Trans-sectional view of wood is finely shown in Fig. 7.
Fig. 7. A. mangium tree with heart rot.
References
Adjers G, Srivastava PBL. 1993. Nursery Practices (Chapter 6). In: Acacia mangium - Growing and Utilization. MPTS Monograph Series No. 3. Winrock International and FAO, Bangkok, Thailand, pp 1-75.
Arisman H, Havmoller P. 1994. Seed supply strategy for a pulp-wood plantation project in southern Sumatra. Proceedings: International Symposium on Genetic Conservation and Production of Tropical Forest Tree Seed, 14-16 June, 1993, Chiang Mai, Thailand, ASEAN Canada Forest Tree Seed Centre, pp 225-228.
Atipanumpai L. 1989. Acacia mangium: studies on the genetic variation in ecological and physiological characteristics of a fast-growing plantation tree species. Acta Forest Fennica 206: 1-92.
Awang K, Bhumibhamon S. 1993. Genetics and tree improvement. In: Acacia mangium - Growing and Utilization. MPTS Monograph Series No. 3. Winrock International and FAO, Bangkok, Thailand, pp 35-57.
Awang K, Taylor D. 1993. Acacia mangium - Growing and Utilization. MPTS Monograph Series No. 3. Bangkok, Winrock International and FAO, Thailand, pp 1-280.
Banik RL, Mannan MA, Sharmila D, Islam SD. 1995. Vegetative propagation of adult trees of acacia hybrid (Acacia auriculiformis × Acacia mangium). Bangladesh J For Sci 24: 74.
Becker ES. 1987. Evaluation of samples of Acacia mangium, Eucalyptus deglupta and Gmelina arborea for kraft pulping, bleaching and paper strength properties. Report to the North Borneo Timbers Berhad, EcoNotech Ltd., pp 1-10.
Bhumibhamon S, Thavorn V, Swatdipakdi R. 1992. Variation in heartwood formation of Acacia mangium. MPTS Res Notes 2: 1-2.
Chai SH. 1989. Wood and veneer quality studies of Acacia mangium. B. S. (For) (Wood Industry) Project Report, Faculty of Forestry, Universiti Pertanian Malaysia, Serdang, Malaysia, pp 1-270.
Darus HJA. 1993. Vegetative Propagation. (Chapter 4) In: Acacia mangium - Growing and Utilization. MPTS Monograph Series No. 3. Winrock International and FAO, Bangkok, Thailand, pp 59-74.
Doran JC, Skelton DJ. 1982. Acacia mangium seed collections for international provenance trials. Forest Genetic Resources Information, FAO, No. 11, pp 47-53.
Doran JC, Turnbull JW, Boland DJ, Gunn BV. 1983. Handbook on seeds of dry-zone acacias. A guide for collecting, extracting, cleaning, and storing the seed and for treatment to promote germination of dry-zone acacias Rome, Italy, Food and Agriculture Organization, pp 1-25.
FAO. 1987. Nitrogen Fixing Trees - A training Guide -. RAPA Publication 1987/15, Bangok, Thailand, pp 1-230.
Guzman LC, Lawrence JH, Marler TE. 1997. Growth and development responses of three Acacia species to long-term light regimes. J Sustain For 4: 119-130.