ANATOMY OF ACACIA-MANGIUM GROWN IN MALAYSIA

A study on the tissue proportions and fibre dimensions of plantation-grown Acacia mangium was carried out. Ten selected trees from two age groups (4- and 8-year-old) were obtained from plantation forests in Selangor. Disks were taken from four sampling heights. Acacia mangium wood is diffuse-porous with mostly solitary vessels. The rays are uniseriate. The average percentage of fibres, vessels and rays of 4-year-old and 8-year-old samples are 85.8%, 9.1%, 5.2% and 84.8%, 9.8%, 5.3%, respectively. Acacia is a short-fibred tropical species. The average fibre length, fibre diameter, fibre lumen diameter and fibre wall thickness are 934, 24, 17 and 3.3 mum for 4-year-old samples and 1017, 20, 12 and 4.3 mum for 8-year-old samples, respectively. The samples near the pith have the shortest fibres and the length increases toward the bark. Fibre length also tends to decrease with height. The vessel percentage decreases with increasing height.