LOCATION OF EXTRACTIVES AND DECAY RESISTANCE IN SOME MALAYSIAN HARDWOOD SPECIES

Abstract

The durability of 24 Malaysian hardwoods has been assessed by a modified ASTM D2017 soil-block method using the white rot fungus, Coriolus versicolor. Using cluster analysis, the 24 timbers have been classified into four groups, viz durable, durable but not after extraction, moderately durable, and non-durable. In general, timbers of the durable group (e.g. chengal, giam, rengas) contain more extractives than the non-durable group (perupok, jelutong, ramin, rubberwood). The extractives are predominantly present in the parenchyma cells with some in the adjacent fibre cells. A higher proportion of extractives exist in parenchyma cells in the durable group. The extractives located in the cell lumina are easier to extract from the durable group than the moderately durable group.