Natural Durability of Twenty Two Malaysian Commercial Timbers

Durability is defined as the ability of a material to withstand environmental stress over an extended period of time. Timber which is a ligno-cellulosic material is liable to degradation due to biological agents such as insects (eg. termites), fungi, bacteria etc. Among these biological agents, termites and fungi cause significant losses not limited to tropical and subtropical countries, but also in some northern parts of the world. Both cause more damage to timber buildings than fire.

Timber consists of two parts which are called sapwood and heartwood. Sapwood of many tree species has no natural resistance (Toole 1970) and thus susceptible to fungus attack. Whereas for certain timber species, the heartwood has a natural resistance due to the presence of extractive substances that are formed during the growth process. It is a protective material to the timber-damaging agents. The natural durability of woods may vary among tree species, among individual trees, and within individual trees (Scheffer and Cowling 1966).

This paper reports on entomological as well as mycological assessment of twenty two Malaysian timber species. It gives the comparison regarding the natural durability classification for the users of Malaysian timber to make decision during procurement.