IN-VITRO DECAY RESISTANCE OF 12 MALAYSIAN BROADLEAF HARDWOOD TREES AS A FUNCTION OF WOOD DENSITY AND EXTRACTIVES COMPOUNDS

This study investigated the factors contributing to the natural decay resistance of 12 Malaysian hardwood species. A 16-week decay test was performed using wood blocks (19 mm × 19 mm × 19 mm) in test jars against three white-rot fungi (Pycnoporus sanguineus, Trametes versicolor and Lentinus sajor-caju). Huge variations in weight loss occurred between wood species. Average weight loss of wood for all species was 0.20-44.80% against P. sanguineus, 0.09-52.51% against T. versicolorand 0.16-33.17% against L. sajor-caju. The corresponding basic densities were between 391 and 1020 kg nr⁻³. When mass loss was compared against chemical characteristics and wood density, it was concluded that contribution of wood extractives in improving the durability of wood was highly significant compared with its density.