SONIC AND ULTRASONIC WAVES IN AGARWOOD TREES (<em>AQUILARIA</em> <em>MICROCARPA</em>) INOCULATED WITH </em>FUSARIUM</em> </em>SOLANI</em>

Abstract

Agarwood or gaharu is a valuable non-timber forest product that has unique aroma and is widely used in many cultures and industries. It develops as a result of fungal infection, injury and non-pathological processes in several genera of trees from the family Thymelaeaceae, including Aquilaria. The presence of agarwood can be determined using non-destructive sound waves to evaluate the internal condition of A. microcarpa trees. The aim of this study was to compare the velocity of sound between ‘stress’ or sonic waves and ultrasonic waves travelling through the trunk of standing A. microcarpa trees inoculated with Fusarium solani. The ultrasonic wave velocities (Vusn) were found to be 29.5% higher than sonic wave velocities (Vsn). Statistical analysis showed no significant difference in velocity in relation to height of measured tree section. Vsn and Vusn values were found to be approximately 700 and 900 m s-1 respectively for trees that contained agarwood. Non-destructive sound wave testing is, therefore, a feasible method to detect the presence of agarwood.