The Adjusted Dynamic Modulus of Elasticity Above the Fiber Saturation Point in Taiwania Plantation Wood by Ultrasonic-Wave Measurement

Abstract

Summary In this study, the effects of moisture content and bulk density on the ultrasonic velocity of Taiwania ( Taiwania cryptomerioides Hay.) plantation wood in the longitudinal and radial directions are investigated. The dynamic modulus of elasticity is adjusted above the fiber saturation point by a simple method. It was observed that ultrasonic velocity tended to increase with a decrease in moisture content, and the effect of moisture content on the ultrasonic speed below the fiber saturation point was stronger than that above. Moreover, for this species ultrasonic speed in the longitudinal direction decreased with increasing bulk density, while that in the radial direction increased. The correlations between ultrasonic velocity, moisture and bulk density could be represented by a polynomial regression model. The K value for ultrasonic wave was affected by density. The adjusted dynamic modulus of elasticity remained fairly constant above the fiber saturation point using this simple method. Therefore, the results obtained by the ultrasonic-wave technique should be adjusted before estimating some physical properties of standing trees.