Effect of wood properties on within-tree variation in ultrasonic wave velocity in softwood.
The radial variations in the velocity of longitudinal waves propagating through Japanese cedar and Japanese cypress were experimentally investigated. In addition, the tracheid length (TL), microfibril angle (MFA), air-dried density (AD), and moisture content (MC) were measured in order to determine the effect of wood properties on velocity variations within the wood trunk. For both species, the longitudinal wave velocities measured in the longitudinal direction (V(L)) exhibited minimum values near the pith. For Japanese cedar, V(L) increased from 3600m/s toward the bark and soon attained a constant value (=4500m/s). On the other hand, for Japanese cypress, V(L) kept increasing from 4000m/s near the pith to 4800m/s at the bark. These radial variations in V(L) coincided with those in the tracheid length. V(L) exhibited strong correlations with TL and MFA with a significant level of (p<0.01). These findings suggest that the TL and MFA greatly affect the radial variation in the ultrasonic wave velocity in softwood.
Department of Agro-Environmental Science, Faculty of Agriculture, Kyushu Univ., 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan. kmgtmsm@agr.kyushu-u.ac.jp
Masumi
M
Hasegawa
Masato
M
Takata
Junji
J
Matsumura
Kazuyuki
K
Oda