가문비나무의 연륜폭 광협에 따른 성숙재와 미성숙재의 초음파적 특성

Ultrasonic properties of juvenile and adult wood of Sitka spruce in relation to the width of annual ring

This study was carried out to analyze the ultrasonic properties of juvenile - and adult-wood, and heartWood and sapwood of Sitka spruce in relation to the width of annual rings. A very wide width of annual ring-wood indicates the lowest longitudinal acoustic radiation and the highest tangential acoustic radiation. Outer sapwood of adult wood very near the bark shows higher acoustic radiation than that of inner heartWood of juvenile wood near the pith in all three direction for a very wide width of annual ring. But middle and narrow widths-wood give that outer sapwood of adult woods very near the bark show lower longitudinal acousic radiation and higher acoustic radiation perpendicular to the grain, especially higher radial acoustic radiation than those of inner heartwood of juvenile woods near the pith. Therefore outer sapwood of adult wood very near the bark seeks to meet the symmetry from acoustic anisotropy. Narrow width of annual ring-wood gives the highest longitudinal acoustic radiation and the lowest tangential acoustic radiation.