关键词: 侧柏（Platycladus orientalis）, 心材, 边材, 直径, 相关关系, 太行山

Abstract: In a 50-year-old Platycladus orientalis plantation in the limestone mountains of Taihang Mountain, the thickness and orientation differences of the tree radial components, including heartwood, sapwood and bark,were investigated by trunk analysis and growth cone method. The correlation between the thickness of each component and the trunk diameter of the tree was analyzed, and a regression model was established. The results showed the trunk diameter of 70 sample trees ranged from 3.92 cm to 15.95 cm with an average diameter of 9.80 cm and an average radius of 4.90 cm, the thickness of heartwood （2.70 cm, accounting for 55% of radius） > sapwood thickness （1.84 cm, 38%） > bark thickness （0.36 cm, 7%）. There was no significant difference among four directions in trunk radius and heartwood thickness; there was a significant directional difference in sapwood thickness and bark thickness, with the largest value in the south direction. There were extremely significant positive correlations between stem radius, heartwood thickness, sapwood thickness and trunk diameter. The nonlinear and linear regression models of each component thickness and trunk diameter were established in different directions of the tree trunk.

Key words: Platycladus orientalis, heartwood, sapwood, diameter, correlation, Taihang Mountains