不同林龄杉木胸径树高与冠幅的通径分析

Path Analysis between Diameter at Breast Height,Height and Crown Width of Cunninghamia lanceolata in Different Age

为了解杉木林分不同发育阶段冠幅因子的变化规律,以及胸径和树高对冠幅因子的影响程度,运用通径分析方法分析了福建将乐林场5种杉木纯林中胸径和树高与冠幅因子之间的关系。结果表明：1）冠幅的增长主要是在中龄到接近成熟这个阶段,冠幅范围主要在0.3~1.8 m;2）杉木林发育不同阶段的冠高率分布在区间0.3~0.9,总平均冠高率为0.50;3）胸径对冠幅具有显著的正向作用,且随着林分的发育,正向作用逐渐增强,树高只在幼龄和过熟阶段对冠幅起正面作用;4）胸径与树高对冠形率均具有显著的负作用,其中,对冠形率起显著作用的主要是树高,这种负作用在近熟林时最小,成熟林时最大。

We studied growth law of crown in different ages,and impact degree between diameter at breast height（ DBH）,tree height and crown by path analysis. Crown width grew mainly from immature to near-mature,and the figure was in 0. 3-1.8 m. Crown ratio distributed in 0. 3-0. 9,and average crown ratio was 0. 5. DBH had a significant positive effect to crown with the development of forest stand,and the positive effect was gradually enhanced. Tree height played a positive influence at young forest and over-matures forest. There was a remarkable negative effect between DBH,tree height and crown shape ratio,and the main factor is tree height. The negative effect was minimum in near-mature forest and maximum in mature forest.