杉木相对冠长指标及其应用初步研究

本文对福建杉木中心产区杉木人工林的相对冠长指标及其在林分密度管理中的应用进行了初步分析和探讨。杉木相对冠长与胸径生长率间存在极显著的幂函数关系,林分株数按相对冠长的分布用正态分布拟合是适宜的,拟合率达73％左右,提出了以林分相对冠长的平均值作为基准,按标准差的一定倍数来划分林分生长级的标准和方法,不同林分各生长级林木的相对冠长临界值或范围随林分的年龄、优势高和单位面积株数的增加而急剧下降,但林分Ⅳ、Ⅴ级木的比例却是逐渐上升的。杉木相对冠长指标可作为杉木人工林抚育间伐的重要参考指标。

Primary Study on Relative Crown Length of Chinese Fir and Its Application

This paper deals with a relative crown length of Chinese-fir plantation and its application to the stand density management. The result showed that the power-function relationship was very significant between the relative crown length and D.B.H. increment. It was suitable to fit the distribution of number of trees classificated by the relative crown length by using normal distribution, the rate of the fitting reached about 73%. It was presented tha a standard and method for classificating grade of growth, according to multiple of stardard deviation based on mean of the relative crown length. The cr-jtical values of the relative crown length of grades of growth in stands was decreasing with the increasing of stand age, dominant height, and number of rees. Regression analysis showed that the number of trees in Ⅳ vand Ⅴ grade was increasing with the increasing of the stand age, dominant height and number of trees in per unit area.