引言树木的生长能力主要决定于其着生树叶的数量。这一数量可以叶面积或叶重表示,但这两个变数很难测定,因此在计算树木生长的方程式中常以绝对活树冠长或相对树冠长(树冠比)来代替(Stage 1973,Danie-ls and Burkhart 1975,Kramland 1982, Introduction The ability of a tree to grow depends primarily on the number of leaves on which it is born. This amount can be expressed as leaf area or leaf weight, but these two variables are difficult to determine and are therefore often replaced by absolute tree crown length or relative canopy length (crown ratio) in equations for calculating tree growth (Stage 1973, Daniels and Burkhart 1975, Kramland 1982,