不同经度天山云杉林分因子随海拔梯度的变化

Stand Factors of Picea schrenkiana var.tianschanica along the Altitudinal Gradient in Different Longitudes

选择新疆天山山脉从西到东处于不同经度的昭苏、巩留、乌苏、乌鲁木齐和哈密的天山云杉林进行垂直样带调查:将各地点划分为低、中和高3个海拔范围,比较不同范围内主要林分因子的差异;分析主要林分因子随海拔梯度(50m间隔)的变化。结果表明:各地点3个海拔范围内主要林分因子呈现出不同的变化规律;天山云杉林分平均胸径和最大胸径随海拔梯度的变化差异不显著,而平均树高、最大树高、林分密度、胸高断面积和蓄积量随海拔的增加总体上呈现单峰型的变化趋势;尽管不同经度位置天山云杉林分布的海拔上下限范围不同,但各个位置天山云杉林分的平均树高、最大树高、林分密度、胸高断面积和蓄积量随海拔梯度的变化都可以用二次曲线方程进行描述。

Vertical transects of Picea schrenkiana var. tianschanica forests in five sites of different longitude （Zhaosu, Gongliu, Wusu, Urumqi and Hami） in Tianshan Mountains were investigated to analyze the stand factors of the forests along altitudinal gradient in different longitudinal sites. Each stie was divided into three ahitudinal ranges （low, middle and high） and the difference in stand factors within each altitudinal range was analyzed, The variation of main stand factors along the altitudinal gradient at 50 m intervals was also investigated. The results showed that the variation of different stand factors within the three altitudinal ranges in five sites presented different patterns. Mean and maximum DBH showed no significant variation while mean and maximum tree height, stand density, total basal area and stand volume of the forests generally showed hump-shaped curves with increasing of the altitude. The changes along the altitudinal gradient could be described by the quadratic curve equations though there was variation in the altitudinal range of the forests in the different sites.