新疆中部天山雪岭云杉种群动态初步研究

A preliminary study on Picea schrenkiana population dynamics in the central Tianshan Mountains,northwestern China

雪岭云杉PiceaschrenkianaFisch.etMey在中部天山林区内分布于海拔1500m～2700m之间,形成一个垂直分布带。作者采用样方法进行调查,沿海拔梯度每隔100m选取两块样地(20m×20m),在海拔1500～2700m的雪岭云杉林内共选样地26块来调查中部天山雪岭云杉种群的年龄结构、密度和生物量动态。在所选样地内,调查所有雪岭云杉树木(h≥2m)的胸径并按5cm分成不同的径级,每一径级至少选取两棵树,每棵树在不同方向上钻取两个树芯,建立年龄-胸径方程推算样地内所有雪岭云杉树(h≥2m)的年龄;调查样地内所有幼苗(h<50cm)和幼树(50cm≤h<200cm)的高度并根据主干上轮枝数查数一定数目幼苗幼树的年龄,建立年龄-高度方程并推算样地内所有幼苗幼树的年龄。研究结果表明中部天山雪岭云杉种群的胸径、年龄结构和种群密度都呈倒-J型分布,种群生物量呈钟型分布,存活曲线基本介于DeeveyⅡ和DeeveyⅢ型之间。以上研究结果表明中部天山的雪岭云杉种群处于不断更新和稳定发展的时期。

Schrenk spruce, Picea schrenkiana Fisch. et Mey. population distributes in a wide altitudinal transect between 1 500 m （lower limit） and 2 700 m a.s.l. （upper limit） in the central Tianshan Mountains. Plots were placed at 100-m elevation intervals from 2 500 m to 2 700 m a.s.l., and two plots （20 m × 20 m） were established at each elevation. A total of 26 forest plots were investigated to study the age structure, density, biomass dynamics and the survivorship rate of the P schrenkiana population. The DBH （diameter at breast height） of each tree was measured and all trees were grouped into 5 cm diameter interval size classes in every plot. At least, two trees per DBH class and two cores per tree were selected randomly in each plot and cored as close to the ground as possible to establish age-DBH relationships. In addition, heights of all seedlings or saplings were measured, and the ages of several ones were determined by counting their branch annuals on the main stem. By the age-height relationships, the age of all the other seedlings and saplings were calculated. As a result, the P. schrenkiana population has reverse-J shaped DBH class, age structure and tree density patterns but with a bell-shape biomass pattern. The Schrenk spruce population also has a classical linear survivorship curves between Deevey Ⅱ and Deevey Ⅲ type. It seems that the P schrenkiana population is a stably developmental one with sufficient recruitment in the central Tianshan Mountains.