黄土高原子午岭天然柴松林种群结构与动态研究

Structure and Dynamics of Natural Pinus tabulaeformis f. shekannesis Populations in Ziwuling Forest Region of the Loess Plateau

对黄土高原地区子午岭天然柴松(Pinus tabulaeformisf.shekannesis)林种群的结构和动态进行了研究。结果显示:柴松种群结构呈反J分布型,种群处于增长阶段;种群的密度随径级的增加而降低,种群密度与径级呈现出明显的负相关;4个函数(生存率函数、积累死亡率函数、死亡密度函数、危险率函数)估计值说明种群具有前期增长、后期稳定的特点,其存活曲线介于DeeveyⅡ型和DeeveyⅢ型之间;随时间推移,种群中树和大树数量逐渐增多,种群在20 a后开始大量进入成熟阶段。表明柴松在本研究区内生长更新良好,在无人为干扰条件下,柴松可通过自我调节能力而保持种群的稳定性。

The structure and dynamics of natural Pinus tabulaeformis f. shekannesis populations in Ziwuling Forest Region of the Loess Plateau were investigated. It was shown that the Pinus tabulaeformis f. shekannesis populations appeared to distribute in an inversed J shape and were at the up-growth stage;the population densities decreased as the diameter grades increased and the population densities and the diameter grades appeared remarkably negatively correlated; the estimated values of four functions （Survival rate function Si ,accumulative mortality function Fi ,mortality density fx ,and hazard rate function λx） indicated that the populations increased at the earily stage and kept stable at the late stage and their survival curves were between Deevey Ⅱ and Deevey Ⅲ ; the populations increased the numbers of their large trees and reached maturity in great quantities twenty years later. These indicated that Pinus tabulaeformis f. shekannesis grew well and was capable of keeping its populations stable through its self-regulation without suffering artificial disturbances in the region under study.