湖北木林子自然保护区大样地小叶青冈种群年龄结构及点格局分析

Age Structure and Point Pattern of Cyclobalanopsis Gracilis Population in Mulinzi Nature Reserve of Hubei Province

小叶青冈是我国亚热带常绿落叶阔叶混交林的主要优势树种之一,也是良好的用材树种和园林树种.本文采用胸径代替年龄和点格局分析(Ripley's K-Function)法对湖北木林子15 hm2大样地内小叶青冈种群的年龄结构和空间点格局进行了分析.结果显示:大样地内小叶青冈种群属增长型种群,其种群的存活曲线特征属DeeveyⅡ型,种群在幼树阶段死亡率较高,之后趋于稳定;种群整体及幼树、小树、中树和大树四个年龄段的个体在空间分布格局上随研究尺度的变化均呈集群分布,而老树年龄段的个体,其空间分布格局随研究尺度的增加由均匀分布向集群分布递变;在呈集群分布的尺度范围内,都存在随研究尺度的增加,聚集强度先减小后增大的规律.

Cyclobalanopsis gracilis is one of the dominant species of the subtropical evergreen and deciduous broad-leaved mixed forest community in our country,and it is also a good timber species and landscape tree.This article employs the method of tree diameter serving as a proxy of tree age and point pattren analysis to research the age structure and point pattern of the Cyclobalanopsis gracilis population of 15hm2 forest dynamics plot（ 300 m×500 m） in Mulinzi Nature Reserve of Hubei Province.The results indicate： The Cyclobalanopsis gracilis population in the forest dynamics plot follows an expanding population,and its survivorship curve follows a Deevey Ⅱ indecating the mortality of this population is high first and then follows stationary; the point pattern of the Cyclobalanopsis gracilis population,the saplings,the young trees,the middle aged-trees and the mature trees are of an aggregated distribution with the research scale,but the old trees＇ changes from a regular pattern to an aggregated distribution; the aggregation intensity decreases first and then increases in all aggregated distribution.