长白山东北红豆杉生境内针阔混交林直径结构分布研究

选择能够拟合长白山自然保护区东北红豆杉生境内针阔混交林的直径结构分布模型,为该区林分经营管理提供参考。以长白山自然保护区龙荒沟林场15块东北红豆杉林分内针阔混交林为研究对象,采用负指数函数和三参数Weibull分布函数2种直径分布模型拟合和χ^2检验,分析了15块样地的直径结构分布规律。15块样地的密度为400~981株·hm^-2,平均胸径变化范围为10.5~19.9 cm,各样地林分的直径分布的偏度均为正值,直径分布函数曲线均往左偏,除了9~11号样地的直径分布用三参数Weibull分布模型效果较好外,其他样地均适合用负指数模型拟合。两种模型均能有效描述直径结构分布规律,三参数Weibull分布模型用来拟合不规则直径分布时效果较好,而负指数分布模型拟合近似“反J”型曲线时效果好。该区东北红豆杉林分内针阔混交林直径结构分布不合理,应加强该林区经营技术措施。

Diameter Structural Distribution of Coniferous Broad-leaved Mixed Forest in Taxus cuspidate Habitat in Changbai Mountain

This research aimed at the management of Taxus cuspidate stand by selecting suitable models for imitating diameter structural distribution of coniferous broad-leaved mixed forest in T.cuspidate stand,Changbai Mountain Nature Reserve.On the basis of 15 coniferous broad-leaved mixed forest in T.cuspidate stands in Longhuanggou Forest Farm,Changbai Mountain Nature Reserve,negative exponential model,threeparameter Weibull model and χ^2 test were used to analyze the diameter structural distribution of 15 plots.The density of 15 plots was 400-981 trees·hm^-2,and the mean DBH was 10.5-19.9 cm.The skewness of all plots was positive,which showed the diameter distribution function curves was partial to left.The three-parameter Weibull distribution model was better for the diameter distribution of the 9-11 plots,while negative exponential model was suitable for other plots.The irregular diameter distribution can be fitted better by three-parameter Weibull model,while the inverse J-shaped curves can be fitted well by negative exponential model.It showed that the diameter structure of coniferous broad-leaved mixed forest of Taxus cuspidate stand in the study area were not reasonable,and the management of T.cuspidate stand should be strengthened.