摘要
选择4种直径分布函数(Weibull函数、负指数函数、Γ函数和β函数)对天然针阔混交林不同择伐强度(弱度13.0%、中度29.1%、强度45.8%、极强度67.1%)作业下直径结构进行了拟合。结果表明:各样地直径分布均为左偏,中小径阶林木居多;除弱度择伐峰度为负,其余样地为正;变动系数随择伐强度的增大而增大。弱度择伐符合Weibull分布和β分布;中度择伐符合Weibull分布、负指数分布和Γ分布;强度择伐符合Weibull分布和负指数分布;极强度择伐对4种分布均不接受。Weibull分布具有较强的灵活性和适应性,基本可以用来拟合择伐作业后林分直径分布,拟合结果可以从侧面检验择伐作业体系的合理性。
Four probability models were applied to simulate diameter distribution of natural forests after different intensities of se- lective cutting, including 1 ow intensity （ 13.0 percent）, middle intensity （ 29.1 percent）, high intensity （45.8 percent）, and over-high intensity （67.1 percent）. The curves for diameter class distribution of all the sampling plots are skewed to the left, indicating that the stands have large populations at small and middle diameter classes. The kurtoses of the curves for the stands are positive except for low intensity, and the coefficient of variation increases with selective cutting intensity. Weibull and beta distribution functions could well describe the structure of diameter for low intensity of selective cutting, Weibull, negative exponential, and gamma distribution functions for middle intensity cutting, Weibull and negative exponential distribution functions for high intensity cutting, but all the above distribution functions could not well describe the structure of diameter for over-high intensity cutting. Therefore, Weibull distribution is the optimal model to express the structure of diameter distribution in natural forests after selective cutting, and the simulation result could verify the rationality of selective cutting operation.
出处
《东北林业大学学报》
CAS
CSCD
北大核心
2009年第9期22-24,共3页
Journal of Northeast Forestry University
基金
福建省自然科学基金资助项目(2008J0327
2009J01232)
福建省科技厅重点科学基金资助项目(2007N0002
2006F5006)
福建省林业厅科学基金资助项目(闽林科[2006]7号第14项)
关键词
直径分布模型
天然林
择伐强度
WEIBULL分布
Diameter distribution models
Natural forests
Selective cutting intensities
Weibull distribution
