桤木幼龄林直径结构规律分析

林分直径结构规律的研究是森林经营的基础工作。以湖南省湘西地区花垣县桤木幼龄林标准地数据为基础,分析了其直径结构特征。利用四种分布函数对其直径结构进行拟合,同时对四种分布函数进行了卡方检验。通过拟合结果及卡方检验得出,湘西桤木幼龄林符合正态分布和Weibull分布,不符合对数正态分和伽马分布。利用Richards模型、Logistic模型及传统的三次方程模型对湘西桤木幼龄林株数累积百分数和相对直径关系进行拟合,结果表明:Richards模型、Logistic模型的拟合效果优于三次方程模型,并具有生物学意义。

Analysis of diameter structure regularities of the young alder

The research of diameter structure regularity is the basis work of forest scientific management.In this paper, based on the data of the sample plot of the young alder in Huayuan County of Hunan Province,the diameter structure reg-ularities were analyzed.Used four distribution functions to fit its diameter structure,and take chi-square test.the results show that,the young alder in the Western Hunan fit normal distribution and Weibull distribution,Which do not fit the lognormal and gamma distribution.Used Richards model and Logistic model and Cubic equation to fit cumulative percent-age and relative diameters,the results show that Richards model and Logistic model are better than Cubic equation and it has more biologically significance.