麻城黄山松天然林直径分布

为研究黄山松天然次生林直径分布特征,以麻城市黄山松天然次生林为研究对象,采用标准样地调查,计算林分直径的偏度、峰度,林分直径分布的Shannon-Weiner和Simpson指数,运用负指数分布、normal分布、lognormal分布、logistic分布和Weibull分布等5种概率密度函数对黄山松天然次生林林分直...

Diameter distribution of a natural secondary Pinus taiwanensis forest in Macheng City

The target is to study the diameter distribution characteristics and diameter distribution diversities of the natural secondary forest of Pinus taiwanensis in Macheng City,Hubei Province and to establish suitable fitting distribution models.A sample plot survey was made of the natural secondary forest of P.taiwanensis,and the skewness and kurtosis of the stand diameters(the diameter at breast height or DBH)were researched to explore the traits of diameter distribution curves.Shannon-Weiner index and Simpson index were counted to study the diversity characteristics of stand diameter distribution.5 probability density functions involving negative exponential function,normal distribution function,lognormal distribution function,logistic distribution function and Weibull distribution function were used to fit the distributions of the stand diameters of P.taiwanensis,and the fitted functions were verified with chi-square test(χ²).The result showed that 1)the diameter distribution curves were mainly positively skewed,while the diameter distribution curves were negatively skewed as the diameter class was larger.2)The diversity and evenness indices of diameter distributions of P.taiwanensis were consistent with the size change of stand diameter classes.3)The goodness-of-fit of Weibull distribution function had an optimal fitting effect and the acceptance rate of it was 75.0%.The research result can provide references to the prediction of the diameter distributions and growth dynamics of P.taiwanensis stands and the guidance of the management of P.taiwanensis forests.