森林工程2025，Vol.41Issue(5)：896-903,8.DOI:10.7525/j.issn.1006-8023.2025.05.003
基于Copula函数的胸径-树高二元联合分布模拟
Simulation of Bivariate Joint Distribution of Diameter at Breast Height-Tree Height Based on Copula Function
摘要
Abstract
In forestry research,the bivariate distribution of diameter at breast height(DBH)and tree height is often con-structed from identical marginal distributions,yet the actual distributions of DBH and tree height within a forest stand may vary.To mitigate the impact of these differences,based on the data from 115 Larix olgensis stands in Mengjia Gang Forest Farm,Jiamusi City,this study employs the Copula function method,which has low application conditions and a broad range of adaptability,to model the bivariate distribution of DBH and tree height in Larix olgensis plantations.Firstly,we selected six distribution functions-Weibull,G-Weibull,Logistic,Logit-Logistic,Gamma,and Log-Normal-as potential base models.These were then screened and used to construct a Copula-based bivariate distribution model for DBH and tree height,based on the results of the Kolmogorov-Smirnov(K-S)test and semiparametric estimation.The model's fit was further evaluated using the negative log-likelihood(NLL),the Sn goodness-of-fit statistic,and the likeli-hood ratio test(LRT),comparing it with the bivariate logistic distribution function and the bivariate Weibull distribution function.Finally,the predictive capacity of the model was assessed using the Reynolds error index(EI).The findings indicated that the Copula-based bivariate fitting results and predictive capabilities(EI=0.318 4)outperformed those of the bivariate Weibull distribution(EI=0.638 1)and the bivariate logistic distribution(EI=0.949 0).This suggests that the Copula method for constructing a bivariate joint distribution model of DBH and tree height can effectively describe the joint distribution in Larix olgensis plantations,making it a viable approach for modeling tree height and DBH distributions.关键词
长白落叶松/胸径树高联合分布/Copula函数/雷诺误差指数/半参数估计Key words
Larix olgensis/joint distribution of diameter at breast height-tree height/Copula function/Reynolds error index/semiparametric estimation分类
农业科技引用本文复制引用
金大庆,董利虎,郝元朔..基于Copula函数的胸径-树高二元联合分布模拟[J].森林工程,2025,41(5):896-903,8.基金项目
国家重点研发计划(2023YFD2200802) （2023YFD2200802）
国家自然科学基金区域创新发展联合基金项目(U21A20244). （U21A20244）
