• 论文 •

### 利用2种非线性混合效应模型(2水平) 对杉木林胸径生长量的分析

1. 1. 中国林业科学研究院资源信息研究所 北京 100091;2. 北京林业大学理学院 北京 100083
• 收稿日期:2011-03-18 修回日期:2011-07-06 出版日期:2012-05-25 发布日期:2012-05-25
• 通讯作者: 唐守正

### Analysis of the Basal Area for Chinese Fir Plantation Using Two Kinds of Nonlinear Mixed Effects Model(Two Levels)

Fu Liyong1, Li Yongci2, Li Chunming1, Tang Shouzheng1

1. 1. Research Institute of Forest Resources Information Techniques, CAF Beijing 100091;2. College of Science, Beijing Forestry University Beijing 100083
• Received:2011-03-18 Revised:2011-07-06 Online:2012-05-25 Published:2012-05-25

Abstract:

Nonlinear mixed effects model(NLMEM) is based on the relationship between the fixed and random effects in the regression function. The NLMEM has a competitive advantage in analyzing repeated measures data, the longitudinal data and multilevel data. This paper chose two kinds of two-level nonlinear mixed model to analyze basal area growth for Chinese Fir(Cunninghamia lanceolata). Model 1 is a general two-level NLMEM and model 2 is based on model 1 to further consider the fixed effects parameters changes with a specific factor. Firstly, through the analysis of these two models, this paper defined the basic model to build the two-level NLMEM. Secondly, 665 kinds of models derived from model 1 and 2 703 kinds of models derived from model 2 were calculated and compared. The results showed that: for model 1,there were 57 kinds of models converging, and when the formal parameter b0considered the block effects and plot effects,b1and b4only considered the block effects, the model fitted the best. For model 2, there were 24 kinds of model converging,and when the formal parameter b5considered the block effects and plot effects, b1 only considered block effects and the fixed effects b0changed with any level of block level, the model 2 fitted the best. Finally, by comparing the traditional nonlinear regression model, model 1 and model 2, the results showed that model 1 and model 2 fitted better than the traditional nonlinear regression, and model 2 was best fitting model.