Abstract: With the branch analysis data of 4 987 branches for 79 Korean pine plantations in Mengjiagang Forest Farm, we established the branch diameter and branch length of the linear mixed model and the branch diameter and branch length growth of the nonlinear mixed model. We used SAS9.22 to solve parameters of the model and used AIC, BIC and LRT to give significance test for the converged model. For branch diameter and branch length linear mixed model, all the parameters were significant for t test of the branch diameter and branch length and the standard error of the parameters was low, and it performed well as for the stability of the models. For branch diameter growth nonlinear mixed model, the combination for b₁ and b₃ for the model performed well based on the low value for AIC and BIC, when the sample plots effect was not considered. When the sample plots effect was considered, the combination for b₁ and b₃ for the model performed well compared to the other combination form. For branch length growth nonlinear mixed model, the parameter combination for b₁ and b₃ of the model performed well based on the AIC and BIC when the sample plot effect was not considered, and if considered, the combination for b₃ and b₄ performed best for the model.

Key words: Korean pine plantation, tree crown structure, branch diameter, branch length, mixed model