Individual Crown Diameter Prediction for Cunninghamia lanceolata Forests Based on Mixed Effects Models Study of the Dominant Height for Chinese Fir Plantation Using Two-Level Nonlinear Mixed Effects Model Effects of diameter at breast height on crown characteristics of Chinese Fir under different canopy density conditions Analysis of Nonlinear Mixed Effects Model Parameter Estimation Methods Analysis of the Basal Area for Chinese Fir Plantation Using Two Kinds of Nonlinear Mixed Effects Model(Two Levels)