Study on Dominant Height Growth of Fir Plantations Based on a Nonlinear Mixed Modeling Approach for Longitudinal Data Modeling of Dominant Height Growth and Building of Polymorphic Site Index Equations of Chinese Fir Plantation Effect of Planting Density and Thinning on Dominant Height Growth Curve in Chinese Fir Plantation Based on Mixed-Effects Model and Empirical Best Linear Unbiased Predictor to Predict Growth Profile of Dominant Height A New Method for Establishing Richards Polymorphic Site Index Model:Parameter Replacement Study of the Dominant Height for Chinese Fir Plantation Using Two-Level Nonlinear Mixed Effects Model Modeling Dominant Height for Chinese Fir Plantation Using a Nonlinear Mixed-Effects Modeling Approach Dominant Height for Chinese Fir Plantation Using Nonlinear Mixed Effects Model Based on Linearization Algorithm