Individual Tree Basal Area Growth Dynamics of Chinese Fir Plantation

The fixed-effect model for individual tree basal area growth modeling for Chinese fir (Cunninghamia lanceolata) in spacing plantations was developed using panel data. The heterogeneity of individual increment basal area among the different blocks was analyzed with independent variables (diameter of breast height (DBH) and live-crown ratio (LCR)), dummy variables with stand planting density, competition indices, and site and stand age effects. The result indicates that there is a strong relationship between stand planting density and competition indices, but both of them are important factors impacting individual increment tree basal area growth. The impact of site condition and stand age varies with different stand density. The fitting deviation of the average individual increment basal area increases along with site indices and stand ages.