Analyzing parameters of growth and yield models for Chinese fir provenances with a linear mixed model approach

Chinese fir is the preferred species for tree farm plantations in south Asia. Height growth and basal-area growth models were used to test the growth performance of Chinese fir originating from 26 provenances grown on two separate planta- tions in southern China. Parameters of the height growth and the basal-area growth models were statistically tested by way of a linear mixed-effects model approach in order to identify the growth parameters that are influenced by site and prov- enance. For the stand height growth model, it was found trees originating from the 26 provenances have different site indices when planted at similar sites. However, the slope coefficient was similar across provenances. Similarly for the basal-area growth model, the model intercept and the density-age related parameter showed no significant differences among prove- nances. No conclusive inference could be drawn concerning the site index-related parameter in the basal-area growth model.