Correlationship between tree characteristics and wood increments of Populus×xiaohei

To clarify the correlationship between tree characteristics and wood increments (juvenile wood area, mature wood area, sapwood area and heartwood area) of Populus×xiaohei T.S.Hwang et Liang in Shuozhou Region, Shanxi Province, correlation analysis method was applied, and empirical models for prediction of wood increments were established.Elasticity analysis was employed to examine these models.Results indicated that the variables of crown width (C_W), crown length (C_L), as well as diameter at breast height (D_BH) were all positively related to wood increments.Empirical models, with the form of power functions including D_BH, height (H), C_W, and stem taper (S_T) as explanatory variables, are the best way to describe the relationship between tree characteristics and wood increments.The coefficients of determination of established models ranged from 0.606 to 0.932.Analysis of standardized regression coefficients of regression models shows that D_BH contributes most to wood increments.Furthermore, elasticity analysis indicates that D_BH has the greatest and most positive influence on wood increments, and both complementary and competitive relationships exist among input variables in these models.