Statistical analysis of an alternative von Bertalanffy model for tree growth

Abstract

This paper proposed an alternative von Bertalanffy nonlinear growth equation by introducing a growth rate stabilizing parameter using hyperbolic sine function. The ability of the integral solution of the alternative von Bertalanffy growth equation in model prediction was compared with the classical von Bertalanffy growth model, an approach which mimicked the natural variability of heights/diameter increment with respect to age and therefore provides a more realistic height/diameter predictions using the coefficient of determination (R 2 ), Mean Square Error (MSE) and Akaike Information Criterion (AIC) results. The “Kolmogorov-Smirnov” test, “Shapiro-Wilk” test and runs test were also used to test the compliance of the error term to the underlying assumptions. The mean function of top “height/diameter” over age using the two models under study predicted closely the observed values of top height/Dbh in the hyperbolic von Bertalanffy nonlinear growth models better than the classical von Bertalanffy growth model while the assumptions of the error term were maintained.