Modeling diameter distribution of Aleppo pine (Pinus halepensis Mill.) natural forest in the Aures (Algeria) using the Weibull, Beta and Normal distributions with parameters depending on stand variables

Abstract

230 temporary plots located in Aleppo pine ( Pinus halepensis Mill.) stands in the Aures (Algeria) were used for modeling its structure with three theoretical distributions, i.e., the Weibull; the normal and the Beta one. Parameters of the Weibull distribution were estimated using two methods: the maximum likelihood and the method of moments. Diameter distribution models were obtained by estimation of each distribution parameters and by their prediction using stand variables. Results revealed the efficiency of the Weibull distribution estimated with the method of moments. The parameter estimation method is more accurate compared to parameter recovery method despite the existence of strong correlations between parameters of the theoretical distributions and some population variables such as arithmetic or quadratic mean diameter and dominant height. Plot characteristics revealed the existence of several distribution shapes: symmetrical; dissymmetrical with left asymmetry and reverse I or J -shaped distributions.