Abstract

CORRAL-RIVAS, Sacramento; ALVAREZ-GONZALEZ, Juan G.; CORRAL-RIVAS, José J.  and  LOPEZ-SANCHEZ, Carlos A.. Characterization of diameter structures of natural forests of northwest of Durango, Mexico. Rev. Chapingo ser. cienc. for. ambient [online]. 2015, vol.21, n.2, pp.221-236. ISSN 2007-4018.  https://doi.org/10.5154/r.rchscfa.2014.10.046.

The diameter distribution of 44 permanent plots (conifers and broadleaf trees) was modeled using the three-parameter Weibull and Johnson's S_B probability density functions (PDFs) in Santiago Papasquiaro, Durango. Four different methods of fitting parameters were used: maximum likelihood (ML), moments (MM), non-linear regression by ordinary least squares (ONLS) and percentiles (MP). The best method of fitting parameters for conifers and broadleaf trees was the method of moments. In modeling the Weibull PDFs, it was assumed that the location parameter (ε) corresponds to the minimum measurable diameter. The scale parameter (λ) was modeled using the method of prediction parameter (PPM) through a linear regression relating to the quadratic mean diameter and dominant height of the stand. Finally, the shape parameter (γ) was indirectly recovered by the method of moments through prediction of the average diameter of the stand. According to the Kolmogorov-Smirnov test (P= 0.05), 71 % of the plots for the group of conifers and 68 % of the plots for the group of broadleaf species come from a population that follows the fitting distribution function.

Keywords : Conifers; broadleaf trees; Weibull function; diameter distribution modeling.