Caracterización de las estructuras diamétricas de los bosques naturales del noroeste de Durango, México

Abstract

T he 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 (e) 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. ResumenL a distribución diamétrica de 44 parcelas permanentes (coníferas y latifoliadas) se modeló a través de las funciones de densidad de probabilidad (FDP) Weibull de tres parámetros y S B Johnson, en el municipio de Santiago Papasquiaro, Durango. Para ello, se emplearon cuatro métodos de ajuste de parámetros: máxima verosimilitud, momentos, regresión no lineal por mínimos cuadrados ordinarios y percentiles. El mejor método de ajuste para las especies de coníferas y latifoliadas fue el método de momentos. En el modelado de la FDP Weibull se asumió que el parámetro de localización (e) corresponde al diámetro mínimo inventariable de la distribución. El parámetro de escala (λ) se modeló con el procedimiento de predicción de parámetros a través de un modelo de regresión lineal simple que relaciona γ con el diámetro cuadrático medio y la altura dominante del rodal. Finalmente, el parámetro de forma (γ) fue recuperado indirectamente por el método de momentos a través de la predicción del diámetro medio del rodal. De acuerdo con la prueba de Kolmogorov-Smirnov (P = 0.05), 71 % de las parcelas del grupo de especies de coníferas y 68 % de las parcelas del grupo de latifoliadas provienen de una población que sigue la función de distribución ajustada. Palabras clave: Coníferas, latifoliadas, función Weibull, modelado diamétrico.

Individual Tree Diameter and Height Growth Models for 30 Tree Species in Mixed-Species and Uneven-Aged Forests of Mexico

“…The Sierra Madre Occidental in the Mexican State of Durango constitutes a hotspot of forest biodiversity, being home to about five million hectares of species-rich and uneven-aged forest stands [26]. It is the first forest reserve in Mexico with an estimate of 422.1 million m 3 of timber volume, and represents 22.4% of the total estimated production at the national level [27,28]. In 2015, Durango produced 28.5% of the total timber volume harvested in Mexico [3].…”

“…Consequently, the development of forest growth models for mixed and uneven-aged stands is imperative to be used as important tools to support the informed decision-making in this type of forest ecosystems. To date in Durango, forest growth studies have been conducted on site quality [31][32][33], stand density management [28], dbh growth models [3], tree competition [34,35], tree volume and biomass equations [27,36,37] and tree diameter-height relationships [38]. However, most of the previous studies dealt with only one or a few tree species and Forests 2020, 11, 429 3 of 16 there have been very limited efforts to develop individual-tree dbh or height growth models for most of the commercial tree species in mixed-species forests.…”