Ciencia forestal en México
Print version ISSN 1405-3586
LOPEZ HERNANDEZ, Juan Antonio and VALLES GANDARA, Arturo Gerardo. Modelos para la estimación del índice de sitio para Pinus durangensis Martínez en San Dimas, Durango. Rev. Cien. For. Mex [online]. 2009, vol.34, n.105, pp. 185-196. ISSN 1405-3586.
Site index is the most commonly used method in Mexico and in several countries to estimate the productivity of forest lands, since it is a numerical expression easy to understand and density-free. The objective of this work was to adjust model groups to predict the site index of Pinus durangensis from data of a the remeasurement of 12 permanent plots settled in a natural forest in the Ejido Vencedores at San Dimas, Durango. Thirteen mathematical models were adjusted through the mean square procedure, ten of which are linear and three non-linear. Were adjusted three groups of models of linear simple regression, logarithmic,quadratic and a mixed model. In regard to the three non-linear, the Chapman-Richards and Schumacher functions as well as the Weibull model were tested. The best models were selected according to the degree of adjustment or Pseudo R2, the F test, the mean square error (MSE), the test of hypothesis of the estimators and the sign of the parameter. Results show that provided the best site index estimation was the logarithmic 6 (Ln[E/H] = β0 + β1[1/E]) since it revealed the highest values for the residual R2 test, which was 0.7419; MSE was 0.01608 and 221.304 in the F test.
Keywords : Chapman-Richards function; Schumacher function; site index; logarithmic model; Weibull modell; Pinus durangensis.