Stem and total tree volume equations, taper and site index, for timber species in the temperate ecosystem of Durango, Mexico

Resumen

Objective: To generate stem volume (SV), total tree volume (TTV), taper and site index (IS) models for Pinus arizonica, Pinus durangensis, Pinus engelmanni, Pinus leiophylla, Pinus teocote, Pinus strobiformis, Pinus lumholtzii and Quercus sideroxyla, in productive landscapes of a temperate ecosystem in northwestern Durango, Mexico. Methodology: Data were collected from 1280 trees (298 with trunk analysis). Based on the dendrometric type, the volume was obtained and estimated the SV, TTV and VC (branches ≥ 5 cm volume). Using a xylometer, the volume of branches and twigs < 5 cm was estimated. For TTV and SV, the Schumacher-Hall model was fitted with a ponderaded regression to correct for heteroscedasticity. The Biging function was used for the stem profile, fitted with nonlinear generalized least squares to correct for autocorrelation. The algebraic difference method with Chapman-Richards base equation was used to generate the site index equations. Results: A biometric system has been developed with 16 equations to estimate SV and TTV, 8 equations for stem profile, and 14 equations to form polymorphic curves and qualify the IS. Limitations: Its use elsewhere, requires a validation process. Conclusions: The results show that the models were unbiased and with significant parameters, so their use is recommended in the estimation of the SV, TTV, stem profile and estimation of the IS in the region of Santiago Papasquiaro, Durango, Mexico