Abstract

HERNANDEZ-RAMOS, Jonathan et al. Generalized equations of height-diameter for Pinus pseudostrobus Lindl. forests in Nuevo San Juan Parangaricutiro, Michoacán, Mexico. Madera bosques [online]. 2018, vol.24, n.2, e242494.  Epub Aug 22, 2018. ISSN 2448-7597.  https://doi.org/10.21829/myb.2018.242494.

Precise estimation of total tree height is critical for proper forest management, however, measurement of all trees on an inventory site is virtually impossible for the time and costs it generates. Therefore, a study was carried out in order to adjust an equation representing the ratio of the total height with normal generalized diameter (h-d) for forests of Pinus pseudostrobus Lindl. in Nuevo San Juan Parangaricutiro, Michoacán, Mexico. With data from 158 inventory sites, 12 generalized h-d models were adjusted. Wang and Tang model which includes normal diameter and dominant height, shows the better fit as indicated by significant parameters, the best values of mean square error sum, mean square error root and adjusted determination coefficient. Influence points analysis of studentized residuals was between 2.5 and -2.5, while Cook's distance does not show problems. The distribution of residuals was homocedastic, the value in the Durbin-Watson test was 1.7 and the Shapiro-Wilk test was 0.97. The kurtosis index was -2.35 and the trend in the Gaussian bell was Leptokurtic. The bias was 0.004 m and the aggregate difference was -0.017%. The selected model proved reliable when estimating the total height up to 60 cm in diameter and can be used in forest inventories for the species.

Keywords : allometry; forest inventory; non-linear regression; Wang and Tang.

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