Taper equations for Nothofagus pumilio (Poepp. et Endl.) Krasser and their use in total volume estimation

J. M. Cellini, G. Martínez Pastur, E. Wabö, M. V. Lencinas

Abstract


Sixty trees of Nothofagus pumilio along a site gradient between qualities 1 to 3 were sampled in Tierra del Fuego (Argentine). Taper equations were fitted for trees living in secondary forests (stands originated from the regeneration after the harvesting) of N. pumilio, comparing four traditional models with a non-traditional equation, which use the site quality as variable. Therefore, form factor was incorporated into the traditional volume equations comparing their fitting by a residual analysis. Muhairwe variable-exponent taper equation, which includes the diameter at the breast height, the total height and the height at a certain diameter, had the best general behavior, with the best fit to several site quality classes, diameter and relative heights. The new proposed model in this work, that included the site quality as variable has poor fit, but increase their usefulness, since it not include the total height mensuration. The inclusion of the form factor in the elaboration of the volume models improves the fit through a simple methodology, without increasing the complexity of the traditional models.

Keywords


taper functions; volume models; lenga; forest inventory; Tierra del Fuego; Patagonia





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