Predicting merchantable volumes of Eucalyptus grandis through total volume and volume-ratio models

Abstract

Eight total volume and four volume-ratio models were evaluated for use in a system for predicting marketable volumes in Eucalyptusgrandis plantations. Data were collected from 101 trees in stands at harvest age, located in Salento, Quindio. Weighted regression was used to avoid problems of heteroscedasticity in the fit of total volume models. An autoregressive error structure was used to reduce autocorrelation of longitudinal data used in the fit of the volume-ratio models. After evaluation of goodness of fit and prediction, the models of Schumacher & Hall (1993) as total volume model and Cao etal. (1980) as volume-ratio model were selected. The bias and average error in the prediction of marketable volumes to variable-top diameter limits of 0, 5 and 10 cm were always below 4.4% and 11.5%, respectively. The functionality of the system to quantify marketable volumes during the construction of stand and stocks tables was demonstrated.

Keywords

• biometría forestal
• modelos de producción
• manejo forestal