Diameter distribution models for Nothofagus pumilio using the site index as variable.

CELLINI M; WABO E; MARTINEZ PASTUR G; LENCINAS MV; BOYERAS M

Brisbane (Australia) 8-13 Agosto

Congreso; XXII IUFRO World Congress.; 2005

IUFRO

Forest structure, expressed by diameter classes, is an important tool to quantify the commercial properties of stands. A Weibull model with two parameters was analyzed in order to characterize diameter distribution of Nothofagus pumilio trees in Tierra del Fuego. DBH and basal area were used as indicators of the tree size, in order to select predictor models of diameter and basal area distributions. The fitting was done with data of individual trees located in 161 sampling plots. The coefficients of the models were estimated trough an iterative method using the plot frequency data. The coefficients of each plot were correlated with forest structure variables, showing a high correlationship. The independent variables utilized for the prediction of the value and QMD (R² = 0.910) were used. The incorporation of QMD and Site Index allowed predicting reasonably the diameter distributions in a wide range of stand conditions.