Diameter growth models for Nothofagus dombeyi

Abstract

Models of diameter growth for Nothofagus dombeyi were developed and the selected model used for this study was non-linear and known as Bertalanffy-Richards. It was fitted from three main data sources: permanent plots (with only two measurements each), stem analysis and tree cores. The data was divided into social strata and then, for each stratum, the model was fitted according to the variables: diameter annual increment (id) and diameter at breast height (dap). The fitting, and both biological and statistical analysis, was carried out taking two different data sets into account: an independent data set, provided by permanent sample plots; and a growth series, provided by tree increment cores and stem analysis.
Models with different uses were obtained through both data sets. With the independent data, we obtained models that allowed us to predict the diameter annual increment in a short time and, with the growth series, we obtained models of a high biological significance.
In this sense, the biological significance of the parameters from each model was discussed when they were fitted.
An interpretation of the dynamic growth of the species studied has been undertaken through the biological models under different competence status.