Modelling mortality in Pinus taeda L. stands

Tree mortality is a factor with direct influence on forest growth and production. Its evaluation requires attention in order to represent an essential component in the simulation of forest dynamics. The aim of this study was to fit and evaluate mathematical models to estimate the probability of tree mortality in Pinus taeda L. stands. Data were obtained from permanent non-thinned plots, located in the region of Telemaco Borba, State of Parana, Brazil, aged from 3.2 to 21 years. Initially mortality dynamics was evaluated by age and site class. Also, the behavior of the number of living trees and mortality were analyzed by diameter class, as well as specifying the diametric range of mortality. The mortality of the stands was estimated using four probability of mortality models by diameter class. The occurrence of mortality was observed from five years of age until the diametric class of 28 cm and the minimum diameter until 75% of the arithmetical mean diameter of the plot. The exponential model that estimated the number of dead trees per hectare for the three site classes, used the basal area index (BAI) as independent variable, as well as site (S), center of diameter class (CCd), age (I) and basal area by diameter class (G(classe)).