Dynamics of the diameter distribution of Pinus taeda stands, in the region of Caçador, SC, Brazil

Abstract

The objective of this work was to fit the probability density functions Normal and S_B, to describe the changes, with age, in the diameter distribution of loblolly pine (Pinus taeda) stands, in the region of Caçador, Santa Catarina State, Brazil. The data came from permanent and temporary plots, with ages ranging from 5 to 11,9, grouped in age classes with intervals of 1 year. The probability density functions were fitted and, the Kolmogorov-Smirnov test and the parameters of skewness and kurtosis were calculated. Basing on Kolmogorov-Smirnov test it was verified that, for ages from 5 to 7.9 years old, the Normal and S_B functions didn´t show satisfactory adherence. The S_B and Normal functions showed better adherence to the ages from 8 to 9.9 and from 10 to 11.9 years old, respectively. Using the Normal probability density functions to analyze the dynamics of the diameter distribution, it was found that there was a shift of the diameter distribution curves to the right, a "flatness" and an "wideness" of these curves, over the years. The skewness was negative for all ages, except for the age from 8 to 8.9 years old. The kurtosis was leptokurtic for all ages, except for age from 8 to 8.9 years old, which was platykurtic.