Diametric distribution and determining height in an Araucaria angustifolia (Bertol.) Kuntze plantation in central region of Rio Grande do Sul

Abstract

This study aim to determine the mathematical model that defines the best hypsometric curve of the relationship between height/diameter from the specie of Araucaria angustifolia, in a plantation located in the area of FEPAGRO FORESTS, Santa Maria-RS. We modulate the diametric distribution of this plantation from probability density function (pdf) and relationship height/diameter using mathematic functions. After adjustment, the results showed that it obtained multiple coefficient of determination values ranging from 0.36 until 0.47, and standard error between 10.58% and 11.64%. When these parameters were analyzed, it shown that the h = b₀ + b₁dap + b₂dap² was the model that had better adapt for the local conditions, obtaining R²aj= 0.47 e Sxy% = 10.59. The function SB of Johnson was the one that had better adapt to diametric distribution, according to the Kolmogorov-Smirnov test. The conclusion is that the hypsometric equations can be utilize to estimate the height variable of the specie in the region with acceptable errors, as well as can be modulate the diametric distribution of the forest, utilizing many functions.