Dinâmica e distribuição diamétrica de espécies arbóreas em fragmento florestal, São Lourenço da Mata - PE

Abstract

The objective of this work was to evaluate the dynamics and diametric structure by means of probabilistic density functions in a forest fragment. The work was carried out in a fragment of the Atlantic Forest, commonly known as Mata do Camurim, located in the municipality of São Lourenço da Mata. A total of 40 permanent plots were systematically allocated in 2013 and in 2016 all tree individuals marked in the first survey were remeasured and those that reached inclusion level ≥ 15 cm in circumference at 1.30 m from the soil were measured. The characterization of the horizontal structure was carried out by the estimation of phytosociological parameters in order to identify the ten species of greatest value of importance (VI). Growth, Ingrowth and mortality in the period 2013-2016 were estimated. The number of diametric classes was defined from the analysis of different formulas, in order to determine the ideal for the community and for the 10 species of major VI. The probabilistic density functions (fdp) analyzed were Normal, Log normal, Beta, Gamma, Weibull 2P, Weibull 3P and Hyperbolic. In order to choose from the best description of the diameter distribution, the standard error of the estimate was used and the Kolmogorov-Smirnov test was applied at 1% probability. The fragment showed equilibrium in recruitment rates and mortality. The Sturges formula was the one that met the determination of the ideal number of diameter classes to define the diametric distribution of the fragment studied. The forest community presented a pattern of diametric distribution typical of natural forests, in inverted "J" form, as well as, in general, the species of higher VI. In the adjustment of the diametrical distribution the functions of Weibull 3P and Hyperbolic were the ones that presented greater adherence to the data, for the community as well as for the ten species of greater value of importance.