Comparison of methods and processes of sampling for phitossociological studies of an ecotonal forest in the matogrosso northern region

Abstract

The main objective of this research was to compare estimated phitossociological parameters obtained by sampling with true parameters obtained from the census of an ecotonal forest of 120 hectares, located in northern region of the Matogrosso State for eight groups of species. It was studied the floristic composition and the diversity, spatial distribution of species and characteristics of the horizontal structure for trees with dbh ≥ 30 cm. The applied sampling processes were random and systematic, with 5 and 10% of sampling fraction, with 22 sizes and forms of plots ranging from 400 m² to 10,000 m². It was identified 7,968 trees distributed in 70 species (6 not identified), 58 genera and 31 botanical families, presenting, in average, 66.4 trees and 11.08 m² of basal area per hectare. The richest botanical family was Fabaceae - Caesalpinioideae and, the densest one was Sapotaceae. The most important species was Micropholis guyanensis (A.DC.) Pierre subsp. guyanensis. The preponderant standard of distribution of the species is the random one for the plot with 400 m² and aggregate for the plots with 10,000 m². Plots with 400 up to 2,500 m² estimated with efficiency the values of covering for the group of the 15 commercial species with greatest VI (Importance value), and for the 6 most important ones. For the rest of the groups of species the errors showed that estimative processes (randon and systematic, with 5 and 10%) are impracticable.