COMPOSIÇÃO E ESTRUTURA FLORÍSTICA DE FLORESTAS DEGRADADAS E SECUNDÁRIAS DA MESORREGIÃO SUDESTE PARAENSE, PA, BRASIL

The goal of this this study is to raise the floristic and structural patterns of the tree component in degraded primary forests (FPD), secondary forests in early stage (FSI) and intermediate (FSM) at two levels of diameter at breast height: level I - 2cm 10cm and level II - DAP≥10 cm. To quantify level II individuals, 63 sample plots with the dimensioning of 10 m x 250 m were installed and within each of these sub-plots of 10 m x 10 m were allocated for sampling of individuals of level I. The phytosociological parameters as the dominance, relative density, frequency, Import Value Index (IVI), Coverage Value Index (IVC), as well as the community diametric structure and Shannon-Wiener diversity (H '), Pielou equability (J) and Simpson (C) by vegetation type and levels were calculated. The density, richness and basal area were compared using the Kruskal-Wallis non-parametric test at the 5% probability level. There were 5,601 individuals above 2 cm of DAP, 181 species, 134 genera and 63 families, where FSM had the highest number of individuals with 2,850 individuals (530 - Level I, 2,320 - Level II), and the FSI with 970 individuals (447-level I, 523-level II) and the FPD with 1,781 individuals (533-level I, 1,248-level II). Vismia guianensis and Cecropia spp. Were more abundant in all areas of secondary forests (FSI and FSM), in the two levels of DAP, while Swartzia spp. and Pouteria sp. were the most representative in FPD. At level II, the individuals density, richness and basal area were statistically similar in the areas of FSM and FPD, differing from the FSI areas. The diametric distribution followed the pattern for natural forests of inverted "J" level II. Keywords: Amazonia; Phytosociology, basal area, Vismia , Cecropia .