Estrutura e regeneração natural em remanescentes de caatinga sobmanejo florestal, Cuité - PB.

Abstract

The biogeographical area known as Caatinga has several faces with characteristics of semiarid regions. The vegetation has economic potential and can be exploited in a sustainable way. So, forest management presents techniques that should be used to ensure the maintenance of economic and ecological balance of potentially exploited areas. Despite its proven benefit in several areas of Caatinga, it is necessary to develop studies on the structure and natural regeneration of areas of Caatinga before and after cutting, in order to support future work and assess the techniques employed. Thus, this study aimed to analyze the forest structure and dynamics of natural regeneration in Annual Production Units (UPAs) subjected to forest management at different cutting times and a legal reserve. This study was developed in the settlement of land reform, Brandão III, in the municipality of Cuité - PB, located in the north central region of the state of Paraíba, in the microregion of Western Curimataú in Paraiba. We conducted a floristic and phytosociological inventory in 30 sampling units randomly distributed, with 10 units in each of the three study areas (two PSUs and one Legal Reserve). Each sample unit consisted of a 400 m2 plot of where the individuals with CAP> 6 cm were counted and a subplot of 40 m2 where regenerating individuals were sampled. Analyzes for diversity, density, frequency, dominance, similarity and importance value were performed. 15 families, 35 species and 4,788 individuals were found in the survey of the adults. In the survey of regeneration there are 15 families, 30 species and 1,907 individuals. The most representative plant families in the two analyzed parameters (structure and natural regeneration) in the three areas were Fabaceae, Euphorbiaceae, Anacardiaceae. The Croton blanchetianus Baill species excelled in the two UPAs with high importance value (14.74% and 13.38%, respectively, for the UPA 04 and UPA 13), while in the Legal Reserve, the species with the highest importance was pyramidalis Poincianella (12.69%), followed by blanchetianus C. (12, 40%). In general forest management did not affect negatively the structure and diversity of the studied areas within the study period. Among adults the Diversity Index Shannon-Weaver (H ') ranged between 2.10 and 2.35 nats.ind-1, and among saplings individuals this ratio was between 1.33 to 2.24 nats. ind-1. The evenness index (J) among adults ranged from 0.68 to 0.70 and among saplings individuals from 0.48 to 0.71, The Simpson Diversity Index (C) among adults ranged 0.77 to 0.84 and among saplings individuals 0.95 to 0.97. The index Similarity Søresen (OS) when analyzed adult individuals was 0.77 to 0,86 and regeneration it ranged from 0.66 to 0.76. As for the behavior of natural regeneration showed that the most recently cropped area (UPA 13), individuals predominate in the lower class size from regrowth, while in other areas (UPA 04 and Legal Reserve), individuals focus the largest size class and are derived from seeds.