Regeneração natural em área de caatinga manejada, no Município de Cuité, no Estado da Paraíba.

Abstract

Despite being one of the most heterogeneous Brazilian biomes, despite the least known, the Caatinga is under strong anthropism. In this way, forest management offers techniques that must be used to guarantee the sustainability of the productive system of areas with management potential. Thus, it is fundamental to develop studies on the dynamics of the natural regeneration of the Caatinga areas that suffered this disturbance, in order to offer subsidy to future work and to evaluate the techniques employed. The objective of this study was to evaluate the floristic composition, structure and behavior of the natural regeneration of the arboreal-shrub stratum, as well as verify the floristic and phytosociological diversity of the soil seed bank in three Annual Production Units (PAUs) submitted to management different cutting seasons and in the Legal Reserve. This study was developed in the settlement of the agrarian reform, Brandão III, located in the municipality of Cuité-PB. In order to evaluate the natural regeneration, 5 x 5 m (25m2) plots were installed within the harvested plots and in the Legal Reserve (RL), totaling 40 sample units, being measured individuals with CNS ≤ 6 cm and with a minimum height of 0,5 m. The floristic composition, the horizontal structure, the natural regeneration structure (RNT) and the type of regeneration origin were studied. The data of density, diversity and origin of the natural regeneration and density and diversity of species of the seed bank in the soil were compared by the Tukey test at 5% of significance. To evaluate the seed bank in the selected areas, 10 samples of the soil seed bank were collected inside each plot (25m2) in the lower right corner, totaling 40 samples of soil + litter. In the survey of natural regeneration, we sampled 2021 individuals, represented by 32 species, 27 genera, distributed in 16 families. The most representative botanical families were: Fabaceae, with 8 sp, Euphorbiaceae, with 6 sp, and Anacardiaceae, with 2 sp. In the 40 trays referring to the seed bank in the soil of the four experimental units, there were 1,993 individuals belonging to 22 botanical families and 49 species. For all comparative purposes, forest management did not negatively affect natural regeneration, although the exploitation reduced the number of species compared to the natural reserve. It is concluded that the techniques applied in the management plan efficiently ensure the recovery of vegetation through the natural regeneration mechanism.