Análise estrutural da vegetação de caatinga sob manejo florestal sustentável.

Abstract

The Caatinga is a biome that covers a large part of the Brazilian northeast region. Over the years this biome has been suffering from the degradation due to the incorrect use of its resources through burnings and indiscriminate vegetal exploitation. The goal of this research was to analyze the floristic composition and structure of the native vegetation of a Caatinga area with a sustainable forest management, after fifteen years of exploration. The study was carried out at Fazenda Cantinho, located in the municipality of Itaporanga, state of Paraíba, Brazil, in an area of 5,94 ha (UPA 1). The forest inventory of the vegetation was made using random sampling, where five plots of 400 m² (20 mx 20 m) were allocated. Circumference at Chest Height (CAP) was measured at 1,30 m from the soil, and Circumference at Base (CNB) at 0,3 m from the soil of trees with CAP> 6 cm (CAP ≥ 6 cm ) on each measurable shaft of the tree, both were performed with the aid of a measuring tape graduated to the nearest 0,5cm. The total height (H) was measured with the aid of a graduated rod at 0.5 m intervals. In the floristic survey of the study area were sampled 1143 individuals belonging to 8 botanical families, 16 genera and 18 species. Euphorbiaceae (69.03%) and Fabaceae (20.56%) were the most representative families, with 89.59% of the individuals sampled, the other families representing 10.41%. The estimated average volume per sample unit was 1.20m³, in stereo meters the sample value was 2.66st, when the volume was 25.02 m³/ha and 66.38 st/ha. C. blanchetianus was the species with the highest basal area and largest volume in the studied area. As for the structure, the woody vegetation of the study area is open, which indicates that the vegetation is still in the initial stage of succession. This succession is characterized by the dominance of a species and the low estimated timber volume.