Análise comparativa de remanescentes de Caatinga destinados ao manejo florestal nos Estados da Paraíba e Rio Grande do Norte.

Abstract

The caatinga's forest resources are mostly responsible for the supply of solid bioenergy consumption in the Northeast of Brazil, and firewood stands out as the most exploited product. Sustainable forest exploitation of caatinga aiming at the obtainment of environmental, economic and social benefits is regulated by law and is permitted through a Forest Management Plan, which can provide information to support scientific studies and better analyses on forest ecosystem where they are implemented. Aiming to analyze the floristic composition, the phytoecological similarities, firewood yield, some environmental, economic and social benefits, provided by the implementation of sustainable Forest Management Plans, two areas for studies were selected which are located in rural properties in Barrentas in the Seridó Potiguar (Backland Depression) and Passagem Rasa in the Cariri Paraibano (Borborema Plateau). Vegetation sampling was carried out in parcels of adult trees with 400 m2, randomly distributed in the study areas, being measured the shrub and tree individuals with diameter at breast height higher than six centimeters, with popular name, diameter and height being written down. Within each parcel it was created a sub-plot in order to count regenerating individuals. The composition and floristic diversity, parametric and volumetric distribution of areas of study were analyzed, as well as the volumetry applied to forest management and its environmental, economic and social benefits. 1,418 individuals were found in the parcels of adult trees distributed into five families, 11 genres and 11 forest species in Barrentas. 1,565 individuals were found in Passagem Rasa distributed into 10 families, 20 genres and 26 species. In natural regeneration, 398 individuals were found distributed into five families, 10 genres and 12 species in Barrentas and 680 individuals were found in Passagem Rasa distributed into five families, 10 genres and 11 species. The forest remnants showed low floristic homogeneity, although the ecological diversity rates produce similar results. Fabaceae and Euphorbiaceae were the families with the largest number of species found in the areas of study, though three pound species were regarded as endangered ones in Passagem Rasa. Poincianella pyramidalis was the found species with the higher value of importance in the areas of study in the stratum of adult trees and Croton blanchetianus in natural regeneration. Passagem Rasa presented higher basal area and volumetry than Barrentas, being estimated an equivalent stock of 19.7 thousand tons of carbon in the areas of study. Economic analysis of the implementation of Forest Management Plans revealed a negative evaluation for a pessimistic market scenario in Barrentas. In Passagem Rasa, the evaluation was positive regardless the market scenario. Social analyses show that sustainable and legalized firewood exploitation can promote the occupation of idle labor force as well as generate and promote extra income distribution in rural areas.