The composition and structure of the shrub-arborealcomponent of the vegetation were analyzedin two areas of the caatinga, with different histories ofuse, in Floresta, Pernambuco, Brazil. Sixty 20x20 m plots were assessed, 40 in an area of secondary vegetation 22 years after clearing (Area I) and 20 in a conserved vegetation area (Area II). Botanic identificationwas made, and circumference at breastheight (CBH), height of trees with CBH > 6.0 cm, calculating horizontal structure parameters and species richness and diversity, were determined. The secondary vegetationshowedgreater species richness, differing from the conserved vegetation in phytosociological structure and physiognomy. In both areas, the species of greatest Importance Value was Poincianellabracteosa, the dominance of which was greater in Area I, where Pityrocarpa moniliformis, Piptadenia viridifolia, Senna spectabilis and Croton blanchetianus were exclusive. Croton rhamnifolius, Manihot glazioviie and Myracrodruon urundeuva were present in both areas but showed greater relative importance in the most conserved area. The vegetation in the conserved area had a larger basal area and larger mean and maximal height values than the disturbed area, demonstrating that the vegetation structure was still in development 22 years after use. Referring to the basal area of Area II and the estimated increment in the secondary vegetation area, regeneration in deforested areas would require more than 40 years to restore the original structure.
Phytosociology; Semi-arid tropics; Ecological sucession
