The Deciduous Thorny Vegetation (DTV) that covers the semi-arid area of Northeastern Brazil, called caatinga, is highly diversified as a function of its climatic and morphopedological characteristics. Since little is known of its characteristics in the border of its distribution, as in the Agreste region on the Borborema plateau, a floristic and phytosociological survey was conducted in an area at Caruaru, Pernambuco. All plants > 1m high e > 3cm of stem diameter within 36 plots, 10 × 10m each, had their height and diameter measured. A total of 96 species, belonging to 41 families were found in the area, of which 55 species were included in the phytosociological survey. Most of them are also found in the dry core of the Northeastern semi-arid region, but a few of them occur in places with higher water availability. Total density (3,810 plant ha-1) and basal area (24.9m² ha-1) and stem diameter distribution were within the range found in other DTV areas but the number of plants taller than 8 m was higher, almost double the previous highest value. The most important species were the same found in other DTV areas but different from those of regional Montane Forests (MF), Deciduous Non Thorny Vegetation (DNTV) and Humid Lowland Forests (HLF), in Northeast. In a cluster analysis, based on flora, HLF formed a separate group and in the other group DTV and MF were more similar than DNTV. Structurally, DTV has less small plants than both MF and DNTV and less large plants than MF but more than DNTV. The vegetation in the Agreste at Caruaru is an arboreal DTV, with tall plants and the presence of a few species more common in more humid areas than the dry core of the Northeast.
Northeast; physiognomy; deciduous thorny vegetation; semiarid; caatinga
