Populational analysis of Caesalpinia pyramidalis Tul. (Fabaceae Lindl.) in the Caatinga in Northeastern Seridó, Brazil

Abstract

This study aimed to contribute to the knowledge of population structure of Caesalpinia pyramidalis Tul. (catingueira) in areas of Caatinga in Northeastern Seridó, to obtain information about the species in the region studied. In two areas, one in Rio Grande do Norte (Area I) and another in Paraíba (Area II) were randomly located 20 plots of 20 m x 10 m, totaling 4,000 square meters of area sampling. All individuals of C. pyramidalis inserted inside the sample units had measured its diameter at the ground level (DGL) and total height. For the evaluation of the structure of the population, were calculated the density and frequency in each ontogenetic stage, the size of the class of natural regeneration for regeneration the basal area for adults, the pattern of spatial distribution and the Pearson correlation coefficient between ontogenetic stages. DGL and height of the subjects were divided into classes of frequency and the DGL x height was assessed by simple linear regression. Area I was sampled 722 individuals of C. pyramidalis, of which 366 were adults and 356 regeneration. Area II 536 specimens were sampled, with 226 belonging to the natural regeneration and 310 adults. The populations studied had a high density, average values for basal area and size class of natural regeneration, aggregated distribution with positive correlation between ontogenetic stages, and variation in height explained by the diameter measured at the ground level.