Estudo da dispersão de sementes e da regeneração natural de três espécies arbóreas da caatinga.

Abstract

Natural regeneration begins with seed dispersion. It includes seedlings and individuals at several stages of development. Cumaru (Amburana cearensis), aroeira (Myracrodruon urundeuva) and ipê-roxo (Tabebuia impetiginosa), the species considered in this study, present a high lumber potential and are characteristic of the arboreal type of Caatinga, however its ecology and distribution were not studied so far. The objectives of this study were to evaluate the community structure of these three species in a preserved Caatinga site, their natural pattern of seed production and dispersion, seedling development and population stratification. The study was carried out in the following phases: litter collection close to the trees before seed dispersion, litter collection close to T. impetiginosa trees after seed dispersion, and data collection for population stratification and seedling monitoring in the field. Seeds of the three studied species are transitory as they germinated within one year after seed dispersal. Tabebuia. impetiginosa seeds seem to be dispersed equally around the tree, and, under controlled conditions, germination occurs within the first four weeks when litter moisture is satisfactory. Tree regeneration in most numerous in the lower height and diameter classes, denoting a high regeneration rate. Among the studied species, A. cearensis contributed the most to the tree stratum.