"Cabrucas" are areas where cacao trees are planted in the shade of thinned native forest. In southern Bahia State, where the forests are few and fragmented, cabrucas are important for native species conservation. Aiming to evaluate the conservation of native tree species in cabrucas on a long term basis, a phytosociological survey of the shade trees was carried out in a 1.7-ha area of cabruca ca. 25 years after implantation, and the dynamics were assessed after a period of seven years. One hundred and twenty trees were counted and 62 species identified. Mean density was 70.5 ind. ha-1, mean basal area was 23.0 m² ha-1 and diversity was 3.88 nats ind.-1 (Shannon). After seven years, there was an 8.4% reduction in density, with a mortality rate of 2.16% year-1 and a recruitment rate of 0.81% year-1. The mean increment in diameter was 0.7 ± 0.6 cm year-1. The trees were mainly mature forest species, but newly recruited individuals were mostly pioneer species. Total estimated richness (Chao) was 110 species, with a reduction of 20 species during the period. The results confirmed indications that the cabrucas represent an important reservoir of native tree species, but these areas are quickly becoming altered, thinned and impoverished. There is an urgent need to modify current management practices in order to conserve mature forest species. The high basal area and growth rate indicate that the cabrucas may be used for carbon sequestration and storage.
Atlantic coastal forest; agroforestry systems; rustic cacao; species diversity; tree species conservation; phytosociology
