PRODUÇÃO DE FLORES E FRUTOS DE Bertholletia excelsa BONPL. EM AMBIENTES FLORESTAIS E DESMATADOS DO NOROESTE DO PARÁ, BRASIL

Abstract

The Brazil nut tree ( Bertholletia excelsa Bonpl) is a well-studied species, and most studies conducted on it have been done in its natural habitat, dense ombrophilous forest. However, there is a lack of information about the biology of this species in deforested areas, and such information would be useful for management and conservation. The objective of this research was to compare the flowering and fruiting of Brazil nut trees in two areas with different vegetation cover (forested and deforested) and to relate this to possible explanatory environmental factors. A total of 120 Brazil nut trees with DBH > 40 cm were monitored at two sites: Boa Vista (Obidos/PA) and Novo Betel (Oriximina/PA), in northwestern Para State. For each stem the following measures were recorded: geographic coordinates, dendrometric and spatial data, stem state and reproductive capacity, and signs of perturbation and regrowth. Flower count showed a flowering rate 4 times greater in the forested areas than in the deforested areas, and extremely low incidence of fruiting in the deforested areas, more than 20 times lower than the estimate for the forested areas. The soils in the deforested areas had higher levels of compaction and fertility than in the forested areas. Among the non-edaphic variables, the percentage of fire damage on the stems had significant differences between the sites and was greater in the deforested areas. It is concluded that soil compaction and fire can partially explain the low fruit production of Brazil nut trees in deforested areas without ruling out other environmental factors not evaluated in this research. Since Brazil-nut trees may provide ecological services on the deforested landscapes and are protected by law, urgent soil management and conservation measures are suggested to be undertaken in the deforested pasture areas in order to guarantee the conservation of these trees in the region, together with reforestation measures in the adjacent legal reserve areas. Keywords: Brazil nut tree; soil compaction; fire.