Successional patterns associated with slash-and-burn agriculture in the upper Rio Negro region of the Amazon Basin.

Weeds established just as readily in plots with Manihot esculenta (the principal crop plant of the region) present as in plots with M. esculenta removed. Repeated farm-plot weedings caused woody plants to decline in numbers and biomass and herbaceous plants to increase. Forbs and grasses dominated immediately following farm site abandonment, but by one year these had begun to senesce and fast-growing successional woody species (particularly Vismia spp) were common. Standing crop biomass at one year was 773 g dry weight m^-2. Several microhabitat types were present on abandoned farm sites. Grasses and forbs showed no microhabitat preference, whereas successional woody individuals had their best establishment near slash and under fruit trees. -Authors