ABSTRACT
The conversion of forests into agricultural land is characterized by considerable changes in the biomass stocks. In Brazil, 87% of the biomass losses in forest conversion are caused by agriculture and in a given area, conversion into agricultural land use can lead to reductions of 95% or more of the above-ground biomass and carbon stocks, as compared to pristine rainforests. Biomass accumulation and, consequently, carbon sequestration depend on the agroecological environment the predominant land-use systems and the respective agricultural practices. The fallow vegetation after short cropping periods of regularly fallowed fields are different from the stands which develop subsequent to the abandonment of semi-permanent plantations, the cultivation of which does not necessarily include fallowing. A similar effect can be observed if the fallow periods in the traditional land use cycle are repeatedly very short. The development of agricultural landscapes in Amazonia could be observed in large areas, e.g., along the Transamazon highway or in the state of Rondonia.
