Summary
Deforestation in the Brazilian Amazon is proceeding at an unprecedented rate. Felling intensity is very uneven, being concentrated in certain parts of the region. A series of LANDSAT satellite images from settlement areas in Rondônia, from 1973 through 1978. indicate that clearing trends may be exponential, but information is too scant for firm conclusions. Available information from LANDSAT images from 1975 and 1978 covering all of Brazil's 5 x 106 km2 Legal Amazon indicate that if clearing were to proceed exponentially at the rate implied by the images at these two dates, the entire region would be cleared by 1991. The unevenness of clearing rates would result in some areas being cleared sooner and others later; if clearing rates within each state or territory were to remain constant, they would be cleared at dates ranging from 1988 for Rondônia to 2159 for Amapá. It is emphasized that none of these calculations represent forecasts of what is expected to happen, but only hypothetical scenarios of what would happen were these rates to continue. Deforestation is far too complex a process to be adequately represented by simple equations.
Forces leading to continued exponential growth of cleared areas include a probable positive feedback relationship between roadbuilding aid deforestation. Many government policies have potential effects on clearing rates, including highway construction and improvement programs, agriculture and ranching incentives, and policies affecting population size, distribution of income, land tenure, and agricultural mechanization both in the Amazon and in source areas of migrants. Brazil's Forest Policy draft law, to cover many aspects of development policy in Amazonia, is a major unknown factor in future deforestation trends.
More important than the precise time remaining for the bulk of Amazonia's rainforests are the designation and defense of areas to be left in forest, and the establishment in present and future cleared areas of agroecosystems which are agronomically and socially sustainable, limitation of concentration of income and land tenure, retriction of total consumption, and maintenance of human population levels below carrying capacity, defined to include an adequate and sufficiently certain standard of living.