Estimation, by remote sensing, of deforestation in central Rondônia, Brazil

Abstract

Rondônia, Brazil has been the focus of extensive immigration, colonization, and deforestation since the early 1970s. We have documented the land-clearing activities in Rondônia through the use of remotely sensed data from the Landsat and the NOAA AVHRR series of satellites, with the objectives of defining the rates and area of forest loss. We found that the total area cleared in the common area of the Landsat scenes increased 3160 km2 from 230 km2 of clearing in 1980 to a total of 3390 km2 of clearing in 1986, that the majority of new clearings were in the 10-100-and 100-1000-ha range. The largest individual forest clearings, however, which ranged up to 28 km2, had been established since 1980. We also found that the total road length in the region has increased from 110 km in 1973 to at least 4660 km in 1986. Although the majority of clearing was to pasture and not for roads, road building allows access to new areas and virtually guarantees future clearing by legal settlers or by squatters. We estimated that the total area of forest cleared in Rondônia by 14 July 1988 was between 37 200 and 37 900 km2 based on two classifications of NOAA9 AVHRR satellite data. © 1991.