Secondary Forest Age and Tropical Forest Biomass Estimation Using Thematic Mapper Imagery

Abstract

The Brazilian Legal Amazon encompasses an area of approximately 5,030,000 km², stretching from the states of Maranhão and Tocantins in the east to Amazonas and Acre in the west, and from Roraima and Amapá in the north to Mato Grosso in the south. Approximately 4,090,000 km² of this area is forested, 850,000 km² is cerrado (wooded grassland), and 90,000 km² is water (Skole and Tucker 1993, Fearnside 1996). As of 1988, 230,324 km², or 5.6%, of the approximately 4,090,000 km² forested Brazilian Legal Amazon had been deforested (Skole and Tucker 1993, Skole et al. 1994) since theconstruction of the Belem-Brasilia Highway in 1958 (Moran et al. 1994). Each year, approximately 15,000–20,000 km² of additional primary tropical forest in this region are cut and cleared (Skole et al. 1994), although estimates of clearing rates have varied greatly among studies and over the decades (approximately 8000–10,000 km²/yr in the 1970s, Mahar 1988; approximately 35,000 km²/yr in the 1980s, Fearnside 1989; approximately 15,200 km²/yr from 1978–1988, Skole and Tucker 1993).