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

Abstract

he Brazilian Legal Amazon encompasses an area of approximately 5,030,000 km 2 , stretching from the states of Maranhao and Tocantins in the east to Amazonas and Acre in the west, and from Roraima and Amapa in the north to Mato Grosso in the south. Approximately 4,090,000 km 2 of this area is forested, 850,000 km 2 is cerrado (wooded grassland), and 90,000 km 2 is water (Skole and Tucker 1993, Fearnside 1996). As of 1988, 230,324 km 2 , or 5.6%, of the approximately 4,090,000 km 2 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 km 2 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 km 2 /yr in the 1970s, Mahar 1988; approximately 35,000 km 2 /yr in the 1980s, Fearnside 1989; approximately 15,200 km 2 /yr from 1978‐1988, Skole and Tucker 1993).