Mapping the regional extent of tropical forest regeneration stages in the Brazilian Legal Amazon using NOAA AVHRR data

The study aimed to map several stages of tropical forest regeneration acros s the Brazilian Legal Amazon using 1.1 km NOAA AVHRR data. Regenerating for est extent was defined using an unsupervised classification of AVHRR channe ls 1, 2 and 3 and the Global Environment Monitoring Index (GEMI). A method for discriminating four forest regeneration stages was then developed, base d on relationships between AVHRR channels 1, 2 and 3 and forest age. This m ethod was applied to AVHRR data to map forests associated with Stages I(ear ly colonization phase, open canopy, <5 years), II (closed, single-layered c anopy, 5-9 years), III (closed canopy with structural development, 9-20 yea rs) and IV (closed multilayered canopy, >20 years). The maps provided new r egional estimates of regenerating forest for the Legal Amazon and indicated that, over the period 1991 to 1994, approximately 35.8% (157 973 km(2)) of the total deforested area of 440 186 km(2) (estimated for 1992) supported regenerating forest, with 48% of these forests aged at less than 5 years. T he study concluded that AVHRR data has an important role in mapping and mon itoring tropical forest regeneration. The datasets generated provide valuab le input to models of regional carbon flux.