Using multi-temporal satellite data to evaluate selective logging in Para, Brazil

Clear cutting in tropical forests is common. A newer phenomenon, selective logging, is evident in Amazonia when examined with high-resolution satellite data. We have quantified selective logging by digitizing satellite imagery and have found that it is much more difficult to detect than clear cutting. Selective logging is likely under-reported in satellite imagery-based estimates of change in Amazonia as the visible signal of selective logging may be evident for only a limited time. We have found that the areas affected by selective logging have increased over time and have become more widely distributed. Little land selectively logged, perhaps 10%, was converted to pasture. Selective logging altered 12% of the total forested area of one study region, yet was undetectable in satellite imagery three years later. It is unclear how long the visual clues of selective logging will remain apparent in satellite imagery in subsequent years.