For a number of decades, people have been logging specific types of trees in the fragile rain forest by stealthily extracting them one-by-one, with the forest canopy covering their tracks. "We discovered that annually an area about the size of Connecticut is disturbed this way," explained Asner. "Selective logging negatively impacts many plants and animals and increases erosion and fires. Additionally, up to 25% more carbon dioxide is released to the atmosphere each year, above that from deforestation, from the decomposition of what the loggers leave behind. Timber harvests are much more widespread than previously thought."
Brazil's Space Research Institute has used remote-sensing to accurately measure deforestation for over two decades. Surprisingly, though, little has been known about the extent of selective logging in the region because the satellite techniques could not penetrate the shielding upper layers of forest leaves. The Carnegie scientists developed the Carnegie Landsat Analysis System (CLAS) to penetrate this layer by analyzing satellite imagery with advanced computational methods and corroborating the results with selected on-ground field studies. "With the new Carnegie system, we can now see what's happening from the top of the forest all the way to the soil; we have a whole new picture of the Amazon region and selective logging," stated co-author Natalino Silva from the Brazilian Agricultural Research Corporation.
From 1999 through 2002, the scientists used remote sensing, with a spatial resolution of 98 ft
Contact: Dr. Greg Asner