You might think that it would be easy to keep track of deforestation around the world. Does the landscape have trees, or not? Turns out, it’s not easy. Much deforestation is associated with small clearings that do not show up on aerial photographs. And, many times governments do not want to admit to the rates of deforestation that they tolerate.
New high-resolution satellite photos are allowing us to improve the global assessment of forest health. In a new paper, published in Science, Matthew Hansen of the University of Maryland assessed the status and trends of the world’s forests.
Since 2000, we’ve lost 890 thousand square miles of forest, largely in the tropics, but trees have reforested 300 thousand square miles that were known to be barren at the study’s onset. While the rate of loss of the Amazon rainforest in Brazil has slowed, the overall rate of loss of tropical forests worldwide is increasing by about 810 square miles per year. Tropical forests are disappearing at a rate of over 200 square miles per day or 5400 acres each hour. Forests were also in decline in the boreal region, due to fire and insect attack.
The loss of forests anywhere affects us all. Tropical forests are a vast storehouse of biodiversity and carbon, which is released to the atmosphere when land is cleared. Boreal forests also release carbon dioxide to the atmosphere when they are cleared—much stemming from losses of soil carbon that has accumulated since the last glacial period.
These new estimates and the techniques used to produce them will provide a reality check on what is really happening to the world’s forests.
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See Hansen et al. (2013), Science doi 10.1126/science.1244693
Photo, taken on March 6, 2011, courtesy of Angela Marie via Flickr.
Earth Wise is a production of WAMC Northeast Public Radio. Support for Earth Wise comes from the Cary Institute of Ecosystem Studies in Millbrook, NY.