April 27, 2010

Forest Cover Shrinking Globally

Results from a study of detailed satellite observations of the world's forests released on Monday show that forest cover has shrunk by 3.1 percent across the globe.

Boreal forests of the northern sub-arctic were hardest hit, the report said, which accounts for about one-third of the overall loss.

Forest destruction is caused by several sources. Human deforestation is a huge factor, but natural phenomena such as fires ignited by lightning also contribute to loss of forests, according to the report.

The study is important because the data on what changes are happening to the world's forests are needed to make estimations on the impact of carbon dioxide emissions, which includes greenhouse gases. The data will also allow scientists to set parameters for "global-scale biogeochemical, hydrological, biodiversity and climate models," read the report.

About 628,000 square miles of forest was lost between 2000 and 2005, researchers said. Boreal forests, which account for 26.7 percent of the world's forest cover, showed a 4 percent drop in total forest cover during the study period. It also accounted for 34.7 percent of total forest loss during the period.

Tropical humid forests, which cover 7.2 million square miles, lost 2.4 percent of their total forest cover, or 27 percent of the overall loss during the study period. Tropical forests in dry regions, which cover 4.4 million square miles, shrunk 2.9 percent during the 2000 to 2005 study, and represented 20.2 percent of total forest loss.

North America suffered the biggest loss of forest cover during the study period, losing 5.1 percent forest cover during the period. It represented 29.2 percent of the overall loss.

The study is published in the April 26-30 issue of Proceedings of the National Academy of Sciences (PNAS).


Image Caption: Fires and Deforestation near the Xingu River. Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team


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