World forest cover shrinking: report

Yahoo News 26 Apr 10;

WASHINGTON (AFP) – The world's forest cover shrunk by 3.1 percent between 2000 and 2005, according to satellite observations detailed in a study out Monday.

Hardest-hit were boreal forests -- the world's far northern sub-arctic forests -- which account for about one-third of this loss, said the report, published in the April 26-30 issue of the Annals of the National Academy of Sciences (PNAS).

There are several causes of forest destruction, including human cutting and natural phenomena such as fires ignited by lightning, the report said.

Data on changes in the world's forest cover are needed to estimate the impact of carbon dioxide emissions, one of the main greenhouse gases, and to set parameters for "global-scale biogeochemical, hydrological, biodiversity and climate models," read the report.

The total forest loss between 2000 and 2005 was estimated to be 1,011,000 square kilometers, the researchers said.

Boreal forests, which account for 26.7 percent of the world's forest cover, showed the greatest shrinkage over this period, losing 4 percent, or 34.7 percent of the total forest loss during the study period.

The report's authors, from South Dakota State University and the State University of New York, attributed two-thirds of the loss in boreal forest cover to fires.

Tropical humid forests, which cover 11.5 million square kilometers and represent the world's largest forested surface, lost 2.4 percent of their cover during the research period, or 27 percent of the overall loss.

Tropical forests in dry regions -- 7.13 million square kilometers, or 21.8 percent of the world's forest surface -- shrunk 2.9 percent between 2000 and 2005, representing 20.2 percent of total forest loss.

Geographically, North America, which had a 5.8 million square kilometer forest cover in 2000, suffered the biggest loss during the study period, losing 5.1 percent or 295,000 square kilometers, representing 29.2 percent of the overall loss.