ROME (AP) -- Ambitious planting programs in Asia and the United States have helped slow the global rate of deforestation but farmers are still cutting trees to clear land at an alarmingly high rate, a U.N. survey released Thursday shows.
Forests absorb and store greenhouse gases so deforestation can exacerbate mean the effects of climate change, said Mette Loyche Wilkie, coordinator of the assessment by the U.N. Food and Agriculture Organization.
Eduardo Rojas, assistant director-general for forestry, said the study of the last decade showed the first decrease in global deforestation since experts began tracking the phenomenon.
Planting programs, notably in China, India and Vietnam, helped dramatically slow the rate of forest loss, from 20.3 million acres (8.3 million hectares) a year in the 1990s, to 12.8 million acres (5.2 million hectares) per year from 2000 to 2010, said forestry experts presenting the study at the Rome headquarters of the U.N. agency.
"Brazil and Indonesia, which had the highest loss of forests in the 1990s, have significantly reduced their deforestation rates," the study found. And the tree planting programs, including in the United States, added millions of acres new forests annually.
But South America overall lost 9.9 million acres (4 million hectares) annually over the last decade, and Africa 8.3 million acres (3.4 million hectares) yearly.
Severe drought in Australia since 2000 has contributed to forest loss, the report said.
Noting that China's reforestation program is scheduled to end in 2020, Wilkie said: "We have a small window of opportunity" to keep reducing the deforestation rate in the coming decade or risk going "back to the high rates of the 1990s."
Agribusinesses buying up pristine forests for conversion into farm land have raised worry in parts of South America, Africa and Asia, but Wilkie said it was unclear how much this factored into the loss of forests for farms.
A U.N. study, to be completed by the end of next year, is aimed at determining the role such purchases play in deforestation, she said.
Trees are also vulnerable to the effects of climate change.
The mountain pine beetle, apparently surviving winters in larger numbers due to less frequently freezing temperatures, have been decimating pine forests in western Canada and western United States, noted Wilkie. The scale of the insects' damage has been "massive and unprecedented" since the late 1990s, destroying a total of 2.7 million acres (11 million hectares), she said.
Copyright 2010 The Associated Press.