By Michael Taylor
JAKARTA (Reuters) - Tree cover lost globally eased for a third straight year in 2014, an environmental research group said, although the three-year average rose to an all-time high, with trees covering an area twice the size of Portugal lost last year.
Brazil and Indonesia, which contain some of the world's biggest tropical forests, both saw a small rise in tree cover loss last year, while losses accelerated in some previously overlooked regions, according to data compiled by the U.S.-based World Resources Institute (WRI) think-tank.
Trees absorb carbon dioxide, the main greenhouse gas blamed for causing global warming, as they grow and release it when they are burnt or rot.
The world lost a total 18.8 million hectares (46 million hectares) of tree cover in 2014, down from 20.64 million hectares in 2013 and 23.53 million hectares in 2012, according to satellite data obtained by the University of Maryland and Google and published by the WRI.
"This analysis identifies a truly alarming surge in forest loss in previously overlooked hotspots," Nigel Sizer, a WRI director, said in a statement, pointing to West Africa, Asia's Mekong River Basin, South America's Gran Chaco region and Madagascar.
"In many of these countries, we're seeing clearing associated with commodities such as rubber, beef, and soy, along with palm oil."
The Brazilian Amazon, the world's largest rainforest, faces incursions from illegal logging and the invasion of public lands near big infrastructure projects such as roads and hydroelectric dams. The government recently called for a zero deforestation rate between now and 2030.
Tree cover loss in Brazil, a major soybean grower and cattle rancher, climbed to 2.3 million hectares in 2014, the WRI said, from 1.9 million hectares the year before although the rate had been slowing in previous years.
Indonesia, home to the world's third-largest tropical forests and also the world's biggest palm oil producer, imposed a moratorium on forest clearance in 2011, partly to slow habitat losses for orangutans, Sumatran tigers and other wildlife.
Tree cover loss in Southeast Asia's biggest economy rose to 1.5 million hectares last year, down from 1.1 million hectares in 2013.
Brazil and Indonesia will have key roles at the United Nation's Paris climate conference late this year, which aims to reach a plan to reduce global warming.
Countries with the fastest acceleration of tree cover loss were Cambodia, Sierra Leone, Madagascar, Uruguay, Paraguay, Liberia, Guinea, Guinea-Bissau, Vietnam and Malaysia.
El Salavador experienced a significant decrease in the rate of tree loss in 2014, but this was mainly because the country had few forests left to clear, WRI said.
The WRI data does not take account of tree cover gains.
For graphic of Tree cover loss: http://link.reuters.com/gyk55w
(Reporting by Michael Taylor; Editing by Richard Pullin)