Tree planting programs in Vietnam, India and China have accounted for most of the recent gains in forest coverage but they are scheduled to end by 2020, a UN official has said.
As a result, governments should quickly put in place similar measures to stop further deforestation, said Mette Loyche Wilkie, coordinator of Food and Agriculture Organization's (FAO) Global Forest Resources Assessment 2010.
"Without such interventions, we risk a sudden return to high rates of net forest loss and of carbon emissions from forests, which we had in the 1990s," she said.
South America had the highest regional level of net deforestation at 4 million hectares a year, followed by Africa with 3.4 million hectares, according to a FAO report quoted by Reuters on March 25.
Asia, by contrast, expanded its forest area by a total of close to 2.2 million hectares a year, thanks to reforestation programs in Vietnam, India and China which added 4 million hectares a year of fresh woodland.
In North and Central America, the forest area remained fairly stable, while it continued to expand in Europe, although at a slower rate than previously.
On March 25, the UN reported that deforestation slowed in the last decade, in the first sign that global conservation efforts are bearing fruit, but an area the size of Costa Rica is still being destroyed each year.
About 13 million hectares of forest a year were converted to other uses or lost through natural causes in 2000- 2010, down from 16 million a year in the previous decade, according to a FAO report.
The net loss of forest area slowed to 5.2 million a year between 2000 and 2010. That was still an area the size of Costa Rica, but down from 8.3 million a year in the 1990s, thanks largely to ambitious tree planting programs in Asia.
"For the first time, we are able to show that the rate of deforestation has decreased globally as a result of concerted efforts taken both at local and international level," said Eduardo Rojas, assistant director of FAO's Forestry Department.