Each year about 13 million hectares of the world's forests are lost due to deforestation, according to the UN Food and Agriculture Organization (FAO).

The annual net loss of forest area between 2000 and 2005 was 7.3 million hectares, down from an estimated 8.9 million hectares between 1990 and 2000, the Rome-based agency said.

Net loss takes into account forest growth from new planting and natural expansion.

"This assessment allows us to gauge the important role of the world’s forest resources in fulfilling the Millennium Development Goals, in particular in meeting the targets set for reducing poverty and ensuring a sustainable global environment," said Hosny El-Lakany, Assistant Director-General of the FAO Forestry Department.

"It provides a comprehensive update on how we manage and use our forests, and shows that while good progress is being made in many places, unfortunately forest resources are still being lost or degraded at an alarmingly high rate."

The five-year report, which covers 229 countries, also found that forests now cover nearly 4 billion hectares or 30 per cent of the world's total land area.

Nearly two-thirds of the world's forest area is found in Australia, Brazil, Canada, China, the Democratic Republic of the Congo, India, Indonesia, Peru, Russia and the US.

South America suffered the largest net loss of forests between 2000 and 2005 - around 4.3 million hectares per year - followed by Africa, which lost 4 million hectares annually, the FAO said.

Oceania and North America saw smaller net forest losses over the same five-year period, while forest areas in Asia and Europe grew.

The FAO also found that new forests and trees are being planted at increasing rates, but plantations still account for less than 5 per cent of forest area.