In preparation for the most comprehensive picture ever drawn of the state of the Earth’s forests, which cover 30% of its land and are a crucial factor in mitigating climate change, the United Nations agricultural agency has put out a call for accurate data.

“Stronger support from countries and advances in communication technology will make the next Global Forest Resources Assessment the most comprehensive and reliable yet,” Jan Heino of the Forestry Department of the Food and Agriculture Organization (FAO) said of the assessment that will be published in 2010. The last survey was produced with the help of over 800 people in teams working in 172 countries and many more are likely to be involved this time around, with some 220 experts are attending a recent meeting at FAO to kick-start the process. Started over 60 years ago, the Global Forest Resources Assessment process provides information on how much forest exists, how it is being managed and how it is being lost, the FAO explains. Global forest cover currently amounts to just under 4,000 Mha. Although the rate of net loss of forest has decreased in recent years, the world is still losing about 200 km2/d of forest, FAO data indicates. Besides generating data on deforestation, new forestation and natural forest expansion, the new survey will provide insight into the land uses that are replacing forests and the forests’ role in climate change. In addition, the 2010 assessment will expand knowledge of the biological diversity of forests and will include a special study on trees outside forests, a survey of the area of forest under sustainable forest management, and data on forest policy. Among the new technologies being used is an ambitious new global remote sensing survey that uses satellite data from 1975, 1990, 2000 and 2005.