This report defines the disparity between various satellite-based measurements of global forest cover. www.nature.com
GR: Remote (satellite) sensing has been unable to reach a consensus on the extent of Earth’s forests. Far better methods of forest mapping are available. On-the-ground surveys using the 1970 UNESCO vegetation classification would give us maps at much less cost, and the maps would include far more information than the satellite maps. Moreover, who minds strolling through the woods with a clipboard? NASA, park the rockets and buy some hiking boots. Do it now.