Forests cover about a quarter of the world's land surface, excluding Greenland and Antarctica.
Global forest cover has been reduced by 20 percent since pre-agricultural times, and possibly as much as 50 percent. Forest area has increased slightly since 1980 in industrial countries, but has declined by almost 10 percent in developing countries. Tropical deforestation probably exceeds 130,000 square kilometers a year. Less than 40 percent of forests globally are relatively undisturbed by human action. Many developing countries today rely on timber for export earnings.