According to a 2010 United Nations report, the rate at which forests are destroyed-logged or cleared to make way for farms or mines-was nearly 20 percent lower from 2000 to 2010 than it had been in the previous decade. Huge tree-planting programs, especially in China, reduced the net loss of forest even further. But vast areas are still being slashed, mostly in the tropics, including each year a Switzerland-size area of previously undisturbed, ecologically precious "primary" forest. Most of those trees are burned, and the carbon stored in their wood literally goes up in smoke. However, a new way of measuring the carbon in forests may help keep them from being cut down.
