Back into the woods: more money, more forests.

MORE PEOPLE don't necessarily mean less forestland, according to a study reported in the November 14 Proceedings of the National Academy of Sciences. "Amid widespread reports of deforestation," the authors conclude, "some nations have nevertheless experienced transitions from deforestation to reforestation." And they are doing so "without depopulation or impoverishment." Analyzing trends in the 50 most forested countries, researchers at six institutions discovered that woodland area is expanding in 36 percent of them, while biomass (the total weight of the trees in the forests) is increasing in 44 percent.

This shouldn't be a surprise to Americans. In the mid-19th century, only 30 percent of New England was covered with forests. Today, with much of the land once used for farming returning to its natural state, 80 percent is forested. Overall, U.S. forest area is essentially the same as it was in 1900; since 1990 it has grown by more than 10 million acres, an area about three times the size of Connecticut. Forestland is also expanding in China, India, and Vietnam.

There appears to be a link between forestation and wealth. While some relatively poor countries have managed to stem deforestation, the researchers note, "no nation where annual per capita gross domestic product exceeded $4,600 had a negative rate of growing stock change." The countries in which deforestation continues at a fast pace are the poorest and worst governed, including Nigeria, the Philippines, and Indonesia.