By the Numbers: Global Forest Cover; November 1996; Scientific American Magazine; by Doyle; 1 Page(s)

Forests remove carbon dioxide from the air, conserve soil and water, and are home to a variety of species. They are also repositories of potentially valuable new products, such as pharmaceuticals, and as a source of building material and firewood they provide employment for millions worldwide.

In 1990 forests took up about a quarter of the planet¿s land surface (not including an additional 13 percent of other woody vegetation, such as sparsely covered woodland and brushland). Russia accounts for perhaps a fifth of the globe¿s forest, Brazil for about a seventh, and Canada and the U.S. each for 6 to 7 percent. Historically, virtually all countries have experienced deforestation, mostly because of the need for new farmland, pasture, fuelwood and timber. In the U.S., forest now covers 22 percent of the land area, a decline of perhaps 40 percent since European colonization began. (Forest acreage, however, has remained about the same since 1920 as rising agricultural productivity moderated the need for new cropland.) Among the most pressing concerns today in the U.S. are declining biodiversity of forests and stagnant or declining productivity of commercial timberland.