North American forests contain only about one-quarter as much carbon as scientists had previously believed, according to new studies by biologist Daniel B. Botkin of UC Santa Barbara. If this finding holds true throughout the rest of the world, as Botkin believes it will, the discovery could have major implications in assessing the role of forests in mitigating potential global warming caused by the accumulation of carbon dioxide in the atmosphere.

Previous estimates indicated that forests contained about the same amount of carbon as the carbon dioxide in the atmosphere. Through extensive sampling, however, Botkin and his colleagues found that the North American forests contain less than a quarter of the carbon found in the atmosphere.

These results suggest two conclusions, Botkin said: That researchers still have a lot to learn about the Earth's carbon cycle, and that planting more trees will not be an effective deterrent to global warming.