Sunday, August 12, 2007

Trees Won't Fix Global Warming

by Andrea Thompson
LiveScience Staff Writer

The plan to use trees as a way to suck up and store the extra carbon dioxide emitted into Earth's atmosphere to combat global warming isn't such a hot idea, new research indicates.

Scientists at Duke University bathed plots of North Carolina pine trees in extra carbon dioxide every day for 10 years and found that while the trees grew more tissue, only the trees that received the most water and nutrients stored enough carbon dioxide to offset the effects of global warming.

The Department of Energy-funded project, called the Free Air Carbon Enrichment (FACE) experiment, compared four pine forest plots that received daily doses of carbon dioxide 1.5 times current levels of the greenhouse gas in Earth's atmosphere to four matched plots that didn't receive any extra gas.

The treated trees produced about 20 percent more biomass on average, but since water and nutrient availability differed across the plots, averages don't tell the whole story, the researchers noted.

"In some areas, the growth is maybe five to 10 percent more, and in other areas it's 40 percent more," said FACE project director Ram Oren of Duke University. "So in sites that are poor in nutrients and water we see very little response. In sites that are rich in both, we see a large response."

Powered by ScribeFire.

No comments: