- The Washington Times - Wednesday, November 12, 2008

DURHAM, N.C. | For more than a decade, the federal government has spent millions of dollars pumping elevated levels of carbon dioxide into small groups of trees to test how forests will respond to global warming in the next 50 years.

Some scientists think they are on the cusp of receiving key results from the time-consuming experiments.

However, the U.S. Department of Energy, which is funding the project, has told the scientists to chop down the trees, collect the data and move on to new research.

That plan has upset some researchers who have spent years trying to understand how forests may help stave off global warming and who want to keep the project going for at least a couple of more years.

“There has been an investment in these experiments, and it’s a shame we are going to walk away from that investment,” said William Chameides, an atmospheric scientist at Duke University, where one of the experimental forests is located. “There is no question that ultimately we want to cut the trees down and analyze the soil. The question is whether now is the time to do it.”

Ronald Neilson, a U.S. Forest Service bioclimatologist in Corvallis, Ore., said the experiments should continue because they still have potential to answer key questions about how rainfall and fertility affect how much carbon a forest will store long-term - essential to understanding how forests may soften the blow of climate change.

But the Energy Department thinks that chopping down the trees and digging up the soil will allow the first real measurements of how much carbon the leaves, branches, trunks and roots have been storing, said J. Michael Kuperberg, a program manager with the agency.

Some scientists say ending the long-term research may be a mistake.

The research program, Free Air CO2 Enrichment, consists of rings of tall white plastic pipes with holes along their length that emit once-liquified carbon dioxide in carefully metered doses. The carbon-dioxide levels around the trees are about 50 percent higher than current levels - the amount expected 40 to 50 years from now.

The Energy Department’s Office of Biological & Environmental Research has informed those managing the experiments that their research will be phased out by 2011. They are to get the definitive measurements on how tree growth, which represents stored carbon, was influenced, and should design new experiments to get rolling by 2012.

The panel found that the current experiments had a useful life of 10 to 12 years, and in a few more years the results would become invalid, in part because the trees were nearly taller than the pipes delivering the carbon dioxide.

Results so far indicate that elevated levels of carbon dioxide make forests grow more quickly, said Ram Oren, associate professor of ecology at Duke University’s Nicholas School of the Environment and Earth Sciences and principal investigator on the experiments there.



Click to Read More

Click to Hide