Gov't wants to change course of forest experiments 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 believe they are on the cusp of receiving key results from the time-consuming experiments. The U.S. Department of Energy, however, 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. Ronald Neilson, a U.S. Forest Service bio-climatologist 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, following the advice of a specially convened panel of experts, believes 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....