Forest Service says trees can slow climate change

National forests can be used as a carbon "sink" with vast numbers of trees absorbing carbon dioxide to help slow global warming, the Forest Service chief said Wednesday, but that goal must be balanced.

He's also concerned about the risk of catastrophic wildfires that produce massive amounts of carbon dioxide.

Forest Service Chief Tom Tidwell said his agency is trying to manage forests to combat climate change while still easing the risk of wildfires that have increased in frequency and intensity, in part because of global warming.

Forests now store enough carbon to offset about 16 percent of the nation's fossil fuel emissions, but that number could be reduced or even reversed if wildfires and insect infestation continue to increase, Tidwell said.

"Disturbances such as fire and insects and disease could dramatically change the role of forests, thereby emitting more carbon than currently sequestered" by tree stands across the country, Tidwell told the Senate Public Lands and Forestry Subcommittee.

Elaine O'Neil, a research scientist at the University of Washington's School of Forestry, said wildfires in California alone released emissions equivalent to that of seven million cars a year from 2001 to 2007.

The Forest Service and Interior Department spent about $2.4 billion last year fighting fires, double the average amount spent a decade ago.

Tidwell said he hopes to increase the resiliency of federal forests through projects such thinning out young trees and underbrush to control wildfires. Some fires must be allowed to cleanse and regenerate forests that are overly dense, he said.

Lawmakers are looking at the role of forests in climate change, with the goal of including national forests as a key part of a climate change bill being considered by the Senate.

"In my view, it is time to manage the nation's forests to address climate change and unlock their potential," said Sen. Ron Wyden, D-Ore., the panel's chairman.

Proper management can ensure healthy forests that create carbon offsets that can be used to help minimize the cost of carbon reduction in other parts of the economy, Wyden said. Use of such offsets - which now are excluded from the Senate bill - would "finally provide a way to truly account for the economic benefit that federal forests provide to our environment," Wyden said.

"We can create good-paying, green jobs while preserving our treasures and helping our climate," he said.