A UA tree-ring researcher testified before the U.S. Senate’s Committee on Energy and Natural Resources Tuesday to discuss how climate change affects wildfires.
“”There is a clear upward trend in the area burned and the numbers of large forest fires in the western U.S., especially since the mid 1980s,”” Thomas J. Swetnam, director of the UA Laboratory of Tree-Ring Research and a professor of dendrochronology and watershed management said in his testimony.
“”The ecological and watershed damages caused by some of these fires are extreme and probably irreversible,”” he said. “”The threats to human lives and properties are increasing.””
Senators from the states of New Mexico, Colorado, Idaho and Montana questioned Swetnam and three other researchers on their proposed strategies for dealing with wildfire issues. Many of the questions regarded the thinning of forests.
“”I personally don’t think we can thin our way out of the problem,”” Swetnam said.
“”We’ve got to move back toward using fire as a tool in these landscapes,”” he said. “”It is a lot less expensive and it’s a more realistic one and appropriate one ecologically.””
Swetnam concluded his testimony by detailing the interacting causes that encourage wildfires, including increasing forest density and fuels, increasing climate change due to rising temperatures, invading plant species like African buffel grass, and the impact of people in areas that are prone to fires.
He cited the 2007 Intergovernmental Panel on Climate Change Report, which he said identified increasing wildfire occurrence as a likely response to global warming.
Swetnam and his colleagues have charted fire history dating back 3,000-10,000 years ago, using tree rings and carbon dating on samples ranging from the fire scars in rings of the great sequoias of California to charcoal records of sedimentary cores from bogs and lake bottoms.
From these century-long tree-ring records, analyses of modern climate histories and documentary records of forest fires, a number of studies have revealed that ocean-atmospheric oscillations, or “”cycles,”” play a part in wildfire frequency by determining whether a season will be wet or dry, Swetnam said.
These oscillation patterns impart some degree of predictability to climate and wildfire hazard months in advance of fire seasons, he added.
Studies of future scenarios consistently have predicted increased burning due to a higher level of greenhouse gases, Swetnam said.
“”I think that it was more of an informational hearing, and we’ll have more on the issue,”” said David Marks, press assistant for the Committee on Energy and Natural Resources. “”We’ve had a lot of climate change and global warming hearings, but we’ve never had one with the consideration of forests.””
After arriving back in Tucson, Swetnam said he thought the hearing went well.
“”There seemed to be a lot of interest in moving forward with management activities that will make forests more resistant and resilient to climate change,”” he said.
Swetnam said he was glad to see the senators unite in acknowledging the environmental problem.
“”Climate change is still somewhat controversial, but people on both sides of the aisle in politics see that it’s real and beginning to have impacts on our forests,”” Swetnam said. “”It was rewarding to carry our scientific research to policymakers who have the opportunity to do something about it.””
