Tucson, AZ, USA — Global warming and fire-suppressing management practices have meant increased size and numbers of forest fires, a University of Arizona researcher told Congress on Monday.
And the threat is growing in southern Arizona.
“Warming temperatures clearly have begun to influence fire activity in the western United States,” Thomas Swetnam, director of the UA Laboratory of Tree-Ring Research, told the Senate Committee on Energy and Natural Resources in Washington, D.C.
“Many other factors are involved: forest changes, increasing fuels, invasive species, more people moving into the environment,” he said. “All this moving together gives us a perfect firestorm.”
Efforts to suppress wildfires have allowed fuels such as small-diameter growth to flourish, which threatens long-standing large trees in case of a fire, he said. Particularly susceptible are forests in Arizona and New Mexico – low-elevation ponderosa pines, he said.
“With climate change and warming, we’re likely to see more large, high-severity fires on Mount Lemmon,” he said during a phone interview after his testimony. “Mount Lemmon still has lots of fuel, lots of unburned areas.”
Thinning small-diameter growth and using prescribed, low-severity surface fires on about 10,000 acres per year on Mount Lemmon would reduce the fuel level and make the local forest more resilient to withstand climate change, he said.
Describing a complex situation to the committee was challenging, he said.
“This is not an easy problem. There is not going to be a single solution,” he said. “I hope our political leaders will further educate themselves on the complexities.”
Dealing with the forest fire issue will take resolve and a lot of money for which a lot of other causes, such as the war in Iraq, are competing, he said.
“I’m somewhat pessimistic but still hopeful that something will come out of this and we will continue this dialog and motivate our policymakers and managers to start dealing with this problem,” Swetnam said.