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ISPE Faculty Spotlight
Don Falk: Beating wildfire to the forest
September 28, 2007
By Stephanie Doster
Don Falk
Wildfire just isn’t what it used to be.
Fueled by the effects of climate change and overgrown vegetation, fires that historically burned as low-intensity surface blazes are increasingly prone to blow up into large, high-intensity crown fires that leap across the tree canopy, inflicting maximum damage to the forest and any lives, homes, or buildings that stand in the way.
That’s why Don Falk wants to get to the forest before the next big fire does.
Among his many research projects, the dendrochronologist and ecosystem restoration specialist at The University of Arizona is out to temper wildfire severity by identifying the best forest treatment plans and options, from thinning by backhoe to burning by prescribed fire to opting for the unthinkable: letting natural fire work its wonders.
Some of Falk’s research takes him to the Sangre de Cristo and Jemez mountains in New Mexico, home to some of the most expensive real estate in the nation. Because it is impossible—and undesirable—to treat every acre of the mountains’ forests and steep slopes, Falk is looking at ways to thin certain areas mechanically and strategically, cutting the fire hazard by influencing how the flames spread across the landscape as a whole.
“What we’re asking has huge implications for how ecosystems are managed in the Southwest,” said Falk, an associate professor in the School of Natural Resources who also has a joint appointment in the Laboratory of Tree-Ring Research. “We want to know how we can reintroduce fire as a process and modify forest structure in such a way as to maintain the adaptability and resilience of the forest ecosystems in the face of a changing climate.”
Falk is working on treatment plans and options for certain forest types, particularly pine-oak and ponderosa, so that when fire strikes them—which it will, he said—it will be a natural, low-intensity fire like those that occurred in those forest types historically.
“We’re not trying to change high-elevation forests, such as mixed-conifer and spruce fir types, that naturally have crown fires into ponderosa pine forests,” Falk said. “We simply want to try to restore each forest type to its natural variability.”
Falk is involved in similar work in the Santa Catalina Mountains north of Tucson, where efforts are underway to safely reintroduce fire to Mount Lemmon. The Bullock and Aspen fires in 2002 and 2003, respectively, raged on the mountain, causing millions of dollars in damage to a patchwork of homes, businesses, and public services. The fires changed the configuration of the landscape, Falk said.
“We want to know whether the new configuration gives us an opportunity to do things on the mountain range that we couldn’t do otherwise,” Falk explained. “For example, areas that burned recently could act as fire breaks, and that could allow you to get fire onto the mountain as prescribed fire or permit natural fire that you wouldn’t dare do before because there was this continuous expanse of very dense forest.”
The budding project, called Southern Arizona Fire and Ecosystem Restoration (SAFER), is a collaboration between Falk, UA dendrochronologist Thomas Swetnam, and the Coronado National Forest, and is designed to help prevent another Bullock or Aspen-type fire. The team is now identifying areas on Mount Lemmon that appear to be safe for prescribed fire or good candidates for mechanical treatments.
“It’s an exciting collaboration because not only do we have the chance to do some very leading-edge science, but the whole exercise is being designed from the outset to feed directly into how the mountain is managed and what steps are taken in a real tangible sense, with people with drip torches and chainsaws out there in real time,” Falk said.
Falk is also involved in a number of other fire regime projects that are taking him to some of the most understudied regions on the continent: the western and eastern Sierra Madre ranges in northern Mexico and the North American Great Basin, which encompasses more than 200,000 square miles and parts of Oregon, California, Nevada, Utah, Idaho, Wyoming, and Mexico, to understand how interannual climate and variation influences widespread fires.
Back in the Southwest, Falk is studying how fire spreads across the forest and grasslands of New Mexico’s Valles Caldera National Preserve. In the Pinaleno Mountains in Arizona, Falk is also collaborating with Ann Lynch and other colleagues at the U.S. Forest Service’s Rocky Mountain Research Station and Coronado National Forest to study how fire, insects, and episodic drought interact. The research is important because drought can set up the right conditions for a large fire which, in turn, can trigger a severe insect infestation in damaged trees, possibly eliminating certain tree species in the area, Falk explained.
“There are immediate and practical implications for ecosystem management because we’re looking at whether areas should be thinned to historical densities and whether prescribed fire should be used to try to maintain resilience of the system,” he said.
When he’s not out in the field or in a lab, Falk enjoys another passion: mathematical theory, which he uses to grasp the underlying relationships that arise in his research of past fire regimes.
“One interesting thing about what I do is that in any given day I can be puzzling over a problem of set theory in the morning, trying to date a difficult piece of wood for a lab in the afternoon, and the next day be out in the forest somewhere carrying a chainsaw and getting covered with sawdust to collect a sample,” he said. “It’s a great life.”