Recognizing the central role fire plays in the ecology of Arizona's sky islands, University of Arizona researchers, public lands managers and other stakeholders are working together to address forest health on a landscape scale.
The relationship between fire and ecosystems has been altered or disrupted by human activities since the late 1800s. The resulting build-up of fuels has led to much more severe wildfire behavior in many ecosystems. Most fires continue to be suppressed, making the fuel problem even worse. Also, mitigation efforts like controlled burns have been small-scale and under-funded.
Enter FireScape, a comprehensive effort that brings together representatives from the UA, the U.S. Forest Service, The Nature Conservancy, Bureau of Land Management, National Park Service and other southeastern Arizona land managers.
The lead scientist for FireScape, Donald A. Falk of the UA's School of Natural Resources and the Environment in the College of Agriculture and Life Sciences, says working at on a large enough scale and restoring fire as a natural process are the keys to the effort.
"We're taking a landscape approach to understanding fire in the sky islands. That was the origin of the whole idea," Falk said.
Sky islands are essentially mountain "islands" – forested mountain ranges separated by vast expanses of desert and grassland plains. They are among the most diverse ecosystems in the world
"Land managers do small-scale forest thinning treatments and prescribed burns, a few tens of acres here, a couple hundred acres there, and that's important, but the problem is getting things to add up to a landscape scale, which really matters for wildfire in ecosystems," Falk said.
Extensive sheep and cattle grazing since the 1800s, active fire suppression during the last century and an ever-increasing population have changed the region's forests. Now, the focus has shifted to restoring the ecological health of the sky islands.
"The underlying premise is that you can't keep fires out of these systems. You're going to get fire occurring whether you like it or not, no matter how much you try to exclude it from the system. Fire is a behavior of sky island ecosystems. It's not something that happens to them," Falk said. "If you prevent one fire, you're just building up the fuel so when the next fire does occur, it's a bigger, more destructive event."
Each sky island landscape is a unique biophysical setting with its own management challenges. Consequently, the FireScape plans for each mountain range are appropriate for their particular needs.
UA researchers are collecting data for each mountain range, building interactive maps with extensive data and photographs, allowing for a scientifically driven approach.
"There are initiatives similar to FireScape in other parts of the West," Falk said. "People are trying to incorporate current science into the management of dynamic landscapes in the face of climate change. That's the challenge we're all facing now."
"What's unique about FireScape is that we're dealing with whole ecosystems at a very high level of detail because that's the nature of working in the sky islands. Each mountain range really is a distinct ecological unit. The ecosystem has a certain level of integrity because we're dealing with it as a whole."
Much of the mapping work comes from the UA's Jim Malusa, a principal research specialist in the UA School of Natural Resources and the Environment who says it's remarkable how little we actually know about these forests.
"The Coronado is so diverse, and it's one surprise after another. My job is essentially to get out there, to the top of every range in the Coronado and go through the canyons, mapping the landscape, on foot most of the time," he says. "I'm as much a professional athlete as I am a scientist."
Falk says the complexity of the ecosystems, changing so rapidly from desert to forest in just a few miles, requires such an extensive mapping effort.
"Originally, the focus was on the fire regime in a strict sense. We're trying to get natural fire process back so as not to burn down the entire forest. But the emphasis in FireScape is also making sure the mountains are resilient so when a fire happens, the ecosystem is able to bounce back," he said.
"Fire interacts with droughts and insect outbreaks and a lot of other processes that are being accentuated by climate change, so the emphasis has broadened. It's not only about fire in the strict sense, but about how sky island ecosystems can remain resilient as all these processes are occurring. We need a much better understanding of what the fuels and vegetation are to better predict fire and fire effects and help the sky islands remain resilient through it all."