A fiery future is in store for Grand Teton National Park, and planning for it with prescribed fires will do little to slow widespread conflagrations forecast to sweep across the landscape starting around the middle of this century.
That dire wildfire outlook for Jackson Hole comes from a recent article published in the journal Ecological Applications.
Wildfires are about to become a whole lot more abundant and large, with acreage burned per year from 2018 onward about 1,700% greater than what burned on average between 1989 and 2017, the article predicts. In the process, projections are that more than a third of northern Teton Park conifers will be wiped out, unable to regenerate due to continued hot weather and the effects of megafires.
Columbia University postdoctoral researcher Winslow Hansen, who headed the study for his Ph.D. at the University of Wisconsin-Madison, said that pronounced changes are coming soon, according to his ecological modeling.
“The whole landscape that we simulated is roughly 40,000 hectares [100,000 acres],” Hansen told the Jackson Hole Daily. “We have years where 10,000 hectares [25,000 acres] of that are burning just in the next couple decades.”
The study area constituted a third of Grand Teton National Park, encompassing Jackson Lake, the John D. Rockefeller Jr. Memorial Parkway and the east slope of the northern Teton Range. Hansen teamed up with Teton Park staffer Diane Abendroth, Werner Rammer, Rupert Seidl and Monica Turner — his advisor — on the research.
Although the results of the climate modeling sound grim, the projections are par for the course for subalpine conifer forests in the Northern Rockies, Hansen said. Wildfire is part of the natural regime, and large stand-replacing blazes have burned over Greater Yellowstone Ecosystem forests approximately every 100 to 300 years since glaciers retreated. That frequency is increasing as human beings continue to warm the planet by spewing unnatural levels of heat-trapping carbon dioxide and other greenhouse gasses into the atmosphere.
Hansen’s model expected the big changes mid-century to coincide with a multi-decade ocean circulation event that’s expected to bring drier conditions to the Northern Rockies than climate change would deliver alone.
“This mid-21st century dry excursion caused many fires to escape suppression and grow large,” the study said. “In the following decades, moisture increased, and fire activity declined, as conditions again became more conducive to suppression.
“However, hot-dry conditions projected for the middle to end of this century caused simulated fires in Grand Teton National Park to grow large in all climate and management scenarios.”
Hansen said that lodgepole pines will likely decrease in abundance and Douglas fir will likely fare well, because it’s a lower-elevation and more drought-resistant conifer.
There’s no telling which parts of northern Jackson Hole will become deforested by the more frequent, larger and hotter wildfires because it’s impossible to predict where fires will start, Hansen said.
“But what we’re finding is that you’re likely to see transitions to nonforest after fires when you have really hot, dry conditions in the first few growing seasons after the fire,” Hansen said. “You can also get transitions to nonforest from having very frequent fires that are burning — like a fire happens and then 10 years later another fire happens, before the trees have produced cones.”
The fire ecologist’s simulations found “no evidence” that prescribed fires meaningfully affected wildfire on the landscape now and in the future.
“Managed wildfire on the landscape didn’t necessarily reduce subsequent burned areas in the 21st century,” Hansen said. “It wasn’t able to keep the fire regime in the historical range of what we’ve seen.”
There could still be benefits, though, to trying to manage wildfire, he said. Controlled burns could continue to be a tool to protect National Park Service infrastructure or old-growth stands of forest. Especially in the near term, prescribed fire could help keep wildfires mid-sized and in doing so help keep the landscape and its inhabitants diverse and resilient ahead of the fiery future to come, Hansen said.
“There certainly were still benefits,” he said.
Those benefits, however, were “washed out” by late in the century, when huge amounts of burned area became the norm.