In the rush to confront wildfire, many forget that what happens afterward matters as much as what happens during.
Across North America, forests and grasslands spent millions of years evolving with fire as a tool to clean out dead plants, regrow new ones and maintain the things animals need. But, as several top researchers at the Fire Continuum Conference in Missoula pointed out on Thursday, the old patterns are getting pulled up by the roots.
“We don’t have a clear idea which species will win out with climate change,” said Jon Keeley, senior research scientist with the U.S. Geological Survey. “Invasives are likely to be favored as the climate warms. That means more flashy fuels, an increase in fire frequency and changes to the types of recovery after fire.”
In the continental United States, that could mean more forests change to shrub country, and more shrubland becomes grassland as bigger, more frequent wildfires overwhelm the slow-regenerating native landscapes. Michael Norton of Natural Resources Canada said climate change in Alberta likely will transform half of the province’s mixed-conifer forests to grassland by 2100.
At the same time, a century of putting out every forest fire possible has unbalanced forests in a different way, according to Forest Service landscape ecologist Paul Hessburg. Historically, 40 percent to 50 percent of the current forest land in the United States used to be “non-forest,” or young forests regenerating from the more frequent low-severity fires.
If that seems contradictory, the mix-up comes from the way landscapes in the West regenerate. Many areas, like California’s chaparral shrublands and Montana’s lodgepole pine forests, depend on frequent fires to clear out decrepit plants and trigger seed growth. Keeley showed research where certain wildflowers actually need chemicals released from wildfire smoke to germinate.
But increasing dry summers and warm winters have allowed insects like mountain pine beetles to upset those old patterns. Invasive species like cheat grass have intruded in shrublands, where they burn much more easily and hotter. The result is more destructive wildfires that overwhelm the typical regeneration cycles instead of triggering them.
One way to counteract that is to change the way we react to wildfire, Hessburg said. Instead of seeing all uncontrolled fires as threats, we should consider the potential benefits of burning.
“We need a new way of looking at fire severity maps,” Hessburg said. “Can we recast the way we think about fire on the landscape, where we use fires as an applied tool?”
Norton added that Native American tribes and Canadian First Nations have far more experience using fire to manage the landscape than current governments. He displayed a tree slice from British Columbia chronicling fire history from 1400 to 1900. It had 48 fire scars, burning on average every nine years. Most of those fires were likely ignited by the First Nations tribes who benefited from the improved grazing and foraging conditions that followed the burns.
“We should be heeding their calls to respect their knowledge about fire,” Norton said. “This kind of turns the concept of technology transfer on its head. Western science might finally be catching up. They’re telling us, ‘I don’t have a textbook. I have a grandma.’”