Since early April, Wisconsin has been under a state of emergency because of wildfires. The Department of Natural Resources asked residents to be careful about off-road vehicles or consider delaying campfires, all because an unusually large number of fires have blazed over an unusually large amount of land. So far this year, 668 fires have consumed 1,880 acres. For comparison, an average of 618 fires and 1,007 acres burned each year from 2015 to 2020.
If the blazes in Wisconsin weren’t on your radar, that doesn't surprise Amanda Carlson, a landscape ecologist studying wildfire at the University of Wisconsin–Madison. “I think there's a good reason why Midwest fire doesn't get as much attention,” she says. “I don't think we're really going to start experiencing the types of really large fires that you see out west anytime soon.” But these Midwestern flames come with their own concerns, and the uncertainty around how climate change will tinker with them has attracted a small number of dedicated researchers.
The Wisconsin Tree-scape
As far back as the late 1700s, large fires — not particularly hot or destructive, but spacious ones — moved across Wisconsin every few years. Now, the state sees several hundred fires every spring, many of them limited to an acre or less in size. During those intervening centuries, humans drastically changed the landscape, which has created new expectations for forested regions.
To begin with, white settlers started suppressing fires in the early 1900s, while similar trends cropped up across the U.S., all with different effects. In Wisconsin, preventing blazes from spreading starved traditional pine ecosystems of the fire they needed to keep out encroaching species, says Jed Meunier, an ecologist and research scientist with the Wisconsin Department of Natural Resources.
Research conducted by Daijiang Li at the University of Wisconsin reviewed the composition of traditional pine barrens across the state and showed that jack pine, one of the most fire-adapted conifers, dropped off from 1952 to 2012 while red maple numbers more than doubled in that time. When maple leaves hit the forest floor, they suck up moisture, Meunier says. “It becomes a wet blanket — you actually get layers and layers of these leaves, and then what happens is it's even harder to carry fire in there.” Pine patches that used to easily host a blaze have become fire-resistant with their new resident species.
And if a fire does ignite, Wisconsin infrastructure reduces the odds that it spreads far. In Western states, larger pieces of land unfurl without roads or railways running through them, Carlson says. Fires in those areas can rip through undisturbed. By carving up larger proportions of the state with roads and other clearings that lack fuel for the flames, Wisconsinites have accidentally made it harder for fires to grow.
Even before humans transformed the area, Wisconsin wasn’t primed for the kind of severe fires that happen in California and Colorado. The perfect cocktail for a catastrophic wildfire starts with a wet, rainy period full of plant growth followed by extreme dry heat, which transforms the plentiful new vegetation into matchsticks. Wisconsin gets the first ingredient, but not the second.
Rain comes down in warmer months, but that makes the hottest part of the year also the most humid in Wisconsin. And when vegetation is at its driest after snow melt, the temperatures are often too cool to prompt intense burns, Carlson says. The weather and climate patterns Wisconsin deals with — combined with the ways humans have changed the landscape over the decades — means the risk of severe fires stays low.
Climate Change Confounds
Of course, conditions change. This year, higher temperatures in April accelerated drying out of greenery, a process made easier by the fact that snow disappeared extra early and rain has stayed sparse, as the Department of Natural Resources explained when the state of emergency started.
It might be tempting to assume that climate change will mean these perfect conditions align more often in Wisconsin. But while temperatures will rise, researchers anticipate global warming will bring more rain and humidity to the Midwest and eastern portions of the U.S. It’s not clear what those two adjustments will mean for fires. Maybe conditions will stay too wet to allow the fires to take off, or maybe the increasing heat means the greenery will dry up and stand ready to burn more often, Carlson says.
Overall, the future fire conditions in Wisconsin remain hypotheticals. “Is climate change going to make fires worse in the Midwest or in the east? It's really hard to answer,” Carlson says. To help model the effects of climate change, researchers like to establish baselines about what past burns looked like.
One of the most popular sources of data fire ecologists turn to is satellite records. However, burns in Wisconsin and other Midwestern or eastern states are often too small to register on the orbiting technology, Carlson says, leaving her and her colleagues with little evidence to work with. Instead, Northeast fire models rely on fire department records, which are less reliable but still capture the hundreds or thousands of ignitions that happen each year. Additionally, local climate, current ecosystems and how humans have changed the regional landscape all determine what fire activity looks like.
Pockets of unique situations cover the Midwest and east, which makes it difficult to characterize what wildfires look like over entire regions, Carlson says. But we do know that people in Wisconsin live close to (or within) flammable landscapes. And, like many parts of the country, humans are responsible for starting most of the state’s blazes that break out.
Despite the baseline data challenges, the small group of researchers studying wildfires in the Midwest and east are focused on developing data and models suited to the unique locations. Most of the framework for modeling fires is based on fire activity out West, and much of that information doesn’t translate the same into the eastern half of the U.S., Carlson says.
The West is still the hot spot for wildfire research, and people don’t always understand why Carlson is studying how the flames work anywhere else. “I got asked a lot, 'why are you studying fire in the Midwest?” she says. “But I think we could still see an increase in fire and the need to adapt to fire beyond what we've historically had to do. I think that's why it's still an issue that deserves attention.”