Northern Minnesota is still smoldering. Sixteen fires broke out in and around the Superior National Forest after a July 6 lightning storm that brought "lots of thunder and lightning but little rain," and by July 13 they had burned nearly 9,000 acres, forcing the U.S. Forest Service to close the entire Boundary Waters Canoe Area Wilderness. Gov. Tim Walz mobilized the National Guard.
The scale of the burn, according to Lee Frelich, director of the University of Minnesota's Center for Forest Ecology, is not a fluke. He said boreal conifer fuel — the fir and spruce that dominate the north woods — is "among the most flammable in the world," and once fires like the Thumb Fire, which had spread to roughly 14,500 acres and crossed into Canada by mid-July, get going, they're "simply can't be suppressed" with hoses or hand crews.
Frelich's research group has spent years tracking what a warmer, drier Minnesota does to the boreal forest that clings to the state's northeastern corner. At the Marcell Experimental Forest, researchers use heated field chambers to simulate warming of 4 to 12 degrees Fahrenheit, and the warmed plots are already flipping from storing carbon to releasing it, losing carbon 4.5 to 18 times faster than they historically built it up. Black spruce and tamarack are failing to regenerate after fires expose bare mineral soil that favors aspen and birch instead of conifers — in one study, spruce regeneration collapsed at 38% of burned sites and failed outright at another 18%.
Frelich has put the long-term trajectory bluntly: "The boreal of Minnesota is going to look more like Kansas in the decades ahead if it's business as usual with carbon emissions." His modeling suggests that if warming continues on its current path, most of Minnesota's boreal forest could vanish by the end of the century, along with a 180- to 300-mile band of it just across the border in southern Canada.
That's the backdrop for the fires burning right now. Heat waves have desiccated the evergreen canopy across the Arrowhead region, and fire crews say some blazes are burning at up to 1,500 degrees — conditions acting Superior National Forest supervisor Drew Stroberg said leave one real option for the fires deep in the wilderness: "the only thing that will put that out is snow."
The University of Minnesota flagged the Star Tribune's reporting on Frelich's work on its own news page this week, tying the current crisis in the Boundary Waters directly to the university's long-running forest ecology research — a rare case where a breaking wildfire story and years of campus fieldwork are pointing at the same conclusion.