Cottongrass springs up on the site of a 2015 wildfire on Birch Creek in Interior Alaska. Photo by Ned Rozell.
Even if voles and red squirrels die in a large hot fire, their relatives fill the empty niche in the months following. The greenery that pops up after a fire is often a better home for small animals than spruce trees over moss over permafrost, Paragi said.
“The net effect of fire (on most animal numbers) is a positive,” Paragi said.
The reported areas of Alaska fires can be misleading, too, Paragi said. When the Alaska Fire Service reports the maximum perimeter of a large fire, about two-thirds of the area inside that perimeter usually burns, he said.
Paragi has flown over parts of Alaska after big fires and has seen a patchwork of muskeg, mature forest, and neon bright greens sprouting from blackened areas.
“You have this tremendous mosaic out there,” he said.
Paragi said large acreage burned in Alaska has partly been the result of overzealous firefighting in the past combined with recent warm and dry conditions. Until the late 1980s, Alaska policy was “immediate suppression of all wildfires,” according to the Alaska Interagency Wildland Fire Management Plan.
That strategy preserved black spruce, the final stage of the boreal forest in many areas of the Interior. Black spruce waits out other tree species, pops up in the understory, grows slowly, and stays anchored in cool soil unless the forest burns, is cut down, gets chewed up by river ice or meets some other fate. The resilient black spruce is the most flammable tree in the boreal forest.
“If you keep putting out all the fires, there’s no breaking up of these large expanses of spruce,” Paragi said. “Fires can get dangerously big really fast.”
Biologists like Paragi team with state fire managers to stage controlled burns to break up large patches of spruce and to stimulate new growth favored by moose, grouse, and other animals.
“Generally, fire is a positive thing for the nutrient cycling of the boreal forest,” he said. “After a June fire, I’ve seen waist-high willow sprouts by fall. We’ve also burned aspen in May and had sprouts well over my head by hunting season.”
Since the late 1970s, the University of Alaska Fairbanks’ Geophysical Institute has provided this column free in cooperation with the UAF research community. Ned Rozell is a science writer for the Geophysical Institute. A version of this column appeared in 2006.