After the fires

by KEVIN STRAUSS

Fifty years of Smoky the Bear telling us that “only you can prevent forest fires,” has made us all a little gun-shy about flames in the woods. Those ads were so effective that not only do we make sure our campfires are out before we leave camp, but we also feel like any forest fire is a “waste” of land and timber. But recent forestry research is showing us that some forests need fire and that many of our current forestry problems like white pine blister rust and the catastrophic forest fires in western states are the result of previous “douse every fire” forestry policies. Historically, about 10,000 acres a year burned in the current million-acre Boundary Waters Canoe Area. Now, even with controlled burns, and after the 1999 blowdown left lots of fuel on the ground, only about 1,000 acres burns each year. But while foresters, homeowners and policy-makers argue about how to manage our public forests, trees and other plants are busy taking advantage of land cleared by the flames.

Fire does several things in a forest, it opens up new space for young trees, it clears dead wood and underbrush from the forest floor and the ashes from the fire return nutrients like nitrogen to the soil. After the flames cool, a burned-over piece of land follows a predictable recovery pattern. In a week, grasses and forbes (green plants like the tall, pink fireweed) sprout on the fire-fertilized ground. Then, if there are parent trees nearby, “pioneer” trees like aspen and paper birch either sprout from underground roots or from seeds.

“Two to three weeks after a burn the aspen and birch will be three inches tall and grasses and forbes will be up to our knees,” said U.S.F.S. Prescribed Fire Specialist Ellen Bogardus-Szymaniak.

Depending on how deep the soil is, most fires up here “sterilize” the top of the soil, killing the herbaceous plants and seeds there. But seeds deep in the duff (leaf, needle and soil layers) often survive a fire and are ready to sprout after the flames die down. In addition, many shrubs and some forbes have roots that survive the flames underground. That’s what happens with blueberries. While fire might burn the stems and leaves above ground, just below the soil, blueberry roots and root crowns survive the blaze and resprout with a vengeance.

What grows in a burned-over area depends a lot of what was there before. If there is aspen or paper birch in the area, those trees will stump-sprout and put up a field of young trees. In other cases, nearby white and red pines will seed the open land. Some northland trees are dependent on fires for reproduction. Jack pine cones don’t even open until temperatures reach 116 degrees.

While some people don’t like looking at the charred remains of a burned forest, Bogardus-Szymaniak reminds us that nature isn’t always pretty, but that doesn’t mean that fire is “bad.”

“Forests are supposed to do this,” she said. “Nature heals itself.”

So instead of thinking of natural fires as a terrible disaster in the forest, perhaps we need to consider them a necessary change that happens from time to time. From that perspective, they are not all that different from changes in season. Given some new perspectives on the importance of fire in our forests, perhaps Smoky will soon be telling us “healthy forests need fire, let nature take its course.”

The next time you are out for a walk, keep your eyes open for some of these less obvious forest insects and the signs they leave behind.