Alaska's summer fires found to be not all-consuming

Wildland fires not as destructive a force as once believed

Posted: Sunday, October 24, 2004

Now that the smoke has cleared from this summer's extensive wildland fires, the Alaska Fire Service reports that more than 612 million acres of Alaska burned this year. That number may be accurate from a fire managers' viewpoint, but it is somewhat misleading.

I spent several weeks in the Fairbanks area this summer, when the air was heavy with smoke and visibility was down to a few city blocks. I watched hillsides burning above the Chena River, and walked through blackened acres of spruce forest that had been ablaze just weeks earlier. As I explored the burns and talked with biologists and foresters, I learned that wildland fires are not the destructive force I had believed growing up.

In July, the Boundary Fire burned the hills and ridges along the Steese Highway, about 30 miles north of Fairbanks. Standing beside the Steese in August, I saw that fully one-third of the "burned" hillside was green. Islands of spruce, poplar and birch stood amid the blackened areas. Scorched, standing dead trees alternated with swaths of living forest, evidence that changing winds or contours of slope altered the fire's path. Wet areas, moist glades and sheltered pockets, completely bypassed by fire, stood out against charcoal-black earth. Stream banks were unburned and formed wide, winding greenbelts.

What I saw is typical, according to Dale Haggstrom, a wildlife biologist and fire specialist with the Alaska Department of Fish and Game in Fairbanks. Riparian areas along streams and rivers rarely burn. "Fire follows the fuel" is the rule, and meadows, fens and muskeg offer little to burn. These areas also serve as refuges for birds and animals during a fire.

In 2001, the Fish Creek and Survey Line Fires burned a reported 200,000 acres of the Interior, and Fairbanks wildlife biologist Tom Paragi has studied these burns. By walking the areas and examining satellite images of the landscape, Paragi found about one-third of the area within the outer perimeter of those fires was unburned.

A walk into the Boundary Fire area along the Steese revealed that even the blackened areas did not totally burn this summer. Throughout much of the countryside fire killed the vegetation but did consume it. In many areas fire charred the ground but did not penetrate the surface. A layer of ash and soot covers 10 or 12 inches of unburned forest litter and duff.

Just six weeks after the fire, grass was thriving and long stalks of wild rose pushed up through the ash. A profusion of buds and leaves sprouted from the base of burned trees, like suckers from a pruned bush. Throughout the burn area, slender, green wands of willow, birch and balsam poplar grew from the roots of fire-killed trees. Many were already two-feet high.

In some places just a few feet away, it was clear that fire had raged intensely, consuming the duff layer and all plant roots. Only scorched soil remained.

"Regrowth will be slower in these spots," Haggstrom said. "But the long-term picture is bright. Deeper burning removes the insulating duff and exposes soil that germinating seeds need. It also exposes soil to sunlight and allows it to warm. In a few years, a variety of flowering plants and young trees will grow where before there was only black spruce, Labrador tea, and moss."

Just weeks after the fire, the boundaries between deeply burned, lightly scorched and untouched green areas are distinct. As regeneration occurs, those distinctions are less clear but still important. The edges between successional plant communities are particularly good for wildlife.

Moose thrive on the regrowth after a fire, as do small mammals, which are food for foxes, lynx and raptors. Standing dead trees provide valuable roosting and nesting sites, and fallen trees provide cover for small animals. This shelter is especially valuable in winter.

Walking through the burned areas, I was also struck by what I didn't see. There were no carcasses, no bones, no singed or burned animals, no dead birds, no evidence that animals were overtaken by smoke or killed by fire.

Robert Schmoll, a fire management officer with the Alaska Division of Forestry in Fairbanks, said it's extremely rare to find a dead animal after a fire. Fires are generally slow moving, and animals simply move out of the way. Even a large, flaming front generally moves less than one mile an hour. Three miles an hour - the average person's walking speed - is considered a fast-moving fire in Alaska.

Fire usually advances in one direction, and animals simply skirt around the edges and walk off to the sides. Schmoll has watched moose and grizzly bears foraging just a few hundred yards from active fires; he's also seen moose browsing in burned areas just a few weeks after a fire.

The extensive mosaic of burned and unburned areas is another reason fire claims few victims. Unburned areas provide ample sanctuaries for wildlife during a fire. Burrowing animals escape the heat and smoke by staying underground as the fire passes over.

Nesting birds and small mammals such as mice, shrews and hares are probably the most vulnerable. Haggstrom said although some may be killed by fire, the populations of these prolific animals quickly replenish because abundant food resources follow the fires.

• Riley Woodford is a writer for the Division of Wildlife Conservation at the Alaska Department of Fish and Game in Juneau.

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