An historical perspective on fire

By Kathy Marieb

The blackened trees creaked eerily in the breeze.
I walked through the charred remains of a forest that had burned last summer in Glacier National Park and wondered about its future. I thought about what Curly Bear Wagner, a Blackfeet storyteller, had said the day before as we watched the clouds roll over Chief Mountain.

"We respected the four elements, fire, wind, water, and earth. Fire was very sacred to us. We needed it to renew the land."

Charred trees at the edge of the Inside North Fork Road in Glacier National Park, a year after the 2003 fires. David Reese photo

Renew the land? I looked down at the black soil. Slowly, I could see life begin to appear before my eyes. Fresh bear grass was growing out of singed tufts, fireweed starts were beginning to poke through the ground and morel mushrooms appeared. This cemetery of trees was transformed into a landscape of new beginnings.

I was exploring Glacier National Park for the weekend with R.J. Devitt, program director for The Glacier Institute, and Dennis Divoky, fire ecologist for the park. My goal was simply to learn more about the wildfires of the summer of 2003, which burned nearly 300,000 acres in Montana. Devitt, gesturing to the forest around us, assured me that fire is what drives this ecosystem.

"People come to Glacier, stand at Apgar, (an area singed by fires last year) and talk about how destructive the fires are. What they don't realize is that they are standing in a forest that burned just 75 years ago," he said.

Detail of fern after Glacier National Park fire in 2003. Montana Living photo by David Reese

The forest at Apgar and most of the west side of Glacier National Park, consist primarily of lodgepole pine. These forests are beautiful in their simplicity - geometrically straight trunks seem to defy nature's chaos under a canopy of green. Without fire, however, these forests would not survive. Divoky pointed out that lodgepole forests have evolved to burn every 80 to 120 years. Lodgepoles are susceptible to fire because of their thin bark and dense growth patterns.

When a fire begins in these forests, it typically burns as a crown fire - one that has intense heat, burns the canopy of the forest and is "stand-replacing," meaning all the trees are burned and killed. But, fire also provides the perfect conditions for lodgepoles to reproduce. The seeds of this tree are trapped inside serontinous cones, or cones that are sealed with resin.

They will not open unless temperatures rise above 115 degrees Farenheit, a temperature they will never achieve even during the hottest summer day. The best germination rates occur when the cones are heated to 450 degrees, a condition that only fires can produce, Divoky said. After the seeds are released, there is plenty of sunlight for this pioneer species to grow because there is no longer a forest canopy that shades them.

North Fork of the Flathead River near Glacier National Park one year after the 2003 fire. David Reese photo

This growth, death and rebirth process is how lodgepole pines endure. Many other plant species are also fire-dependent. These include red-stemmed ceanothus, a plant whose seeds will lay dormant in the soil for 100 years or more, waiting for the heat from a fire to crack its hard seed case.

The seed will then take in moisture from the winter snows and be ready to germinate the next spring. The rock harlequin is another fire-dependent plant. This rare delicate yellow flower with red highlights grows only after a fire has burned its seeds.

After two to three seasons it will go dormant, and allow its seed bank to wait in the soil until the next fire, decades down the road. Fire can actually help some species. Devitt pointed out that every ecosystem has adapted to natural disturbances such as hurricanes, floods and fires, and every ecosystem has a response to the disturbances that it evolved with. In the northern Rocky Mountains, fire is death and catalyst for growth.

Indian Paintbrush in Glacier National Park one year after the 2003 fire. David Reese photo

Fire may kill the above-ground portion of trees and shrubs such as willow, aspen and snowbrush, but fire will also stimulate their roots to re-sprout the next year. This sprouting increases the amount of food available to deer, elk and moose. Not only is more food produced, the young, succulent shoots are more palatable to elk, deer and moose than the mature vegetation that was there before the fire. Traveling out of the park and into the Moose fire of 2001, the regeneration of the land after a fire is immediately apparent. Many of the blackened snags of lodgepole still stand, but the ground is covered in a lush carpet of vibrant green life. Fireweed, yarrow, pinegrass, kinnikinnick, aspen, wild strawberry and birch-leaved spirea cover the ground. Tiny lodgepole pine seedlings are already reaching toward the sky. A species does not have to be fire-adapted to grow after a burn. During a fire, nutrients from organic matter are released into the soil and act as fertilizer. This nutrient release, combined with higher temperatures of the soil in the spring due to the solar conductivity of the blackened ground, provides the perfect bed for seed germination. Mushrooms also proliferate after a fire. This phenomenon is complicated to explain, assured Divoky, but 95 percent of plant life depends upon these fungi to obtain the necessary nutrients for growth. As we drove up the Going-to-the-Sun Road, a perfect U-shaped valley splayed out before us. From our vantage point, the hillsides and mountains seemed untouched by fire. According to Divoky, the fires affected only 12 percent of the park last summer and most of this fire activity was not very severe. Further on, looking at the north shore of Lake McDonald, I saw some areas that were singed, others that had burned but still looked green, and others a rusty orange from the fire's heat, the needles on the dead trees giving the impression of warmth amongst the swirling of green and black on the hillside. This is called a fire mosaic. Ground fires and surface fires burn at more moderate temperatures and will leave much of the vegetation unharmed. These different fire types diversify the landscape and create a variety of habitats for wildlife. This mosaic, adjacent to areas that have not burned recently, gives a picture of a landscape buzzing with change, growth, death and rebirth. Looking at the effects of last year's fires, I began to see in geologic time and get a sense that nature was functioning on a far different scale than my own fleeting existence. My eyes, now honing in on the effects of fire, could recognize areas that burned many years ago. We drove past the fires of 1910, the Half Moon Fire of 1929, and the fire of 1967, which burned from the Glacier Wall all the way up the Garden Wall. Looking at these old remnants of fire, it seemed that part of Glacier National Park had burned at one time or another. Even the all of the wildlife that historically occurred in this ecosystem can still be found here. In the Yellowstone fires of 1988, there was concern that much of the wildlife perished, but it was discovered that only one to two percent of the larger animals were lost. When fires move into areas, wildlife will simply move out. Deer that have suddenly become surrounded by fires have been seen to seek the safety of a river as flames rose high above both banks. The smaller animals may not fare as well, but it has been found that mice and other rodents often ride out fires in underground burrows. Experts say just four inches of dirt can reduce temperatures from 2,000 degrees on the surface to 100 degrees underground. Wildlife can also benefit from fire. Fires stimulate the growth of huckleberries, one of the main fall food sources for grizzly bears in the park. Twenty to twenty-five years after a fire, huckleberry crops come into their prime. Food is so abundant in these areas that bears tolerate each other in close proximity to feed on the nutritious fruits. "Because bears depend on huckleberries," Devitt said, "a case can be made for them being a fire-dependent species." Farther up the Going-to-the-Sun Road, we walked through the Trapper Fire of last summer, listening for another fire-dependent species, the black-backed woodpecker. After a fire, wood-boring beetles take advantage of dead and weakened trees, feeding on snags and laying their eggs in burned trees. The black-backed woodpecker moves into burned areas to live off of this proliferation of beetles. Beetle numbers will dwindle five to six years after a fire, forcing the black-backed woodpecker to move on and look for another recently burned area to call home. A woodpecker drilling away at a tree echoed in the distance, but it was too far away to tell if it was the rare black-backed species. The holes that woodpeckers make for nests, once deserted, will become homes for other bird species - called secondary cavity-nesters. Owls like the saw whet, screech, boreal and pygmy are examples of these nesters that take advantage of the woodpeckers' work. Sometimes, the birds give back to the trees after a fire. In 2000, in the Bitterroot National Forest, Divoky recalls seeing a Clark's nuthatch collect seeds from a whitebark pine tree. He watched the bird fly directly from the tree to an area that had just burned. The nuthatch buried its cache of seeds from this fire-dependent species in the still-smoking soil, helping to create a new stand of whitebark pine trees in the process. Nature knows its cycles. Glacier National Park evolved from fire and depends upon the death and rebirth of its forests. The fires of 2003 may have been shocking to us, but they were within the 80 to 120-year fire schedule of these forests. For many of us, fires as widespread as the ones of 2003 may be a once-in-a-lifetime event. I left the park knowing I would be back soon to observe more of the burned forests returning to life, to hunt for the rare rock harlequin, and to spy on a black-backed woodpecker. Curly Bear Wagner's soft and rhythmic voice echoed in my head. "Everything is connected, everything on this earth is here for survival." The soil, the birds, the plants, the trees, the insects, and even the fire, I realized, are necessary for the survival of the Glacier National Park and the Northern Rocky Mountain Ecosystem I call home. 20