Wildfire is a natural process in Alaska that has shaped the boreal forests for thousands of years. With the high occurrence of lightning-caused wildfires, it is natural to consider that plants and animals have adapted to fire as a natural part of their existence.
Fires burn at different intensities, influenced by the type of vegetation, terrain, weather conditions and many other factors. When fire moves through a landscape, it leaves areas that are unburned, lightly burned, or heavily burned (severe fire, deeper into organic layer of soil). This mosaic burn pattern creates a variety of habitats for wildlife. Heavily burned areas usually seed in and repopulate over a period of many years while lightly burned areas resprout fairly soon under the right conditions. Alaska’s iconic flower, the fireweed, gets its name from the fact that it can revegetate quickly after wildfires. This is due to having deep roots that are well-insulated beneath soil from the heat of the fires.
Black Spruce is an example of a tree species that has adapted to fire, or long periods of hotter weather. The cones are sealed with resin and only open in heat from a fire, or from years of hot summers in the sun. When the cones open and the seeds scatter on the ground, many of them will sprout into new trees. Another example is quaking aspen – a minor, but widespread forest type in Interior Alaska. Fire that top-kills the standing trees allows the connected root system of the clone to sprout young stems, often in the same year of the fire. There are many other examples in the fire-adapted ecosystems in Alaska.
Unfortunately, some animals perish in fire from the smoke and flames. Many animals, however, survive by moving into unburned areas, or burrowing underground until the fire passes. The changes in habitat brought on by fire affect wildlife differently. Intense fire that has removed the trees, shrubs and other vegetation causes some wildlife to relocate to different areas for food and cover, while other wildlife is attracted into a newly burned area once the new plants begin to appear.
Examples of wildlife attracted to burned areas include bark beetles who feed on the inner bark on trees that were killed or injured in a fire. As the beetle population grows, they attract woodpeckers who feed on them. The new grasses, shrubs and trees that sprout or seed into newly burned areas provide a rich source of food for insects, birds and small mammals. Predators are then attracted to the areas because of the abundance of prey and their ability to find voles and other small mammals more easily. Bears and other larger mammals soon find their way into burned areas with the new growth of grasses and shrubs carrying edible berries.
The edges between burned and unburned areas also offer opportunities for a variety of wildlife. The edges are easier to travel and to find food in the burned and the unburned areas. Many animals thrive in the diversity of more than one habitat during the changes in seasons. According to an article titled “Regeneration Following Fire Creates Fertile Habitat for Wildlife ” by the Alaska Department of Fish and Game, lynx, marten, moose, black and brown (grizzly) bears, snowshoe hares and resident birds like ruffed and spruce grouse feed on early successional plants following a fire and seek cover in the neighboring unburned forest.
As trees and shrubs become established in burned areas years later, they provide habitat for many nesting birds as well as moose, who feed on the bark of willows and leafy trees in winter. As this new forest continues to age and the hardwood trees are replaced by spruce, porcupines, red squirrels, and caribou become established as part of the boreal spruce habitat.
For thousands of years wildlife has lived in tandem with fire—causing a natural and essential adaption. As long as there is lightning, Alaska will continue to experience wildfire. Weather conditions and receptive vegetation help spread fire, which continues to play a vital role in the rich animal and plant life found in the boreal forest region of Alaska.
The link to the attached flyer illustrates logging practices that emulate natural disturbances like fire and fluvial action (flooding, ice scouring). It has the fire succession diagram that illustrates post-fire succession: http://www.adfg.alaska.gov/static/lands/habitatrestoration/pdfs/managing_alaska_boreal_forest_wildlife_flyer.pdf
~Story by Public Information Officer Pat York, Alaska Fire Information Center, (907)356-5511, email@example.com.
Categories: AK Fire Info