Wildfire Concepts Wildfire










Fire has different effects on the many species of animals in a burned area.  Those that do not survive a fire, either from direct contact with the flames or due to smoke inhalation, will become fresh carrion for the carnivorous animals.  The herbivores and omnivores will soon find new grasses growing from which they can feed.

The 1988 fires were responsible for the deaths of fewer than one percent of the mammals in Yellowstone National Park (YNP).  Of these, most probably died as a result of smoke inhalation and not by direct contact with the flames (Singer 1989).  However, the amount of burned forest and meadowland had a considerable effect on those that survived.


Fire causes both shrubs and grasses to burn to the ground.  The shrubs are not able to grow again until new seedlings have sprouted.  While the shrubs are waiting for seeds to sprout, grasses are able to grow quickly in the burned areas, providing food for elk and bison.  A burned area can thus provide ungulates with increased quantities of foraging grasses for approximately three to four years following a fire.  This can be particularly helpful in harsh winter seasons (Pearson et al. 1995).  According to one plant ecologist, for the first three years following the 1988 fires, there was fifty percent more forage available than before the fire (Robbins 1998).


Elk may benefit in many ways from fire.  For example, seed production in Northern Yellowstone National Park grasses was found to be enhanced due to burning in one study on elk herbivory.  Elk returned to the grasslands soon after the fires, but they did not return to the burned forests for about three years.  This was likely due to the lack of a forest canopy, thus deeper snow on the forest floor, and less efficient foraging for elk  (Singer and Harter 1996).

The winter directly following the 1988 fires was particularly harsh and was responsible for the deaths of 38%-43% of the northern range elk.  Approximately 14%-16% were harvested by humans and 24%-27% died of natural causes.  This was a dramatic increase compared to the 1987-1988 winter in which the elk mortality was less than 5% (Singer and Harter 1996).

Lodgepole pine (Pinus contorta) is usually a less preferred choice of food for elk because they are not able to digest the bark very well.  After the fires, however, studies showed that more elk were consuming the bark from these trees.  One study found burned bark to be more than twice as digestible as live bark for elk, primarily in the winter ranges (Jakubas et al. 1994).

In the following years, the elk have made a healthy comeback.  Depending on the season, there may be anywhere from 15,000 to 30,000 elk in Yellowstone (National Park Service).  For more information, please see our elk pages.


Moose and elk may share foraging areas and thus may compete for food following a fire.  Both animals feed on aspen and willow trees, both of which are likely to burn to the ground in a fire.

The most successful moose during and after the 1988 fires in YNP were those that focused on unburned or lightly burned mature conifer stands at high elevations.  Moose that shared winter ranges with elk were successful if they moved to mature conifer stands with deeper snow, for such areas were not favorable to elk (Tyers and Irby, 1995).

Although the YNP moose population suffered a loss of habitat to some degree due to the fires, the first five years after the fires brought abundant summer foraging for moose in certain areas (Knight 1994).  The winter ranges, however, could take up to 200 years to recover, for the forest canopies that catch a lot of snow in the winter (allowing for better foraging areas) were burned in the fires.

Moose will often forage on saplings and seedlings that grow in the forest understory.  The 1988 fires wiped out a large portion of this food source.  Up to 50% of the moose population in YNP has died as a result of starvation; some have moved to other habitats (Robbins 1998).


Studies have shown that fires can improve bison foraging habitats and that bison may actually prefer to forage on recently burned sites. In the winter after the 1988 fires, almost all of the 900 YNP bison moved to the edges of the park or left the park in search of food.  As a result, more than 500 bison were shot as game (Schullery 1997).  Over the years, as the bison have returned to the open grasslands and meadows, the Yellowstone bison population has recovered (USDA Forest Service).  A 1998 estimate places the bison population at approximately 2200 (National Park Service). Please see our bison pages for more information.

Grizzly Bears

Fire suppression threatens the future of whitebark pines.  Whitebark pine nuts are a common food for YNP grizzlies, especially in the summer and fall, before hibernation (Robbins 1998).  White pine blister rust is a pathogen that is threatening the pines. 

Whitebark pine has been found to grow again on burned areas, but only after about 100 years are they truly successful.  These issues not only threaten the whitebark pine; they in turn threaten the grizzly population of YNP by wiping out one of their primary food sources (Pease and Mattson, 1999).

Ants are also an important food for grizzlies and can thrive with all of the burned trees falling to the ground, providing more places for ants to live (Robbins 1998).  For more information, please see our grizzly pages.


Due to their agility and speed, cougars are likely to escape from a fire with little difficulty.  Research has shown that the effect of fire on a cougar population depends on the size of the fire.  One study was completed in a variety of burned habitats: chaparral, oak woodlands, coastal scrub, and conifer forests.  Three cougars were included in the study and were found to avoid the burned area for only 2-6 weeks (Beier and Barrett, 1993).  In a second study, two cougars were observed in a conifer forest that had undergone a catastrophic fire, one that burned the canopy and the understory.  The study found that a conifer stand greater than three square kilometers suffering a catastrophic fire may reduce cougar habitat quality until the vegetation grows back and the prey returns (Williams 1995).


Coyotes can survive in a wide variety of habitats and can escape from most fires without suffering any harm directly from the flames.  In fact, fires studies have shown that fires may be beneficial to coyote habitats.  Because fires create a mosaic of burned versus unburned areas, coyotes may find more carrion to feed on and more places to hide while hunting or being hunted (USDA Forest Service).

Mule Deer

Mule deer, like coyotes, are often able to escape from fires.  Research has shown that fire may also improve mule deer habitats, for mule deer feed mostly on grasses and forbs.  When fires burn the old vegetation, new plants grow which are often more nutritious.  However, some favored shrubs take longer to recover, which could have a detrimental effect on the mule deer population or cause them to search for another habitat (USDA Forest Service).

Bighorn Sheep

Fire is an important factor for healthy bighorn sheep habitats.  Fire suppression can allow conifers to take over grassland areas, effectively wiping out the bighorn sheep’s feeding area.  If fire occurs at a time when forage quality is poor, such as during a drought, then it may take longer for new grasses to grow, and the sheep population may suffer (USDA Forest Service).  Today, there are approximately 150 – 225 bighorn sheep on Yellowstone’s northern range (National Park Service).