Wildlands

Fire:

Basics of Fire:
Fire must have three elements before combustion can occur. There must be heat to start the combustion process, fuel to burn, and air to supply oxygen. These three items are known as the fire triangle. Without all three elements, fire cannot burn.

Many topographic features affect the way fire spreads. Elevation controls the type of vegetation present. Forest fuels at higher elevations tend to dry out quicker in the spring than those at lower elevations because they are better drained, drier and more windswept. Slope also controls the rate at which fire spreads. Fires burn quickly uphill because they heat the fuels in front of the fire-head. Aspect, the direction a slope faces, is important because fire burns differently depending which side of the mountain it is on. Slopes that face south, southwest, and west tend to be warmer and drier because they receive more sun, so fire travels quickly over them. North-facing slopes tend to be wetter and cooler. Fire moves quickly through canyons because of the slopes and tendency to jump back and forth between slopes.

Weather plays an important part in the intensity of wildland fires. Wind may push a fire. Thunderstorms produce strong, gusty winds, which can blow in a variety of directions. They also create lightning, which can cause even more fires. Humidity determines how wet the air is and how well fuels will burn. Rainfall, or lack there of it, will affect how well fuels burn. The higher the temperature, the drier the fuels become, and the more intense the fire will be.

Fire Succession:
Succession is an orderly change in plant communities that occurs naturally through time. Succession occurs when an environment becomes disturbed. Fire is a common cause of this disturbance on Kanuti National Wildlife Refuge. The following is one scenario of forest succession.

The first year after a fire passes there is limited new growth. The duration of limited growth directly depends on how intense the fire was. An intense fire can consume all the vegetation, including the organic mat on the soil surface, leaving bare mineral soil. A low intensity fire can leave vegetative roots underground unburnt, thus allowing growth to occur quickly after a fire passes. In both cases, nutrients that were once locked up in woody debris are released into the soil and are available for plants to recolonize the area. There are some plants, such as fireweed, that take advantage of recently burned areas. Their seeds are extremely lightweight and can easily blow into a burned area. This is one of the first plants to initiate growth in a burned area of Alaska.

Three years after a burn, shrubs and saplings begin to regenerate the burned area. This is the stage of the most wildlife productivity. A variety of wildlife species are dependent on this successional stage. Wildlife abundance and diversity tend to be high at this particular stage because many animals can reach the vegetation to forage when it is at this height and many more will find comfort in the shrub stage to escape from predators.

Saplings can become quite dense after 30 years, and after 50 years hardwoods, such as birch and aspen, dominate the forest. Slowly but surely, spruce trees will begin to overwhelm the hardwoods until they have eventually out competed all other tree species. A mature spruce forest may emerge 150 years after a burn. Unbroken stands of forest at this stage are susceptible to insect outbreak and disease. Extensive stands of mature black spruce provide very little wildlife habitat and diversity. Fire breaks up these stands up and provides a mosaic of different successional stages. This creates a variety of habitats for wildlife species and increases the diversity of plants and animals in an ecosystem.

Fire Management:
For a long time, “Smokey Bear” had been very successful urging people to prevent forest fires. While this message was directed toward human-caused fires, suppression of all fires, even naturally-occuring, was encouraged. The effects of suppression are being felt all over the country, resulting in many intense fire seasons lately. Without fire, forests get very thick and eventually may shade lower plants of needed sunlight. As a result, those plants die and accumulate on the forest floor, resulting in a condition known as “fuel loading”. When the weather heats up and rainfall is scarce, those fuels become good fuel sources. One ignition source or lighting strike and thousands of acres could go up in smoke.

Benefits of Fire:
Fire can enhance an area. Low-intensity, periodic fires can be beneficial to both plants and animals. Fire recycles nutrients and minerals trapped in the vegetation and returns them to the soil and atmosphere through ash and smoke. These mineral and nutrients are available for plants that arrive after a fire. Fires will increase berry production. Blueberries, raspberries, and others flourish after a fire due to less competition from other plants and increased nutrients. Many small mammals are attracted to an area after a fire. When the new growth of grasses and small shrubs begin, small mammals tend to move in. Once the small mammals return to the area, their predators follow as well. Herbivores are attracted to burned areas because the new shoots are preferred forage. Eventually, a burned area may have more diversity then it did before the burn.

Most importantly, fire creates a mosaic patchwork of habitat types. The edge between these successional stages provides another opportunity for animals to benefit from a fire. For example, snowshoe hare prefer to forage in early successional areas but find protection from predators in the shrub stage. They can have the best of both worlds in an edge habitat. Even intense fires can be beneficial to plants and wildlife. Although the land may look scarred for years to come, the fire actually provides another successional stage for plants and wildlife.

Fire In Alaska:
Wildfires caused by lightning are a natural part of Alaska’s boreal forest and tundra ecosystems. By looking at charcoal layers found in local lakebeds and wetlands, researchers are sure Alaska has been affected by fires for thousands of years. Some plants are dependent on fire. Black spruce occurs throughout the boreal forests of Alaska. Black spruce has semi-serotinous cones: these are cones that stay on the tree for many years and do not fall to the ground. The cone scales open when the resin holding them closed is heated. Black spruce have thus adapted to fire by allowing the lower branches to reach toward the ground where a passing fire can climb up the tree and reach the cones. Once the fire passes, the black spruce seeds are the first entering the cleared, nutrient-rich soil. Without competition from other plants, these seeds can get a rapid start on germination.

Wildfires on Kanuti Refuge are allowed to burn naturally where they do not endanger life or property. Throughout the state, firefighters will occasionally burn an area on purpose, a process known as a “prescribed burn”. This could be done for a variety of reasons including fuels reduction, slowing succession, and creating desired habitat. Prescribed fire will only be used on Kanuti National Wildlife Refuge on a limited basis, since the natural fire regime is the desired management condition. Before any prescribed burn begins, a series of steps must be followed. First a fire prescription must be written. This is a plan that describes the roles individuals will play throughout the fire. It sets limits for weather and environmental factors that must be present before a fire can be started. It also lists the steps that will be taken if the fire should get out of control. Second, firebreaks must be constructed or acknowledged to ensure the fire stays within a set area. Firebreaks can be natural features of the environment that won’t burn, such as river, rockbeds or lakes. They can also be man-made firebreaks. These might include roads, powerlines or fire lines created by a bulldozer. Third briefings are held so each fire crewmember understands the burn and what to do in case it should go wrong. Finally, the fire can be started. Normally a backing fire is started first. This entails lighting a fire into the wind to create an area of burned fuel, or a black line, next to the firebreak. This ensures the fire will not cross the firebreak and continue burning where it is not intended.

Fire and Permafrost:
Once an area is burned, the soil becomes black and absorbs more heat from the sun. If permafrost is close to the surface, as the heat increases, the permafrost layer will begin to shrink, increasing the active soil layer, where plants send their roots. The more soil available to plants, the more nutrients from the soil the plants can utilize. This may result in a vegetation layer growing quickly after a burn, thus insulating the permafrost and preventing more shirking.

Fires also can prevent permafrost from forming. A severe fire will burn off the entire vegetative layer that protects and insulates the underlying permafrost. Vegetation in a severely burned area will take much longer to return compared to a low intensity fire. The soil temperature will rise, thus increasing the active layer. If this happens often enough, permafrost will never have a chance form.

Wildland Firefighter Equipment:

Helmet:
A helmet is worn to protect a firefighter’s head from falling debris and burning embers.

Goggles:
Goggles are used to prevent stinging eyes from smoke and ash. When not in use, they are stored on the helmet for easy access.

Nomex Clothing:
Nomex is a fire-resistant material that will not burn unless exposed to very high temperatures. Firefighters use a bright yellow Nomex to ensure crewmembers are easily seen. All wildland firefighters wear the same Nomex shirts so they are easily recognized.

Radio:
Communication is a vital element on the fire line. Crew leaders carry a radio in chest holsters to ensure clear communication. Radios are used throughout the entire fire so that crews are in contact with each other at all times. Spare batteries are also carried in the chest harness.

Backpack with Fire Shelter:
A Nomex backpack is also carried on the fire line. Contents vary by region but all firefighters are required to carry a fire shelter in their packs. This is a small tent-like piece of equipment that folds up into a small package. A fire shelter is deployed when a wildland fire corners a firefighter. It can be quickly set up and protects firefighters from the brunt of the fire’s heat. Other backpack contents may include food, extra water, a Nomex jacket, fire starting-materials, and a first aid kit.

Leather Gloves:
Leather gloves prevent a firefighter’s hands from being exposed to the fire’s heat. They also protect against blisters when working with fire tools.

Water:
Firefighters must constantly be aware of dehydration. To combat dehydration, firefighters carry water on their person or in their packs. This way, if they travel away from a water source they have some with them.

Leather Boots:
Well-made leather boots are a must for every wildland firefighter. Boots have to be comfortable with good support for walking on uneven terrain like fire lines. They also should not be insulated or have a steel toe in case they do catch fire. Insulation would burn quickly and steel would keep in the heat.

Last updated: October 10, 2008