Basic Concepts of Wildland Fire
The Natural Role of Fire
|The Fire Triangle shows the three requirements for fire: heat, fuel, and oxygen.|
There is no doubt about it: Fire is a dangerous and powerful force. Fire in wildland areas
—areas with very little or no development—is a natural process. Fire is a part of natural systems, just as precipitation and wind are. Fire will continue to burn in wildland areas and, in fact, plays an essential role in many ecosystems. Recurring fires are often necessary to maintain healthy ecosystems. Fire helps to recycle plant nutrients into the soil, for example, and in forests, it can reduce undergrowth and competition from other plants. Wildlands have been changed and shaped by natural fires for thousands of years.
Fire is a chemical reaction requiring heat, fuel, and oxygen—the "fire triangle." The heat source for a fire can be a match, a spark from a machine, or a lightning strike. Fuel for a fire can be anything that will burn—grass, trees, or houses. Oxygen is found in the air around us. A fire can start when all three of these elements—heat, fuel, and oxygen—are present.
Historical and Cultural Aspects of Fire
Native Americans used fire as a tool. Along the east coast, tribes practiced "slash and
burn" agriculture—burning to clear the land for crops and then moving to a new area a few years later. Native Americans also used fire to make travel easier, improve hunting, harvest berries and seeds, increase the availability of plants used for medicinal purposes and basket making, and keep prairies and meadows open and free from trees.
Early pioneers and settlers used fire much as Native Americans did. However, with the increase in the size and number of communities, fire became more of a threat and less of a tool for managing land. In the early 1900s, wildland fire suppression activities were organized. A national fire prevention campaign signaled a new emphasis in fire prevention. This program was begun during World War II to reduce human-caused fires, and Smokey Bear soon became its popular icon.
Learning to live with fire goes beyond fire prevention. It means understanding the role of fire in ecosystems; that fires are sometimes necessary; that firefighters cannot suppress all fires immediately; that some fires should be "managed" rather than suppressed; that individuals can take steps to protect their families, homes, pets, and other structures from wildland fires; and that we must live "carefully and compatibly" in fire-prone areas.
The Wildland-Urban Interface Zone
The wildland–urban interface is more than a geographic area. It is anywhere homes exist among flammable vegetative fuels. Three elements that are present in the wildland–urban interface zone are: wildland fuels (trees and shrubs), urban fuels (homes and landscape plants), and limited fire protection resources. The zone can be a house in the woodlands, a subdivision on the edge of a community, or a home with a combustible roof surrounded by large amounts of landscape vegetation.
As people move into areas where fire plays a role, homes become a possible fuel source and the potential for human-caused ignitions increases. Because wildland fire is an essential component of healthy ecosystems, people need to live compatibly with wildland fire.
Communities and wildland fire managers need to work as partners to protect communities from wildfire while maintaining healthy ecosystems. Firewise practices increase the likelihood that homes, office buildings, and other community resources will survive wildland fire damage. Firewise practices include: using fire-resistant building materials, especially on the roof; removing flammable materials from around homes; creating fire breaks with lawns, driveways, and walkways; and many other steps.
Homes can be made safer! Work done around a home before a fire starts can save property and lives. Homeowners and communities, working as partners with firefighters, can effectively reduce losses caused by wildland fires.
Fire Management—Fuels Treatment and Prescribed Fires
Wildland fire suppression is not always the objective of fire management. Fire suppression is an effort to put out the fire. Fire management may include fire suppression,
but it also involves fire prevention and fuels treatment, including prescribed fire, research, and monitoring, to protect communities and provide for healthy ecosystems.
One of the results of the long history of wildland fire suppression has been the buildup of the amount of vegetative material available for fires to burn. This material is called fuel. Because of the fuels buildup, fires can burn unnaturally hot, damaging the soil and the ecosystems.
Four methods of controlling the amount of fuel in an area are:
(1) mechanical treatment, cutting or chipping material and removing it from a site;
(2) biological treatment, which relies on the consumption of plants by animals
(3) chemical treatment, such as the use of herbicides and
(4) prescribed fire, a fire intentionally set by professionals. Prescribed fires are carefully planned to burn under the right conditions (fuel moisture, temperature, humidity, season, and wind) to produce the desired results (such as reducing fuel, removing unwanted plant species, or stimulating new growth).
Fire management involves balancing public safety, firefighter safety, fire management costs, the protection of communities and property, and the protection and maintenance of ecosystems.