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Wildfire suppression is a range offirefighting tactics used to suppresswildfires. Firefighting efforts depend on many factors such as the available fuel, the local atmospheric conditions, the features of the terrain, and the size of the wildfire. Because of this wildfire suppression in wild land areas usually requires different techniques, equipment, and training from the more familiarstructure fire fighting found in populated areas. Working in conjunction with specially designedaerial firefightingaircraft, fire engines, tools,firefighting foams,fire retardants, and using various firefighting techniques, wildfire-trained crews work to suppress flames, constructfire lines, and extinguish flames and areas of heat in order to protect resources and natural wilderness. Wildfire suppression also addresses the issues of thewildland–urban interface, where populated areas border with wild land areas.
In the United States and other countries, aggressive wildfire suppression aimed at minimizing fires has often protected and saved significant wildlands, but has sometimes contributed to accumulation of fuel loads, increasing the risk of large, catastrophic fires.[1][2][3][4][5][6][7][8][9]
Protection of human life is first priority for firefighters. Since 1995, when arriving on a scene, a fire crew will establish safety zones and escape routes, verify communication is in place, and designate lookouts (known in the U.S. by the acronymLCES, for lookouts, communications, escape routes, safety zones). This allows the firefighters to engage a fire with options for a retreat should their current situation become unsafe. Although other safety zones should be designated, areas already burned generally provide a safe refuge from fire provided they have cooled sufficiently, are accessible, and have burned enough fuels so as to not reignite. Briefings may be done to inform new fire resources of hazards and other pertinent information.[10]
A great emphasis is placed on safety and preventingentrapment, a situation where escape from the fire is impossible. Prevention of this situation is reinforced with two training protocols,Ten Standard Firefighting Orders andEighteen Situations That Shout Watch Out,[11] which warn firefighters of potentially dangerous situations, developed in the aftermath of theMann Gulch fire. As a last resort, many wildland firefighters carry afire shelter. In this inescapable situation, the shelter will provide limited protection from radiant and convective heat, as well as superheated air. Entrapment within a fire shelter is called aburnover. In Australia, firefighters rarely carry fireshelters (commonly referred to as "Shake 'N' Bake" shelters); rather, training is given to locate natural shelters or use hand tools to create protection; or, in the instance of 'burnover' in a tanker or other fire appliance, 'fire overrun' training is used.[12]
Hazards beyond the fire are posed as well. A very small sample of these include: unstable/hazardous trees, animals, electrical cables,unexploded ordnance, hazardous materials, rolling and falling debris, and lightning.[10]
Personal safety is also vital to wildland firefighting. The proper use ofPPE (personal protective equipment) and firefighting equipment will help minimise accidents. At the very minimum, wildland firefighters should have proper fire-retardant clothing (such as Nomex), protective headgear, wildland firefighting-specific boots, gloves, water for hydration, fire shelters, eye protection, and some form of communication (most commonly a radio).
Resources are ranked according to importance and value almost like a checklist that starts from the top and goes all the way down. The importance of these resources gets mentioned to the people involved in combating wildfires, including the volunteers who gather at fire safety Councils, where they get taught the importance of these resources and try to prioritize them when mitigating fires.[13][14] These include human health and safety, construction cost, ecological impacts, social and legal consequences, and the costs of protection however, there are other resources that also count towards that list such as soil which is one of the most important resources for the environment that gets cared for by volunteers that are on the lookout, they also get trained on the right amount of heat that is required for soil to flourish hence why they go through prescribed fires to properly nurture it.[15][13]Defendability is also considered, as more effort will need to be expended on saving a house with a wooden-shake roof than one with a tile roof, for example.[16][17]
While wildfire suppression focuses more on benefiting human safety and resource protection, the lack of natural fires can lead to various negativeecosystem changes, such as ruining the overall quality of the soil, as can the size of fires when they do occur at a different level than what is recommended for the soil.[15]Fire ecology is accordingly not as simple as many might assume due to the plethora of different effects that it can have on both people and the landscape.[18] Across the globalgrassland andsavanna ecosystems, fire suppression is frequently found to be a driver ofwoody encroachment and poor quality soil, which in return also affects wildlife due to the lack of nutrients.[15]
Wildfire, known in Australia asbushfire, has long played a major role in Australian ecology and society. Early European navigators of the 17th century, who approached the west coast of Australia, reported seeing fires on the land. Records of the 1830’s and 1840’s indicated that aboriginals used fires for driving game from thickets of scrub and to induce young growth which would attract the game. It is also recorded that they lit such fires against the wind and were careful to try and control the fires- a matter in which they were reputed to be astonishingly dexterous. When the early European settlers attempted to emulate the Aboriginal methods in order to clear land or improve pasture, indiscriminate burning and a lack of knowledge of fire behaviour soon led to an intolerable situation, and a need for a controlled approach became apparent.[19]
Early bush fire legislation across the colonies in the second half of the 19th century restricted when, where and by whom prescribed burns may be lit. Many of these acts also provided for the creation of volunteer bush fire brigades, their registration and legal protection.[19][20]
The early 20th century saw the evolution of local bushfire brigades into statewide agencies spurred by many large and devastating fires that highlighted the need for further organization, modernization, and centralized command structures. In NSW the need was recognized for improved access to remote and mountainous terrain for the purpose of fire mitigation and defence. In 1958 Fire Prevention Associations were established to developfire trails on Crown Land. These trails evolved into a strategic network providing engine access and control lines, largely shaping the engine based tactics used in the region.[20][21]
Canada contains approximately 3,964,000 km2 (1,531,000 sq mi) of forest land.[22] Seventy-five percent of this isboreal forest, made up primarily of coniferous trees. More than 90 percent of Canadian forest land is publicly owned, and the provincial and territorial governments are responsible for fire-suppression activities. TheCanadian Interagency Forest Fire Centre (CIFFC) coordinates assistance between all provincial and territorial wildfire management agencies.[23]
During a typical year there are over 9,000 forest fires in Canada, burning an average of 2.5 million hectares (ha) or 9,700 square miles (25,000 km2). The number of fires and area burned can vary dramatically from year to year. Average suppression costs are $500 million to $1 billion annually.
In Canada, two-thirds of all forest fires are caused by people, while lightning causes the remaining third. Despite this, lightning fires account for over 85 percent of the area burned in Canada, largely because many of the lightning-caused fires occur in remote, inaccessible areas. Currently about ninety percent of forest fires are fought. Generally fires near communities, industrial infrastructure, and forests with high commercial and recreation value are given high priority for suppression efforts. In remote areas and wilderness parks, fires may be left to burn as part of the natural ecological cycle.[24]
Indigenous communities embraced fire as an ally in preserving nature, but oncepopulations began to grow across the U.S., wildfires started to trigger unprecedented destruction of property and sometimes resulted inmassive death tolls. Greater impact on people's lives led to government intervention and changes to how wildfires were addressed.
One of the first turning points for firefighting philosophies in the U.S. happened in October 1871 with theGreat Chicago Fire. Six years removed from theCivil War, the Fire destroyed more than 17,000 buildings across the Windy City, upended thousands of lives and devastated their thriving business community.[25]
The same day as the Chicago Fire, a much larger, more deadly fire occurred. ThePeshtigo Fire broke out on the morning of October 8, 1871. It burned for three days, and while estimates vary, the consensus is that it killed more than 1,200 people – making it the deadliest wildfire in American history to this day.[26] In addition to the number of people killed, the fire burned more than 1.2 million acres of land and spread to nearby towns, where it caused even more damage. The entire town of Peshtigo was destroyed within an hour of the start of the fire.[26]
As a result of the 1871 fire breakouts, the federal government saw that it needed to act. This led in 1876 to the creation of the Office of Special Agent in theU.S. Department of Agriculture to assess the quality and conditions of forests in the United States.[27] As the forerunner of theU.S. Forest Service, this was the first time that wildfire management was placed under government purview.
In the aftermath of theGreat Fire of 1910, the U.S. Forest Service received considerable recognition for its firefighting efforts, including a doubling of its budget from Congress. The fire is often considered a significant impetus in the development of early wildfire prevention and suppression strategies.[28]
Notable fire services tasked with wildfire suppression include NPWS (National Parks and Wildlife Service, NSW), theNew South Wales Rural Fire Service (NSWRFS), theSouth Australian Country Fire Service, the Western AustralianParks and Wildlife Service, the VictorianDepartment of Environment, Land, Water and Planning (DELWP),Country Fire Authority in Victoria, Rural Fire Service Queensland,Tasmania Fire Service, and several privately managed forestry services. The majority of wildland firefighters in Australia are volunteers.[29][30][31] Currently NSWRFS maintains the largest wildfire management service in the world in membership andappliance strength.[32]
Wildfires are managed byThe Canadian Interagency Forest Fire Centre (CIFFC) which is a not-for-profit corporation owned and operated by the federal, provincial and territorial wildland fire management agencies to coordinate resource sharing, mutual aid, and information sharing. In addition, CIFFC also serves as a collective focus and facilitator of wildland fire cooperation and coordination nationally and internationally in long-range fire management planning, program delivery and human resource strategies.[33]
In the United States, wildfire suppression is administered by land management agencies including the U.S. Forest Service, Bureau of Land Management, U.S. Fish and Wildlife Service, National Park Service, the Bureau of Reclamation, the Army Corps of Engineers, and state departments of forestry. All of these groups contribute to the National Wildfire Coordinating Group and the National Interagency Fire Center.
The National Interagency Fire Center hosts the National Interagency Coordination Center (NICC). NICC's primary responsibility is positioning and managing national resources (i.e. Hotshot Crews, smokejumpers, air tankers, incident management teams, National Caterers, mobile shower units, and command repeaters). NICC also serves as clearing house for the dispatch ordering system. Reporting to NICC are 10 Geographic Area Coordination Centers (Alaska, Great Basin, Northern Rockies, Rocky Mountains, Southern California, Northern California, Eastern, Southern, Southwest and Northwest).[34] Under each GACC are several dispatch zones.
Managing any number of resources over varying-size areas in often rugged terrain is extremely challenging. Anincident commander (IC) is charged with overall command of an incident. In the U.S., theIncident Command System designates this as being the first on scene providing they have sufficient training. The size of the fire, measured inacres orchains, as well as the complexity of the incident and threats to developed areas, will later dictate the class-level of IC required.Incident management teams aid on larger fire incidents to meet more complex priorities and objectives of the incident commander. It provides support staff to handle duties such as communication, fire behavior modeling, and map- and photo-interpretation. Again in the U.S., management coordination between fires is primarily done by theNational Interagency Fire Center (NIFC).[35]
| A | B | C | D | E | F | G |
| 0–1/4 acre | 1/4–10 acres | 10–99 acres | 100–299 acres | 300–999 acres | 1000–4999 acres | 5000+ |
Specific agencies and different incident management teams may include a number of different individuals with various responsibilities and varying titles. Afire information officer (PIOF) generally provides fire-related information to the public, for example.Branch chiefs anddivision chiefs serve as management on branches and divisions, respectively, as the need for these divisions arise. Investigators may be called to ascertain the fire's cause. Prevention officers such asforest rangers may patrol their jurisdictional areas to teachfire prevention and prevent some human-caused fires from happening to begin with.[10]
Information may be communicated on fires in many forms. Radios, vocals, visual signals such as flagging and mirrors, literature such as anIAP or incident action plan, whistles and mobile touch-screen computer terminals are some examples.[36] TheUSFS Visual Signal Code system provides symbols used to communicate from ground to air, while aircraft may use wing tilting, motor gunning or circling to communicate air-to-ground.[10]
Radio communication is very typical for communication during a wildfire. This is due to the wide coverage provided and the ability to communicate in a one-to-many format. One of the most popular radio manufacturers for this application is Relm Wireless (also known as Bendix King and BK Radio). The company is based in Florida, U.S., and holds many contracts with various government entities.[37] The other up-and-coming company entering this niche market is Midland Radio. Its U.S. headquarters is in the midwest (Kansas City, Missouri), and it manufacturers many radio models, including mobiles and portables.[38]
Operating in the U.S. within the context offire use, firefighters may only suppress fire that has become uncontrollable. Conversely, fires or portions of a fire that have previously been engaged by firefighters may be treated as fire use situation and be left to burn.
All fire suppression activities are based from ananchor point (such as lake, rock slide, road or other natural or artificial fire break). From an anchor point firefighters can work to contain a wild land fire without the fire outflanking them.
Large fires often become extended campaigns. Incident command posts (ICPs) and other temporary fire camps are constructed to provide food, showers, and rest to fire crews.
Weather conditions and fuel conditions are large factors in the decisions made on a fire. Within the U.S., theEnergy Release Component (ERC) is a scale relating fuel energy potential to area. TheBurning Index (BI) relates flame length to fire spread speed and temperature. The Haines Index (HI) tracks stability and humidity of air over a fire. TheKeetch–Byram drought index relates fuels to how quickly they could ignite and to what percentage they should burn. The Lightning Activity Level (LAL) ranks lightning potential into six classes.[10]
Fuel models are specific fuel designations determined by energy burning potential. Placed into 13 classes, they range from "short grass" (model 1) to "logging slash" (model 13). Low-numbered models burn at lower intensities than those at the higher end.
Direct attack is any treatment applied directly to burning fuel such as wetting, smothering, or chemically quenching the fire, or by physically separating the burning from not burned fuel but in order to properly launch a direct attack, there has to be proper evidence that is collected from agencies that are involved in wildfires such as fire Safety Councils (NSW),[13] they collect data of the effects that these fires have had on certain regions/lands and provide said data to government agencies that they are affiliated with and start garnering support from them to properly and effectively launch these direct attacks.[13][39] support includes the work ofurban andwildland fire engines, fire personnel and aircraft applying water orfire retardant directly to the burning fuel. For most agencies, the objective is to make a fireline around all fire meant to be suppressed however, they don’t necessarily suppress all of the fire, there are certain times where these agencies will keep a close eye on the fire rather than fully eliminating it due to the importance of having some sort of natural fire going in these areas, they can help by nurturing wildlife and have positive effects on soil when the temperature is right but when the fire gets unmanageable, they usually resort to suppressing it.[13][40][15]
Preparatory suppression tactics used a distance away from the oncoming fire are considered indirect. Firelines may be built in this manner as well. Fuel reduction, indirect firelines, contingency firelines, backburning and wetting unburnt fuels are examples. This method may allow for more effective planning. It may allow for more ideally placed firelines in lighter fuels using natural barriers to fire and for safer firefighter working conditions in less smoke filled and cooler areas. However, it may also allow for more burned acreage, larger hotter fires, and the possibility of wasted time constructing unused firelines.[10]
Attempts to control wildfires may also include by controlling the area that it can spread to by creatingcontrol lines: boundaries that contain no combustible material. These may be constructed by physically removing combustible material withtools and equipment, or portions may be naturally occurring. Lines may also be created bybackfiring: creating small, low-intensity fires usingdriptorches orflares. The resultant fires are extinguished by firefighters or, ideally, directed in such a way that they meet the main fire front, at which point both fires run out of flammable material and are thus extinguished. Additionally, the use of long-termfire retardants,fire-fighting foams, andsuperabsorbent polymergels may be used. Such compounds reduce the flammability of materials by either blocking the fire physically or by initiating achemical reaction that stops the fire.
However, any method can fail in the face of erratic or high-intensity winds and changing weather. Changing winds may cause fires to change direction and miss control lines. High-intensity winds may cause jumping or spotting as burning embers are carried through the air over a fireline. Burning trees may fall and burning materials may roll across the line, effectively negating the barrier.
Another method for controlling fires is forest thinning. According to the U.S. Department of Agriculture, “Mechanical thinning of forests is a multifaceted process and often involves piling brush, pruning branches, and creating fuel breaks. ”[41] Mechanical forest thinning combined with controlled ground fire is an effective method for wildfire suppression. Forest thinning and ground burn are more effective in reducing wildfire risk together rather than just thinning or burning. According to an article in the journal ofForest Ecology and Management, “Combined treatments (thinning + burning) tended to have the greatest effect on reducing surface fuels and stand density, and raising modeled crowning and torching indices, as compared to burning or thinning alone.”[42] Thinning and burning also must be continued through follow up maintenance, according to the Western Watersheds Project, but this follow up rarely happens.[43] Forest thinning has brought up concerns that it could increase fire severity, as the sun can reach the lower vegetation and cause additional moisture loss. With climate change already making the ground less humid, according to the NIDIS, “cause of the rapid increase of wildfires over the western U.S. is the rapid increase of surface air vapor pressure deficit, or VPD, a measure of how thirsty the atmosphere is.”[44]
The threat of wildfires does not cease after the flames have passed, there can actually be various instances where certain areas will catch on fire however, this can also have some positive effects such as being at almost the perfect heat level to help in properly nurturing soil,[18]smoldering heavy fuels is a good example of something that continues to burn unnoticed for days after flaming[45] which is what a lot of fire safety Council agencies bring up when discussing there funds and bonuses with government agencies, they also use it as another instance for bringing in more volunteers so that they can work together on the checkups while also offering proper training and the necessary tools to deal with the potential fires.[14] It is during this phase that either the burn area exterior or the complete burn area of a fire is cooled so as to not reignite another fire which is something that can also be helped by the tools provided from the fire safety Council such as water sprinklers that are placed according to the expected fire areas and by having the volunteers taking turns in checking up on it while also in difficult situations using helicopters to have a better view on the area, this is able to happen thanks to the funds that get provided from government agencies.[14]
Constructed fire-lines, breaks, safety zones and other items can all damage soil systems and affect both wild and human life, as well as how people decide to tackle there rehabilitation tactics and the types of regulations that can be implemented,[15] encouragingerosion from surface run-off andgully formation which are things that can actually be worked at by gathering volunteers that all gather at specific agencies that specify in allowing people to have hands on experience and to actually effect the environment themselves.[13] The loss of plant life from the fire also contributes to erosion. Construction ofwaterbars, the addition of plants and debris to exposed soils and other measures help to reduce this hence why agencies and groups such as the NSW, garner support from government agencies and get certain perks such as approved regulations for rehabilitation and combat purposes, and financial support to further help the volunteers when they help out.[13]
Wildfires can pose risks to human settlement in three main scenarios. The first can happen at the classicwildland–urban interface, where urban or suburban development borders wild land. The second happens at the mixed wildland–urban interface, where homes or small communities are interspersed throughout a wild area, and the boundary between developed and non-developed land is undefined. The third occurs in the occluded wildland–urban interface, where pockets of wild land are enclosed within cities.[46]
Expansiveurbanization and other human activity in areas adjacent towildlands is a primary reason for the catastrophic structural losses experienced in wildfires.[47] Continued development ofwildland–urban interface firefighting measures and the rebuilding of structures destroyed by fires has been met with criticism.[12] Communities such asSydney andMelbourne inAustralia have been built within highly flammable forest fuels. The city ofCape Town, South Africa, lies on the fringe of the Table Mountain National Park. In the western United States from the 1990s to 2007, over 8.5 million new homes were constructed on the wildland–urban interface.[48]
Fuel buildup can result in costly, devastating fires as more new houses and ranches are built adjacent to wilderness areas. However, the population growth in these fringe areas discourages the use of current fuel management techniques. Smoke from fires is an irritant and a pollutant. Attempts to thin out the fuel load may be met with opposition due to the desirability of forested areas. Wildland goals may be further resisted because of endangered species protections and habitat preservation.[48] The ecological benefit of fire is often overridden by the economic benefits of protecting structures and lives.[49] Additionally, federal policies that cover wildland areas usually differ from local and state policies that govern urban lands.[50][51]
In North America, the belief that fire suppression has substantially reduced the average annual area burned is widely held by resource managers,[52] and is often thought to be self-evident. However, this belief has been the focus of vocaldebate in the scientific literature.
Wildfire suppression requires specialist personnel and equipment that can be acquired thanks to government funds being funneled directly into fire safety councils which in return start investing into these useful equipment that is used in fire suppression, there are certain times where the funds will exceed the set budget and that when certain agencies keep it to themselves.[40] on top of getting the necessary equipment that is needed for suppressing wildfires, agencies need to invest in professionals in order to actually combat these fires,[53] notable examples includesmokejumpers (firefighters who parachute into remote areas) andhelicopter support however, what’s interesting is that depending on which area these agencies are in the professionals that work in them can vary, for example Australia mostly relies on actual volunteers to help in suppressing wildfires while other areas hire professionals directly, Australia relies on the volunteer method in order to build a deeper connection between the people and the government which is another reason as to why the government agencies are more on board to helping out and providing funds.[40][13]
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The success of wildfire suppression techniques is debated amongst the scientific community. A number of studies (produced during the 1990s) using Ontario government fire records compared either the number of fires or the average fire size between areas with and without aggressive fire suppression policies.[54][55] They found that the average fire size was generally smaller in areas of aggressive policy. One report, written in 1998 by Stocks and Weber, said; "Use of fire as a management tool recognizes the natural role of fire and is applied judiciously for ecosystem maintenance and restoration in selected areas."[56] A later 2005 study concluded that "Fire suppression is (functionally) effective insofar as it reduces area burned".[57]
Other studies have concluded that the 20th century change in the fire cycle is a result of climate change.[58] A 1993 study by Bergeron & Archambault said: "post-'Little Ice Age' climate change has profoundly decreased the frequency of fires in the northwestern Québec boreal forest".[59] Critics have also pointed out that small fires are virtually unreported in areas without aggressive fire suppression policies, where detection often relies on reports from settlements or commercial aircraft, leading to incorrect average fire size data for those regions.[60]
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