Forest Fires- Impact And Measures to Control It
What is a Forest Fire?
A forest fire is a fire in an area of combustible vegetation that occurs in the countryside or rural area.
Causes of Forest Fire-
The frequency of forest fires has drastically increased in the last few years partly due to environmental factors especially climate change and other man-made intentional activities. The change in climatic conditions such as rising temperature, wind speed and direction, level of moisture in soil and atmosphere and duration of dry spells cause wildfires. Other natural causes include the friction of bamboos swaying due to high wind velocity, lightning strike, global warming and rising instances of EL-Nino. All these factors have a cumulative effect on rising temperature, change in precipitation patterns and air moisture, increasing heat waves and drier soil etc. On the other hand, Man-made factors include small fires by grazers and gatherers, shifting cultivation, tourist bonfire, and timber mafia.
Properties of Forest Fires
Wildfires occur when all of the necessary elements of the fire triangle come together in a susceptible area.
That is when an ignition source is brought into contact with a combustible material such as vegetation which is subjected to sufficient heat and has an adequate supply of oxygen from the ambient air.
A high moisture content usually prevents ignition and slows propagation, because higher temperatures are required to evaporate water within the material and heat the material to its fire point.Dense forests usually provide more shade, resulting in lower ambient temperatures and greater humidity, and are therefore less susceptible to wildfires.
Less dense material such as grasses and leaves are easier to ignite because they contain less water than a denser material such as branches and trunks.
Plants continuously lose water by evapotranspiration, but water loss is usually balanced by water absorbed from the soil, humidity, or rain. When this balance is not maintained, plants dry out and are therefore more flammable.
Impact of Forest Fires
Forest Fires cause wide-ranging adverse ecological, economic and social impacts.
In a nutshell, fires cause:
- Loss of valuable timber resources and depletion of carbon sinks.
- Degradation of water catchment areas resulting in loss of water.
- Loss of biodiversity and extinction of plants and animals.
- Loss of wildlife habitat and depletion of wildlife.
- Loss of natural regeneration and reduction in forest cover and production.
- Loss of carbon sink resource and increase in the percentage of CO2 in the atmosphere.
- Change in the microclimate of the area leading to unhealthy living conditions.
- Soil erosion affecting the productivity of soils and production.
- Ozone layer depletion.
- Health problems leading to diseases especially respiratory diseases.
Whereas if the forest fire is natural and controllable then it plays important role in the ecosystem.
- Many types of forests have evolved to utilize fire disturbances to maintain ecosystem health and to regenerate. For example, many tree species actually require fire to germinate their seeds, and forest fires return important nutrients to the forest soil that was previously being stored in biomass.
- Wildfires help to clear out dead wood and other materials that would otherwise have taken much longer to break down and provide soil nutrition for the next generation of trees and plants living in that forest. This process helps in keeping a forest ecosystem healthy.
- Burned forests serve as habitat for many species, such as the Black-backed Woodpecker, that is specialized to live and thrive in forests that have experienced severe burning.
- After a forest fire occurs, a process called ecological succession takes place, where the ecosystem goes through a series of changes and eventually develops into a mature forest again. At each stage of succession, the changing forest provides habitat for many types of species, including plants, animals, and birds.
Historically, when fires from natural or other causes began, efforts were made to control them as quickly as possible. However, with current understanding of the forest fires as natural and healthy part of the forest ecosystem, forest management efforts are now focusing on a combination of containment strategies necessary to protect human communities from the periodic fires for the sustainability and health of forest ecosystems.
Measures to Control Forest Fires
Better fire shelter: The newest generation of fire shelters are being used by The U.S. Forest Service (USFS) since 2003. This, as shown in the above photograph, consists of an outer layer made of high-temperature resistant silica cloth and an inner layer composed of a lightweight, fiberglass scrim cloth. Both layers are laminated to aluminum foil, which is an excellent reflector of radiant heat. This aluminum foil is designed to slow heat transfer from the outside to the inside of the shelter.
Improved wind models: The most dangerous types of wildfires occur during what scientists call extreme fire weather when conditions are hot, dry, and windy. To combat this kind of fire, researchers are developing computer models to simulate how wind moves across the landscape. With the help of this modeling software and taking into account the weather, landscape and fuel conditions, scientists can now predict wind motion on ever smaller scales. This model helps in providing snapshots of the fire’s potential and thereby help in channeling and blocking the wind speed and direction thereby restricting the progress of forest fires.
Surveillance through drones: Drones can play a big role in wildfire suppression in the future. One of the most effective time to fight a fire is at night when the winds are down and containing fire during that time is slightly easy. Unmanned vehicles could be useful for fighting fires. It can also be effective instruments for doing aerial surveillance and monitoring of the forest fires areas, especially in the night. Drones equipped with thermal cameras could do the job better and more safely than airplanes and helicopters. However, one limiting factor is that such drones are expensive. Further, In contrast to a manned airplane, the remotely piloted aircraft doesn’t risk the life of the pilot and can fly over the fire for much longer. Firefighters are using information gathered by the drones to guide the allocation of firefighting resources on the ground to where they are most needed. The aerial view also reveals the location of critical infrastructure such as power lines, gas lines and water systems in the fire’s path.
Use of satellite images: To better understand when and where wildfires occur, researchers comb through satellite imagery. The satellite data helps in determining the best techniques for preventing wildfires. This information helps in understanding forest thinning and prescribed burns — both of which aim to eliminate fire fuel before the fire occurs, which is described as best methods to control forest fire.
Firing out: Firing out is a technique when firefighters create a controlled burn to direct the fire’s spread. In this technique a fire is created between the wildfire and a natural barrier, such as a road, to remove any vegetation in the wildfire’s path.
Spraying of flame retardant chemicals: Helicopters fly over and dump water or sometimes suppressant foam on fire hotspots. The foam acts as insulation to prevent unburned fuel from catching fire. Fixed wing aircraft called air tankers fly over the blaze dumping flame retardant chemicals, such as ammonium phosphate.