Wildfires
Nutrient minerals are locked in dry organic matter and are freed by the combustion that occurs during a fire. The ashes left behind after fires are loaded with phosphorous, potassium, calcium, and other nutrient minerals necessary for plant growth (Raven & Berg 2004). There are ecosystems that are fire-dependent, which means the health of that ecosystem depends on frequent fires. A chaparral is an ecosystem that depends on fires. In California’s moist, warm winters and dry, hot summers chaparral shrubs grow fast, and so they soon lock up the nutrients in their foliage. Fires recycles many of these nutrients into the soil, and after a fire, when chaparral shrubs sprout again from their roots, they grow much faster than before (Fuller 1991).
Setting fires are a method used in crop growing to clear croplands and help put nutrients into to the soil. Prescribed fires clear away dead and dying vegetation to help revitalize forests and decrease the risk of larger, uncontrolled wildfires. Fire is also an instrument developers use to help clear away forests for human developments.
Fires kill plants that provide cover for soil, making the soil more susceptible to wind and water. Wind and water are the main agents of soil erosion. Erosion will remove the top-soil first. Once this nutrient-rich layer of soil is gone, few plants will grow in the soil again. Without soil and plants the land becomes desert-like and unable to support life this process is called desertification. It is very difficult and often impossible to restore desertified land (Soil erosion 2001). Fires are able to damage the soil by burning the roots and humus that hold back the runoff and by burning the tress and shrubs that once took in water. Such damage makes erosion more likely. Fires can also make streams murky with sediment, which could harm fish offspring (Fuller 1991).
When the water reserves in the soil are between 30%-100%, the evaporation of water in plants is balanced by water absorbed from the soil. Below this point,, the plants dry out, releasing flammable essences to keep some moisture. One of the dire results of a long hot and dry period is an environment more susceptible to fire (Wildfires 2005).
The consequences on the environment after a forest fire can be more devastating then the initial fire itself. Plants and trees that prevent erosion are burned away during a particularly destructive fire. If heavy rain occurs after a devastating fire, landslides, ash flows, and flash floods can take place. Property damage in the immediate fire area can be a result of the previously stated natural disaters, and can affect the water quality of streams, rivers and lakes (Wildfires 2005).
Burning of living and dead plant life is called biomass burning. “Scientists estimate that humans are responsible for about 90% of biomass burning with only a small percentage of natural fires contributing to the total amount of vegetation burned” (Kaufman 2005). Large amounts of particulates and gases, including greenhouse gases that help aid in the warming of the Earth’s climate, are released from burning vegetation during a wildfire. Increases in global warming may result in larger and more numerous fires, all directly related to the hazardous effects of biomass burnings. Biomass burning particulates impact climate and can also affect human health when they are inhaled, causing respiratory problems (Kaufman 2005).
The carbon dioxide released from biomass burning has significant implications for Earth’s atmosphere and climate. There are short and long-term affects that need to be taken into consideration. Vegetation stores carbon dioxide via the process of photosynthesis. This stored carbon dioxide can accumulate over hundreds of years and upon burning will be released into the atmosphere in a short time period. Burning also will permanently destroy an important sink for carbon dioxide if the vegetation is not replaced (Kaufman 2005).
Most of the Earth’s weather and air pollution reside in the troposphere, the part of the atmosphere that extends from the surface of the planet to a height of between 8 and 13 kilometers. A severe thunderstorm in the area of a large wildfire can have its vertical lift enhanced to boost smoke, soot and other particles as high as the lower stratosphere (Wildfires 2005).Satellite observation of smoke plumes from wildfires revealed that the plumes could be traced intact for distances exceeding 5,000 kilometers. This observation suggests that the plumes were in the stratosphere above weather conditions that would have brought the plume back to earth. Atmospheric models suggest that these concentrations of sooty particles could increase absorption of incoming solar radiation during winter months by as much as 15% (Wildfires 2005).
Prescribed fires cause air pollution when the fires release smoke into the atmosphere. A main case against this is that although prescribed fires release smoke, they do not release as much smoke as uncontrolled fires do. Several precautions such as monitoring wind and fuel moisture are taken to guarantee that the minimum amount of smoke will be released. Forest managers do a lot to meet the guidelines on air quality put into action by government agencies.
The smoke of wildland fires contains carbon monoxide, particles of charcoal, ash, and as many as 60 different chemicals including hydrocarbons from the burning oils and resins, and the tiny particles of ash, charcoal, and chemicals are what make smoke black. When they penetrate deep into the lungs, they remain there. A researcher estimated that working on a fire line for one day equals smoking four packs of cigarettes. The smoke also irritates the lungs of the animals that remain near the fire; however, most of these animals live relatively short lives, and so lung damage is less likely to matter (Fuller 1991).
The existence of human beings and their actions have manipulated ecosystems. Native American tribes used fires keenly in ancient and significant times to change plant life patterns. The ecosystem evolved with the existence of fire. Early North American settlers observed how Native Americans used fire to improve hunting, and ridding the land of undesirable species so they could farm (Steve Nix 2005). Human influence changed after European settlement in North America because fire was soon found to be very dangerous if not controlled. Fire was firmly excluded for many years to protect public and private investments and to prevent the destruction of forests, savannahs, scrublands, and grasslands. The immediate unhelpful, deadly side of fires was very obvious to everyone; so it just made sense to them to prevent all fires, but they never took into consideration how fire exclusion could affect them over a long period of time (Role of Wildland Fire in Resource Management 2005).
For hundreds of years man has suppressed wildfires. The federal government controls fires on federal forestland, and state government controls state forestland. It was believed that by suppressing the fires man ensured a healthy future for the forest. But, as scientists have gathered more information on the effects of fire on forest ecosystems, they have learned that fire exclusion might not have been the best practice for land management. A new technique known as prescribed fire has been used in the last twenty years to reintroduce the natural process of fire back into the forests. While not all the effects of prescribed fire are seen right now, we do know the effects of fire exclusion, and we do know some of the benefits of prescribed fire.
Governmental officials, alongside environmentalists and academics have increasingly advocated setting fires in the wilderness to restore ecosystems and prevent natural wildfires from raging out of control. Fires are simply a natural occurrence within the environment, and it is important that we don’t perpetrate further damage; and to help maintain a broad diversity of habitats for wildlife. For decades the policy has been to suppress fire, but ever since the 1960’s this policy has begun to be questioned and new vegetation and wildlife are born out of wildfires (as can be seen with the new sequoias in the redwood forests). The expenditure of the federal government regarding fire suppression has been $1 billion/year. Only now has the Federal government embraced “prescribed fire” as a means of controlling habitat diversity and maintaining natural balance within the ecosystem (Wildfires 2005).
Forest management has noticed that over the last few decades, the act of fire suppression by man has caused severe problems in the natural forest ecosystem. Fire exclusion causes thick vegetation and large amounts of dead fallen materials to pile up. The dead vegetation and other materials on the forest floor act as fuel for future wildfires. When fires begin in such environments, the intensity of the fire is much greater and the forest ultimately suffers greater damage. Forest management teams have noticed that over the past couple of decades fire suppression has caused many problems in the forest ecosystem. Fire exclusion causes thick vegetation and large amounts of dead fallen materials to pill up. The fuel quantity on the forest floor is increased by the large amount of vegetation and dead material, and may cause fires to ignite more easily. When a fire does begin on the thickly covered floor, the blaze burns at a much higher intensity causing more damage to the forest ecosystem. Not only does fire exclusion cause an accumulation of thick vegetation on the forest floor, but also causes and increased density of smaller trees. When fire does occur, these small trees guide the raging fire from the forest floor to the crown of the older trees causing a crown fire (Wildfires 2001).
The amount of fires that occur have been rapidly increasing over the past hundrend years in part because of population growth. “Urbanization can result in fuel buildup and devastating fires, such as those in Los Alamos,New Mexico, East Bay Hills, within the California cities of Oakland and Berkeley between October 19 and 22, 1991, all over Colorado in 2002, and throughout southern California in October 2003” (Wildfires 2005).
Wildfires are not in the best interest of every forest, but some ecosystems’ survival depends on them. Trying to preserve life by suppressing fires can be more devastating then helpful in certain ecosystems. When fires are used properly they can create more life then ever thought possible. Fires let carbon dioxides and other harmful gases and particles into the atmosphere, but fires are a very natural and necessary part of life. Fires are not completely bad for the environment and they are not completely good either, having the correct balance is the key.
Works Cited
Brown, Arthur A., & Davis, Kenneth P. (1973). Forest fire: control and use. Texas: McGraw-Hill, Inc.
Collins, Jocelyn (2001). Soil erosion. Retrieved on November 27, 2005, from UWC Environmental Facts. Web site: http://www.botany.uwc.ac.za/Envfacts/facts/erosion.htm.
Eilperin, Juliet (2005, July 31). Benefits of planned forest fires are cited. Retrieved November 31, 2005 from Washington Post online. Web site: http://www.washingtonpost.com/wp-dyn/content/article/2005/07/30/AR2005073000999.html.
Fuller, Margaret (1991). Forest fires: an introduction to wildland fire behavior, management, firefighting, and prevention. Canada: John Wiley & Sons Inc.
Kaufman, Yoram (2005). Natural hazards. Retrieved November 29, 2005, from Earth Observatory: Natural Hazards. Web site: http://earthobservatory.nasa.gov/NaturalHazards/natural_hazards_v2.php3?topic=fire.
Nix, Steve (2005). Prescribed fire: controlling a burn for ecological benefits. Retrieved November 29, 2005, from About.com: forestry. Web site: http://forestry.about.com/cs/forestfire/a/prescribe_burn.htm.
Pitzl, Mary Jo (2004, September 26). Wildfires offer some benefits. Retrieved on November 29, 2005, from AZCentral. Web site: http://www.azcentral.com/specials/special38/articles/0926goodburn26.html.
Raven, Peter H., & Berg, Linda R. (2004). Environment. United States: Wiley Inc.
Role of wildland fire in resource management (2005). Retrieved November 27, 2005 from USDA Forest Service. Website: http://www.fs.fed.us/land/wdfire6.htm.
Wildfires (2001). Retrieved on November 29, 2005, from Arches.uga.edu. Website: http://www.arches.uga.edu/~ajwaters/.
Wildfires (2005). Retrieved November 28, 2005, from Wikipedia. Web site: http://en.wikipedia.org/wiki/Wildfires.
Wilfires and prescribed burning (1996). Retrieved November 29, 2005, from U.S. Environmental Protection Agency. Web site: http://www.epa.gov/ttn/chief/ap42/ch13/final/c13s01.pdf.
