On average, more than 100,000 forest fires occur in the United States every year. These fires clear between four million and five million acres of land every single year. While not all forest fires make national news, many have become more aware of this issue because of the recent fires in California.
Forest fires occur across the United States and the world, but they are most common in the Western United States. In the hot, dry desert, fires are easily sparked. While approximately 4 out of 5 are caused by humans, some are caused by nature itself. 1 This article will explore the effects of forest fires on humans and the environment as well as discuss the potential benefits of forest fires to animals and plants.
How Forest Fires Start
Three elements are required in order for a forest fire to start: fuel, oxygen, and a heat source. Fuel is any flammable material, and a forest is full of these—trees, brush, grass, and small cabins. The air provides oxygen, and both humans and the environment have the ability to provide the heat source.
Forest fires can either be caused by human negligence or environmental conditions. In many cases, it is a combination of the two. In a hot, dry climate, one single flame can send an entire forest up in flames. During the summer in the Western United States, most parks and campground have a complete fire ban to minimize the risk. Unfortunately, these bans are often ignored. Poorly extinguished cigarette butts, fireworks, or idling a car on dry brush can also start a forest fire. Even a broken glass bottle on the side of the road can direct sunlight onto a blade of dry grass, sparking a flame.
Lightning is the biggest natural cause of forest fires. Fires that are caused by human activity often occur in relatively populated areas, allowing the fire to be caught in time to help extinguish it. Those that are caused by lightning may be located in extremely remote areas, taking much longer to be noticed. Although they are rarer than fires caused by human activity, fires caused by lightning often destroy more vegetation. 2
Fires are much more likely to occur when the climate is hot and dry. Low humidity and high wind can quickly turn a small fire (such as the remnants of a campfire) into a raging forest fire before you know it.
Types of Forest Fires
There are two different types of forest fires: surface fires and crown fires. Surface fires spread along the ground of the forest. Twigs, dry leaves, and other debris are engulfed in flames as it spreads. Crown fires burn trees up their entire length and spread quickly through the canopy. Crown fires are extremely dangerous and unpredictable and are often sustained through surface fires.
If a fire starts downhill, it can quickly spread up the slope and get out of control. If a forest fire starts at the top of a slope, there is less of a chance of it spreading as far. 3
How Are Forest Fires Fought and Contained?
Forest fires are contained by a wide variety of strategies, depending on the location and size of the fire. For smaller fires, firefighters often use a tool called a “flapper” to smother small patches of fire and stop spreading. A line of vegetation is cleared around the fire to further avoid spreading. Backpacks filled with water can help suppress smaller fires.
I n some cases, tractors and other heavy machinery may be brought in to clear out the vegetation faster. Water trucks may be brought in to spray the area that the fire is moving towards. The wetter the area, the less likely it is to catch fire.
If a forest fire is extremely large or difficult to get to, planes or helicopters are brought in to pour massive water buckets. These buckets are filled from nearby lakes and then quickly dumped from the air. Other helicopters have built-in tanks that are filled with a combination of water and flame-retardant chemicals.
In situations where the fire can’t be reached by land, smokejumpers are used. These are firefighters who parachute out of planes to the forest fire. Essential tools are dropped from another parachute to help them fight the flames and reduce spreading. 4
Human Impact of Forest Fires
Forest fires can quickly wipe out large patches of land or destroy many homes and local businesses, taking lives in the process. Firefighters who risk their lives to fight the fire can develop serious health problems due to smoke inhalation.
The ash and smoke from forest fires can cause serious health problems to any humans who are exposed to them. As seen in California recently, you don’t need to live right next to a forest fire to feel the effects. Smoke can travel many miles, negatively affecting both visibility and air quality.
Those who have allergies, compromised immune systems, or respiratory problems are particularly susceptible. Breathing in too much ash and smoke can permanently damage the lungs and throat.
Environmental Impact of Forest Fires
Forest fires are often devastating to the environment. Ground cover is necessary to protect the soil. If all of this vegetation is burned away, the soil is left exposed to the elements. Heavy rain can degrade soil and cause flooding and erosion. Ash from the fire can be washed into deeper soil layers, which in turn leads to the extinction of plants that cannot live in alkaline soil.
Additionally, trees and plants are burned away, reducing the amount of habitat and food for local animals. Animals that aren’t fast enough to escape from a forest fire may lose their lives. Although some types of trees are resistant to forest fires, many trees need to be replanted in order to thrive once again. The massive loss of vegetation also removes thousands of beneficial terpenes from the environment, while the extreme amounts of smoke can damage the ozone.
On the other hand, burning away the top layer of trees can allow sunlight to reach places it may not have reached before. This can create a new habitat that helps different types of plants and animals thrive. 5
For example, certain mushrooms thrive in the environment after a forest fire. Morels, a commonly sought-after edible mushroom, tend to pop up wildly after coniferous forest fires in the Western United States. 6 Some trees even rely on forest fires to spread their seeds.
Giant sequoia trees, spruce trees, and pine trees have adapted to fire and actually have to burn in order to regenerate themselves. The extreme heat opens up their cones and allows the seeds to spread. 7
There is only one particular instance in which forest fires are intentional. Controlled burns are often used by forest management to benefit the forest. This puts a whole new spin on the phrase "fight fire with fire."
By lighting small fires under the proper conditions and with the proper tools on hand, the highly combustible layer of plant debris can be burned away. This helps prevent uncontrolled fires from happening in the future.
Controlled burns are also used to help continue the growth of certain species of trees. The giant sequoias and other tree species that rely on fire to spread their seeds do this best under controlled conditions. 8
How Can You Help Prevent Forest Fires?
Since the majority of forest fires are caused by humans, it is extremely important to be aware of your actions. This is true year-round but especially true during the hot, dry summer months. Respect all fire bans, completely extinguish campfires and never leave them unattended, and don’t throw cigarette butts into nature. If everyone takes these small, simple steps, it's possible to reduce the number of annual forest fires.
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