Earth Science for Kids
Forest fires are large uncontrolled fires that take place in the forest. Some of the fiercest fires occur in the forest because there is so much fuel (trees) to burn. Forest fires are a type of wildfire. Other types of wildfires include grass fires, brush fires, and hill fires.
Major Causes of Forest Fires
The major cause of forest fires in the United States is human activities. This can be carelessness such as not putting out a campfire or dropping a lit cigarette. It may also be arson, which is setting a fire on purpose and is against the law. Around 80% of forest fires in the United States are caused by humans.
Most fires that are started by natural causes are started by lightning. Other natural causes include volcanic eruptions and sparks from falling rocks.
How do forest fires spread?
There are many factors that contribute to how a forest fire will spread and how intense the fire will be. They include:
- Weather - The weather has a large impact on how a fire will spread. Fires are much more likely to start and spread during droughts when the grass and plants are dry. A strong wind can help a fire to spread and move quickly. The temperature (how hot it is) and humidity (how dry the air is) will also impact how well the fire will spread.
- Fuel - Fires need fuel to burn. The type of fuel will impact how quickly the fire will spread as well as how intense it will be. In a forest there can be plenty of fuel including trees, leaves, needles, shrubs, and grasses growing beneath the trees.
- Topography - The topography is the shape and features of the land where the fire is burning. Fire tends to move faster uphill. Fires may spread quickly up steep slopes on the sides of mountains and hills.
Forest fires can be extremely difficult to put out or control. Forest fires can be enormous in size and may quickly change directions. They can move over 6 miles per hour and can jump over natural gaps such as rivers and roads. That being said, modern firefighters are well trained and know how to control forest fires.
Two of the main techniques used in controlling forest fires are the firebreak and the air drop.
- Firebreak - One of the best ways to stop a fire is to get rid of the fuel (trees, grass, etc) that is helping it to burn. Firefighters will often remove the fuel in a long line ahead of the where the fire is advancing. This line is called a firebreak. When the fire reaches the firebreak it runs out of fuel and stops spreading.
- Air drop - Sometimes firefighters will use airplanes and helicopters to drop water or special firefighting chemicals on fires from the air. These aircraft can carry thousands of gallons of liquid or gel to drop on hard to reach areas of the fire.
Yes, some forest fires are helpful to the forest. They can clean out debris that has accumulated below the trees. By burning debris, fires help to enrich the soil and make room for new trees to grow.
Whenever you go camping you should be very careful when building and extinguishing your campfire. To keep safe you need to build your campfire in a safe location, you should have a proper campfire pit, and you should make sure that the fire is completely put out. You can learn more about this on Smokey Bear's website at http://www.smokeybear.com/campfire-safety.asp.
Interesting Facts about Forest Fires
- A crown fire is a fire that spreads quickly by burning across the tops of trees.
- Wildfires in the United States typically burn between 4 million and 9 million acres each year.
- Billions of dollars is spent every year fighting fires in the United States.
- Many fires in southern California are spread by dry hot winds called the Santa Ana winds.
- Sometimes the winds around a fire can begin to spin causing a fire tornado to form.
- If you live near an area that is known for wildfires, it is good to have a plan in place on what you will do in the case of a wildfire.
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