Forest Fire: Causes and Effects

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Forest Fire: Causes and Effects
Ron Hilton
National American University

One morning you wake up and look out the window. Off to the west, you see an orange glow over the hills. You ask yourself “Is that a forest fire? What caused it? What is it going to do to the ecosystem?”

The answer to the first question comes down to two main causes, man and nature. According to the U.S. Fire Administration (2000), “Human activity is seven times more likely to be the cause of a wildland fire than that of lightning strikes.”

We can narrow down the human-caused fires into two further categories, accidental, such as campfires, outdoor debris burning, smoking materials, electricity, and fireworks. We also have intentionally set fires. For instance, those that were used by Native Americans as signals or to drive game, those set by forestry experts, or those set by arsonists

In 2009, there were 69,650 human caused wildfires that burned over two million acres (National Interagency Fire Center, 2010). Campfires, especially if left unattended or improperly extinguished, can spread to adjoining fuels and start a wildfire. Fireworks can ignite dry vegetation with sparks and hot debris. After the fire, part of the firework, its packaging, or a crater from its explosion may remain.

In many locations, outdoor debris burning is permitted. Where it is not permitted, persons may still illegally burn refuse, especially if conditions are dry, outdoor burning can get out of control and spread to vegetation in the surrounding area.

Another factor is discarded smoking materials, they can ignite a wildfire, however the conditions must be conducive to ignition in the time the smoking material is still burning before it consumes itself and dies out. Although though smoking materials burn at a very high temperature, if that heat does not come into close, confined contact with a dry, fine fuel, ignition will probably not occur.

Power transmission lines are a common source of ignition of wildfires. The ways in which power lines can start fires include: Electrical transformer malfunction or explosion, dropping flaming, sparking, or hot material onto fuels. Overhead power lines can come into contact with trees. Animals can short-circuit the power line, and then fall to the ground and spreading flame to fuels. Fallen wires from wind or storm damage also may spark and ignite fuels. Arcing between conductors brought into accidental contact, often by high winds and/or tree limbs are another means of starting a blaze. Trees can fall on power lines and ground them, igniting a fire.

On the other hand, there are the fires intentionally set such as arson. Wildland fires set intentionally often begin in accessible areas because they are easily reached, but often lightly traveled and therefore the fire setter is less likely to be discovered. The method of ignition varies and may be immediate or an improvised delay device. Juveniles may intentionally or accidentally set a fire using matches, a lighter, or other device. . The method of ignition is limited only by the imagination of the arsonist, but Kirk's Fire Investigation reports that the most common time-delay device is a bundle of matches or matchbook surrounding a burning cigarette (Haan, 2006)

Equally important are the natural fires. In 2009, there were just over 9000 fires cause by lightning which burned almost four million acres. (National Interagency Fire Center, 2010).

When lightning strikes, it can spark a fire. Lightning often strikes trees, power lines, transmission towers, and rocky peaks. Lightning can also strike open ground. A lightning strike often splinters or explodes the item it hits. Be aware that a fire might not start immediately after a...
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