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Every year thousands of acres of forests burn. Sometimes careless campers let their campfires get out of control.
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There are several things that influence the likelihood that a fire will spread.
A forest with more leaves and dead branches on the ground has more fuel to help the fire spread. As the trees and ground cover dry out in the summer, it is easier for these fuels to catch on fire. If it is a windy day the fire is pushed to other trees which helps to spread the fire.
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Forest rangers analyze these factors to predict the danger of forest fires. If the forest rangers predict a high danger of fire, they will warn people not to have campfires or to burn trash.
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Lightning causes hundreds of forest fires every year. A lightning bolt can heat the air and anything it passes through up to a temperature of 30,000 degrees Celsius. If a lightning bolt strikes a tree, the sap in the tree may get hot enough to cause the tree to explode.
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As the tree explodes, burning splinters land on the ground and trees around it. If the neighboring trees are dry, they may catch on fire.
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This natural fire may be good or it may be bad. If the forest has a lot of fuel on the ground but it is very dry, the fire may rapidly spread and threaten homes and peoples' lives. If the same fuel is moist a small section of forest may burn reducing the fuel load.
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These small burns can create natural firebreaks. If a forest is dotted with low fuel spots, some people feel it is less likely that a fire will spread and burn a large section of forest.
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Forests rangers need to decide which fires to let burn and which to put out. This activity allows you to examine how a fire spreads through a forest under different conditions.
