There’s no denying the destructive power of wildfires. Lightning, campfires, power lines or other sources may spark these infernos. They mainly ravage natural areas, such as forests and grasslands. But when they encroach on populated places, wildfires can endanger human lives and property. In 2022 alone, U.S. wildfires ate through more than 7.5 million acres of land and destroyed more than 1,200 homes.
Still, wildfires have always been a part of some forest and prairie ecosystems. And regular burns can be vital for keeping those ecosystems healthy.
For one thing, wildfires can get rid of pests. The animals native to an area often know how to escape a wildfire by fleeing or hiding underground. But invasive species may not, so those trespassers could get wiped out.
Fires can prevent trees from overcrowding each other. This allows smaller plants and animals that need a lot of sunlight to thrive below. Plus, wildfires burn up a lot of leaf litter, pine needles and other dead matter on the ground. This clears out junk that may stifle new plant growth and releases nutrients back into the soil. Importantly, it also prevents the buildup of dead matter that catches fire easily. If the ground is covered with too much highly flammable stuff, that can fuel more extreme, more dangerous wildfires.
There are also species that have evolved to depend on regular wildfires. The seed pods of Banksia trees in Australia, for instance, only release their seeds in the heat of a wildfire. These trees need fires if they are to produce more trees. And birds such as the black-backed woodpecker prefer to live in recently burned areas, because freshly scorched trees may offer easy access to a feast of insects.
As a result, fire experts may start “prescribed burns” in certain places. Professionals set these fires only in areas and under weather conditions where they are sure they can control the flames. Prescribed burns are meant to provide the benefits of natural, low-intensity fires. That includes preventing more extreme fires that could endanger people. So, ironically, one important way to protect against fires is experts setting them.
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In an activity from PBS Learning, use historical data to see how wildfires have changed across the western United States in recent decades.