Wildfires are common nowadays. Lightning, campfires, power lines or other sources may lead to big wildfires. 【小题1】 But when they break out on populated places, wildfires can endanger human lives and property.

Still, wildfires have always been a part of some forest ecosystems. 【小题2】 For one thing, wildfires can get rid of trespassers(入侵者). The native animals often know how to escape a wildfire. But harmful species may not, so they could get wiped out.

Fires can prevent trees from overcrowding each other, which allows smaller plants and animals that need sunlight to grow 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 stop new plants from growing and releases nutrition back into the soil. 【小题3】

There are also species that have evolved (进化) to depend on regular wildfires. Banksia trees in Australia, for instance, only release their seeds in the heat of a wildfire. 【小题4】 And birds such as the black-backed woodpecker prefer to live in recently burned areas, because newly burnt trees may offer easy access to a feast of insects.

【小题5】 They set these fires only in areas and under weather conditions where they're sure they can control the flames. Specific burns are meant to provide the benefits of natural, low-intensity fires. So, one important way to protect against fires is professionals setting them.