A wildfire is a large and uncontrolled fire that spreads rapidly, typically in a woodland setting. In order to start and perpetuate, wildfires require three things — oxygen, fuel (any flammable material in the wildfire's vicinity), and a heat source to spark the fire and heat fuel sources enough to be ignitable. While lightning, changing weather patterns and the sun itself can serve as heat sources, 80-90 percent of wildfires are caused by humans or human-related incidents.
A form of natural disaster, wildfires become deadly and destructive very quickly. They can engulf acres of land and consume everything in their wakes in a span of minutes, moving as fast as 14 mph. 4 million acres of land are estimated to be burned every year in the US due to wildfires.
Despite their highly damaging nature, wildfires also play a key role in preserving ecosystems. They destroyed diseased plants, help return nutrients to the forest floor by burning dead matter, and help sunlight reach seedlings by burning through forest canopies. In Australia, where wildfires are especially common, certain native flora have even evolved to depend on wildfires for their existence. (Photo: Wikimedia Commons)