Fire Ecology and Effects
Yellowstone’s landscape has been shaped by naturally caused fire for thousands of years. Lightning may ignite dozens of forest fires in a single summer, although most of them go out for lack of combustible fuel before spreading to more than a fraction of an acre. Without frequent small and occasional large fires to create a mosaic of plant communities in different stages, biodiversity declines and leaf litter and deadfall accumulate much faster than they can return nutrients to the soil through decay. The National Park Service therefore allows lightning-ignited fires to carry out their ecological role in Yellowstone to the extent that this is possible without risking human life or property.