NPS Photo

A prescribed fire starts at the edge of the grassland.

Historically, the tallgrass prairie experienced repeated natural fires with frequency of five to 10 years. Most wild fires occurred in late summer, before the fall rains when fuel was dry and grasses were going into dormancy. A second fire season occurred in late winter and early spring during dry years. These fires were frequent and of low severity, eliminating most of the young woody species that had established since the previous fire and rejuvenating perennial grasses and forbs.

Aboriginal people may have purposely started fires in late winter or early spring to promote early greening and to refurbish grasslands for game species. They also caused accidentally fires. The fires maintained the prairie ecosystem in a climate that favored woodlands. People began to suppress fires in the mid-1800s. Only occasional wildfire and prescribed fire occur today.