North American prairies evolved with fire as a common occurrence in their ecosystem. Prairies respond very positively to fire and are rejuvenated because the burning of dead vegetation releases nutrients for the plants to use and allows the soil temperatures to warm up more quickly in the spring. In fact, prairies need fire to help them thrive against the competition from woody vegetation that will take over through succession if there are no fires. Native Americans realized the value of fire for the prairie and were responsible for many of the fires that occurred over the past several millennia in this area. It is recommended that prairies be burned approximately every 3-5 years.