More of a prairie's plant material (biomass) exists below ground than above ground. (click image to enlarge)
Prairies are found from the Rocky Mountains through Illinois.
Short-grass prairies are found in the arid west, whereas Illinois, with plenty of rainfall, has tallgrass prairies.
Fire is an important part of restoring and maintaining prairies. Trees and exotic species not adapted to survive fire are destroyed while prairie grasses regenerate from their underground biomass. Watch this video of a prescribed burn - a fire intentionally set by restoration ecologists.