Bur Oak

Bur Oak
Quercus macrophylla
Prairie fire keeps dead plant mass from accumulating too deeply and returns nutrients to the soil. Prairie fire keeps woodland trees from turning the prairie into deciduous forest. But the thick corky bark of an established bur oak tree protects it from fire, so occasional stands, called savanna, appear in the prairie. However, since bur oak seeds, acorns, need sunlight to grow, the trees remain in open patterns and the savanna areas remain limited in size.