Summer Scene

Mix of yellow coneflower, rosin weed, prairie dock with bur oaks and shelter belt trees at horizon.

Bur Oak

Bur Oak

Quercus macrocarpa

70' tall
90' wide

Prairies are kept free of trees and shrubs by prairie fires. The fire kills a woody plant not by burning it but by boiling the water in the vascular system near the surface of the thin bark. This oak seedling would be killed or at least knocked back by a fire. It might sprout back from the root. If there is no fire for a number of years, maybe 5 to 10, the tree sapling will develop a corky bark about an inch thick thick enough to insulate the the tiny water carrying tubes just below its surface from the fire and the tree will continue to thrive.

Bur Oak

Bur Oak

Quercus macrocarpa

In flower in May

Early August Mixed Tallgrass Prairie Forbs

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.