As more settlers came, roads, fences, plowed fields and overgrazing created barriers to wildfires. These obstructions reduced their occurrence to the point that large wildfires became rare. In Kansas, the same pattern occurred, except in the area known as the Flint Hills. Here, fire was and continues to be used virtually uninterrupted since settlement. As a result, large expanses of almost treeless prairies are common in the central and southern Flint Hills.
Fire plays an important role in preventing the invasion of woody plants.
In some areas, woody plant invasion has progressed to the point of forming closed woodland communities. Essentially no grass remains in such areas. Use of fire as a management tool is steadily spreading westward across the state. Its use in western Kansas is primarily limited to controlling brush and weeds and improving grazing distribution. Using fire also is limited to certain moisture and weather conditions.