A field study of wind erosion following a grass fire on the Llano Estacado of North America

Interactions between earth, wind, and fire have always played an important role in the formation and evolution of the level plains of the Llano Estacado of North America. The uppermost sediments of this vast region are aeolian deposits, formed by aeolian deposition into grassland vegetation. Grass cover enhances aeolian deposition by slowing near-surface winds and vegetation secures sediments once they are deposited. The benefits of grass cover, however, are lost when occasional fires remove protective vegetation fromfields. After a fire, the underlying soil surface becomes exposed and susceptible to wind erosion until the vegetative cover is re-established. The purpose of this studywas to explore the post-fire recovery process bymonitoring temporal variations in aeolian transport and changes in the threshold velocity of a burned grass field located in Lubbock County, Texas. A continuous record of wind erosion activity was obtained during a six-month period as the surface recovered from a highly erodible state to a more vegetated and stable surface. Results suggest that the threshold wind speed of the field increased from less than 10 m/s immediately following the fire to above 19 m/s in a three-month period as vegetation naturally recovered