Chapter 11: The High PlainsThe High Plains covers more than 80 million acres in several states,including 18 million acres in the Texas Panhandle also known as the StakedPlains or Llano Estacado. The region supported coniferous forest until the latePleistocene, but is now a dry steppe (Wells 1970). The low and variable rainfall(15-20 inches annually) mostly occurs during summer and is sufficient to supportthe shortgrass prairies described by early writers as a "sea of grass" (Bray 1906).These rangelands attracted the cattle industry by the 1870s. Cultivation began inthe 1920s and intensified with utilization of the vast (but diminishing) OgallalaAquifer. Where dryland farming has not displaced ranching activities, native rangedominated by blue grama, buffalograss, and other midgrasses and shortgrassesstill covers areas of the High Plains and extends throughout the Great Plains northto the Canadian border. However, the majority of rangelands in Texas have beeninvaded by low-growing mesquite in the last century, perhaps a result ofovergrazing (Allred 1956, Box 1967a).127In addition to upland short grasslands, range sites on the High Plainsinclude areas of hardlands, wind-blown sand drifts that support Havard oak andother shinnery species, and a few riparian areas. The southwestern part of theregion is increasingly arid, grading into semi-desert brushlands (Havard 1885,Petersen et al. 1987). The eastern edge of the High Plains falls away at ...