Responses of Semidesert Grasses and Shrubs to Fall Burning

Abstract

Four 0.8-ha plots south of Tucson, Ariz., were burned November 12, 1975, in a pasture where cattle had not grazed for 12 months. The fire top-killed most small mesquites, killed almost all of the burroweed and much of the cactus, except in unburned patches. Within 5 years regrowth of mesquite and newly established stands of burroweed equalled or exceeded pre-burn levels. Lehmann lovegrass increased following the burn; most other perennial grasses were not greatly affected. Results suggest that periodic burning can maintain a grassland aspect if the intensity and frequency of grazing allow enough dry herbage for an effective fire to accumulate between burns.