Optimum concentration of Ashe juniper in the Edwards Plateau of Texas
The specific problem ranchers face is to optimize the level of brush control, considering the costs involved in removing the initial brush and maintaining high productivity of the range. Clearing operations undertaken in the past were most often aimed at improving herbaceous production for livestock benefits. Several studies have shown that herbaceous production will increase following brush reduction, despite the fact that little is known about the rate of growth of the brush over time. Aro (1971) reported that burned areas produced 300% more herbage than controlled areas following burning of pinon juniper in the South West. Ashe juniper removal by chaining produced an increase in the standmg crop of grass to 657 kg/ha compared to 424 kg/ha on untreated areas (Rollins, 1983). These studies found that brush control may be beneficial to livestock production. Ethridge et al. (1985) reported an additional present value of $36.16/ha and an additional cost of $10-12.5/ha following prescribed burning on tobossagrass in the Rolling Plains region of Texas. Carpenter et al. (1991) indicate that control of moderate and heavy infestations of broom snakeweed are generally economically feasible, and that benefits from livestock efficiency gains are generally greater than the value of increased grass production. Thus, the pattern of brush control to improve livestock production considers removing substantial amounts of brush to insure maximum grass and livestock production.