Economic optimum big sagebrush control for increasing crested wheatgrass production

Abstract

An approach was developed for estimating the economic optimum rate of initial overstory kill for increasing seasonal forage availability. The model was formulated using: (1) a biological production function relating understory production to initial kill percentage, (2) a derived demand function for seasonal forage value, and (3) a cost of overstory kill function for each control method. The specific optimum solution will vary with the situation; however, the general model may be applied to any ranching situation where understory forage production is constrained by undesirable overstory vegetation. The model was illustrated using the big sagebrush-crested wheatgrass vegetation type on a Utah cow-calf-yearling operation with prescribed burning, 2,4-D spraying, and tebuthiuron application as control methods. For the ranch analyzed, a big sagebrush kill rate between 92 and 100% is optimal depending on the derived demand and cost-of-kill functions used. Kill rates that differ from the optimum caused significant opportunity costs to be incurred.