The grazing of livestock, a primary use of rangelands, is also a powerful and fundamental tool for land managers. While forage growth is dependent on rainfall and site characteristics that are beyond the control of managers, stocking rate (the number of animal units (AU) per land area per unit of time) is the direct result of a (hopefully) informed managerial decision. Determining stocking rate is a primary way that managers deploy grazing strategy into their larger land management plan.