Shift level analysis of cable yarder availability, utilization, and productive time

Decision makers, loggers, managers, and planners need to understand and have methods for estimating utilization and productive time of cable logging systems. In making an accurate prediction of how much area and volume a machine will log per unit time and the associated cable yarding costs, a reliable estimate of the availability, utilization, and productive time of the cable machine must be known. This study analyzes the important estimators for the Christy SWY III cable yarder operating in the southern Appalachian Region of the Southeastern United States. Shift data were collected on 12 logging units of timber sales on the National Forests in North Carolina from April 1986 through August 1987. The Christy SWY III is a small cable yarder and the results can be generalized to similar cable yarders and applications to estimate better the yarding costs for small cable systems.