A case study of the subjective workload of forest equipment operators in South Carolina

Abstract

Logging operations in the Southern United States have become more mechanized over time. However, extensive use of complex and heavy forest machineries for long durations increases operator workload, especially the cognitive demand. Working under demanding conditions can decrease the health of forest equipment operators over time, reducing productivity and increasing the risk of accidents. This study provides an initial assessment of the workload of logging equipment operators during timber harvesting operations using conventional wheeled feller-buncher, grapple skidder, and knuckle-boom loader harvesting systems by assessing the subjective workload of the logging equipment operators in South Carolina. In addition, we observed the heart rate of equipment operators to study the activities causing excessive physical and mental workload. Logging equipment operators self-evaluated their workload using the NASA Task Load Index, a subjective measure of workload. Results show no significant difference in the overall workload of equipment operators working at clearcut and thinning sites. The workload dimensions of Effort and Frustration contributed the most to the overall workload, while Performance had the least contribution. Sudden heart rate spikes occurred when operators conducted physical activities such as clearing debris from a felling head but were otherwise unobserved.