Operators' mental strain in operating the high proficient forestry machine

This study was designed to assess the mental aspect of the work load in operators of high proficient forestry machines. Workers engaged in the operation of harvesters, processors, tower-yarders, forwarders and an excavator were included in this study. Mental fatigue and stress generated by operating these five types of forestry machine were assessed. The stress intensity as a measure of mental strain was high in all types of work surveyed. In some types of work demanding a complicated operation of machine, complaints of both mental and physical strain were frequent. In the type of work such as undertaken on a contract basis, operators worked with a feeling of mental pressure to complete the work by the deadline in the contract. The results suggest that the work load needs to be assessed from the physical and mental aspects combined. The titles are tentative translation from Japanese title by the auther of this paper.