Operators' physical strain in operating the high proficient forestry machines

This study was undertaken to assess physical strain during work in forestry workers operating high quality forestry machines. The types of machine used in this study consisted of harvesters, processors, tower yarders, forwarders and excavators. Characterization of labor load in operation of these five types of machine and fatigue sensation in operators was attempted mainly from the physical burden inflicted on them. The results showed that though the heart rate, an indicator of physical strain, stayed low in all types of work, assessment of labor stress on the basis of heart rate was difficult and that local pain, a manifestation of physical strain, developed in operators. The results suggested the necessity of improving labor conditions in operators of these machines.