Abstract
In forest work, mechanization is progressing, yet much pruning work is still performed by hand. This report provides a comparative study of the manual work and the mechanical work utilizing a remote-controlled machine to prune Chamaecyparis obtusa. Two forest workers pruned to height of 6 to 8m above the ground level. Each pruning, both manual and mechanical, was classified into work elements, and then the energy expenditure of each worker was estimated from the consumed time and the measured heart rates. It was found that the energy expenditure of the mechanical work was half that of the manual work. Analysis of the work elements indicates that pruning accounts for 75% of the total time consumed in manual work and observation of the situation accounts for 75% of the time consumed in the mechanical work. This difference in energy expenditure is connected with the higher load in the manual work. In terms of the number of trees which one worker can prune in a day, the years of forestry experience was a significant factor in the manual work, but it made almost no difference in the mechanical work. Highly experienced workers were more efficient in the manual work and less experienced workers were more higher efficient in the mechanical work. Therefore, it will be useful to adopt remote-controlled type pruning machines in order for new workers to do pruning work efficiently.
