In this study we considered the perception of burden and the actual costs of operating high-performance forest machinery for lowering the costs of investment by logging contractors. We surveyed authorized contractors in Miyazaki, Oita, and Kumamoto prefectures. The perceived burden was rated on a scale from zero to five, with five being the highest. The burdens of the purchase, repair, fuel, and social insurance costs were high, and the perceived burden and the actual cost ratio of purchase costs were high. Therefore, the repair cost is a priority for lowering the overall cost. Although the perceived burden of the cost of labor was not high, the actual cost ratio was considerably high, and it was assumed that many contractors regarded labor as a necessary expense. The actual cost ratio for repair costs was low, and the perception of this cost being high may be related to the high frequency of occurrence of repair costs, thereby increasing the perceived burden. Therefore, it was suggested that reducing the frequency of repair costs could reduce the perceived burden of these costs. The perceived burden and the actual cost ratio of machine insurance premiums were low. Therefore, it was suggested that insurance is effective in controlling repair costs. In addition, to lower the fuel costs, using machines that are suitable for conditions is important, and although the perceived burden of social insurance costs was high, the improvement of working conditions is necessary, and cost reductions in social insurance should be carefully considered.

We conducted actual analyses of the maintenance of 98 spur roads running of a medium truck in the Shirasu area(formed from the pyroclastic flow deposits from Aira Caldera) of Southern Kyushu. Most of the spur roads in the study had been established for 4-6 years. Eighty percent of the maintenance of sites was required due to clearing and grubbing and non-land correction of trucks and for concretization of the road surface and granular filling of the roadbed. About 90% of maintenance costs were due to concretization of the road surfaces and granular fill used for the roadbed. Costs increased as the number of years after the establishment of the roads increased. After 16 years, the total cost of maintenance of the spur roads is expected to be > 25% of their establishment costs.