Comparison of productivity and cost depending on slope when forwarding short length logs with small Japanese forwarders

Demand for forest biomass is growing in Japan, which makes cost-effective harvesting operations important. Information about the cost and productivity of machines helps in selecting the most cost-effective machines. However, there are some limitations in the available information about forwarders with > 3 t load capacity in Japanese conditions. An IHI F801 (F801) and an IWAFUJI U-5CG (U5) forwarder were investigated in a thinning with 0–73% slope. The F801 was found to have significantly higher speed than the U5, but no significant difference was found for loading and unloading time. The speed decreased slightly with increased slope, this decrease was more evident for the U5 than for the F801. Loading and unloading time (s/log) decreased with increasing number of logs per crane cycle. Time consumption per m3 was 25–32% higher for the U5 than for the F801. However, the cost per hour was about 31–32% higher for the F801 than for the U5, resulting in a cost per m3 that was 1.9–5.8% lower for the U5. This situation indicates that the U5 is more cost-effective than the F801, in Japanese conditions. It also seems that larger self-loading forwarders like the F801 and U5 are more cost-effective than smaller forwarders and forwarders loaded with loaders. However, the F801 could become more cost-effective than the U5 if changes in salary cost, scheduled hours, maintenance rate, and/or utilization rate occur. These facts are particularly important to consider if the F801 would be used overseas.