Consideration on flow harvesting system utilizing system dynamics
2010
Sugimoto, K., Kyoto Univ. (Japan) | Niinaga, S. | Hasegawa, H.
Operation time, cost, and productivity of a flow harvesting system were compared with a disjointed system, utilizing system dynamics models. The models were developed using the cycle time information obtained for four processes: tree felling with a chain saw, hauling with a long-reach grapple, skidding with a grapple, and bucking with a processor, in a forest harvesting system at a thinning site operated by a logging contractor in Hyogo Prefecture, central Japan. The results of simulations indicated that the operation time of the flow system was about 60% lower than that of the disjointed system, but its operation cost was about 40% higher. In the flow system, the net working rate of each process after the felling process declined, which increased the cost. A further simulation in which the standard deviation of cycle time of the felling process doubled indicated that the operation time of the flow system was 9% higher than that of a model with a constant cycle time in the felling process. These results indicate that the disjointed system should be used especially in cases where the cycle time varies greatly, such as immature operation or qualitative thinning.
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