Abstract
A simulation program for the operation system cooperated with a mobile tower yarder, a log-making processor and a skidder was developed with the use of simulation language: GPSS. The purpose of the simulation program is to examine the best combination and the relative location of these machines from the viewpoint of log productivity. It was proved that this program was able to simulate adequately the condition and the flows of the operation system, judging from the comparison of the simulation results with the actual results of a study case. Then, the best condition of the system in the study case was examined throughly, as an example of its application. The results of the simulation indicated that the system using both the mobile tower yarder (K303) and the skidder (Bell super logger) would work most efficiently, when the log-making processor in which productive capacity was duplicated, was used, and when the processor on the forest road was placed within the distance of 150 m from the mobile tower yarder.
