Location in the forest is important for fields such as autonomous forest machinery. In this study, we analyzed the control error during autonomous driving of forestry machinery caused by positioning errors assuming localization in the forest using simulations. Based on the kinematic model of the tracked vehicle, simulations were conducted on a hypothetical curve, actual single-track roads, and circular strip roads. We found that the effect of the curve radius on the control error was negligible. The control error of both the single-track and circular roads was minimized at a positioning error of 0.05 m, which was 0.160 m and 0.161 m, respectively. The difference in the average control error between the positioning errors of 0.05, 0.5, and 1.0 m was approximately 0.4 m. Assuming autonomous driving with the 3 t and 5 t class forwarder on a 3-m wide strip road, the tolerable control error in the width was 0.6 m and 0.3 m, respectively. The maximum control error was over 1.3 m in all positioning errors, which exceeded the allowable control error. The increase in the control error was smaller than the increase in positioning error. The findings suggested that even if a positioning error occurred, the effect on the control error would be limited.