Introduction Study Area Helicopters Methodology Results Conclusions Suggestions References Acknowledgements Appendix 1 Appendix 2 Appendix 3 Appendix 4 Appendix 5

Acknowledgements This work was supported by a Forest Service contract AG-9A72-C-06-0011. The authors wish to recognize two technicians, Chris Real and Susan Newman-Harrison of Murphy & Harrison Inc., who assisted in this study. They uncomplainingly hauled instruments and recorded data, and awoke far before the sun under less than ideal conditions. We also thank Columbia Helicopters’ Max Merlich and George Warren, and Superior Helicopter’s Carson Johnson and Dick Baldwin for participating in the study and allowing us to take sound measurements during operations. We also thank Jon Menten of the BLMs Coos Bay District for allowing us access to the timber sale areas.