Improvements to the National Park System : hearings before the Subcommittee on Parks, Historic Preservation, and Recreation of the Committee on Energy and Natural Resources, United States Senate, One Hundred Fifth Congress, first session, to address the future of the National Park System and to identify and discuss needs, requirements and innovative programs that will ensure the Park Service will continue to meet its many responsibilities well into the next century, March 13, 1997, March 20, 1997.