Subject
- Cascade Range -- Environmental conditions5
- Nature conservation -- Washington (State)5
- North Cascades Conservation Council5
- Wilderness areas -- Oregon5
- Wilderness areas -- Washington (State)5
- Wilderness areas -- United States4
- Oregon. Natural Area Preserves Advisory Committee3
- Wilderness areas3
- Wilderness areas -- Recreational use3
- Forest reserves -- United States -- History2
- Forest reserves -- United States -- Recreational use2
- Mount Jefferson Wilderness (Or.)2
- Natural areas -- Oregon2
- Nature conservation2
- Nature conservation -- Oregon2
- Wilderness area users2
- Wilderness areas -- United States -- History2
- Absaroka-Beartooth Wilderness (Mont. and Wyo.)1
- Camp sites, facilities, etc. -- Environmental aspects1
- Conservation of natural resources -- United States1