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- Agriculture 2
- Lakes--Oregon 2
- United States. Bureau of Biological Survey 2
- Wildlife refuges 2
- Burning of land 1
- Conservation of natural resources 1
- Conservation of natural resources--Law and legislation 1
- Forests and forestry 1
- Game and game-birds 1
- Geological Survey (U.S.) 1
- Groundwater 1
- Hunting 1
- Izaak Walton League of America 1
- Lakes--California 1
- Land use--Planning 1
- Midge 1
- Oregon State Agricultural College 1
- Oregon State Planning Board 1
- Oregon State Planning Council 1
- Oregon. Advisory Research Council 1
