1929: Forest Service L-20 Regulation for Primitive Areas
Five years after the Forest Service established the Gila as the nation's first Wilderness Area, in 1929 the agency enacted a broader measure to protect certain areas within the national forests. The L-20 Regulation provided a policy to designate Natural Areas, for scientific and educational purposes; Experimental Forests and Ranges, for long-term research unfettered by other management objectives; and Primitive Areas "to maintain primitive conditions of transportation, subsistence, habitation, and environment to the fullest degree compatible with their highest public use."
Using the authority granted by the L-20 Regulation, the Forest Service established 75 Primitive Areas and two Canoe Areas on 14.2 million acres during the next ten years.
In 1939, the Secretary of Agriculture issued Regulations U-1, U-2, and U-2A (collectively, the "U-Regulations") to replace the L-20 Regulation.
"Briefing on Primitive Areas in the National Forest System," Statement of M. Rupert Cutler, Assistant Secretary for Conservation, Research, and Education, U. S. Department of Agriculture, Before Subcommittee on Public Lands of the Committee on Interior and Insular Affairs, U.S. House of Representatives, July 24, 1979.