Edgar Wayburn, a volunteer conservationist who is credited with protecting more U.S. wilderness and parkland than any other American, died Friday at age 103 at his San Francisco home, The Washington Post reports.

A physician and five-time Sierra Club president, Dr. Wayburn was instrumental in the 1980 enactment of the Alaska National Interest Lands Conservation Act, which created 10 new national parks and preserved more than 104 million acres, effectively doubling the size of the nation’s parkland.

Dr. Wayburn also played a key role in establishing California’s Point Reyes National Seashore, Golden Gate National Recreation Area, and Redwood National Park. He was awarded the Presidential Medal of Freedom in 1999.

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