- Chief of the United States Forest Service from 1898 to 1910
- Advocate of conservation and sustainable forest management
- Pushed for the establishment of national forests and parks
John Muir:
- Scottish-American naturalist and environmental philosopher
- Co-founder of the Sierra Club
- Credited with preserving Yosemite Valley and Sequoia National Park
Theodore Roosevelt:
- 26th President of the United States (1901-1909)
- Strong advocate for conservation
- Established numerous national parks, monuments, and wildlife refuges
Aldo Leopold:
- American ecologist and forester
- Author of "A Sand County Almanac," which is considered a foundational work in the environmental movement
- Developed the concept of the "land ethic," which emphasizes the ethical responsibility humans have to the environment