Born on Jan. 11, 1887, Aldo Leopold, an influential American scientist and conservationist and the author of "A Sand County Almanac" (more than 2 million copies of which have been sold since it was released in 1949), continues to influence writers and thinkers in modern times.
Leopold is regarded as the founder of the science of wildlife management. "The Land Ethic," a chapter of his book, popularized the idea of ecological thinking — that animals, plants, soil, geology, water and climate all come together to form a community of life — that they are not separate parts, but integrated pieces of a whole.
His understanding of the natural world is captured in many of his quotes, a collection of which are gathered below — a fitting tribute on what would have been his 129th birthday.
In the summers, Aldo Leopold's parents took the family to the Les Cheneaux Islands area of Michigan's Upper Peninsula, where the children had free range to explore the natural world. (Photo: Scott Smithson/flickr)
Leopold's early life included lots of time outdoors with his father and siblings in Iowa (and summers in the Les Cheneaux Islands of Michigan's Upper Peninsula); he was a strong student and spent hours outside counting and cataloguing birds.
By the age of 24, Leopold had been promoted to the role of supervisor for the Carson National Forest in New Mexico, pictured above. (Photo: Greg Westfall/flickr)
Leopold went on to study at the then-new Yale School of Forestry, and from there he went into a career with the Forest Service, where he spent more than a decade in New Mexico and Arizona. He went on to develop the first comprehensive management plan for the Grand Canyon.
Leopold recognized the importance of apex predators like bears and wolves decades before this idea was more commonly accepted (though in some places, that's still an ongoing battle). He wrote about this concept of trophic cascade in a chapter of "The Sand County Almanac" called "Thinking Like a Mountain" when he realizes the implications of killing a wolf.
When you see Grand Teton, you don't question the importance of saving wild places, and Leopold championed the idea. (Photo: Dave Hensley/flickr)
Leopold also saw the future wrought by a world filled with automobiles (and roads) crisscrossing the country, and the demands of a rapidly increasing population. He wanted to protect large areas for their own sake, away from human development (including roads) and was the first person to use the world "wilderness" to describe the idea.
Are animals, like this elk, valuable only inasmuch as they can be bought or sold by human beings, or do they have inherent value? Leopold advocated the latter idea. (Photo: Josef Pittner/Shutterstock)
Leopold rejected the utilitarian viewpoint that many conservationists of his time held, who used the ideas of how valuable a piece of land was — in mineral rights, animals that could be hunted, or how rich a river was with fish — to judge its worth. He believed animals, plants and natural systems had worth in the own right.
Aldo Leopold Shack near the Wisconsin Dells in Wisconsin on land that he and his family restored over time from a barren landscape. (Photo: Jonathunder/Wikimedia Commons)
Leopold moved to Wisconsin in 1933, and he and his family began an experiment of their own — on 80 acres of land that had been logged, consumed by several wildfires, over-grazed by cattle and finally left barren, they planted thousands of pine trees, and worked on restoring prairie areas. Following the rehabilitation of landscape along the Wisconsin River gave Leopold a greater understanding of how natural systems worked and inspired him to write "A Sand County Almanac" later.
Though Leopold died in 1948 at the age of 61, a wilderness area was named after him in 1980. The Aldo Leopold Wilderness comprises more than 200,000 acres in the Gila National Forest of New Mexico.