Aldo Leopold was born on January 11, 1887, and died on April 21, 1948. He was an American writer, philosopher, naturalist, scientist, ecologist, forester, professor, conservationist, and environmentalist. He taught at the University of Wisconsin and is best known for his book A Sand County Almanac (1949). This book has been translated into 15 languages and has sold more than two million copies.

Leopold played an important role in creating modern environmental ethics and the movement to protect wilderness areas. His ideas about protecting nature and wildlife greatly influenced the environmental movement. He believed in protecting land as a whole, not just individual parts. He focused on biodiversity and ecology and helped create the science of wildlife management.

Early life

Rand Aldo Leopold was born in Burlington, Iowa, on January 11, 1887. His father, Carl Leopold, was a businessman who made walnut desks. Carl was also the first cousin of his wife, Clara Starker. Clara’s uncle, Charles Starker, was Carl’s father. Charles moved to the United States from Germany and studied engineering and architecture. Rand Aldo was named after two of his father’s business partners—C. W. Rand and Aldo Sommers—but he later stopped using the name "Rand." The Leopold family had younger siblings named Mary Luize, Carl Starker, and Frederic. Leopold’s first language was German, but he learned English quickly and became fluent at a young age.

Aldo Leopold’s early life involved a lot of time outdoors. His father, Carl, took his children on trips into the woods and taught his oldest son about woodcraft and hunting. Aldo had a talent for observing nature, spending hours counting and recording birds near his home. His sister, Mary, later said, “He was very much an outdoorsman, even in his extreme youth. He was always out climbing around the bluffs, or going down to the river, or crossing the river into the woods.” He attended Prospect Hill Elementary School, where he was the top student in his class, and then went to Burlington High School, which was very crowded. Every August, the family traveled to Michigan to visit Marquette Island in Lake Huron, a forested area where the children enjoyed exploring.

Schooling

In 1900, Gifford Pinchot, who led the new Forestry Division in the Department of Agriculture, gave money to Yale University to start one of the country's first forestry schools. Learning about this, a teenage boy named Leopold decided he wanted to become a forester. His parents allowed him to attend The Lawrenceville School, a preparatory school in New Jersey, to help him get into Yale. The principal of Burlington High School wrote a letter to Lawrenceville's headmaster, stating that Leopold was "a very serious and dedicated student… careful with his work… with excellent behavior and strong morals." He arrived at Lawrenceville in January 1904, just before his 17th birthday. He was seen as a focused student, though he still enjoyed spending time outdoors. Lawrenceville was in a rural area, and Leopold often mapped the land and studied its animals. He studied at Lawrenceville for one year, during which he was accepted to Yale. Since Yale's Forestry School only offered graduate degrees, Leopold first took undergraduate forestry classes at Sheffield Scientific School in New Haven, Connecticut. While at Lawrenceville, Leopold often spent time outdoors, sometimes affecting his studies. At Yale, his busy schedule with school and social activities left little time for outdoor exploration. Leopold graduated from Yale's Forestry School in 1909.

Career

In 1909, Leopold was assigned to the Forest Service’s District 3 in the Arizona and New Mexico territories. At first, he worked as a forest assistant at the Apache National Forest in the Arizona Territory. In 1911, he moved to the Carson National Forest in northern New Mexico. Leopold stayed in New Mexico until 1924 because he was creating the first detailed management plan for the Grand Canyon, writing the Forest Service’s first handbook about game and fish, and proposing the Gila Wilderness Area, the first wilderness area in the Forest Service system. During this time, Leopold also helped make many changes in New Mexico and Arizona by developing these plans.

In 1916, Leopold traveled across New Mexico to encourage local sportsmen to form wildlife protection groups. His tour began in Silver City, where he met Miles W. Buford, who later started the Sportsmen’s Association of Southwestern New Mexico. Leopold suggested creating a statewide group, the New Mexico Game Protection Association (NMGPA), which gained support in cities like Rincon, El Paso, Alamogordo, Cloudcroft, Carlsbad, Roswell, and Albuquerque. In March 1916, the NMGPA held its first meeting, with more than 1,000 members. The group set three goals: ending political control of game warden jobs, creating safe areas for wildlife in national forests, and keeping a balance between predators and prey.

After forming the NMGPA, Leopold returned to his work with the U.S. Forest Service. After the Term Permit Act was passed, he helped choose locations in Arizona for private recreational projects. During this time, he also helped start Game Protection Associations in Arizona towns like Flagstaff, Springerville, Tucson, and Payson.

In January 1918, Leopold became Secretary of the Albuquerque Chamber of Commerce. In this role, he supported efforts to include labor groups in the chamber, promote Hispanic and Pueblo architectural styles, and drain parts of the Rio Grande Valley to grow more farmland.

Leopold returned to the Forest Service on August 1, 1919, as Assistant District Forester in Charge of Operations, overseeing Region 3, which included 11 national forests. During this time, he studied soil erosion in areas like the Prescott and Carson National Forests. In December 1923, he wrote The Watershed Handbook, a guide for Forest Service workers on managing water resources and controlling livestock based on watershed conditions.

Soon after starting his new job, Leopold’s boss, District Forester Paul Redington, left Region 3 and was replaced by Frank C. W. Pooler, who doubted Leopold’s ability to lead. Pooler even offered Leopold a new job in a different area. However, Leopold refused and stayed in Albuquerque and New Mexico, where his family and many projects were based.

Leopold’s management plan for the Grand Canyon was forward-thinking, focusing on using resources wisely and protecting the environment. He planned rules for tourism, resource protection, and recreation, and wanted to control businesses like shops and restaurants because they harmed the canyon’s natural beauty. He suggested creating special areas for visitor facilities to reduce environmental harm. He also recommended cleaning up garbage and sewage to improve the Colorado River’s water quality. He emphasized protecting the canyon’s rocks, plants, and animals. For recreation, he proposed activities like hiking, hunting, and fishing to let people enjoy the canyon without damaging it. He suggested building trails to help visitors access the area while protecting sensitive spots. His long-term goal was to ensure “the greatest good for the greatest number in the long run,” a principle used by the U.S. Forest Service. He set the stage for future park management by balancing human use and nature.

At the time, wildlife management had few rules, and many animals were harmed by overhunting, habitat loss, and poor oversight. Leopold saw the need for a better system. In his handbook, he explained how to monitor and manage wildlife populations, such as deer and fish, to stop overharvesting. He promoted hunting and fishing practices that kept animal populations healthy. He also wrote about protecting habitats like forests, rivers, and wetlands to support wildlife. He gave advice on reducing the harm from grazing and logging on animal homes. In a section about ecological balance, he described how removing predators like wolves affected ecosystems. He argued for managing land in a way that included wildlife as part of nature. He also outlined steps for Forest Service rangers to collect wildlife data and enforce rules. He suggested working with local people and hunters to teach them about conservation.

In 1921, Leopold wrote an article in the Journal of Forestry titled “The Wilderness and Its Place in Forest Recreational Policy,” arguing for protecting roadless areas in national forests. He proposed the Gila as a place without roads, vehicles, or industrial projects. He defined wilderness as “a large area of land kept in its natural state, open to hunting and fishing, and free from roads, buildings, or other human-made structures.” As a Forest Service leader, Leopold worked with colleagues like Fred Winn and Don Johnston to study the Gila and create a plan. He suggested protecting 750,000 acres of the Gila National Forest, an area with canyons, hills, and wildlife like elk, deer, and trout. His plan was approved in 1924, and the Gila Wilderness Area became the first of its kind. Leopold saw the Gila as a place to study natural processes like predator-prey relationships without human interference. This idea later appeared in his essay “Thinking Like a Mountain.” He also valued the Gila for its cultural importance, offering people a chance to experience the frontier through outdoor activities.

On April 5, 1923, Leopold was elected an associate member of the Boone and Crockett Club, a wildlife conservation group started by Theodore Roosevelt and George Bird Grinnell.

In 1924, Leopold moved to the U.S. Forest Products Laboratory in Madison, Wisconsin, and became an associate director.

In 1933, he was named Professor of Game Management in the Agricultural Economics Department at the University of Wisconsin, the first person to hold this position.

Family life and death

Leopold married Estella Bergere, the daughter of a well-known ranching family in northern New Mexico, in 1912. They had five children together. The family lived in a modest two-story home near the UW–Madison campus. His children became teachers and naturalists: Aldo Starker Leopold (1913–1983) was a wildlife biologist and professor at UC Berkeley; Luna B. Leopold (1915–2006) became a hydrologist and geology professor at UC Berkeley; Nina Leopold Bradley (1917–2011) was a researcher and naturalist; Aldo Carl Leopold (1919–2009) was a plant physiologist who taught at Purdue University for 25 years; and Estella Leopold (1927–2024) was a noted botanist and conservationist and professor emerita at the University of Washington.

Leopold bought 80 acres in the sand country of central Wisconsin. The area had been logged, burned many times, overgrazed by cows, and left without vegetation. He applied his ideas in the field and began writing his best-selling book, A Sand County Almanac (1949), which he completed shortly before his death. Aldo Leopold died of a heart attack on April 21, 1948, while helping neighbors control a grass fire near his farm in Baraboo, Wisconsin.

Leopold’s home is an official landmark in Madison.

Ideas

Early in his career, Leopold was asked to hunt and kill bears, wolves, and mountain lions in New Mexico. Local ranchers disliked these animals because they harmed livestock, but Leopold began to respect them. After killing a wolf, he saw the animal and noticed a "fierce green fire dying in her eyes." This moment changed his thinking and led him to develop an ecocentric outlook. He created an ecological ethic that replaced the earlier idea that humans should dominate nature. His work showed the importance of predators in keeping ecosystems balanced, which helped bears and mountain lions return to New Mexico’s wilderness areas.

By the early 1920s, Leopold believed that a specific type of preservation should be used in the national forests of the American West. This idea came from the growing number of roads built to support cars and the increasing use of public lands for recreation. He was the first to use the term "wilderness" to describe this kind of protection. Over the next two decades, he added ethical and scientific reasons to support the idea of preserving wilderness. Leopold argued that it is easier to keep wilderness areas than to create them. In one essay, he asked, "Of what use are forty freedoms without a blank spot on the map?" He believed that ethical awareness grew from caring about people, then society, and finally the land. This led to fewer actions based on short-term goals, control, or personal gain. Leopold disagreed with the ideas of conservationists like Theodore Roosevelt, who focused on using nature for human benefit.

By the 1930s, Leopold became one of the first Americans to write widely about wildlife management. He promoted the scientific care of wildlife habitats by both public and private landowners, rather than relying only on game refuges or hunting laws. In his 1933 book Game Management, he described wildlife management as "the art of making land produce steady yearly supplies of wild game for recreation." As Curt Meine noted, Leopold also saw this work as a way to restore and keep environmental diversity.

The idea of "wilderness" changed for Leopold. He no longer saw it as a place for hunting or recreation but as a space for a healthy natural community, including wolves and mountain lions. In 1935, he helped start the Wilderness Society, which aimed to protect and expand wilderness areas. He viewed the society as a key part of a new attitude: a respectful understanding of humans’ role in nature. Science writer Connie Barlow said Leopold wrote in a way that matches what is now called Religious Naturalism.

Leopold’s thinking was also shaped by studying how populations change and how resources are used. By examining wildlife population changes, he built on ideas about carrying capacity and environmental harm that scientists Raymond Pearl and Edward Murray East had discussed. These ideas helped him develop groundbreaking thoughts about how ecosystems are connected. Although later readers often link Leopold to wildlife ecology, his work shows how ideas about human society, such as those from Malthus, influenced his views on nature. He was inspired by ecologists who used Malthusian models of human society and often compared events like the Great Depression and World War II to his studies of animal populations and resource use.

One of the most important books for Leopold during this time was Our Vanishing Wildlife by William Temple Hornaday. This early work, which focused on the dangers facing wild animal populations, strongly influenced Leopold’s ideas. It helped him focus on protecting wildlife, a concern that remained central to his work for many years.

Nature writing

Aldo Leopold is an important figure in nature writing. His work was influenced by earlier writers like Henry David Thoreau, and he helped shape the ideas of later authors such as Kathleen Dean Moore, Wendell Berry, and Scott Russell Sanders. Sanders said, "Aldo Leopold remains a vital figure for us today because he clearly explained the causes of environmental harm and wrote about solutions in a powerful way."

Leopold’s writing is known for being clear and direct. He described many natural places he lived in or studied for a long time, showing a deep understanding of nature. His work includes detailed records of his time with the Forest Service, his hunting and field experiences, and observations from his Sand County farm. He criticized how people often harm natural systems by treating land as something owned by society, ignoring the idea that humans are part of a larger community of life. He believed that modern farming tools give people time to think about nature’s value, but he also questioned whether this truly helps protect it.

In A Sand County Almanac, Leopold’s writing is both beautiful and urgent. He uses poetic and simple language to express his love for nature and his belief in protecting it. The book was published in 1949, after Leopold’s death. It includes monthly essays about land ethics and nature, with sketches of landscapes and plants. Some essays also include philosophical ideas that explain his views on land ethics. One famous quote from the book says, "The concept of a trophic cascade" is explained in the chapter "Thinking Like a Mountain," where Leopold describes how killing a wolf can harm the entire ecosystem. This idea was later supported by Bruce Babbitt, a former Secretary of the Interior.

"Thinking Like a Mountain" was written during World War II, showing how the global conflict influenced Leopold’s thinking. In another chapter, "The Land Ethic," Leopold wrote, "Conservation is a state of harmony between men and land." He noted that at the time, conservation efforts often focused on following rules, joining groups, and using land in ways that were profitable, leaving the government to handle the rest.

Leopold’s work in conservation, like helping create the Gila Wilderness Area, was shaped by his changing ideas. Early in his career, he worked for the U.S. Forest Service, focusing on using natural resources for economic benefit. Over time, his experiences and observations led him to see humans as part of a larger "land community." This idea, called the "land ethic," is central to his philosophy.

A key moment in Leopold’s change of view happened in the early 1900s when he shot a wolf and saw its eyes filled with "a fierce green fire." He later realized that killing predators like wolves can cause problems for ecosystems, such as overpopulation of deer, which harms plants and soil. This experience helped him understand that all parts of an ecosystem are connected.

In "Marshland Elegy," Leopold wrote about the destruction of wetlands and the efforts to restore them. He noted that stopping farming in these areas helped cranes and other wildlife, but he also pointed out that some conservation strategies might backfire if people do not truly care for the environment. Today, sandhill cranes have recovered, with over 15,000 in the Midwest, thanks to efforts inspired by Leopold’s work.

Leopold’s book Game Management, published in 1933, was a major contribution to wildlife preservation. It combined ideas from agriculture, biology, and ecology to teach how to manage ecosystems. It became a leading textbook in wildlife management and helped establish the Department of Game Management at the University of Wisconsin.

The River of the Mother of God, published nearly 45 years after Leopold’s death, includes 59 essays from his unpublished work. It covers themes like wilderness, ecology, and land ethics, showing how his ideas evolved over his lifetime.

In A Sand County Almanac, Leopold’s essay "A Man’s Leisure Time" explores how spending time in nature can enrich people’s lives by helping them connect with the natural world.

Legacy

In 1933, Aldo Leopold became a professor of Game Management at the University of Wisconsin-Madison. This was the first position of its kind in the United States. Leopold helped create the program’s curriculum and led its development. Over time, the program was renamed Wildlife Ecology.

At that time, "Game Management" referred to the scientific study and practical use of methods to keep wildlife populations healthy, especially those hunted for sport. Leopold’s work expanded the field from simply managing wildlife populations to a broader approach that considered the entire ecosystem.

Game management was a part of conservation biology to Leopold. He believed in protecting the balance of the entire environment, not just one species. His work influenced many areas, including ecology, policy, forestry, and ethics. He also wrote a textbook titled Game Management, which was published in 1933.

In 1950, The Wildlife Society honored Leopold by creating an annual award in his name.

In 1965, the Sand County Foundation was formed after the publication of Leopold’s book A Sand County Almanac. This nonprofit organization helps farmers, landowners, and others use environmental and farming data to improve agriculture and protect the environment in the United States. It also created the Leopold Conservation Award to recognize individuals who lead conservation efforts.

The Aldo Leopold Foundation in Baraboo, Wisconsin, was founded in 1982 by Leopold’s five children. It is a nonprofit organization that promotes the "land ethic" Leopold taught. The foundation manages the original Aldo Leopold Shack and Farm, along with nearby land. Its headquarters, the Leopold Center, offers educational programs and land stewardship activities. The foundation also manages Leopold’s writings, supports research on his work, and provides resources for educators. It hosts thousands of visitors each year and offers a curriculum for teaching Leopold’s ideas. The center has a website and many printed materials. In 2012, the foundation and the U.S. Forest Service released a film titled Green Fire: Aldo Leopold and a Land Ethic for Our Time. The film was shown on public television and won a Midwest Emmy award.

The Aldo Leopold Wilderness in New Mexico’s Gila National Forest was named after him in 1980.

The Leopold Center for Sustainable Agriculture at Iowa State University was established in 1987. It was named in Leopold’s honor and has developed new farming methods that protect the environment.

In 1993, the U.S. Forest Service created the Aldo Leopold Wilderness Research Institute at the University of Montana. This group is the only federal organization in the United States focused on improving the management of wilderness, parks, and protected areas.

The Aldo Leopold Neighborhood Historic District in Albuquerque, New Mexico, was added to the National Register of Historic Places in 2002. It includes Leopold’s former home.

In 2007, the state of Wisconsin created the Aldo Leopold Legacy Trail System, which includes 42 trails covering more than 1,700 miles. These trails pass through forests, natural areas, and parks. Signs along the trails share information about Leopold’s life, work, and the environment.

The Leopold Center for Sustainable Agriculture in Iowa was created in 1987 through the Iowa Groundwater Protection Act. It works to find ways to farm profitably while protecting natural resources and reducing harm to the environment.

The Leopold Heritage Group in Burlington, Iowa, promotes Leopold’s legacy by organizing events, educational programs, and conservation projects. It also helps preserve places connected to Leopold, such as his childhood home.

In 1985, Leopold was inducted into the Wisconsin Conservation Hall of Fame, along with John Muir, a naturalist and preservationist. The Hall of Fame is in Stevens Point, Wisconsin, and honors individuals who protect the state’s natural resources.

The Leopold Residence Hall at the University of Wisconsin-Madison was named after him and opened in 2013.

Leopold’s Preserve in Haymarket, Virginia, was established in 2014. It is a 380-acre park that protects diverse ecosystems and prevents land from being developed for industry or business.

Aldo Leopold is known as the founder of wildlife management. He helped shape ethical practices in the field and played a key role in creating the Gila National Forest Wilderness. The Gila National Forest, established in 1924, continues to protect natural resources today.

Works

• Report on a Game Survey in the North Central States (Madison: SAAMI, 1931)
• Game Management (New York: Scribner's, 1933)
• A Sand County Almanac (New York: Oxford, 1949)
• Round River: From the Journals of Aldo Leopold (New York: Oxford, 1953)
• A Sand County Almanac and Other Writings on Ecology and Conservation (New York: Library of America, 2013). ISBN 9781598532067