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Leopold, Aldo


(b. Burlington, Iowa, 11 January 1887; d. Baraboo, Wisconsin, 19 April 1948),

wildlife management, ecology, game surveys, forestry.

During his lifetime, Leopold was recognized as an innovator in the field of wildlife management and an important contributor to ecology. After his death his writings became widely known and influential to a growing community of environmental thinkers. He undertook the first large-scale game survey in the United States, was the author of the first textbook on game management, and became a founding member of the first academic department in wildlife management. Leopold incorporated concepts from plant and animal ecology as he worked to reform state and federal wildlife policy during a period of intense growth in knowledge of wild populations and concern over human interactions with those populations.

The Development of a Sport Hunter . Leopold grew up in the town of Burlington, Iowa, in a house overlooking the Mississippi River. He was the oldest of four children. His sister, Marie, was a year younger, and his two brothers, Carl Jr. and Frederic, were five and eight years younger, respectively. The bluffs along the river provided a training ground for natural history, and the Leopold children came to know the flora and fauna well. The boys were especially well versed in the knowledge of nature that made for success in hunting. Carl Leopold, Aldo’s father, taught them to recognize the grasses, shrubs, trees, birds, and mammals of the hills and wetlands surrounding the town. Under this tutelage, Aldo developed an understanding of the interconnections among species and an awareness of how human communities relied upon the natural world.

Even with all the time he spent outdoors with his father and siblings, Aldo’s mother, Clara Leopold, made sure that he was immersed in subjects including poetry, philosophy, and German literature. She took pride in his achievements at school and encouraged his writing. She aspired to have all of her children attend finishing school, and Aldo would be the first, in 1904, to venture eastward.

The Training of a Forester . When Leopold recognized forestry as a legitimate career option in the first decade of the twentieth century, the educational opportunities in that field were only just emerging. Yale University offered the only program in the country that would provide a young forester with the credentials to manage public forest lands. President Theodore Roosevelt appointed Gifford Pinchot to administer the nation’s forests as chief of the newly formed Forest Service in 1905. Together, Roosevelt and Pinchot formulated a conservation plan that focused on a utilitarian philosophy for protecting resources from excessive harvesting that might deplete the public value of lands. Pinchot’s inspiration came from Europe, after receiving his own forestry training in Germany. Programs such as the one at Yale adopted this conservation philosophy for forestry. Forests would be managed by people trained to recognize their short-term productivity as well as the need to sustain them for the public good over generations. Leopold therefore entered forestry at a pivotal time in the history of the profession.

In order to apply to the Yale program with more than his Burlington public school credentials, and to meet his mother’s ambitions, Leopold entered the Lawrenceville Preparatory School in New Jersey. He spent a year there, which proved to be a valuable experience in his personal as well as academic development. Upon leaving his family in Iowa, he was instructed to write home regularly and to include in his letters every detail of his new experiences. Those letters became a vital part of his development as a writer; his mother regularly corrected grammar and made suggestions for improving the narrative flow of his writing. For his part, Leopold sought to relate his experiences in an engaging literary fashion. He also continued and expanded his habit of daily writing in a journal that included personal reflections and natural history observations.

After a year at Lawrenceville, he applied and was admitted to the Yale forestry program. There he received the training that would prepare him for a career in Pinchot’s Forest Service. He completed his coursework and received a bachelor’s degree in the spring of 1908. He returned to Yale in the fall for a final year of training as a master’s student. Students at Yale were immersed in the utilitarian approach that became a motto for the conservation movement in those years: “for the greatest good for the greatest number over the long run.” The field experience provided in the last year also gave Leopold and his peers a practical sense of the work that lay ahead.

Raising Questions about Conservation . Through his training at Yale Leopold had adopted the views of the Forest Service and its administrators. However, once he began to experience the work of forest management he articulated some innovative notions, incorporating his perspective as a sport hunter.

His first months as a forester included a move to New Mexico, where he was stationed on the Apache National Forest. There he attempted to familiarize himself with a diverse landscape of mountains, rivers, forests, and wildlife. Amid surroundings very different from the countryside of his youth, he relished the challenge, but his inexperience also took its toll. After just a few weeks, Leopold was placed in charge of a reconnaissance crew, a team of men who rode through the forest making estimates of the timber. Their daily tasks included arduous horseback rides and careful measurement of forest and geographical parameters. In the evening, Leopold worked out calculations of the day’s measurements. His crew, lower ranking but more experienced, found him rather incompetent. Leopold had struggled with mathematics during his education, and the pressure of his new responsibilities amplified his shortcomings. He responded by denying his errors and further alienating his crew. The reconnaissance survey lasted three months, and in the end, Leopold was as enthusiastic as ever about fieldwork, but his supervisors began to recognize he lacked the skills to manage a Forest Service crew in the field.

Over the years, Leopold moved into positions that involved less direct fieldwork. The challenges of developing new policies for management of the public forests suited the young forester, especially as continued reconnaissance provided a more detailed picture of the existing forest conditions. He became particularly interested in linking emerging concerns about game and soil conditions in the forests. He observed firsthand how natural communities had changed in recent decades. Since the arrival of settlers in the foothills and valleys of the mountain west, farmers and ranchers had taken a toll on native game populations. Extending Pinchot’s resource management philosophy to include game, Leopold began a reconsideration of the relationship between public lands and hunting practice that would involve private landowners and government policy at every level. He recognized that the best management practices for government forests did not necessarily provide adequate conservation of game habitat. Although Roosevelt had hoped to create hunters’ paradises in specific locations throughout the West, as a hunter, naturalist, and president, he lacked a sound understanding of what it would take to maintain viable game populations in areas where timber harvests and other resource extraction enterprises took their toll on wildlife. It would take Leopold, and a generation of range managers and ecologists, decades to work out the details of effective game management.

In 1912, Leopold married Estella Bergere. Together they had five children, two girls and three boys. Leopold’s wife’s family included several generations of prominent sheep ranchers. Her Spanish heritage and family connections to practical range management broadened Leopold’s personal and professional perspective. As much as her family cemented his bond to the Southwest, he also longed to be closer to his own family in Iowa. Another personal experience that shaped his view of natural resource management came while he was traveling alone in a remote area of the Carson National Forest, where he was superintendent, in 1913. A rainstorm created flood-waters that soaked his provisions as he rode, then the weather turned cold, and he was caught in a blizzard. Wet and freezing, he contracted an inflammatory disease. He nearly died and spent months recovering at home. During his slow recovery, he began to think more systematically about game conditions and resource management.

A key motivation in Leopold’s rethinking of game policy came from the well-known and bombastic writings of William T. Hornaday, a naturalist who established his reputation as the superintendent of the New York Zoological Park. Hornaday decried the wasteful practices of eastern hunters who had depleted the forests and marshes of game. He railed against poachers, especially recent immigrants who, he claimed, lacked an appreciation of American hunting ideals. In 1915, Leopold met Hornaday in Albuquerque and became an immediate disciple. Declining game populations in the West seemed to be following the pattern established in the eastern states since colonial times, and Leopold believed that it was time to reverse that trend. Leopold read Hornaday’s books and the two men corresponded regularly. More than any scientific or rational understanding of the conditions, Leopold gained from Hornaday a sense of urgency that sparked him to action. He worked actively with the Albuquerque Game Protective Association for nearly a decade, and from his position with the Forest Service, helped to establish the Gila Wilderness Area, the first designated wilderness in the national forest system.

Contributions to an Emerging Field . Health problems and a persistent yearning to get back to the Midwest provided the impetus for Leopold to take a position in Madison, Wisconsin, at the Forest Service’s Forest Products Laboratory. The move, in 1924, kept Leopold in the employ of the federal government, but meant a significant shift from the responsibilities that had enabled him to be involved in game issues in New Mexico. His new tasks of managing and directing research gave him more time than ever to devote to his growing interests in conservation. Game conservation related to forest management, but not to the work he was doing in Madison. Wisconsin residents, however, had a much more vital awareness of conservation as a political and social concern. The state was populated by hunters who had a particularly keen interest in deer.

Leopold’s professional interests continued to shift from research at the forest lab to game management. He began planning a survey of game, which soon expanded to include collaborations with game experts in several midwestern states. In the midst of his planning, an offer from the Sporting Arms and Ammunition Manufacturers’ Institute gave Leopold an alternative to the Forest Service job. Work for the sport-hunting industry, which had a vested interest in the conservation of game that would perpetuate sales of their products, gave Leopold freedom to explore his interests.

Leopold spent much of 1928 learning game protection, preservation, and conservation at the national level. His connection to the Sporting Arms and Ammunition Manufacturers’ Institute placed him in a prominent position. He met with experts on the East Coast, including Hornaday. Leopold’s plans to conduct research into the conditions for game in various states initially drew criticism from Hornaday, who believed that the time for action was long overdue, and that research would only delay policy makers. Yet Leopold persisted with the plan and soon began meeting systematically with state officials and university scientists across the Midwest. This approach yielded a groundbreaking publication, a Report on a Game Survey of the North Central States, in 1931.

So detailed that some reviewers found it overwhelming, the publication’s gaps also highlighted the lack of knowledge in certain areas. The overriding message was that game populations were either in decline or undergoing significant shifts that needed local as well as broader attention in the form of policy and regulation. Leopold noted that local conditions needed ongoing study to determine how game populations might respond to increased hunting pressure, decreased quality habitat, ongoing predator control, or short-term weather effects. Game management assumed that certain factors could be controlled, but Leopold pointed out that in most cases, the factors were not yet defined, and the control was not at all understood.

The report also appeared against the backdrop of national awareness of the failures of past game protection practices. In some places those failures had been spectacular. Leopold was particularly aware of the deer management efforts on the Kaibab Plateau, an isolated forest region north of the Grand Canyon. Deer protection, initiated by Roosevelt in 1906, led to a population explosion that many observers blamed on the cessation of hunting coupled with ongoing predator control. These practices resulted from conflicting state and federal goals for the area. Leopold’s experience in the Southwest, where similar instances of game mismanagement had scarred the landscape, suggested that game experts needed to provide a more sophisticated solution than protection. He coined the term irruption to describe what happened when game populations were allowed to expand without control, and the Kaibab case became his key example. Although he had not visited the Kaibab and seen the conditions there firsthand, he corresponded regularly with foresters there, and invited one, S. B. Locke, to write a chapter on the events for a textbook Leopold was preparing. Locke never wrote the chapter, but their correspondence revealed the persistence of the Kaibab case in Leopold’s thinking about game management.

In 1933, Leopold published Game Management. The book was widely hailed as the first textbook in the field, and it remains a classic reference for wildlife management. In it, Leopold acknowledged his debt to the Sporting Arms and Ammunitions Manufacturers’ Institute, stating that the support he had received to conduct the game surveys had made possible his articulation of empirical principles of game management. He referenced European principles and practices, as well as the expertise of North American ecologists.

The book, which contained eighteen chapters in three sections, united game theory, practice, and administration into a comprehensive, empirically based profession. Leopold introduced principles from animal and plant ecology, including population growth and fluctuations.

He suggested new terminology for certain population cycles, most notably irruption for the rapid increases that led to dramatic declines in game. His admiration for rational management for sustainability, as found in European forests, inspired suggestions that game could be similarly maintained. In the early 1930s, he did not yet advocate the end of predator control, but his enthusiasm for the practice had waned. He proposed more research in order to determine the proper role of predators in rational game management practices.

Another outcome of Leopold’s success with this book was establishment of a faculty position at the University of Wisconsin in Madison. The Alumni Research Foundation provided funding for a program in game management, including a salary and other expenses for Leopold. He became the first professor in such a program in the country. In that capacity, he interacted more frequently with his academic colleagues and developed closer ties to research ecology. By the late 1930s, he had integrated ecological views more explicitly into his articulation of game management as a profession. In 1939, he presented a paper to the Society of American Foresters and the Ecological Society of America at their joint meeting in Milwaukee. He titled the paper “A Biotic View of Land” and incorporated recent ecological concepts, which had appeared only marginally in Game Management. For example, Leopold used the “pyramid of numbers” to illuminate ecological relationships and demonstrate how management tended to oversimplify those relationships. Leopold also dismissed principles that had previously guided game managers. Ecology began to replace “economic biology,” and the role of species in an ecological discussion could no longer be assigned to purely utilitarian categories such as “useful, harmless, or injurious to man.” Instead, species served as links in complex food chains, the prevailing metaphor in ecology by that time.

Legacy . As a testament to Leopold’s stature in fields affiliated with game management, he was named an honorary vice president by the American Forestry Association. The Ecological Society of America, much to Leopold’s surprise, elected him as their president in 1947. Because he was not an active member of either group and rarely attended those meetings, these elections discomfited him to a degree, but he acknowledged the privilege, stating that he felt the responsibility of serving in spite of his previous lack of direct involvement.

Leopold died suddenly the following year. On 19 April 1948 Leopold, along with his wife and daughter, joined neighbors to fight a grass fire that had spread from a trash pile in a farmyard adjacent to the Leopold property near Baraboo, Wisconsin. This weekend property had become a family retreat for the Leopolds. They referred to its sole building as “the shack,” and studied its surroundings as a kind of experiment in restoring prairie to a landscape depleted by farming. Leopold was anxious to protect his land that day, but carrying a water tank on his back, he suffered a heart attack.

In the last decade of his life, Leopold wrote a series of essays, mostly at the shack, considering the proper role of humans in managing and appreciating the natural world. These essays blended natural history and philosophy with a call to action. For example, having realized the importance of predators in ecological systems, he wrote with regret about his own role in killing wolves in the Southwest. He expanded his definition of wilderness, and advocated for preservation of more such areas. After his death foresters, game managers, and ecologists recognized Leopold’s contributions as central to their profession. His philosophical contributions to ecology and conservation inspired the conservation minded, but were somewhat marginal to researchers in those fields. The influence of Leopold’s general works, however, became established nearly twenty years later, after the publication of Rachel Carson’s Silent Spring, in the midst of growing concern about the degradation of the natural environment. Leopold’s A Sand County Almanac became a major source of that message. In essays that included “Thinking Like a Mountain” and “The Conservation Ethic,” Leopold had described the complex and essential role of humans in terms that resonated with an expanding public awareness of environmental degradation. His ability to connect ecological concepts with the sense that humans should bear responsibility for their activities and impacts on future generations has prompted some to refer to him as a “prophet” for conservation.



“Wanted—National Forest Game Refuges.” Bulletin of the American Game Protective Association 9 (January 1920): 8–10, 22. An early example of Leopold’s appeals for the Forest Service to adopt game protective policies.

“Determining the Kill Factor for Black-Tail Deer in the Southwest.” Journal of Forestry 18 (February 1920): 131–134. Leopold’s avocation as a hunter demonstrated in the context of his professional role as a forester.

“Game Methods: The American Way.” American Game 20 (March–April 1931): 20, 29–31. An example of Leopold’s emerging professional views of game management.

Game Management. New York: Charles Scribner’s Sons, 1933. The first “textbook” of game management, in which Leopold referred to some basic ecological principles along with considerable speculation and experiential explanations of population phenomena.

“Deer and Dauerwald in Germany: I. History.” Journal of Forestry 34 (April 1936): 366–375. An overview of Leopold’s experience touring forests in Germany and considering the history of game and forest management practices.

“Deer and Dauerwald in Germany: II. Ecology and Policy.” Journal of Forestry 34 (May 1936): 460–466. A further demonstration of the influence of European forestry had on Leopold, including discussion of recent ecological developments and the implementation of policy.

“A Biotic View of Land.” Journal of Forestry 37 (September 1939): 727–730.

“Deer Irruptions.” Wisconsin Conservation Bulletin 8 (August 1943): 1–11. A discussion of how game management efforts had gone awry in various locations, pointing to the need for more scientific management.

A Sand County Almanac and Sketches Here and There. New York: Oxford University Press, 1949.


Callicott, J. Baird, ed. Companion to A Sand County Almanac: Interpretive and Critical Essays. Madison: University of Wisconsin Press, 1987. This standard volume examines a wide range of the philosophical and naturalistic views of Leopold in his best-known work.

Flader, Susan L. Thinking Like a Mountain: Aldo Leopold and the Evolution of an Ecological Attitude toward Deer, Wolves, and Forests. Madison: University of Wisconsin Press, 1974. This book remains the best analysis of Leopold’s shifting views on game, ecology, and resource management across his career.

Lorbiecki, Marybeth. Aldo Leopold: A Fierce Green Fire. Helena, MT: Falcon Publishing, 1996. This biography is the most readable, detailed account of Leopold’s life. Special emphasis is placed on the philosophical aspects of his writings.

Meine, Curt. Aldo Leopold: His Life and Work. Madison: University of Wisconsin Press, 1988. Includes the most complete bibliography currently available in published form.

Meine, Curt, and Richard L. Knight, eds. The Essential Aldo Leopold: Quotations and Commentaries. Madison: University of Wisconsin Press, 1999.

Ripple, William J., and Robert L. Beschta. “Linking Wolves and Plants: Aldo Leopold on Trophic Cascades.” BioScience 55 (July 2005): 613–621. A discussion of the persistence and significance of Leopold’s influence on ecological thinking about connections between vegetation, herbivore populations, and predators.

Christian C. Young

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Leopold, Aldo

Aldo Leopold

American forester, conservationist, and author, Aldo Leopold (1887-1948), a father of wildlife manage ment, deeply influenced the modern environmental movement a generation after his death. His collection of essays, A Sand County Almanac, published posthumously in 1949, expressed the need for peo ple to develop an ethic around preserving the natural balance of wild land.

Leopold was born on January 11, 1887, in Burlington, Iowa. His father was a desk manufacturer and his grandfather was a landscape architect who had designed several of Burlington's buildings. He grew up in a mansion overlooking the Mississippi River, learning about nature. The trees and flowers on his family's land needed constant attention because of the thin and stony soil. Meanwhile, the Mississippi provided a migration route for vast numbers of North America's ducks and geese, and Leopold and his brothers and father often went down to the river valley to hunt them. Young Leopold became a curious observer of birds and natural history and began recording his experiences with nature every day in a journal, a habit he kept up all his life.

Leopold the Forester

After attending Lawrenceville Prep in New Jersey, Leopold enrolled in Yale University in 1905, graduated from the Sheffield Scientific School at Yale in 1908, then earned a master's degree from the Yale Forest School in 1909. The Forest School was the first in the country, and the profession of forestry was growing thanks to the 1905 creation of the U.S. Forest Service. Leopold joined the service after graduation, and he was put in charge of a crew sent into the Apache National Forest in Arizona Territory to map the forest and look for timber.

In 1912, Leopold was promoted to supervisor of New Mexico's million-acre Carson National Forest. That same year, he married Estella Bergere, whose prominent Santa Fe family had been active in settling the Southwest. Leopold spent 18 months in 1913 and 1914 recovering from a severe case of nephritis, a sometimes fatal inflammatory kidney disease, and afterwards he accepted a less physically strenuous position as acting head of grazing at the Forest Service's district headquarters in Albuquerque.

In 1915, Leopold began pressing Forest Service employees to enforce fish and game laws—limitations on hunting—in New Mexico. Americans had hunted the country's native wildlife so aggressively in the late 1800s that many species were in danger of extinction, and hunters were advocating strict hunting laws to preserve deer, turkeys, and other commonly hunted wildlife. New Mexico and Arizona had agreed to let Forest Service rangers enforce their game laws when they became states in 1912, but rangers had not arrested a single person for violating them. Leopold created a handbook defining forest rangers' powers to limit hunting. He also traveled across New Mexico and Arizona to talk with citizens and local forest officers about forming local game protection associations, establishing wildlife refuges, and restocking lakes with trout. In addition, he founded a newspaper, The Pine Cone, the official bulletin of the New Mexico Game Protective Association.

To protect deer and other game, as well as cattle ranches, Leopold argued forcefully during the 1920s for completely eradicating populations of predatory animals: wolves, coyotes, bobcats, and mountain lions. “It is going to take patience and money to catch the last wolf or [mountain] lion in New Mexico,” he said in a 1920 speech to the National Game Conference (as quoted in Susan Flader's book Thinking Like A Mountain). “But the last one must be caught before the job can be called fully successful.” Leopold's efforts gained the admiration of former U.S. President and avid hunter Theodore Roosevelt, who sent him a supportive letter.

Between 1915 and 1924, Leopold worked in various administrative jobs with the forest service in the Southwest. In 1916 and 1917, he helped implement a new policy that added summer homes, campgrounds, and other recreational areas to the forests. From 1919 to 1924, he was placed in charge of operations for the Arizona and New Mexico forests, including personnel, finances, roads, trails, and fire control. Reluctant to see all forests opened to roads, he worked on a successful 1924 proposal to set aside a halfmillion acres in the Gila National Forest as a roadless wilderness preserve, an approach that eventually evolved into the National Wilderness Preservation Act of 1964. Meanwhile, Leopold wrote many newspaper and journal articles about game preservation and the health of wild land.

Moving to Wisconsin

In 1924, Leopold accepted a position as associate director of the U.S. Forest Products Laboratory in Madison, Wisconsin. The job did not fit his interests in game management and wilderness protection, however, so he dedicated his spare time to those pursuits. He worked on a booklength manuscript, Southwestern Game Fields, which included life histories of wildlife in the Southwest, but changes in the region, including an explosion in the deer population, made the work outdated, and he abandoned the project. He joined a local conservation group and helped push for the passage of Wisconsin's Conservation Act of 1927, which created a department that oversaw the state's hunting laws and forests.

Leopold left the Forest Service in 1928 for a new project: compiling game surveys of the Midwest. He secured funding from hunting-gun manufacturers and traveled through nine states, consulting with hunters and local officials and scientists. He published his findings in his 1931 Report on a Game Survey of the North Central States, making him one of the country's top experts in hunted wildlife.

Leopold's second published book, Game Management, finished in 1933, became a classic wildlife management textbook. It promoted a new approach to dealing with game animals, instead of relying only on wildlife refuges and hunting limits or on breeding efforts. Leopold argued that wildlife managers had to understand animals' biology and their relationship to their habitats, and preserve, manage and restore those habitats. “The central thesis of game management,” he wrote in the book (as quoted by Flader in Thinking Like A Mountain), “is this: game can be restored by the creative use of the same tools which have heretofore destroyed it—axe, plow, cow, fire, and gun.”

In August of 1933, Leopold joined the faculty of the University of Wisconsin. He and his students performed field research on wildlife and worked on wildlifepreservation programs that encouraged cooperation between farmers and hunters. In 1935, Leopold bought an old farm on the Wisconsin River in central Wisconsin's “sand country” that would become his retreat and muse for the rest of his life. He and his family planted thousands of trees there in an effort to restore its natural state.

Changing Philosophies

Later in 1935, Leopold traveled to Germany to observe forest and wildlife management there. He found the highly managed German forests too artificial. They had no predators or independent wildlife. Rangers fed deer on straw bales. Brick walls surrounded rivers. Fences protected recently planted trees. Leopold also saw that clear-cutting forests and letting them re-grow, as he had in the Southwest, produced inferior trees compared to forests with small, selective annual harvests. “We, Americans, have not yet experienced a bearless, wolfless, eagleless, catless woods,” Leopold wrote after his trip to Germany (as quoted in Marybeth Lorbiecki's biography, Aldo Leopold: A Fierce Green Fire). “We yearn for more deer and more pines, and we shall probably get them. But do we realize that to get them, as the Germans have, at the expense of their wild environment and their wild enemies, is to get very little indeed?”

The trip to Germany convinced Leopold that forests could not be controlled, but that foresters should preserve wild lands' natural balance. In 1939, Leopold presented a paper, “A Biotic View of Land,” arguing against old methods of wildlife management, which saw species as competing with each other and intervened to favor species people found useful (deer for hunting, corn for harvesting). Instead, he argued, conservationists needed to encourage diversity of species and stable, healthy land—wilderness that could always renew itself.

In 1943, Leopold was named a conservation commissioner in Wisconsin. He campaigned in favor of reducing deer herds and against eradicating wolves. It was a complete reversal from his public position of two decades earlier, but Leopold was putting his new views into action to address a concrete problem. With their natural enemies exterminated, deer were dying of starvation, their populations grown too large. Yet Leopold faced strong public opposition in Wisconsin, as the public was not ready to change its mind and allow predators to live freely.

The Classic Essays

World War II drew most of Leopold's graduate students out of school, so he spent more of his time writing literary and philosophical essays about wildlife and the land. In early 1944, Leopold began writing his landmark essay “Thinking Like A Mountain,” in which he vividly admitted that his years of wanting to eradicate predators were a mistake with terrible consequences for nature. In poetic language, he recalled shooting a wolf in the southwest decades earlier.

“We reached the old wolf in time to watch a fierce green fire dying in her eyes,” he wrote (as quoted in Flader's book Thinking Like A Mountain). “I was young then, and full of trigger-itch; I thought that because fewer wolves meant more deer, that no wolves would mean hunters' paradise. But after seeing the green fire die, I sensed that neither the wolf nor the mountain agreed with such a view.” Between then and the 1940s, he went on, “I have lived to see state after state extirpate its wolves.” As a result, he had seen mountains with “every edible brush and seedling” eaten to death by deer, followed by “the starved bones of the hoped-for deer herd.” Nature replaces deer killed by wolves within a few years, he said, but a mountain range's overeaten vegetation still might not be replaced decades later.

By the 1940s, Leopold was famous in conservation circles, consulted on nearly every conservation issue of his time by more than a hundred government agencies, activist groups, professional societies, and journals. In 1947, he was elected president of the Ecological Society of America. In late 1947 or early 1948, he wrote his most important essay, “The Land Ethic,” which argued that people needed to develop a new ethic around preserving the health and integrity of natural areas. The essay would later become an important statement of the goals of the environmental movement. “A thing is right with it tends to preserve the integrity, stability and beauty of the biotic community,” he wrote (as quoted in Flader's Thinking Like A Mountain). “It is wrong when it tends otherwise.”

In January of 1948, the federal government invited Leopold to help represent the United States at a 1949 United Nations conference on conservation. That April, he learned that Oxford University Press had accepted a collection of his essays, including “Thinking Like A Mountain” and “The Land Ethic,” for publication as a book. A week later, on April 21, 1948, Leopold died of a heart attack while helping to fight a grass fire on his neighbors' farm. He was 61.

Leopold's book of essays, titled A Sand County Almanac in tribute to the land where he wrote and set his writing, was published in 1949. His blending of natural history, scientific knowledge, and narrative and literary skill eventually made the work a classic. Though it fell out of print in the 1950s, it was republished as a mass-market paperback in the 1960s, and a new generation of people concerned about the environment discovered it. It has sold more than a million copies. “We abuse land because we regard it as a commodity belonging to us,” Leopold wrote in the book's foreword (as quoted by Curt Meine in an American National Biography article on him). “When we see land as a community to which we belong, we may begin to use it with love and respect.”


Brown, David E., and Neil B. Carmony, editors, Aldo Leopold's Wilderness, Stackpole Books, 1990.

Flader, Susan L., Thinking Like A Mountain, The University of Wisconsin Press, 1994.

Loribiecki, Marybeth, Aldo Leopold: A Fierce Green Fire, Falcon Press, 1996.


Meine, Curt, “Leopold, Aldo,” American National Biography Online, (December 16, 2007).

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Leopold, Aldo

Leopold, Aldo (1887–1948)An American ecologist and author of Sand County Almanac (1949), in which he expounded his view that all living organisms are related and the biosphere they inhabit is a partnership to which humans belong. His book became very influential in the 1960s, in the early days of the environmental movement. Leopold was born in Burlington, Iowa, and educated in New Jersey and then Yale University, where he obtained a master's degree in forestry. He worked for the US Forest Service, then for the Sporting Arms and Ammunition Manufacturing Association, promoting game management. He was a keen hunter throughout his life. He became president of the Ecological Society of America and the Wildlife Society and was one of the founders, in 1935, of the Wilderness Society. From 1943 until his death he was a member of the Wisconsin Conservation Commission.

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"Leopold, Aldo." A Dictionary of Ecology. . 13 Dec. 2017 <>.

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Leopold, Aldo

Aldo Leopold, 1886–1948, American ecologist, b. Burlington, Iowa. He was an advocate for a "land ethic," in which humans see themselves as part of a natural community. After work in the U.S. Forest Service, he taught wildlife management at the Univ. of Wisconsin and helped found the Wilderness Society. In 1924, he succeeded in having the Gila National Forest in N.Mex. designated as the first extensive wilderness area in the United States. He wrote A Sand County Almanac (1949), which helped provide the impetus to the environmental movement.

See studies by C. Meine (1989) and T. Tanner, ed. (1989).

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