Henry Chandler Cowles:
Ecologist, Teacher, Conservationist

By Victor M. Cassidy

Through his life and work, he prefigured today’s conservation movement--and Chicago Wilderness.


Photos courtesy of the University of Chicago Library, Special Collections Research Center, University Department of Botany Records

On April 25, 1896, Henry Chandler Cowles visited the Indiana Dunes for the first time. “We climbed up the wonderful piles of sand and saw acres and acres stretching up and down the lake, billowy like a prairie or vast drifts of snow,” the University of Chicago graduate student wrote in his diary. “The sand dune flora is very characteristic and new to me.”

Fired by this experience, Cowles spent much of the next two years studying the dunes and their flora more systematically than anyone before him. Combining careful observation with disciplined thinking, he worked out the complex interactions between plant life and the dynamic dunes environment. In a pioneering ecological study, he described the natural phenomenon called plant succession (see sidebar).

Cowles (it’s pronounced “coals”) later taught ecology at the University of Chicago, both in the classroom and, memorably, in the field. He led enthusiastic groups of students to local sites on weekends and organized month-long trips all over North America, where everyone worked hard all day, slept in tents, cooked over open fires, and had a perfectly wonderful time.

As he studied natural areas, Cowles witnessed thoughtless destruction of the environment and became an active conservationist. Working through several organizations, he helped to defend the Forest Preserves of Cook County, establish state parks in Illinois, and protect forest resources. What started as a penchant for making focused observations of nature would draw him into a life of deep civic engagement.

His skills for reading the landscape, thinking through what he saw, and reaching conclusions are echoed in the work of site stewards and land managers today.

Henry Cowles (second from right) made many trips to the Indiana Dunes, often bringing along others.

Henry Cowles (second from right) made many trips to the Indiana Dunes, often bringing along others.

Knew What He Wanted

Henry Cowles was one of those lucky people who always seemed to know what he wanted to do. Born in 1869 on a Connecticut farm, he became fascinated with plants and trees during childhood walks with his mother. By the age of 12 he was keeping a diary, which tells with academic exactitude how he tended crops (“pulled 175 beets,” “potted 242 of my tomatoes”), delivered orders in a horse-drawn cart, and watched over the family seed supply. In church, he learned how to express himself and function in organizations. In school, he learned Greek, Latin, science, and history.

Outside the classroom, Cowles botanized as much as he could in the fields and woods near home. By the time he was 16, he knew the plants in his area and was reading Asa Gray’s authoritative Manual of Botany. He got a sound scientific education at Oberlin College in Ohio, where his botany professor pointed him toward graduate school at the University of Chicago.

Cowles was “a remarkably successful teacher” who “devoted himself mainly to his students, rejoicing in their progress and subsequent accomplishments.”

Cowles (front row, third from left) created the ecology curriculum at the University of Chicago. Here he poses with members of the botany department in front of the Botany Building in 1917.

Cowles (front row, third from left) created the ecology curriculum at the University of Chicago. Here he poses with members of the botany department in front of the Botany Building in 1917.

Origins of Ecology

German and Danish botanists first developed ecology—the study of interactions between living organisms and the environment—in the late 19th century, just as Cowles was entering academia. He enrolled at the University of Chicago in 1894, when the institution was just two years old and eager to explore new fields that elite eastern universities disdained. Ecology was so new that no textbooks existed, and most of the published literature was in German. Cowles actually taught himself Danish so he could read a key study that was only available in its original language.

He originally came to Chicago to study geology, not botany. But he was never more than an average geologist. In the course of his studies, however, he learned the glacial history of the Great Lakes, which gave him a dynamic vision of nature and laid the literal groundwork for success in the newer field.

Professor John M. Coulter eventually recruited Cowles into the newly established Department of Botany. Coulter saw ecology as the coming thing. He knew the dunes flora and encouraged Cowles to write his doctoral thesis on the subject. Cowles’ thesis on the Indiana Dunes environment became one of the first ecological studies in North America. He followed it up with an ecological study of the Chicago vicinity and papers on plant succession, which established his reputation throughout the United States and Europe.

Still a graduate student when he started teaching at Chicago, Cowles created the entire ecology curriculum as he rose through the academic ranks—and decisively influenced America’s first generation of ecologists.

Studying Outdoors

Outdoor field study was central to Cowles’ teaching, and he led ecologists-to-be through Jackson Park near the University of Chicago, the Calumet region south of the city, the dunes, and other local sites. Short and a bit stout, he wore calf-high boots, knickers, a white shirt, and a floppy hat in the field — and always a tie. Students said that you had to “climb through the fence, keep up with the teacher, and take notes at the same time” if you wanted to pass his courses.

Charles C. Adams, a colleague, called Cowles “a remarkably successful teacher” who “devoted himself mainly to his students, rejoicing in their progress and subsequent accomplishments.” Fair-minded, modest, “never at all aggressive,” and “never dogmatic,” Cowles preferred “non-technical language, avoiding new terminology, and the formulation of any rigid system for his science,” Adams wrote. Most all of Cowles’ surveys were descriptive rather than quantitative; his reports almost never used numbers, nor anything resembling the scientific methods used today.

Cowles always took time for a joke, and to just enjoy life. He was said to carry two watches set one hour apart. If someone proposed lunch, he pulled out the slower timepiece.

Illustration of Dunes Growth

At the Indiana Dunes, Henry Cowles could face away from Lake Michigan, hike inland, and see the results of centuries of plant succession, the process in which communities of plants come into a landscape, flourish, and create conditions for their replacement by other communities. As Cowles walked through space, he walked through time.

Succession is easy to follow on the lightly vegetated landscape of the Indiana Dunes. No plants grow at the edge of Lake Michigan because waves wash constantly over the land. At the back of the beach, where waves come less often, a few plants grow on the sand and stabilize it with their root systems

Over many generations of growth, reproduction, and decay, these pioneers produce a rich organic soil called humus, which makes it possible for a new group of plants to move in and replace them. A third generation eventually follows this second generation, and a fourth replaces the third, until an ending point, called climax, is reached. The climax community—at the dunes it’s an oak forest—does not change until something disturbs or destroys it. If the forest burns down, for example, succession starts all over again, but often from an intermediate stage.

Cowles published his study as “The Ecological Relations of the Vegetation on the Sand Dunes of Lake Michigan” in 1899. Though plant succession was first noted in antiquity and was known to many scientists of Cowles’ day, he described it more clearly and comprehensively than anyone before him

For the rest of his life, Cowles loved and studied the dunes. In 1916, he testified to a Congressional Committee on behalf of the proposed National Sand Dunes Park in Indiana. This initial effort failed, but it strengthened the movement to save the dunes that triumphed long after his death.

Today’s visitors to the Indiana Dunes National Lakeshore can follow Cowles’ footsteps on a “Succession Trail” that starts on the beach and heads inland. This 0.9-mile trail is a moderate hike with varied terrain, crossing exposed dunes on the beachfront to forest-covered back dunes and ponds. Pick up a brochure near the trailhead to guide you through the plant succession along the trail.

To get to the Dune Succession Trail, take County Line Road north from US 12 or US 20 to the Indiana Dunes’ West Beach, where you’ll find the trailhead. Click here for map to West Beach. The beach is open until 9 p.m. from May 1 to September 30. The rest of the year, it closes at sunset. The beach is free, but the park charges a $4 parking fee from Memorial Day to Labor Day.

Illustration adapted from Reading the Landscape of America by May Theilgaard Watts.

Conservation Grunt Work

After about 1910, Cowles published very little. But he continued his field teaching and helped to build the conservation movement of his time. In 1913, he co-founded the Friends of Our Native Landscape with landscape designer Jens Jensen. As Jensen told it, the Friends sought to preserve “examples of landscape types that are fast disappearing before the encroachments of industry.” Working with like-minded organizations, the Friends raised public awareness of the Indiana Dunes and worked to defend them. Jensen, who was an excellent public speaker, recruited people to the conservation cause, but it was Cowles’ grunt work that led to victories.

Cowles’ surveying skills would be called into service many times. By 1918, roughly two-thirds of the presettlement forest in Illinois, largely on hills along the Mississippi River, was gone. Farmers had cut the trees, worked the land to exhaustion, and walked away. Stephen A. Forbes, who was director of the Illinois State Laboratory of Natural History, wanted to know how much forested land remained in the entire state of Illinois. Then he could recommend which areas should remain untouched as nature preserves, which could prudently be cut for timber, and which cutover lands should be replanted. Working without pay, Cowles participated in this survey by creating large-scale maps of northern Cook County. Some of this material survives in fragmentary form among his papers.

On behalf of the Friends of Our Native Landscape, Cowles surveyed ecologically important sites in southern Illinois between 1919 and 1923. His work helped persuade the state legislature to buy lands that are today incorporated into the Cache River State Natural Area and several Illinois state parks, including Giant City, Ferne Clyffe, and Cave-in-the Rocks.

Late in 1914, just as the Forest Preserve District of Cook County was officially becoming established, local conservation groups formed the Conservation Council of Chicago to improve communications and increase their public impact.

The coalition faced problems that ranged from grazing of sheep on vulnerable natural lands to the poaching of native orchids. Membership included the Friends of Our Native Landscape, the Chicago Academy of Sciences, the Ecological Society of America, and many others. Cowles, who often presided at monthly meetings, called the Council “a very informal organization…a clearing house for discussion of conservation matters.” Everyone exchanged information at meetings. When some natural area was threatened, member groups raised the alarm on their own initiative, so the public heard many voices instead of just one. The Conservation Council, which apparently survived into the 1930s, was in many ways a precursor to today’s Chicago Wilderness consortium.

Garlic Mustard

Cowles and his botany students on one of their many field expeditions.

Cowles started Botany 36 (Field Ecology) in 1900, and it became his signature course. For four weeks at a time, he took students all over North America—Tennessee one summer, Yosemite the next, and, more often than not, somewhere in the Great Lakes Region.

Soon after signing up, students got an instruction sheet from Cowles that suggested “stout tramping shoes” for all participants and “a riding habit made of khaki or other suitable material” for the women. The women’s outfits guaranteed modesty but were heavy, hot, and hopelessly unsuited for covering rough ground, exploring swamps, or scaling dunes. Sunblock didn’t exist in those days, so students wore sun hats and long sleeves. Insect repellents were said to be “heavy on the citronella.”

The expeditions were intense and instructive. Cowles kept up such a pace in the field that students divided up into teams. When the professor stopped to make an observation, one student got a look at the plant specimen and (hopefully) sketched it, while the second wrote down the Latin and common names, and a third tried for specifics on soil, microclimate, and the like. At the end of the day, team members combined their notes.

May Theilgaard (Watts) took Botany 36 in 1916 and toured the Lake Superior region. In five weeks, the party visited 16 towns, observed climax forests and several types of succession, and identified numerous plants. When she returned home, Theilgaard transformed her field notes into an 87-page expedition notebook with hand-drawn maps, photographs, and plant lists. Later, May Watts, who adored Cowles, taught botany and ecology at The Morton Arboretum to the next generation, including botanist Floyd Swink. Her notebook is preserved in the arboretum’s library.

Harriet Cowles, Henry’s daughter, went on Botany 36 expeditions in the 1920s. “Often the roads were washed out, at which time we all got out and pushed,” she wrote of the group’s travels in open, seven-passenger Packard touring cars. Another of Harriet’s passages: “My father was seldom happier than when he was on his way to visit a new place, accompanied, preferably, by a small group of interested Botany students.”

Park Dreams

In 1920, Cowles and others planned the First National Park Conference, which was intended to get the nation’s state governments to purchase land for parks. At the Conference, in January of 1921, Cowles said: “We dream of a time when we will have many parks in Illinois…We would like to see today a continuous parkway along the entire length of the Mississippi River…from Minnesota to the gulf [of Mexico]…We should like to see this parkway all along [the rivers of Illinois].” The Nature Conservancy of Illinois still works every day to make this happen.

There is a special way that Henry Chandler Cowles still speaks to today’s site stewards and Chicago Wilderness. His subjective method—reading the landscape, thinking through what he saw, and reaching conclusions — is what stewards use today as they determine which initiatives are most likely to return a site to ecological health. Cowles thus assists in the most challenging ecological work of our time. His spirit helps heal the land.

Victor M. Cassidy is a writer and conservation volunteer. His new biography, Henry Chandler Cowles: Pioneer Ecologist, is the product of three years of research, and is available for purchase at sigelpress.com.

Chicago Wilderness Magazine — Henry Chandler Cowles