Curtis Prairie

Prescribed prairie fire

Prescribed prairie fire


“A vast rolling prairie, broken here and there with groves and openings and every hill and valley was radiant with the glossy foliage and gaily variegated wild flowers of June. It was a paradise of loveliness, a veritable garden of Eden. At every step, at every turn, new and startling beauties came into view. The bur oaks stood out upon the hillsides like old orchards. . . .” — Simeon Mills, describing land just south of Madison in June 1837

Although the terrain of the prairie lands in the Arboretum are restorations and don’t happen to be on a vast rolling terrain, we enjoyed a mild day to get a glimpse of what some of the earliest European visitors saw as they travelled to this area. We live in the tallgrass prairie region, where a wetter climate regime favors one of the dominant species of grasses, big bluestem (Andropogon gerardii). The big bluestem we saw today had grown to their full height, mostly about 8 feet tall or a bit taller.

Where did all the prairie land go? Within a few generations after European settlement, most of it was turned into cropland, some to grazing, and the rest to urban development. By the early 1900s, less than 1 percent of the original prairie land was left—and most of it in strips along railroads, or patches among property lines between farmland, or at the edges of public spaces or cemeteries, or in yet-to-be-sold lots. In fact, some of the seeds and plants for the restoration of the prairie in the Arboretum came from these scattered remains. The settlers, farmers, developers and town-dwelling European settlers had little use or appreciation for the prairie. However, for thousands of years this habitat and the borders along this habitat provided plant food and habitat that Native Americans favored for hunting and gathering. In fact, from observing and valuing the berries and other edibles that grew in and along the edges of the prairie and what animals grazed and traveled along these areas, the Native peoples encouraged and increased the prairie habitat in some areas.

They did this by observing and using one of the key components that creates and maintains prairies: fire. Archeological evidence and first-hand accounts tell us about Native Americans intentionally setting fires to clear out vegetation in certain areas for access and to create prairie and related savanna and edge habitat for desired plants and game animals. Hundreds of years later, we rediscovered the element of fire in creating and maintaining habitat. Now it is used less as a utilitarian tool, but rather as restoration of habitat to conserve and support plants and wildlife that depend on the prairie habitat. The plants of the prairie are adapted to withstand and thrive on periodic fires that will burn off and suppress many other plants, including most trees, that would dominate in the absence of fire. Large herds of animals did feed on prairie grasses and flowering prairie plants, however they were much more destructive to tender tree seedlings and saplings and small shrubs, and thus also played a part in tilling up the soil and maintaining the prairie.

The prairie was a prominent part of the current southern Wisconsin area, estimated at a bit over 10 percent of the area. The more dominant pre-European settlement landscape was the oak savanna. This was what our early visitors to the Dane county area were describing when they wrote about the lovely “park” or “orchard-like” landscape. Oak trees, especially the bur oak (Quercus macrocarpa), are much more resistant to fires than other species of trees. The oak savanna habitat was a product of the climate and also a result of its ability to thrive among and on the outskirts of the prairie fires. You can see the corky bark on the burr oak will extend all the way out on the branches, including the youngest branches which protects the tree from being consumed by fire. The oak savanna is defined by a moderate density of tree cover, so that the trees at full leaf would collectively provide somewhere between 10–50 percent shade. Today, like the prairie, this habitat is extremely rare—also less than 1 percent of the landscape. In this area prior to the 1830s, more than half the landscape was oak savanna.

In addition to the animals that grazed and traveled through the savannas and prairies in this area, the other essential resource was water. There were abundant wetlands, natural springs, lakes, and streams. These wetlands were breeding grounds and habitat for all kinds of insects, fish, reptiles, amphibians, and birds that nested, fed, and migrated throughout these wetlands.

By way of comparison, walking through the 1,200 acres of the Arboretum today versus a walk through the area hundreds of years ago, we would encounter about the same amount of open water, but today significantly less marsh and wetlands. Today the woodlands are much more extensive, and the amount of savanna is much less extensive.  We cannot totally re-create the habitat of hundreds and thousands of years ago, but there are ways in which the Arboretum can give us a glimpse, and provide a living laboratory for ongoing study of this legacy and these habitats.

—Paul Borowsky