Prairie Restoration

The Willamette Valley was once a land of open prairies and savannahs. The park is working to restore some of that original landscape.

Key Concepts:

  • For thousands of years, Native Americans shaped Willamette Valley ecology by annually setting fires. This practice pushed back forest, creating prairies and savannahs.
  • Most of this landscape was eliminated by farming.
  • Despite challenges, the park has ongoing projects to restore both wet and dry prairies.

As everyone knows, we have greatly altered the natural world to suit us. The Willamette Valley is mostly farms, towns, and highways. Dams hold back the rivers, and forests have been logged. We tend to think of this as being a modern phenomenon, only made possible by the tremendous technology that has been invented since the industrial revolution. But in fact, human beings have always altered their world to make life easier, sometimes a little, and sometimes a lot.

The Native Americans in Oregon, on both sides of the Cascade Mountains, relied on a simple and ancient tool to make their lives easier: fire. When conditions were right, Indians set their own “prescribed burns” to clear underbrush and create open areas. On the eastern side of the mountains, regular burning led to the open Ponderosa pine forests that so astonished the settlers coming over the Oregon Trail. In the Willamette Valley, the fires of the Kalapuya Indians, set in late summer and early fall, created vast prairies and savannahs. Dense fir forest grew only on the floodplains of rivers and streams, or on steep slopes.

Today we would find the open, grassy prairies, covered with blossoms and teeming with birds and mammals, to be utterly beautiful. For the Kalapuya, the purpose was to support the plants and animals they used for food, such as roots, seeds, nuts, insects, deer and elk. (The valley also had grizzly bears, wolves, and cougars). The Indians’ annual fires had been going on for so long—for thousands of years—that we can only guess at what the “natural” Willamette Valley would be like.

Prairies encouraged farming; farming ended the prairies

Fire made life easier for the Kalapuya. But in the end, the prairies helped lead to the Kalapuya’s destruction. Euro-Americans realized, as soon as they saw the prairies, how easy it would be to begin farming. Just plow and sow your seeds; no clearing required. Oregon farming began in about 1830, and towns like Champoeg soon began to spring up. Settlers stopped the Kalapuya from setting fires by the mid-1840s. Valley ecology has been changing ever since, and very little of the Kalapuya landscape still exists.

The park land once contained prairies of two types. “Dry prairies” (also called “upland prairies” or “grassland”) are what usually come to mind when we think of prairies: a great sweep of assorted grasses, sprinkled with blossoms. The rains drain off quickly, and the ground is thoroughly dry by summer. Easily farmed, the dry prairies were plowed and planted in wheat early in the valley’s settlement.

“Wet prairies” (or “wetland prairies”) were once common throughout the valley, and still encircled the town of Champoeg at the time of its destruction in 1861. Because of soil and terrain, they hold the winter’s rains for long periods of time, through the spring and into summer. Their amazing assortment of plant and animal life— much more varied than the dry prairies’—was an important food source, not only for the Kalapuya, but also for the first generation of Oregon settlers. Later farmers, however, saw wet prairies as a nuisance, and drained them whenever possible. Champoeg’s wet prairies disappeared into a network of drainage ditches during the late 19th century.

Restoring the look of the past

One of the park’s goals is to maintain the look of the 1850s—the time of the town—as much as possible. Portions of the park have continued to be farmed down to the present day. Other parts have been reforested. And two prairie restoration projects are underway. (The locations of both are on the park map.)

The first wet prairie restoration began in 1996, and was both easy and successful. A 10-acre prairie was created when the park simply blocked one of the old drainage ditches. Native plants, frogs and waterfowl returned on their own. Mallards, wood ducks, and hooded mergansers began raising their young there. Unlike the Kalapuya, the park has not set fires in this area, so cottonwood and willow trees have also become established, making it, technically, a “wet shrub community.” Because the shrubs and trees provides extra shelter for birds, and is more interesting for visitors, the park has chosen to leave things as they are. Fire, however, is always an option if needed.

Dry prairie restoration is far more difficult. The problem comes from the fact that so many exotic plant species have been introduced since settlement. Prickly lettuce, mullein, thistle, and numerous introduced grasses tend to overwhelm native species of grasses and forbs (broadleaved flowering plants). In 2000 we plowed and disked the rise just north of the wet prairie, but chose not to use herbicides. The area was then seeded with prairie Junegrass, tufted hairgrass (Deschampsia), fescue, and other native grasses. Although the 10-acre field looked good the first season, by the next year it had been taken over by meadow foxtail, an exotic commercial grass introduced during the 1940s. The effort had failed, but we learned a lesson.

A second attempt

In 2006 we had a new plan, and were ready to try again. Our target was a 40-acre commercial ryegrass field that had lain dormant for a couple of years. It was covered with invasive weeds. But this time we understood about the huge bank of weed seeds waiting to sprout. And like it or not, we knew we needed to kill those seeds by using the proven techniques employed by commercial farmers. If we didn’t, we would fail again.

The first step was to mow, plow, and disk, then spray with herbicides—twice. In fall, blue wildrye (a native grass) was planted as a cover crop. During the 2007 growing season we sprayed again. Not until fall, 2007, did we plant a permanent crop of native grasses: Roemer’s fescue, prairie Junegrass, blue wildrye, California brome, and slender hairgrass. By the end of 2008, the grasses should be well established and, we hope, free of meadow foxtail and other exotic grasses.

Notice that at this point we have not yet planted any forbs—the broadleaf flowering plants. We expect that invasive forbs will continue to be a problem for a couple of years. By planting only the grasses, we can continue to use broadleaf spray until the exotics are gone. Only then will we move on to planting native forbs.

Dry prairie restoration in the Willamette Valley is a grand experiment. Will our plan work? Can we succeed in recreating a prairie without exotics? Even if we succeed at first, the exotics are all around us, waiting to get in. Is it possible to maintain a prairie for more than a few years without having to start over?

We will probably learn some new lessons along the way. But if we succeed, visitors will be able to see and enjoy a part of the Willamette Valley past that is nearly gone.

Further Reading

  • A search on the web for “Willamette Valley prairie” will find numerous sites about prairie plants, research, and restoration, such as
  • To learn why the early settlers were able to make use of the wet prairies, read the handout called “Who was Kitty Newell?”
  • More of John Ball’s story appears in handouts called “Whispers of the Past,” and “Archeology at Champoeg.”
  • If you have land with oaks, advice for managing them can be found in A Landowner’s Guide to Restoring and Managing Oregon White Oak Habitats, by David Vesely and Gabe Tucker, published by Pacific Wildlife Research, 2004.