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goat grazing on buckthorn

Goats Boost Effort to Restore Woods Through their Browsing Habits!

July 9, 2022  |  Topics: Places, Stories

Demonstration Project, Pukaite Woods:

Using Goats to Manage the Land Naturally

By Christine Bohn

Photographs by Eddee Daniel

Many anticipate the coming of spring each year. As the earth begins to awaken and warm, so do we. It’s a beautiful feeling after a long winter.

Spring was especially anticipated at Pukaite Woods in Mequon’s Rotary Park this year. After two years of using goats to control an invasion of non-native buckthorn, those of us following the progress looked forward to seeing the results.

Rotary Pukaite Woods trailhead with flowering trees.
“My amazement at the wealth of spring flowers that greeted me in the woods this year began at the Rotary Pukaite Woods trailhead.” ~ Eddee Daniel.

The spring ephemerals were the first to emerge from the soil. Like old friends, the sight of their blooms was a warm welcome. Spring ephemerals have adapted to flower before most trees and shrubs leaf out. Capturing all the sunlight that they need in a short period; they produce seed quickly then return to a dormant stage to await their turn to bloom again the following spring.

Tiny and delicate, spring beauties are among the many wildflowers that have bounced back in the newly cleared woodland.
Tiny and delicate, spring beauties are among the ephemeral wildflowers that could be seen in the newly open understory.

As the season continued, buds began to unfold on trees and shrubs throughout the woods.

When the buds broke and leaves began to emerge, we discovered that almost none of the buckthorn was growing. I walked around snapping dead stems, marveling at the nearly six acres of skeleton buckthorn stems. Then, more spring rains hit and growth in the woods began to explode.

Skeleton buckthorn stems, defoliated by last season’s grazing goats.

The majority of the dead buckthorn stems (ranging from 2 -6 ft in height) soon had little re-sprouting stems armed with leafy foliage coming from the bottom. Invasive plants are persistent, armed with many advantages that make them strong competitors, such as the ability to resprout from the stem when stressed or cut.

A goat munching on buckthorn leaves.
A goat munching on buckthorn leaves.

The battle to control the buckthorn invasion and restore woodland diversity is not over, but the competitive advantage seems to be shifting back in our favor. Six-acres of buckthorn has not produced any seed in four years, and buckthorn that once stood in some areas up to 15 feet tall is now the height of my ankles.

Time to bring back the goats!

Jack in the pulpit, another spring ephemeral.
Jack in the pulpit, a woodland wildflower that produces a cluster of bright red berries late in the summer. Birds and mammals eat the berries of this plant.

Historical Context

By understanding how the land was, we can better understand the current conditions.

In 2014, Ozaukee Washington Land Trust (OWLT) was asked by the Mequon-Thiensville Sunrise Rotary Club to assist with stewardship of the 18-acre Pukaite Woods. At present, about 10 of those acres have been invaded by a monoculture of invasive buckthorn. This has created a less inviting atmosphere for park users, as well as degraded habitat for wildlife.

The woodland budding out in spring, leaving a band of defoliated stems near the ground.
The woodland budding out in spring, leaving a band of stems near the ground defoliated by last year’s grazing goats.

Towering over the buckthorn understory, a relatively young but diverse canopy of trees is struggling to regenerate. But the buckthorn leaves both shade new native tree seedlings and consume nutrients they need to grow. Below the buckthorn, diminishing populations of native wildflowers also have struggled to retain their age-old territories.

Wild strawberry, a spring wildflower that (of course) produces lush berries.

What will happen as canopy trees begin to die-off and there is little native regeneration to take their place? I imagine a dark thicket of tree-sized buckthorn, plants and wildlife disappearing, as might be found at the beginning of an apocalyptic movie where society has collapsed and environmental catastrophe unfolds.

Pukaite Woods thicket.
Pukaite Woods thicket in an area not previously grazed by the goats was added to this year’s grazing regime.

The woodland was once a part of an expansive forest that covered southeast Wisconsin. Following European settlement, the woodland became isolated as land was cleared for cropland and pasture. The edges of the woods were likely overgrazed, and trees cleared for timber as development pressures increased. These disturbances created the perfect conditions for invasion by weedy, non-native species such as the buckthorn we see in the woods today.

Grazing goats hard at work!
Grazing goats hard at work!

As a consequence of invasions by non-native species, we are experiencing a crisis of biodiversity loss at both local and global scales. This crisis has had, and will continue to have, massive effects on the economy and quality of life in our communities.  

Common ninebark, a flowering shrub.
Showy white flower clusters of common ninebark will be followed by papery seed capsules that attract seed-eating birds.

Stewardship and Restoration

Community volunteers began stewarding Pukaite Woods over 25 years ago and have cut many a buckthorn, but the volunteers lost momentum. An area that was cleared of buckthorn one season was met 2-5 seasons later by another large crop of buckthorn that required more cutting. There were neither enough people nor money for this.

Jacob's ladder, a spring ephemeral wildflower.
Jacob’s ladder seed was spread at the Pukaite Woods as part of the restoration effort. This year, we saw the first blooms appear!

When OWLT first became involved in stewardship planning, we tried another tool and brought in the machines. Forestry mowing is an effective way to mow down large infestations of invasive buckthorn, especially fruiting sized shrubs and small trees. Since fruits eventually bear seeds, and seeds in turn produce new plants, removing the fruiting sized individuals is an important place to begin control efforts. But there is a downside.

A healthy patch of beech woodland, undisturbed by buckthorn.

As mentioned earlier, these hardy plants have evolved to vigorously resprout from the stem when cut. Additionally, once large trees and shrubs are cleared more sunlight is available to germinate seedlings in the seedbank. To manage this, many modern-day land managers turn to chemical herbicides. There are a few methods that work. Herbicide can be applied to “cut-stems” selectively or applied by foliar application to the leaves.

Sphagnum moss appears in damp sections of the ground cover.
Sphagnum moss appears in damp sections of healthy ground cover.

While the cut-stem method can be quite selective, minimizing herbicide use and adverse impacts to the surrounding environment, foliar applications have increased risk of “drift” or spray that harms non-target vegetation. Foliar applications, in general, also take more herbicide.

A grazing goat in the woodland.
A grazing goat in the woodland.

Increased awareness of the negative consequences that chemical herbicides have on both human health and the environment, along with the fossil-fuel intensive process required to create and distribute them, has led to a search for more organic methods of control.  Prescribed grazing is one of those options. With leadership from the Mequon-Thiensville Sunrise Rotary Club and OWLT, and in partnership with the City of Mequon, fundraising began in 2019 to bring goats to the Pukaite Woods to assist in restoration efforts.

A patch of mayapples, a spring ephemeral wildflower.
Mayapples colonize by rhizomes and can be found in dense patches like this throughout the woods. The edible, golden yellow fruits are a favored commodity by wildlife, often disappearing quickly after ripening.
A yellow violet, a spring wildflower. Over seven different species of violets native to Wisconsin can be found in the southeast region and range in color from purple to white and yellow.

Managed Goat Browsing

Managed goat browsing, can be used for vegetation restoration projects by precisely matching food selections with the goats’ natural behaviors, especially when there is significant aggressive brush and sapling growth in the mid-story reachable by goats. Using goats for restoration is common in other countries and other parts of the United States, but it is not yet commonly accepted as a vegetation management tool in the Upper Midwest.

The herd takes a siesta in the afternoon sun.
The herd takes a siesta in the afternoon sun.

While goats can be indiscriminate eaters, studies have shown that they prefer woody species (like buckthorn) to forbs (wildflowers) and graminoids (grasses and sedges).

The goats have now returned for the third year of the demonstration project at the Pukaite Woods. About two of the six acres that were browsed by goats in previous years will be browsed again. In addition, about an acre of buckthorn not previously browsed will be added to the rotation.

The ever-popular white trillium, another spring ephemeral wildflower.
There are three species of trillium native to the southeast region; the large-flowered trillium is the most common and occurs in small numbers throughout the woods.

The goats are increasing our ability to manage the buckthorn problem at the Pukaite Woods through their browsing habits. However, there remains no silver bullet when it comes to controlling invasive species. Careful thought must be given to understanding native plant communities and avoiding adverse impacts to those native plants that remain so that native species may recolonize as invasive populations are reduced.

Having eaten most of the easily reachable foliage, goats will stretch for taller tree trunks.
Having eaten most of the easily reachable foliage, goats will stretch for taller tree trunks.

Properly managed and cared for, these animal companions could make a significant impact on invasive plants in our region. In time, this management change could play an important role in restoring diverse plant and animal communities and help to alleviate the growing reliance on chemical herbicides.

This is the third installment in the Grazing Goats series. To read the first two follow the links below.

Part 1: Grazing Goats Help Eradicate Invasive Buckthorn!

Part 2: The Dramatic Effect of Grazing Goats on Invasive Buckthorn!

Editor’s note: This story has been revised at the author’s request in order to more accurately represent the actions of goats, which browse rather than graze. See author’s addendum for explanation.

Authors addendum:

We received input from one of our readers after this post was published suggesting we clarify our use of the term grazing. “If goats were dedicated grazers, they would be worthless for buckthorn control.”

Grazing and browsing are feeding habits that are common to herbivorous animals, or animals that eat plants. The major difference between grazing and browsing is in the type of vegetation that the animal feeds on. Grazing refers to the process of animals feeding on the vegetation that grows near the ground such as grass or other low-growing vegetation.Browsing refers to the process of animals feeding on high-growing plants such as the leaves or bark of trees and shrubs.

Examples of grazers include sheep and cattle. Goats and white-tail deer are examples of browsers. Each group are adapted differently for their feeding habits and some animals are adapted to both.

Although goats will graze, this essay shows the power of timed and reasoned goat browsing. This essay was edited to reflect the difference between the two feeding habits and animal groupings.

Christine Bohn is the Stewardship Coordinator for Ozaukee Washington Land Trust (OWLT) and owner of Kettle Moraine Grazing, LLC. Eddee Daniel is a board member of Preserve Our Parks. OWLT is a partner organization to A Wealth of Nature.