The Avon hills are seen as a place of natural beauty for area residents and visitors. It is also a haven for the plants, trees, insects and wildlife that inhabit it. More specifically, the Avon Hills Forest Scientific and Natural Area, or SNA, which preserves 350 acres of land. It reveals the area’s best undisturbed natural features and species.

Unfortunately, many native species are affected by invasive species such as garlic mustard, wild parsnip and buckthorn. Efforts are being made, however, to prevent further spread of them. Such an effort was done Oct. 19 at the Avon Hills Forest SNA, where a group of volunteers spent the day pulling buckthorn.

“Buckthorn is an issue in many area forests,” Stephen Saupe, Avon Township clerk, said. “Some areas are completely overrun. Others, like the [Avon Hills Forest] SNA has comparatively little and by treating it early, we hope to keep it at bay.”

Saupe was one of the volunteers pulling buckthorn that day.

The shrub is detrimental to a forest as it fills the understory, hindering native forest regeneration. It also contributes to soil erosion by shading out other plants that grow on the forest floor.

About a dozen volunteers set out to remove buckthorn seedlings by hand on a one-half acre section of the Avon Hills Forest SNA.

“Seedlings are ripped out of the ground by hand and then hung in the crotch of a tree to allow the roots and plant to dry out, killing it and preventing it from resprouting,” Saupe said.

This is the first year a buckthorn pull was held at Avon’s SNA.

“Buckthorn pulls are typically done in October through November when the leaves of most native plants and shrubs have dropped or turned and buckthorn is the only green left, so it’s easy to spot,” Kari Wallin, volunteer and site steward specialist for the SNA program with the Minnesota DNR, said. 

Buckthorn was brought to the U.S. from Europe by humans in the early 1800s. It was used extensively as a hedging material as it grows rapidly and responds well to cutting. The shrub/tree possesses prominent leaf veins and leaves edged with small teeth. A thorn grows at the tip of a twig, giving the shrub its name. Buckthorn holds its leaves much later in the fall than other trees and shrubs. Seeds on a buckthorn shrub are round black berries and can be spread by wind and birds through their droppings after consuming them.

The infestation at the Avon site, Wallin said, is relatively small.

“Most of the site is still a very high quality hardwood forest ecosystem,” she said.

The Avon SNA supports an extensive hardwood forest of oaks, maples, birch, black ash and tamarack and is a habitat for many bird species, including cerulean warblers, red-shouldered hawks and veeries (thrush), according to the Minnesota DNR. In a one-year bird watching survey, 120 species were recorded.

A wide variety of wildflowers – ferns, grasses, sedges and shrubs – can also be found in the area.

SNA history

The Avon Hills Forest SNA is one of 169 in Minnesota, with over 192,000 acres of land protected and open to the public. 2019 marks the 50th anniversary of the program. It was established “to protect and perpetuate in an undisturbed natural state those natural features which possess exceptional scientific or educational value.” The goals of the SNA program is to preserve Minnesota’s natural features – such as native plants, animal communities, geological features, etc. – in all ecological regions in the state; and to provide nature-based education and scientific research opportunities.

The SNA program relies on the help of volunteers and site stewards in maintaining their goals.

“Volunteer projects on SNAs throughout the state vary greatly based on the site’s features, timing and seasonality and our available volunteer base,” Wallin said. “This year, the program held 34 volunteer events to date, with 224 volunteers contributing 740 hours.”

A few examples of how volunteers contribute include controlling invasive species, collecting native seeds and gathering information, such as identifying species, for the program.

Collecting native seeds in the fall are used on site to “maintain genetic diversity, provide cost-effective management and provide a way for people to learn about native ecosystems and the plant communities within them,” Wallin said.

Volunteer site stewards assist SNA staff with land protection, management, education and research on the site they choose to monitor.

“Our site stewards are active all year round, making observations, participating in or leading events, giving interpretive hikes and keeping an eye on the sites,” Wallin said. “Out of our 169 sites, about 135 have stewards. This year, our stewards have contributed about 820 hours.”

The reward, whether a volunteer or a steward, is worth their work. The hills of Avon are alive with plants, trees, insects and wildlife – and they hope to keep it that way. 

For more information about SNAs, visit