Restoring the Forest
With access to the Natural Lands — a 350-acre network of trails, forests, and prairies adjacent to campus — the St. Olaf College community has an outdoor haven right in its backyard. But the Natural Lands haven’t always been the network of trees and paths they are today. Behind the dense, ecologically diverse forest is 30 years of tree restoration work.
Part of the Big Woods habitat, the Natural Lands was part of a maple-basswood forest that once covered a large part of south central Minnesota. European settlers cut down much of the area’s forest for agriculture, leading to the depletion of the landscape and depriving many native species of needed habitat. To bring back the habitat for local plants and animals, St. Olaf has invested in various tree restoration projects over the years.
Now spearheaded by Kathleen Shea, professor of biology and environmental studies and curator of the Natural Lands since 2009, the ongoing restoration efforts contribute to the health of the land and environment while providing enriching research opportunities for students
Shea was part of the first tree restoration effort in 1989 in an area just north of campus, as well as the first community planting on campus in 1990. “For Earth Day 1990, we had a tree planting in two fields just west of Ytterboe Hall. This was a community event, as many faculty and students participated in planting several thousand two-year-old seedlings,” Shea explains.
Efforts continued in the 1990s with several conifer tree restoration projects. The goal of these projects was to learn more about tree species from northern Minnesota. Restoration projects from 2002 to 2017 have experimented with different planting methods using seedlings and seeds.
Forest restoration provides many benefits to the environment of the Natural Lands and the St. Olaf community as a whole. “Besides providing habitat for a variety of plant, animal, and soil organisms, forests provide other ecosystem services, such as carbon sequestration and a reduction of nutrient runoff into waterways,” Shea says. “The forest restoration is also valuable for educational purposes, providing students and members of the Northfield community a place to learn about local species and the opportunity for students to do long- and short-term studies on restoration.”
“Forest restoration never stops. Ecology isn’t a science where you can say, ‘Oh look, we found an answer. That solves that problem.’ It keeps going.”
While many of the restoration projects thus far have focused on planting trees, Shea and student researchers are now tasked with recording the effects of this long-term restoration and documenting the succession, or the change in the composition of species, in the Natural Lands over time.
Allie Raduege ’21 is one of the student researchers who has been instrumental in documenting and furthering this forest restoration work. For the past two summers, she has conducted research with Shea on forest ecology in the Natural Lands as part of the college’s Collaborative Undergraduate Research and Inquiry (CURI) program. In 2018, her project focused on tracking the composition and succession of species in deciduous forest restoration areas in the Natural Lands. The goal of these ongoing restoration efforts is to restore the land to what a current maple-basswood forest would look like, rather than what it may have looked like before European settlement.
“You can only account for so much, and the world is changing,” Raduege says. “The goal of it isn’t so much to say, ‘This is what the land looked like so many years ago,’ but to show that this is what it looks like now. We’re trying to get more of it back from the agricultural land it was.”
Raduege was tasked with conducting research in the areas that had new plantings in 2002, 2003, 2005, and 2009. While earlier areas were planted with seedlings (essentially, baby trees), newer areas were planted by broadcasting (scattering) a mix of different seeds over a plot of land. By measuring the circumference and height of the trees and documenting species composition, Raduege was able to record growth patterns over time as well as the species diversity.
“Forest restoration never stops,” Raduege says. “Ecology isn’t a science where you can say, ‘Oh look, we found an answer. That solves that problem.’ It keeps going. We’re going to keep looking at how it changes.”
With her Ph.D. in forest ecology, Shea has been pursuing this kind of work in various ways throughout her career, and sees the research of ecological succession in the Natural Lands as a uniquely important endeavor. While interest in forest restoration has been gaining ground, there has been little research into the long-term ecological succession of restored areas. To fill this gap, Shea and Sonja Helgeson ’15 wrote a paper, published last year in the journal Restoration Ecology, titled “Tree Growth Patterns, Mortality and Colonization in a Restored Maple-Basswood Forest.” The paper documents their studies of the tree restoration changes over 23 years.
“We have shown that certain tree species grow better in open fields and that it is better to plant other species, such as sugar maple, later in the restoration process,” says Shea. These findings on the long-term changes of plant species in restored areas allow comparison between restored areas and inform future restoration and management efforts.
The forests in the Natural Lands have greatly changed throughout the restoration process. “Over the past 30 years, it has been exciting to see the forest developing,” Shea says. “In the 1990 restoration that my students and I have studied in detail, we finally see canopy closure in places. This means that the understory is more shaded, and plants that normally grow in the understory can now survive.”
The goal of these ongoing restoration efforts is to restore the land to what a current maple-basswood forest would look like, rather than what it may have looked like before European settlement.
And the restoration efforts continue. “The long-term goal is that the forest will be self-sustaining. Small areas and strips cannot hold as many species, but with over 200 acres of restored and existing forest on St. Olaf lands, the forests should be able to support a wide variety of species and reproduce,” Shea says.
The goal of the forest restoration is also to provide a flourishing space for St. Olaf students, faculty, and staff to interact with nature. “We want the St. Olaf community to know that we are working to restore native forest and we hope people will walk on the trails to enjoy and learn about our forests,” Shea says. “There are also opportunities to be involved in research or maintenance projects, such as removing invasive species. We are privileged to have these natural areas within walking distance and close to prairie and wetlands.”
Anna Barnard ’21 is majoring in English and religion at St. Olaf College.