Every fall, we’re struck with the beauty of trees revealing the pigments that are hidden all summer by chlorophyll, waiting to have their moment. Some of the campus trees have been around for many years, their roots remaining, even as the campus undergoes transformations around them. As you observe trees around campus, you may notice that some have plaques at the base. I’d encourage you to read them, as they sometimes offer a little look into the history of Gustavus. The Linnaeus Arboretum Memorial Tree Endowment Fund was announced on Arbor Day in 1993 with the goal to “raise one million dollars for the endowment.” The donors receive memorial plaques that honor and commemorate Gustavus alumni, as well as other events. They help show people’s dedication to both the College and the ecosystem that we are a part of here. Many of these trees can be found in the Arboretum. Since the spring of 1973, students, faculty, and community members have planted the trees that are found in our Arboretum. The Arboretum’s diverse community of trees is no small feat: developed on an originally treeless area, the land was historically an area with just a few trees that served as boundaries between farmlands that surrounded campus.
There’s 67 species of trees located on campus, and today I’ll discuss a little about six of them—but if you’re interested in learning more, the Arboretum’s website shares a little about every species you can find in our campus ecosystem! Trees are not just a static part of our environment, but rather fascinating organisms that we ‘indirectly’ interact with on the daily.

Green Ash (Fraxinus pennsylvanica)
In the same family as olive trees, the Green Ash is an important tree for our region, planted in banks after strip mining. It’s naturally found on stream sides and in floodplains, and with the Minnesota River right here in St. Peter, it’s no surprise we can find them on campus. These trees, as well as other Ash trees, are currently threatened by the invasive Emerald Ash Borer, a beetle whose larvae eat the inner bark of trees, oftentimes resulting in tree death.

Red Maple (Acer rubrum)
On the 45th anniversary of their class graduation, the class of 1941 decided to donate to Gustavus, and there is now a Red Maple in the Arb that bears their class’ mark. This particular maple also happens to be a Pokestop. These trees are pretty distinct, especially in the fall (could it be because they’re… bright red?). Anthocyanin is the pigment that lends red trees their vibrancy this time of year. Many animals utilize these trees as important food sources, especially in the winter. This isn’t just deer! Moths and butterflies, including the Rosy Maple Moth, find these trees to be particularly important.

Honeylocust (Gleditsia triacanthos var. inermis)
Found widely around campus, these trees are gorgeous because of their compound leaves. The inermis variety of these trees are planted because the “regular” variety of these trees have thorns growing in clusters on the trunk that can be up to three inches long! The thorns are thought to have evolved to protect the trees from browsing herbivores in the Pleistocene (think giant deer). Ever wondered where those long, flat bean pods scattering the ground come from? They’re the fruits of this tree! In fact, the name “Honeylocust” comes from the sweet pulp that these seed pods contain. These trees are also in the Fabaceae family, which means they’re related to peas!

American Linden (Tilia americana)
You can find many of these trees around campus, and many of them have memorial plaques. In fact, it was an American Linden that was the first tree planted after the tornado of 1998. You can find this historic organism on the side of Old Main! These trees are often also called “Bee-Trees” because in the spring, their light yellow flowers attract large numbers of bees. Their broad heart-shaped leaves turn yellow this time of year, and the inner bark of the tree is characteristically soft, used in the past as a fiber source to make baskets, ropes, and more.

Ginkgo biloba
Found around campus, these trees are hard to miss. A misspelling of the Japanese gin kyo, this tree’s unique fan-shaped leaves are similar to that of the maidenhair fern, causing the Gingko to also take the alternative name “Maidenhair tree.” They’re the only surviving member of an ancient order of plants and live an incredibly long, with some thought to be as old as 2,500 years. The trees found on campus are the “male” trees—the “female” trees produce small fruits that smell sort of like vomit when they fall from the tree, which is not typically the sort of smell we want filling campus air.

Bur Oak (Quercus macrocarpa)
Dedicated to students of North Elementary School on April 25, 1998, one of these trees recognizes students for helping Gustavus with planting Bur Oaks in the parks of St. Peter. With around 17,000 trees lost in the tornado in March of that year, many trees in the community had to be replanted. Bur Oak trees produce the largest acorns of any North American oak, but they only produce substantial amounts of these squirrel treasures every three years. When the trees do this, it ensures that at least some acorns will escape the hungry mouths of animals that eat them, allowing new trees to grow. Larger trees of this species are classified as fire resistant, as their thick bark serves as a protectant.