I write this after just returning to Boston from our expedition to Wisconsin and opening a box of hand-carried plants and seeds at the Arboretum’s Dana Greenhouses. It was incredibly fulfilling to view the work that Plant Production staff had already put into cleaning, counting, and accessioning the Wisconsin seed. The time that Kyle and I committed to collecting over the last week will pale in comparison to the years of effort each individual plant will require at the Greenhouses.

During the second leg of our expedition, Kyle and I experienced additional triumphs. After a FedEx stop to mail off all of the propagules collected in southeastern Wisconsin, we drove up to the Baraboo area of southcentral Wisconsin.

At Baxter’s Hollow, the Nature Conservancy’s largest preserve (5,636 acres) in the Baraboo Hills, we did not fall short of seed to collect. Serendipitously, as I parked the car at the trailhead, Kyle reached his arm out the window and broke off a stem of a neighboring Carya cordiformis (bitternut hickory)—box checked for the first target taxon of the day! We collected C. ovata (shagbark hickory) earlier on the expedition, but this is the first bitternut hickory we encountered. Not only were we able to distinguish between bitternut and shagbark hickories by the latter’s characteristic peeling bark, but also by bitternut hickory’s stunning sulfur-yellow bud scales. We gathered all the green fruits we could from the 25-foot tree.

Vibrant yellow bud scales of Carya cordiformis (bitternut hickory). Bitternut hickory nuts were collected at Baxter’s Hollow in Sauk County, Wisconsin.
Vibrant yellow bud scales of Carya cordiformis (bitternut hickory). Bitternut hickory nuts were collected at Baxter’s Hollow in Sauk County, Wisconsin.

Throughout our hikes in Baxter’s Hollow, we occasionally saw a shrub with attractive, glabrous (smooth) foliage and stunning blue-black drupes. We identified it as Viburnum lentago (nanny-berry), and collected as many ripe fruits as three nearby plants could supply. Later walking down along the main road, we spied a mass of Hamamelis virginiana (American witch-hazel), and we were grateful to find capsules that had not dehisced (explosively expelled) their seeds. Our last collection of the day was Acer spicatum (mountain maple). This will be the Arboretum’s second Midwest accession of mountain maple (the first came from Lake County, Minnesota). On our drive to Hemlock Draw, another one of the Baraboo hollows, Kyle excitedly shouted out for me to stop the car. He had spotted Menispermum canadense (moonseed) along the road, its large leaves glistening in the morning sun. This woody vine resembles wild grape, and is named for its crescent-shaped seeds. We saw many other vines (bittersweet, greenbier, and grape species) throughout our hikes, but this was our first encounter with a moonseed vine.

The pointed collections we pursued over the last few days were also successful. We identified a Betula pumila (bog birch) site in Black River Falls, 90 minutes northwest of Baraboo. As we parked along the roadside near our GPS coordinate, what should we glimpse but another target tree—Acer rubrum (red maple)! Red maples dehisce their samaras in early summer, so we carefully dug up a few saplings to send back to the Arboretum to be containerized. We walked for 100 feet up the road and noticed several masses of shrubby bog birch along the drainage ditch! We did a decent job of stepping on grass clumps as we made our way out into the swamp with the pole pruner (for extended reach) to collect catkins. I am certain that anyone passing by could not fathom what we were doing!

Kyle Port taking GPS coordinates of a mass of Betula pumila (bog birch) in a swamp along highway 54 in Jackson County, Wisconsin.
Tiffany Enzenbacher digging Acer rubrum (red maple) saplings. This is the Arboretum’s first wild-collected red maple accession from the western United States.

Perhaps the most satisfying collection we made during the trip was our final one. The Fagus grandifolia (American beech) population along Wisconsin’s eastern edge and in Michigan’s Upper Pennisula is at its most northwestern range, so we drove up to Shivering Sands the last day of our expedition with the hope of finding beech nuts. Shivering Sands is The Nature Conservancy’s southernmost property on the Door Peninsula, the peninsula between Green Bay and Lake Michigan. As we hiked through the preserve, we were ecstatic as saw the distinguishing smooth, gray bark of American beech. However, our moods soon grayed as the sky literally darkened and it began to rain. We found that the American beech population was not as dominant at Shivering Sands as we had hoped, and we could not find any trees with nuts. Nearing the end of the trail, we spied exactly what we sought—the mother tree to all of the other American beeches at the preserve! The specimen was easily over 60 feet tall, so we foraged in the leaf litter for precious three-winged nuts. Most of the prickly involucres (nut coverings) had already opened and dehisced the nuts, but we were able to find many still intact.

Kyle Port standing next to a mature Fagus grandifolia (American beech) specimen. Beech nuts were collected on the ground near this individual.
Kyle Port standing next to a mature Fagus grandifolia (American beech) specimen. Beech nuts were collected on the ground near this individual.

Kyle and I enjoyed hiking through the scenic woods of Wisconsin, delighting in local delicacies along the way—cheese curds, frozen custard, kringles, and a Friday night fish fry. I am incredibly thankful for the opportunity to act as an expedition participant for the Campaign for the Living Collections. As the manager of plant production, I enjoy the privilege of cultivating Campaign taxa. But the ability to be involved in population mapping, harvesting fruit in the wild, and filling out collection notes that will accompany these Arboretum plants for centuries to come has been an invaluable experience.

Tiffany Enzenbacher with Tsuga canadensis (eastern hemlock) seedlings dug from Hemlock Draw in Sauk County, Wisconsin. Tiffany stopped at the Dana Greenhouses enroute from Logan Airport to drop off hand-carried plants and seeds.
Note the spiny involucre that houses the three-winged American beech nuts. This is the final seed collection from the 2017 Wisconsin expedition.

From “free” to “friend”…

Established in 1911 as the Bulletin of Popular Information, Arnoldia has long been a definitive forum for conversations about temperate woody plants and their landscapes. In 2022, we rolled out a new vision for the magazine as a vigorous forum for tales of plant exploration, behind-the-scenes glimpses of botanical research, and deep dives into the history of gardens, landscapes, and science. The new Arnoldia includes poetry, visual art, and literary essays, following the human imagination wherever it entangles with trees.

It takes resources to gather and nurture these new voices, and we depend on the support of our member-subscribers to make it possible. But membership means more: by becoming a member of the Arnold Arboretum, you help to keep our collection vibrant and our research and educational mission active. Through the pages of Arnoldia, you can take part in the life of this free-to-all landscape whether you live next door or an ocean away.

For more tree-entangled art, science, and writing, subscribe to Arnoldia by becoming a member of the Arnold Arboretum.