So far, 29 dwarf hackberrys have been identified in woodlots near the university's Stadium Drive Apartments, said Stephan Keto, WMU's manager of natural areas and preserves.
Rarely found this far north, dwarf hackberrys are listed as a species of special concern in Michigan and also are protected under Canada's Species at Risk Act.
"It's probably one of the least known of the Michigan trees — probably one of the rarest," Keto said.
One of the trees is a 46-foot specimen that is potentially a contender for the tallest dwarf hackberry in the state, he said. Unofficially, it tops the current national champion by as much as 5 feet.
Official measurement for the Michigan Botanical Club Big Tree Program and the National Registry of Champion trees will be completed this spring, Keto said.
The news comes after WMU was named a Tree Campus by the National Arbor Day Foundation for the sixth year in a row, "in recognition of its commitment to community forestry management." WMU has won the distinction every year since the program was launched in 2008 and was one of 30 inaugural campuses, along with the University of Michigan in Ann Arbor. Until 2012, the two Michigan universities were the only state schools on the list.
"WMU has a great natural heritage. It's our goal to get the word out so that future generations of Broncos will get to enjoy it," said Keto, who said the discovery of the trees means it would be more difficult for that site to be developed in the future.
The WMU trees are the first recorded dwarf hackberrys in Kalamazoo County, Keto said. They also are believed to be the second-most northern stand of dwarf hackberrys located in North America. The northernmost is located in Canada and is managed by the Canadian government, he said.
Given that the trees weren't planted overnight, Keto believes that others are out there to be found.
"We didn't plant these trees. They've been overlooked until now ... Are there others, yes, probably. We just don't know where they are yet," he said.
WMU biology professor Todd Barkman and his students first discovered the trees, which have been identified as dwarf hackberry, during a fall 2011 class, said Dean Simionescu, who was one of the students in that class.
"I didn't quite realize the true implications and the wow factor at the time. It was something exciting," said Simionescu, adding that, once he started doing research, "now it's a lot cooler."
In 2013, Barkman and his students used DNA sequencing to help confirm the identity of several of them and samples were sent to the University of Michigan herbarium, which also confirmed that the trees were dwarf hackberry.
Simionescu, who now works as Keto's student assistant and is graduating in the spring, won a $4,000 grant from WMU's Office of Sustainability to conserve the trees, which he said are in danger of being crowded out by invasive species.
"We're going to do invasive species removal and plant native plants in and around these trees," Simionescu said.
The trees prefer dry conditions and poor soil and are more commonly found in the Ozark and Appalachia. Simionescu and Keto said there was some evidence that the land, which used to be owned by Amelia Streeter, the wife of famous horse breeder Daniel Streeter, was used to pasture horses. They hypothesized that the animals' grazing may have mimicked the habits of prairie animals, such as bison, and made the area more conducive to the dwarf hackberrys.
"These trees were associated with the now-rare burr oak savannas that were part of the pre-settlement vegetation of Kalamazoo County. The ones we've discovered at WMU have been slowly surrounded by a forest of invasive species and larger trees that will eventually shade them out," Keto said.
Volunteers, including faculty, staff and students are working with landscape services personnel to conserve the rare trees by removing invasive species and managing the area to encourage survival.
"We're feeling that we can, in some ways, recreate on a small scale a historic landscape of Kalamazoo," Keto said.
As part of the grant, students will establish signs, build wilderness benches and make the site accessible. WMU has also taken seeds from the trees and are going to attempt to propagate them in the WMU Biology Department Finch greenhouse, Keto said. If successful, they hope to plant one of the trees on the university's main campus. Keto said he also hopes a student might take on the project as a master's thesis.
"It opens up all these great questions: Why is this possible? Why did people overlook them for 150 years?" Keto said