By Tara Henderson
For the last three years, Emily Ellingson (Applied Plant Sciences, M.S.) has spent her days studying and growing a single type of tree: the eastern hemlock. Ellingson, who is advised by Stan Hokanson and Jim Bradeen, is utilizing microsatellite markers to determine genetic diversity within Minnesota’s native eastern hemlock population in the hopes of improving conservation efforts for the tree.
The eastern hemlock is a slow-growing and long-lived conifer that acts as a foundation species across its range, helping to regulate the ecosystems in which it occurs. While these trees numbered somewhere around 5,000 in Minnesota in the early 1900s, they have since dwindled to less than 50 mature trees in the entire state, earning them a spot on the state’s endangered species list in 2013. Because of its endangered status the Minnesota Department of Natural Resources (DNR) protects current stands of eastern hemlock, but Ellingson hopes that combining basic genetics and conservation science will further efforts.
Just like the trees she studies, Ellingson is a Minnesota native who became fascinated by plants while studying biology and environmental studies at Saint Olaf College. After college she started working at botanical gardens and arboreta, developing a passion for plants and the unique ways in which they enrich our lives. “Public gardens offer a valuable blend of art and science,” she says, “and offer unique teaching opportunities for our daily lives.” Her work with eastern hemlock combines her passion for the work done by public gardens and her interests in conservation.
“We take a basic to applied approach,” says Ellingson. “Using basic genetics and propagation approaches, we can understand how we can most effectively conserve the species in Minnesota.” Her goal is to understand the genetic diversity of eastern hemlock native to Minnesota, which will help to determine if cultivated trees and their seedlings can be considered native—and thus used in conservation efforts.
Her research started with a list of 21 published genomic markers, which help identify individuals or species. Of those 21, eight were highly variable, showing large amounts of selectively neutral mutation across Minnesota eastern hemlock. “These markers have a high mutation rate,” she says. “We’re able to measure the variation in different areas of the genome and put together a robust genetic analysis of the populations. We could even find differences that we’d want to preserve in our conservation efforts.”
While the genetic information is useful, Ellingson has noticed that different trees have different propagation needs, which could hinder the eastern hemlock’s success in the future. For the second part of her project, Ellingson has propagated vegetative cuttings—small clippings from trees that are genetic clones—and over 1300 seedlings from 20 different mother trees. Understanding the propagation needs of these seedlings while also being able to examine their genetics helps to inform the best growing strategies.
“Our end goal is to provide an action plan for land managers to help restore native Minnesota eastern hemlock,” says Ellingson. “The DNR, public gardens, and state and municipal parks with eastern hemlock will then be able to use this information for conservation.” Ellingson hopes that resources provided at the Minnesota Landscape Arboretum can help bring awareness to the tree, and with public support her research will build the foundation for the future of the eastern hemlock in Minnesota.