Elms in Acadia

Along with Therie Moore, a National Science Foundation intern, I visited Acadia National Park to look for more American Elms to include in my project in August 2024. This was our last stop on the Great American Elm Field Research Trip, which began at the US National Arboretum in Maryland. We visited several New York state parks in the Palisades region, then Green Mountain National Forest in Vermont, followed by White Mountain National Forest in New Hampshire, before heading to Katahdin Woods and Waters National Monument in Maine and finally reaching Acadia National Park.

In addition to our previous collection, I was able to collect samples from seven American elm trees in Acadia. The 1894 botanical inventory of Mount Desert Island lists the American elm as rare, but I have found several iNaturalist observations on the island, making it a promising place to look. To sample the trees, I remove three to five leaves from the tree and take some measurements on the tree so the tree is not harmed in the process. Of the seven trees I sampled, only two had severe DED, so it is possible that there are some resistant trees in Acadia National Park.

Each of these trees has a story. Interestingly, we found three large trees in a perfectly straight line along an old driveway built around 1899 that is being converted into a new walking path. Finding trees growing in such a straight line is rare, but not impossible. Upon closer inspection, historical newspapers mention a shaded walkway built along the road in 1914. It is possible that these large elms were planted around that time. Between these large trees were several smaller American Elms. I decided to collect from two of the large trees and one of the smaller trees. Hopefully we can determine if the small tree is a descendant of the larger trees, and I may be able to tell if the large trees originated from another region and were brought to Acadia to be planted along the driveway.

We will begin the next steps of the project with lab work at the Chicago Botanic Garden. I will spend the next few months extracting DNA from approximately 700 different trees before beginning the sequencing process and data analysis. I hope that the results of this study, expected sometime in late 2025, will provide a framework for reintroducing American elms into natural areas. Hopefully, through strategic restoration, it will be possible to return the American elm to its historical population numbers with the level of genetic diversity that existed before DED emerged.