Monitoring Forest Health in Northern Michigan’s 'Big Wild'
Huron Pines staff explore the Pigeon River Country State Forest in February 2025 in search of emerging invasive species.
Huron Pines staff ventured deep into the Pigeon River Country State Forest earlier this month looking for signs of an invasive insect pest threatening Northern Michigan’s native trees.
Two invasive species — hemlock woolly adelgid and balsam woolly adelgid — are tiny insects that feed on the sap of native hemlock and fir trees. Affected trees exhibit needle loss and dead branches. The fuzzy white egg sacs of hemlock adelgids can be found at the base of needles; while balsam adelgid eggs appear on the trunks of infected trees.
An up-close view of balsam woolly adelgid egg sacs on the trunk of a fir tree from another site in 2024.
Adelgid infestations eventually kill their host trees so early detection of this emerging invasive threat is essential in protecting Northern Michigan’s forests. Huron Pines has long partnered with the Michigan Department of Natural Resources’ Wildlife and Forest Resources divisions in managing invasive species within the Pigeon River Country State Forest.
“We’ve been working collaboratively with DNR staff to manage these threats in a strategic way long term,” said Shelby Bauer, Senior Conservation Coordinator with Huron Pines. “Each year we come together and bring our invasive species concerns to the table along with recommendations for management. Their staff have a great understanding of priority species and report their findings to us, and we bring the capacity for treatments and further surveys. Having shared priorities and goals makes for effective invasive species management.”
Josh Leisen (l) and Amber Hubbard inspect the boughs of a hemlock tree for ovisacs, the fuzzy white waxy egg structures of invasive hemlock woolly adelgid.
DNR foresters recommended Huron Pines survey the forests around Cornwall Creek Flooding based on the concentration of hemlock and fir trees in that part of the Pigeon River Country State Forest. Additionally, areas with high recreational use like Cornwall Flooding are at elevated risk for the introduction of new invasive insects and plants, whether through the movement of firewood, plant seeds in the treads of boots or tires, or invasive plant fragments on watercraft.
No signs of hemlock or balsam woolly adelgid were found by our staff during the surveys in February. Hemlock infestations have mostly been reported along the Lake Michigan coast but also as near as Antrim County. The nearest balsam infestations are in Missaukee and Clare counties. Control measures exist for both species, including cutting and removing infected trees from the forest to prevent the spread.
"In this line of work, you don’t often get the chance to get ahead of an emerging invasive species so taking the time to conduct regular surveys is worth it for the chance to catch one early,” Bauer said.
Huron Pines leads two Invasive Species Networks (ISNs) which bring together regional partners in early detection & rapid response across 11 counties. We also provide education, resources & services for landowners seeking to address environmental concerns on their properties.
This work is supported by the Michigan Invasive Species Grant Program, michigan.gov/invasives.
Josh Leisen, Amber Hubbard, Shelby Bauer and Abby Macek (l-r) pause for a photo while surveying the Pigeon River Country State Forest for invasive insects in February.