New report describes health of Michigan’s forests; key issues are ice storm, pests and disease

Many people think that if you plant trees and leave them alone, they’ll grow into a healthy, beautiful forest. But pests, disease and even the weather can create challenges for the state’s 20 million acres of forest.

The Michigan Department of Natural Resources manages nearly 4 million of those acres as state forest land, and DNR Forest Resources Division staff works with local, regional, federal and tribal partners to assist with forest-related matters on other lands.

The DNR's annual Forest Health Highlights report is now available to the public. It looks at factors affecting the health of Michigan’s trees statewide and describes actions being taken to remedy them. 

For example, the March 2025 ice storm in northern Michigan led to disaster declaration for 13 counties and thousands of trees broken like toothpicks across the landscape. Forest Resources Division staff will spend the next few decades addressing short- and long-term effects of that historic weather event. 

Read the report.

Much ground covered in 2025

During 2025, the forest health team – comprised of three forest health foresters, one outreach forester and two invasive species wildlife biologists stationed around the state – worked to catch forest health concerns early to lessen their impact. Among its many activities, the team:

• Surveyed 360 acres and treated 170 acres for hemlock woolly adelgid.
• Participated in aerial surveys of more than 18.2 million acres and mapped more than 100,000 acres of damage.
• Treated 23 oak wilt sites.

The team also surveyed nearly 3,000 acres for invasive plants on the state's Invasive Species Watch List. It detected cinnamon vine at Three Rivers State Game Area, lesser celandine at Grand River State Game Area and stiltgrass in several southern Michigan locations. Treatment occurred at all sites, but follow-up will be needed in 2026. The watch list highlights species that pose immediate or potential threats to Michigan’s economy, environmental or human health.

Catching problems early

The report also highlights progress through research, collaboration with partners and guidance for landowners to help protect forests.

Forest health experts at the DNR work every day to protect the state’s trees and woodlands. They survey Michigan’s forests and train foresters and land managers to recognize early signs of damage. Monitoring outbreaks, managing infestations and preparing for future challenges ensure continued recreation opportunities, wildlife habitat, healthy waters and renewable forest products.

You can find more information the DNR’s Forest Health webpage.