A new annual report that surveys the health of Michigan’s forest says 2025 was a year of “progress and challenges.”
Every year, the Michigan Department of Natural Resources compiles a forest health report that details new and existing threats to those forests. In the 2025 edition of Forest Health Highlights, the DNR outlines how Michigan’s forests faced ongoing challenges from invasive species, climate change, and natural disasters.
The “disastrous” late March ice storm that struck the northern half of the Lower Peninsula left department staff with “a slew of new challenges, from timber salvage to reforestation,” the report said. It had a “substantial impact” on multiple key tree species for the region’s forest ecosystem, notably red pine, oak, aspen and hardwood trees.
“Regenerating the forests in the most severely impacted areas will now be the focus of forest management staff across the northern Lower Peninsula,” the report said. It added that “moving forward, the level of planned harvest under normal conditions in the impacted area will need to be adjusted to account for the loss due to mortality and additional salvage harvest.”
The report stated that climate change is already bringing more unpredictable weather and extreme storms to Michigan.
“In 2025, rainfall was remarkably erratic during the growing season; in extreme cases, adjacent counties were vastly different, where one county may have been abnormally wet next door to a county that was abnormally dry,” the report said. It goes on to say that “we anticipate more frequent impacts from droughts, wildfires, floods, pest outbreaks, and other events in the future.”
The report said erratic weather patterns can stress trees in a variety of ways. For example, “Over the long-term, moisture fluctuations in the soil can be a major tree stressor, with both dry and excessively wet conditions damaging root systems,” it stated. “Trees then have to use energy reserves to regenerate roots. This becomes a factor in tree decline syndromes, where weakened trees become vulnerable to attack by insects and diseases, leading to dieback and mortality.” As a result of such climate-driven impacts, “Michigan’s forest composition and productivity will likely shift in unpredictable ways with unknown consequences."
In terms of invasive species, the report said the spotted lanternfly, first seen in Michigan in 2023, has now spread to seven additional Southeast Michigan counties. Meanwhile, the hemlock woolly adelgid, which has been spotted in Manistee and Van Buren Counties, also continues to be a threat. “Infestations now affect federal forests and several state parks, threatening unique ecosystems, migratory bird habitat, and critical dune systems,” the report noted.
The 2025 report concludes with a summary of a variety of state forest restoration efforts, among them an Assisted Tree Migration project to help some tree species thrive and promote forest resiliency in a shifting climate. The project is a partnership between the DNR and Michigan State University.
