Prevent Oak Wilt by Pruning Oak Trees in the Winter

lschultz • November 19, 2020

Wilt pattern in oak leaves. Photo by Joseph O’Brien, USDA Forest Service.

Oak wilt is a fungal disease that is carried to oak trees by small beetles that feed on the sap produced from fresh wounds to the tree (i.e. pruning, storm damage). The spores of the fungus then move through the vascular system of the infected tree, which is responsible for transporting water throughout the tree. Once the tree detects the infection, it tries to mitigate the further spread of the fungus by plugging infected cells. This in turn leads to the browning of leaves and the wilting of branches on the oak tree. Oak wilt disease is prevalent throughout the Lower Peninsula and in regions of the Upper Peninsula along the Wisconsin border and it primarily impacts red oaks.

Although the spring season is usually the ideal time for many people to complete yard work, oak trees benefit greatly from being pruned during the winter months instead.  Oak trees are far less likely to become infected with oak wilt disease when pruned in the winter since the beetles that carry and spread the disease to the trees are almost completely inactive during the cold winter months. Thus, those who intend to prune their oak trees are encouraged to do so in the winter instead of the high-risk period from April 15-July 15 when the beetles are most active.

Firewood is also a known contributor to the spread of oak wilt disease, and oak firewood should not be moved to prevent the chance of healthy oak forests being impacted by firewood that is host to oak wilt disease. If you suspect your oak firewood to be infected, the Michigan Department of Natural Resources (DNR) recommends the wood be burned, debarked or chipped before April. Or, once the wood has dried for a year and the bark has loosened, the oak firewood is unlikely to spread disease.

If you’re interested in learning more about oak wilt disease and what you can do to prevent it, please review the Michigan State University Extension article on the topic HERE . More information is also available from the Michigan DNR HERE .

Recent Posts

Species Spotlight: The Kirtland's Warbler

By Katelyn Helsel • April 30, 2025
As spring gets fully underway and the warmer weather hits, many birds are in the process of migrating back to Michigan. One migratory species you might see (if you live in northern Michigan) is the rare Kirtland’s warbler. This bird has a long and detailed conservation story, coming back from the brink of extinction with the help of strong conservation efforts. 

The Legacy of Michigan Logging

By Olivia Triltsch • April 24, 2025
Historically, Michigan experienced a lumber era in which the state was a leading producer for 50 years starting in 1860.

MUCC celebrates a successful Clinton River Cleanup

By Katelyn Helsel • April 23, 2025
Rochester Hills, MI — On the Ground, MUCC’s volunteer stewardship program, celebrated its 250th habitat improvement project in Oakland County this past weekend. In partnership with Metro-West Steelheaders and the Clinton River Watershed Council , 62 volunteers removed more than 460 pounds of trash from the Clinton River watershed and surrounding areas, restoring more than 80 acres of fish and wildlife habitat. Volunteers focused on picking up trash and other debris in the river near Yates Park and along various walking trails near the Yates Cider Mill. Many different items were collected, including a couple of tires, fishing line, old cans, a sign, and even a car bumper. “We definitely wanted to clean up as much trash as possible because that's going to help the watershed as a whole, and it’s going to clean up the river for both humans aesthetically, and also the animals that live in it, and create safer drinking water” said Olivia Triltsch, MUCC’s Habitat Program and Partnerships Coordinator.
More Posts