If your oak tree needs to be pruned, trimmed, or removed, the fall and winter months are the best time to do it.
A fungal disease called oak wilt can infect trees in spring and summer. That’s when sap beetles, sometimes called picnic beetles, are attracted to the fungus of infected trees. It can spread it to other trees.
“Trying not to prune or wound during the high-risk period of April 15th to July 15th is best,” advised Cheryl Nelson, a forester with the Michigan Department of Natural Resources.
Red oaks, those oaks with pointed leaves, are the most at risk. If struck by oak wilt, the trees can die within weeks or months.
White oaks will eventually die from oak wilt infections, but might survive for several years.
The beetle that is responsible for spreading the fungus is less active in fall and winter.
“Pruning or doing any work on your trees, especially your red oaks, is perfect this time of year,” Nelson said.
During the spring and summer, if construction or landscaping damages your tree, Nelson said you should take precautions.
“You can help prevent the tree from getting killed by spraying on a tree-wound dressing or latex-based paint as soon as possible.”
The DNR maintains and interactive online map of verified and treated locations of oak wilt across the state.
If your oak tree is killed by oak wilt, the DNR advises you can use it for firewood, but warn that you should not transport the oak firewood from your property because that could spread the oak wilt fungus farther.
