Michigan: prune oak trees in winter to avoid oak wilt

Leaves are down, temperatures are cooler, and that means it’s prime time for pruning oak trees, which can be infected by the oak wilt fungus if they’re pruned during the high-risk period April 15-July 15.
“Beetles that can carry the disease from tree to tree are not very active now, and the trees are not vulnerable to infection,” said Simeon Wright, forest health specialist with the DNR Forest Resources Division. The beetles are attracted to fresh bark damage or wounds where tree limbs have been removed.
Firewood can harbor the fungus, too. If you suspect your firewood is infected, burn it, chip it or debark it before April. Once the wood has been dried over a year and/or all bark loosens, it can no longer spread oak wilt. Read more