Crown thinning is appropriate when the tree is young and dormant.
Mar 14, If you have oaks in your landscape that need pruning and you live in an area of Minnesota where oak wilt occurs, pruning must be done before the oak wilt fungus and it's insect vector become active. Oak wilt is a fatal disease of oak trees that can be found in some counties of Minnesota. If you live in an area where oak wilt occurs, it is critical to prune oak trees before the high risk infection period begins in April. To avoid oak wilt disease DO NOT prune oaks from April to October.
If oaks are wounded or must be pruned during these months, apply wound dressing or latex paint to mask the odor of freshly cut wood so the beetles that spread oak wilt will not be attracted to the trees.
Oak trees should be pruned in the winter months when the trees are dormant and beetles are inactive to prevent the spread of oak wilt. Winter pruning is also great for arborists as the harder ground provides them easier access to trees and the bare canopy makes branches easier to see and handle.
Sep 21, The University of Minnesota Forestry Department posts the oak wilt risk levels for pruning oaks: high risk in April through June, low risk in July through October, and no risk in November through March.
You can safely prune Minnesota oaks in winter and take appropriate precautions as needed to protect the health of your tree.
The sap-feeding beetles are very active in spring and early summer.
Recommended Timing To keep trees' health intact, the safest time to trim is during the late dormant season in winter, typically between the months of February and early April. Because deciduous trees are bare at this time of year, gardeners can easily see the branches to make cuts. Mar 17, Our general recommendation is to not prune oaks after April 1.
While this date is a good rule of thumb, the actual date for the start of the high-risk period of oak wilt is slightly different every year. Our decision to set the oak wilt high-risk period to high is based on several factors.
Raise the lowest scaffold branches to 10 feet or more when the tree is 15 to 20 feet tall.
Apr 08, April 8, To help prevent oak wilt, forest health specialists in Minnesota are asking homeowners and landowners to avoid pruning or wounding oak trees in the spring. High risk months in Minnesota are typically April, May and June.
Oak wilt covers a large area in Minnesota and affects all species of oak trees. Check the DNR website for an up-to-date oak wilt disease map. To manage oak wilt Don't prune oaks from April through July to prevent spread by insects.