Question about pruning Oak tree, oak wilt concern - Ask Extension
I am having a tree company fall some dead trees on my property in the next week or so and he is bringing a man lift to reach some of the limbs safely....
Knowledgebase
Question about pruning Oak tree, oak wilt concern #878716
Asked July 25, 2024, 11:24 AM EDT
I am having a tree company fall some dead trees on my property in the next week or so and he is bringing a man lift to reach some of the limbs safely. While he is here I am going to have him take a limb off from one of my oaks that has a large limb hanging over my garage. Worried about oak wilt by trimming at this time of year so I was wondering what you would recommend to paint the the area that will be exposed. If I wait until winter to do it I would have to pay the entire cost of renting the lift where he will do mine along with a couple others the same day thus sharing the cost. I have included a couple of pics of the oak in question and am concerned about what looks like a crack in the bark but I don't see any evidence of seepage or bugs. I live in southern Jackson county and in the last couple of years storms of upended or taken the tops out of probably 30 oak trees on the 30 acre area where my home is. Wondering if they are all subject to oak wilt. Thank you for any information you could provice. Brooklyn, Michigan
Jackson County Michigan
Expert Response
First of all, I apologize for the delay in replying to your inquiry. Apparently the system assigned your questions to me, but the message never reached my inbox. That is not how we like to assist people, so thank you for your patience.
All oak trees are susceptible to the oak wilt disease. This disease is vectored by sap beetles which are attracted to fresh wounds in the tree. If these insects feed from an oak-wilt infected tree and then goes on to feed from a health oak tree, it will transmit the disease to that tree.
You may be aware that oak trees root-graft with one another. That means that they share the same vascular system, so if one becomes infected with oak wilt, every tree that is connected to in via the roots will also become infected. Oak wilt can kill trees in the red oak group within a few month; members of the white oak group are not impacted as quickly.
Due to this systemic nature of the disease, oak wilt is difficult to
control; prevention is the best management tool. Not pruning or damaging oak trees during the warm season is probably the most effective tool for avoiding oak wilt. If storm damage or other emergencies necessitate that an oak tree be pruned during the growing season, promptly repair the damage and immediately seal the wound with latex paint or wound dressing. (One insect species that transmits the disease is known to arrive on wound surfaces within 10 minutes of their creation!) This rule also applies to damage caused by tree-climbing spikes, nailing signs on trees and accidental bark removal.
While risk of oak wilt infection decreases after mid-July, According to Michigan State University's Horticulture Dept., it’s prudent to avoid pruning of any type of these majestic trees until November. This would include removal of limbs except in the case of extreme danger.
We do not recommend painting tree wounds as was the habit in
the past, except in the case of oak tree wounds made during warm weather. Please see the information in the links below:
https://www.canr.msu.edu/news/prune_oaks_in_winter_to_avoid_oak_wilt
https://www.canr.msu.edu/news/we-can-all-help-prevent-oak-wilt
I totally understand you desire to avoid the extra cost of waiting to remove the limb hanging over your garage. Just keep an eye on the trunk of the tree and watch for any sign of mycelial mats. These are pictured in the links above.
All oak trees are susceptible to the oak wilt disease. This disease is vectored by sap beetles which are attracted to fresh wounds in the tree. If these insects feed from an oak-wilt infected tree and then goes on to feed from a health oak tree, it will transmit the disease to that tree.
You may be aware that oak trees root-graft with one another. That means that they share the same vascular system, so if one becomes infected with oak wilt, every tree that is connected to in via the roots will also become infected. Oak wilt can kill trees in the red oak group within a few month; members of the white oak group are not impacted as quickly.
Due to this systemic nature of the disease, oak wilt is difficult to
control; prevention is the best management tool. Not pruning or damaging oak trees during the warm season is probably the most effective tool for avoiding oak wilt. If storm damage or other emergencies necessitate that an oak tree be pruned during the growing season, promptly repair the damage and immediately seal the wound with latex paint or wound dressing. (One insect species that transmits the disease is known to arrive on wound surfaces within 10 minutes of their creation!) This rule also applies to damage caused by tree-climbing spikes, nailing signs on trees and accidental bark removal.
While risk of oak wilt infection decreases after mid-July, According to Michigan State University's Horticulture Dept., it’s prudent to avoid pruning of any type of these majestic trees until November. This would include removal of limbs except in the case of extreme danger.
We do not recommend painting tree wounds as was the habit in
the past, except in the case of oak tree wounds made during warm weather. Please see the information in the links below:
https://www.canr.msu.edu/news/prune_oaks_in_winter_to_avoid_oak_wilt
https://www.canr.msu.edu/news/we-can-all-help-prevent-oak-wilt
I totally understand you desire to avoid the extra cost of waiting to remove the limb hanging over your garage. Just keep an eye on the trunk of the tree and watch for any sign of mycelial mats. These are pictured in the links above.
Thank you do much for the great info. I was going to take the whole tree down but hate to lose it. It is leaning pretty good right toward the house/garage. I'm thinking now I'll just remove the limb. I may have to wait until November as you suggest. Just really bothers me all of the oak trees that tops and large limb have been damaged in the last couple of years around us. Guess we have been lucky that they haven't been infected. Thanks again, Larry
Sent from my Galax
My pleasure. Thank you for caring about our majestic oak trees!
