Oak tree dying - Ask Extension
I have an old oak tree behind my house that is saying. I noticed last year that it looked stressed and this year it is much worse. It is not Oak Wilt ...
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Oak tree dying #871853
Asked June 06, 2024, 10:05 AM EDT
I have an old oak tree behind my house that is saying. I noticed last year that it looked stressed and this year it is much worse. It is not Oak Wilt or the gypsy/spongy moths but as you can see it is slowly dying. I also noticed some of my fruit trees are starting to dye off the same way. They are located near this big oak. I noticed large ant colonies (I do not believe they are carpenter ants) under the weed barriers around the fruit trees. I have since removed them all to eliminate that as a shelter for the ants. I also notice huge numbers of ant colonies in the ground in the back yard area. A few years ago an arborist literally poured Sevin down the hollow part of another oak tree that was being eaten from the inside. We have used 7 bags of Sevin on this back yard area and it literally did nothing to the ants. I do not know for sure whether it is the ants killing my trees but that is my guess at the moment. Suggestions? I purchased a tree drench as I am at a loss.
Cass County Michigan
Expert Response
Hello,
It is unlikely that ants had anything to do with the original tree stress. Some types of ants are drawn to an area with plentiful rotting/moist wood, which may be why you are seeing so many ants. Putting that much poison in your yard is just killing all of your beneficial insects that keep pest insects in check and is not a recommended practice.
Instead, look for the cause of your poor tree health at the root and trunk level. I see mulch piled deeply against the tree trunks on the two small trees that I have photos of. I also see some sort of tape around one of the trunks. Both of these practices can cause rot and canopy death. I do not have a view of the root area of the oak, but it may be too late for that tree. The growth you are seeing right now is called epicormic shoots. This is the tree's last effort to survive but rarely prolongs the tree's life for long. It may have to be removed, but please do this in the late fall or winter to avoid spreading oak wilt.
The smaller trees may be salvageable. Remove the mulch away from the tree trunks and spread it out to a depth of no more than 3 inches. Read the following article to learn more about what happens when trees are improperly mulched: https://njaes.rutgers.edu/fs099/
The tree drench is not something I would recommend at this time. Use products like this only when you have a positive diagnosis for something that the drench is formulated to treat.
Thank you for contacting Ask Extension.
Ruth
It is unlikely that ants had anything to do with the original tree stress. Some types of ants are drawn to an area with plentiful rotting/moist wood, which may be why you are seeing so many ants. Putting that much poison in your yard is just killing all of your beneficial insects that keep pest insects in check and is not a recommended practice.
Instead, look for the cause of your poor tree health at the root and trunk level. I see mulch piled deeply against the tree trunks on the two small trees that I have photos of. I also see some sort of tape around one of the trunks. Both of these practices can cause rot and canopy death. I do not have a view of the root area of the oak, but it may be too late for that tree. The growth you are seeing right now is called epicormic shoots. This is the tree's last effort to survive but rarely prolongs the tree's life for long. It may have to be removed, but please do this in the late fall or winter to avoid spreading oak wilt.
The smaller trees may be salvageable. Remove the mulch away from the tree trunks and spread it out to a depth of no more than 3 inches. Read the following article to learn more about what happens when trees are improperly mulched: https://njaes.rutgers.edu/fs099/
The tree drench is not something I would recommend at this time. Use products like this only when you have a positive diagnosis for something that the drench is formulated to treat.
Thank you for contacting Ask Extension.
Ruth
Thank you for your response however in response to your email please note the following:
1) there is zero mulch around the smaller trees. There is not now nor ever has been mulch around those fruit trees. They have been healthy until the past spring.
2) the bags of Sevin was used with a broadcast spreader over multiple acres. My “yard” is very large- acres.
3) the oak does not have oak wilt. I have witnessed multiple trees dying from oak wilt and this tree does not have that. No leaves falling, tree has been declining over a number of years. In regard to other issues, there also are no mushrooms or fungus near or on any of the trees
4) we have had issues with ants in another oak tree and the arborist said the tree was getting eaten from the inside from… ants.
♀️♀️♀️
Denise
Hello,
I agree that the oak in question probably does not have oak wilt. What I mentioned was that oaks should not be cut during the growing season because that practice can spread oak wilt. This happens when the sap beetles flock to a freshly cut tree- some of which may be carrying the oak wilt spore from trees far from your property. That oak wilt can travel through the root system and infect nearby oak trees. It is always best to prune and cut oak trees in winter.
Ants only eat rotting wood. So if there was a tree that was getting "eaten from the inside out", it was because that tree was already rotting. The ants do not eat healthy trees in that way. Here is an article that explains this:https://www.purdue.edu/fnr/extension/question-are-carpenter-ants-harmful-to-my-tree/
As for the fruit trees in question, my apologies about thinking I saw mulch. It can be hard to see details in a photograph. What I saw was that there is no widening of the trunk at the bottom where you should be able to see some root flare. I thought this was because of mulch, but now I think they may have been planted too deeply. The root flare is a widening of the tree trunk directly above the root system. If a tree is planted too deeply, that can cause the types of problems I see in the photo- dead branches and cracking trunk. I would recommend clearing some of the dirt off the top of the root system and remove the turf from below the tree around the dripline. You do have to be careful not to damage the roots when you are doing this, because most roots are fairly shallow. You also have to take care not to create a drainage problem by making a bowl-shaped area around the tree. The tree will not do well if it stands in water after rain events. Here is an article about planting too deeply: https://extension.umd.edu/resource/trees-planted-too-deeply/
Make sure the tree is getting sufficient water during dry periods.
Thank you for contacting Ask Extension.
Ruth
I agree that the oak in question probably does not have oak wilt. What I mentioned was that oaks should not be cut during the growing season because that practice can spread oak wilt. This happens when the sap beetles flock to a freshly cut tree- some of which may be carrying the oak wilt spore from trees far from your property. That oak wilt can travel through the root system and infect nearby oak trees. It is always best to prune and cut oak trees in winter.
Ants only eat rotting wood. So if there was a tree that was getting "eaten from the inside out", it was because that tree was already rotting. The ants do not eat healthy trees in that way. Here is an article that explains this:https://www.purdue.edu/fnr/extension/question-are-carpenter-ants-harmful-to-my-tree/
As for the fruit trees in question, my apologies about thinking I saw mulch. It can be hard to see details in a photograph. What I saw was that there is no widening of the trunk at the bottom where you should be able to see some root flare. I thought this was because of mulch, but now I think they may have been planted too deeply. The root flare is a widening of the tree trunk directly above the root system. If a tree is planted too deeply, that can cause the types of problems I see in the photo- dead branches and cracking trunk. I would recommend clearing some of the dirt off the top of the root system and remove the turf from below the tree around the dripline. You do have to be careful not to damage the roots when you are doing this, because most roots are fairly shallow. You also have to take care not to create a drainage problem by making a bowl-shaped area around the tree. The tree will not do well if it stands in water after rain events. Here is an article about planting too deeply: https://extension.umd.edu/resource/trees-planted-too-deeply/
Make sure the tree is getting sufficient water during dry periods.
Thank you for contacting Ask Extension.
Ruth
