Four trees abruptly died this spring #763109 - Ask Extension

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Four trees abruptly died this spring #763109

Asked July 21, 2021, 5:57 PM EDT

We had four trees die abruptly this spring. Last fall they were all alive and appeared healthy. But none of them put out any leaves this Spring and appear to be dead. They are all near to each other, within ~30 ft radius. Most of our property is grass, but we have maybe 10 different groupings of trees and shrubs that the previous homeowner planted 10-15 yrs ago (We moved into this house last summer and have a little over an acre of property). This particular planting area had a cherry, ash, oak, maple, and a couple large bushes that all abruptly died this spring. In that same area is a white pine that looks ok, and a hackberry that looks stressed. It’s a planting area adjacent to our kids playset, so I really don’t want to lose either of the two remaining trees. I had an arborist come out and look and he wasn't sure what the problem could be. We removed some sod and put in lawn edging in the grass adjacent last fall, occasionally spray for weeds, but can’t think of what could have so abruptly killed them. It is downhill from our drainfield (a long gentle slope downhill). Not sure if that could be a culprit. Any ideas what could have caused that? Who could I reach out to to help test and identify the problem? What can I do to prevent the remaining hackberry and pine from dying? Should I be concerned about planting a new tree in that area?

Anoka County Minnesota

Expert Response

Thanks for the question.

Well, this is an interesting puzzle! Four different species of trees and some bushes all died between last fall and this spring. My first question is going to be a rather stupid one. How do you know they are all dead? Brown foliage or even no foliage at all, does not necessarily mean the plants are dead. There are two pretty quick ways of determining this. First, when you break off a twig or branch, does it “snap” quickly. If it doesn’t that twig is not dead. Secondly, if you lightly scrape off some of the bark from a twig or branch, what color is the underlying plant tissue? If it is green, the twig is alive. If it is brown or yellow, the twig is dead.

When we see many different species die in a rather short period of time, it is unlikely that it was caused by insects or a specific plant infection (fungal, bacterial, viral). Some environmental effect must be involved. Your herbicidal spraying comes to mind. Even if you did this spraying away from the planting, herbicidal drift might have occurred. This often happens when the temperature is high and there is some wind. The spray volatilizes into small droplets that are carried by the wind to other plants. This could take place even over a distance of 30 feet or more.

I suspect that you have had your drain field in its current location for at least a few years. So I can’t understand why it should suddenly be a problem unless the septic system failed. If this did happen, I would think you would be aware of this.

It is difficult to know how to prevent this unless we know what is the cause. Soil analyses could be done but they generally measure nutrient (nitrogen, phosphate, potash) levels and soil pH. They would not determine any toxins that might be present.

Another possibility is that this planting and bushes had been exposed to road salt over the winter. This assumes the plants were fairly near a road. From what you wrote, this does not seem a likely possibility.

So I keep coming back to the possibility of herbicidal drift. So when you said the trees died abruptly, did that mean they never developed any foliage at all this spring, or did it mean that they developed spring foliage and then things took a turn for the worst?

Looking forward to your thoughts and responses. Thanks for asking us your questions.

Steve Hedman Replied July 22, 2021, 12:10 AM EDT
Thanks for the quick and thoughtful reply! Good idea to validate a basic assumption. 

I snapped off a few twigs on each tree and bush. Every branch I tried on the cherry and the two bushes snapped off easily and the underlying tissue was dry and brown. The ash, maple, and oak each had some dry branches but I did find some branches where the bark peeled off into strips and the underlying tissue was kind of a yellowish green and had some moisture in it. I compared it to a branch on a healthy maple tree in another part of the yard and that branch was noticeably more difficult to break off, tore off a longer and tougher strip of bark, and was greener and more moist then the other “dead” trees. So I’m not sure what you’d call the maple, ash, and oak, maybe “almost dead” or “struggling to survive”? 

I did notice that the ash has some ~6-12” suckers growing at the base. Other than that, they never did develop any spring foliage. Although I think the maple has some buds that started to form (unless that’s just part of the shape of the branch?) 

Regarding the drain field, we haven’t had any problems at all, but the only difference I can think of is we are a family of six whereas the previous owners most recently had just two people living in the home (and presumably used less water?). This is also our first time living in a home with a septic so still learning/developing habits of what can/cannot go down the drain.

This planting area is about two hundred feet from any road, so the road salt won’t be an issue.

As far as treating weeds, I sprayed once last fall and once this spring (just spot treating) with a Spectracide weed and grass killer. (I wouldn’t have used a vegetation killer anywhere near that area). I did this in all 10 planting areas. I always have the nozzle pattern set to much more of a stream than a mist. I also spread some Preen at the base of trees and bushes because I don’t like to spray within a few feet of the base of the trees/bushes.

Thank you for helping me investigate this!!
Dave

On Wed, Jul 21, 2021 at 11:10 PM Ask Extension <askextension@eduworks.com> wrote:
David Bluml Replied July 24, 2021, 9:00 AM EDT

Thanks for getting back to us. If the ash, maple, and oak had some green branches on them, that would indicate that each of them each had some active roots. I am hesitant at this time time to suggest to you that they should be removed.  Besides this time of the year (late July 2021) is not a good time to plant replacement trees.  For these three trees,I would suggest that you prune off all of the dead branches.  However do this pruning by starting at the ends of the branches and remove small pieces at a time, working your way back to the trunk.  For each cut look at the ends.  Sometimes a branch is dead at the end but not towards the trunk.  In other words, for the dead branches only remove those sections that are dead.  Keep up daily watering.

It's good that we can eliminate the possibility of road salt.  The Preen that you applied is also a non-factor as it would not have affected the trees. Often ash are grafted trees.  The suckers that you see coming up from the base may be from the grafted base.  These suckers can just be nipped off.

It sounds as if your weed spraying was done in an acceptable manner.  However I don't think that it can be completely eliminated as a cause.  The septic tank cause was a long shot on my part.  You could have someone out to inspect the system, but that will be your decision.

For the time being it just may be wait and see.  If towards fall nothing has improved for the better, please get back to us so we can revisit your situation.

Thanks for using our forum.

Steve Hedman Replied July 24, 2021, 8:29 PM EDT
Sounds good. Thanks for your help! Is there anything I can do to try and improve the health of the hackberry that seems a little stressed out? 


On Sat, Jul 24, 2021 at 7:29 PM Ask Extension <askextension@eduworks.com> wrote:
David Bluml Replied July 26, 2021, 7:08 PM EDT

Thanks for getting back to us.

Your hackberry may just be experiencing sun scorch.  This has been very common this season.  This occurs under conditions of high temperature, intense sunlight, and drying winds.  This can cause leaves to yellow and even become brown or black.  Sometimes the leaves curl at their edges.  Unless wide spread in the hackberry, there should be no significant damage to the shrub.  Just keep watering it.  DON'T add any fertilizer.  If not this fall, I suspect that it will look much better in spring 2022.

Thanks again for asking us the question.

Steve Hedman Replied July 26, 2021, 11:31 PM EDT

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