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summer dieback

Posted by Michael Phillips 
summer dieback
July 24, 2018 01:22AM
Others have started reporting "summer dieback" in various places, specifically in Maine, Vermont, and downstate New York. This kind of tree death can be attributed to the way last fall was so warm through all of October and then it got cold very quickly. Leaves froze on the trees by mid-November, and by early December it was even dropping below zero in more northern locations. Trunk tissues on certain varieties weren't prepared for sudden cold. Vascular damage occurred but the results of that contortion to both xylem and phloem tissues were essentially on time delay. (You might observe unhealthy stretch marks and/or darker tissue in the bark near ground level prior to canopy decline but not necessarily.) Trees always leaf out as nutrients stored in cambium for spring green-up are already in place. And cold-damaged trees indeed grow and seem to be doing okay in the immediate weeks following fruit set . . . but by the height of summer . . . those improperly-functioning cambium tissues cannot deliver nutrients, all the more when good rains have been lacking. Thus new foliage cannot replenish the tree's energy stores. Vascular flow has failed. The tree gives up the ghost as a result. Sometimes this decline can take a few seasons to play out but the current scenario appears bent on delivering a final verdict sooner rather than later.

My losses from the double whammy presented late last fall have been limited to 14 trees on Geneva rootstock planted in spring 2017, but that winter death was immediately noticeable from the get-go this spring. Certain varieties along with some of the more dwarfing rootstocks are noted for hardening off at a slower pace. Usually this doesn't matter but Fall 2017 created a perfect one-two knockout punch. One grower is reporting this happening on 28 year-old-trees so it's not just young stock either.

You can help partially damaged trunk zones recover with a mixture of clay and cow manure and /or rich compost. The clay helps rejuvenate callus and the organisms in manure/compost hold pathogens at bay. Check out the thread on Biodynamic Tree Paste. Doing this determinedly each spring to all trees can help turn around the unforeseen but I will admit I primarily tend to hurting trees only. The wise however will take that advice to heart.

Apple growers need to be incredibly tenacious given that so many things can go awry. Report in and maybe we can start to recognize certain varietal patterns and thereby curb untested enthusiasm when planting grand visions. No surprise but the cider apple Dabinette has been reported twice already as testy in regard to vascular hardiness.

Lost Nation Orchard
Zone 4b in New Hampshire

Edited 1 time(s). Last edit at 07/24/2018 02:46PM by Michael Phillips.
Re: summer dieback
July 24, 2018 03:30AM
Interesting this "summer dieback" issue.
For my part - and as one of the most northern location on this forum - I have never seen it.
However I did see winter damage from last year's exceptional conditions.
And yes I had quite a number of young trees where leaves didn't fall and froze on the tree. Actually, some are still attached!

Here is the sort of damage I have seen on young juvenile trees. I have about 40 trees that are considered juvenile (i.e. they haven't started fruiting yet). Note I didn't see any damage on mature trees. And most of my trees are on standard or semi-standard roots.
2 small trees died back to about 12" above soil, but had this summer good vigorous growth.
About a half dozen trees that had very vigorous growth last year, didn't harden well and had the leaves freeze on the tree had very modest growth this year. Often the higher buds were killed and they restarted this year from about 4 to 12" below the terminal bud with reduced vigor.
And 2 trees had what I call abnormal budding, indicating the buds were still alive but the vascular tissues that should feed them were not functioning. This shows in the beginning as normal bud break, a small bouquet of leaves start emerging from the bud, but soon after I can see these buds are not developing normally, and they finally dry out by mid July. In the case of those 2 trees lower buds did eventually break and had good growth.

So yes, winter damage can take many forms...


Jolicoeur Orchard
Zone 4 in Quebec
Re: summer dieback
July 24, 2018 09:29PM
I have the same issue here in Upper Michigan. We had an extremely wet summer and fall and I noticed that many of my 1 and 2 year old trees still had leaves on them halfway thru winter. Didn't think too much about it this spring, but many of those trees did not leaf out on time and a about half of those trees looked completely dead. Knew it wasn't the cold winter, it was relatively mild here with a low of only -19F, usually gets to at least -25F or colder a few night every winter. We had plenty of snow cover also. I don't recall having real mild weather and then it getting really cold like Michael, but that could have been the case? I just remember it being very wet here all summer and fall.

Almost all of the trees that I thought were dead have resprouted about 12-16" above ground and the new growth is vigorous, but a 2 year old branched tree is now a one year old whip....again . I noticed that the bark on the trunks and lower limbs looked kind of orange-brown in color instead of the normal dark green/brown. Many of the 2 year old trees eventually leafed out but have weak growth and just look sickly, although some are starting to look better. I'm just wondering now if the tissues underneath have been damaged to the point where the tree will eventually die anyway?

The funny thing for me is that I have very sandy soil here and drains extremely well, so I'm not sure if the trees just simply retained too much water? Not sure that is even possible, but it sounds basically the same as what Michael and Claude observed.

I have several 4-6 year old trees and they seemed a little slow to get going this spring but look pretty good now. However, many of those trees were loaded with fruit buds and out of about 35 trees, I don't remember seeing any blossoms this spring and I've found only 1 apple out of all of them. So I believe they were affected too. A few varieties that seem to be unfazed by whatever was going on were Mantet, Arlet, Snowsweet, Honeycrisp, Sweet 16, Zestar, Akero, Brock, and a few others. But for the most part the tree damage was done only to trees less than 3 years old. And the smaller the tree the more damage it seemed to sustain.


Brampton Lake Orchards

Zone 4a Upper Michigan

Edited 1 time(s). Last edit at 07/24/2018 10:11PM by Pat Pryal.
Re: summer dieback
July 25, 2018 06:54AM
Sounds familiar! We had a very mild fall and then a foot of snow first of November. Nov. 12 we had -15F. Most varieties had frozen leaves still on this spring. I had 15 Wedge whips stone dead, 1 Bonkers with extreme die back, 2 Sweet Sixteen and one Wolf River with very reduce vigor. Honeycrisp came through with flying colors.

Oxbow Orchards
Zone 4a Grafton ND
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