Hi Tim,

I am sorry to hear about your tree!

While the physical symptoms do seem consistent with weather-related injury, the progression this year does seem concerning.  I see that the top of the tree has died and you have some interspersed needle browning.

You said that you had an arborist evaluate the tree last year.  Were the symptoms then similar?  When did they begin, and do they seem to progress the same throughout the year or is it isolated to certain seasons?

Do you have any photos that show the entire tree at once?

Thanks,

John

The arborist said it was winter drought and nothing I could do but try deep watering. I've done some deep watering and of course we have had tons of rain. The tree is at the edge of my lawn and has a couple drip sprayers under the tree. I don't see and insects on the tree but it's getting worse quickly!

Thanks

Hi Tim,

Looking closely at the base of your tree; I think it will be worth your time to investigate the root zone.  From what I can see, the tree may be sitting a little bit too deeply (something that would have occurred at planting).  This can cause trunk-girdling roots to develop, which start to cause problems 20-30 years after the problem started.

Pull back the soil from the trunk until you can find the root flare, that part of the tree where the trunk fans out fairly dramatically as it transitions to roots (it helps me at least to think of a child's drawing of a tree).  From the photos, it looks like this portion of your tree is underground.  This can lead to the development of a trunk-girdling roots, which grow around the trunk and eventually cut off the supply of water and nutrients, leading to dieback like what you are seeing.  If you find a girdling root, you can try to remove it or hire an arborist to perform the "surgery" to get it out of there; the tree may be able to recover.  In general, if the root is not larger than 1/4 the diameter of the trunk, they can be safely removed without causing so much stress to the tree that it dies from the treatment.  This section of our Colorado Master Gardener curriculum includes more information as well as a good picture: https://cmg.extension.colostate.edu/Gardennotes/659.pdf

Second, I would recommend removing the landscaping fabric from beneath your mulch.  The fabric has been shown to reduce water and air movement into the soil and can further stress the tree.  3-4" of wood chip mulch will suppress weeds without any  need to add fabric beneath.

Finally, because stress on trees is cumulative and trees respond to environmental factors slowly relative to us, every best effort might not save the tree.  Correspondingly, though, a successful treatment may take a year or so to show signs of recovery.  

I hope this helps!

Cordially,

John