Issues with ash trees this year (not ash borer)

Asked July 18, 2019, 4:34 PM EDT

I have an ash tree that has several major branches without leaves this year. I have also noticed others in my neighborhood having the same issue. I have consulted with a tree service and they said it is not related to the emerald ash borer insects, but they have seen this issue with ash trees all over the Denver metro area. Can you provide some insight on the cause and the likelihood of the tree surviving? I would also appreciate any recommendations on how to save the tree.
I have attached pictures of the tree.
Thank you in advance!
Mike in Arvada

Jefferson County Colorado

1 Response

Hi Mike,

We have indeed been seeing similar problems across the front range this year. Ash trees in particular have had a difficult time. Our current thinking is that the Ash decline we have been seeing is primarily weather/climate related.The weather earlier this spring was quite unfavorable with relatively warm temperatures followed by multiple sharp cold snaps.This stunted new growth and killed portions of sensitive trees.

I would suggest continued care for the tree and closely monitoring it next year. I would also suggest pruning out any dead wood, but it would be best to confirm whether the leader is dead before pruning it out.

References:
Pruning Mature Shade Trees: http://cmg.colostate.edu/Gardennotes/615.pdf
Pruning Cuts: cmg.colostate.edu/Gardennotes/612.pdf

I would also consider giving your tree fall and winter water, if you are not already: https://extension.colostate.edu/docs/pubs/garden/07211.pdf

More information on watering throughout the year: http://cmg.colostate.edu/Gardennotes/657.pdf

Lastly, here are a few references for 'general Ash Decline':
from 2009: http://jeffcogardener.blogspot.com/2009/08/whats-wrong-with-my-ash-tree-by-mary.html

From Iowa State Extension: https://hortnews.extension.iastate.edu/ash-decline