Thank you, Jerry, for sending your three excellent photos.

Putting aside your concerns about ash trees for a moment, I have a couple of general tree questions about what I see in the third photo you sent.

I see what may be a wound to the trunk on the left side and that your tree has fewer branches and leaves on that same side, above the wound. I see that a large branch was removed on that same left side. What happened there?

Why do I ask? If the bark is damaged, the tree will have trouble getting water up from the roots to the leaves. Are the leaves brown and curling on the edges more on the left side of the tree?

I also see that your tree is close to a fence and there’s rock mulch on the other side of the fence.

What did you see change in the past 2-3 years? The fence? When did the fence go up? Before or after the trees were planted? How big are the holes for the masonry fence supports? When was the rock mulch installed? Any other construction or environmental changes?

How do you treat weeds that come up in the rock mulch area?

Can you tell me about your watering program? Winter watering? What changes have you noticed in the tree canopy during the past 3 years?

Which way is north? I’m trying to figure out if there’s sunscald on the southeast side of the tree, due to wild shifts in our temperatures.

Usually in the case of damage due to Emerald Ash Borers, homeowners start to notice sparseness in the TOP of the tree. (Refer to https://planttalk.colostate.edu/topics/insects-diseases/emerald-ash-borer-colorado-1499c/) That’s not what I see in your photos. At advanced stages, you might see the D-shaped exit holes of the borers in the trunk at about chest height. What do you see?

Yes, I’ve asked a lot of questions. Getting your observations will give us more information that will lead us to a correct diagnosis of the problems. Only then can we suggest treatments that will work for you.

I hope to hear from you before the end of the week.

Thank you.

Sue

Weld County Colorado Master Gardener

Great questions Sue and I'll try and address them below.

We’ve been living at this location for 13 years and planted the tree there about 11 years ago. For reference, there is a sidewalk and street on the other side of the fence with photo #1 facing north (street side) and photo #3 facing SW (from backyard).

The tree has never been randomly pruned, but instead was pruned by me this year to remove dead branches. These dead branches did not leaf out last year either, so I decided they were not only unsightly but may be negatively impacting the tree’s health. Thus I removed the dead branches this summer leaving what appears to be a wound. I followed recommended limb removal practices found on YouTube. The trunk looks to be in good condition to me overall, and I have attached some closeup pics of the trunk for your review.

The leaves that are curling are on the healthier left (west) side of the tree in photo#1. We have not changed any elements to the landscaping over the past 10 years; the fence was always there and the mulch and rock were installed shortly after planting the tree. As for weeds, we typically apply Preen in the spring according to instructions and pick any weeds that grow by hand throughout the summer.

In addition to the water obtained from daily lawn watering of 4-5 minutes, I have a drip watering system set up which waters the tree 3 times a week for ~15 minutes. This is what we've done successfully for the past 11 years. I also water the tree by hand during the winter months if there has been a lack of snow. However since the fence provides winter shade there is often snow there during much of the time.

During the past 2-3 years the tree has begun to drop leaf clusters and the canopy started thinning out in the process. Starting last year several branches did not leaf out at all and it was the same this spring. Thus I removed these branches this year. As for borers, we have sprayed the tree twice a year since it was planted and I have never seen obvious evidence of borers.

As an interesting aside, we have been seeing this exact same type of die back (random branches throughout a tree) in ash trees all over the Vista Ridge neighborhood, so ours is not a unique case. If there is any hope of saving our tree, then I would think others in our neighborhood could certainly benefit from your input as well. I look forward to hearing from you again.

Thank you very much,

Jerry

Hi, this is Steve and I'm on duty this week, replacing Sue who asked the correct questions and you have given good information in response. We have seen serious tree issues for the past several years, believed to be long term effects of our weather for one thing...early freezes, late frosts, drought - summer and winter. It's been a theme for some time, and we find that an issue which happened a few years ago take time to show in a tree. So, I feel that is an underlying issue although you have done the correct things by watering summer and winter - but there is nothing to be done about wild temp swings. In addition, I really think that trunk wound is an issue as well. I believe Sue mentioned any damage to the bark affects the tree - even if water is available, a damaged trunk impedes water movement. 

The leaf scorch on the west side could easily be from the intense sun on that side (and if the tree isn't taking up enough water, that is how it can react).

I'm not suggesting that PREEN has any bearing on what's going on, but until things turn around, I would suggest not using any weed preventer/control around the tree - and realize the roots will go out at least as far as the canopy and often 2-3 times that. 

As for an arborist visiting, we recommend using a Certified Arborist. Below is a VERY detailed piece about pruning mature trees and on page one, there is a link to finding such a professional along with a search feature to find them in your area. If you are not using a Certified Arborist for your visit, you may want to search for one and hopefully they can visit sooner (often you will find many, many available locally). 

My advice at this point is to keep doing what you are doing and perhaps even increasing the water during our hot dry summer. Again, our trees have suffered extensive and long term damage over the last few years. Please don't hesitate to continue to contact us on this or other horticultural questions. 

Oops....I'd like to say there was a glitch and the program omitted the link to the pruning article including the link to the arborist site, but Momma told me not to lie. Here it is

https://static.colostate.edu/client-files/csfs/pdfs/616_pruning_shade_trees.pdf