Hi Eric,

Thanks for your email. This last storm really took a toll on a lot of ash, so you're not alone (which is no consolation for you).

Do not apply pruning paint or any spray to the wound. It's better to let it seal as it's able naturally. Pruning paint and other products have actually been found to inhibit wound closure.

The bigger thing to consider is whether this tree is worth continuing to invest in. With emerald ash borer confirmed in Larimer County and the young age of this tree (and now it has a pretty large wound), it may not be a candidate for treatment going forward. But it's your choice and take time now to consider your options.

Removal and replacement could be done...or even plant another tree near this one and let that one grow for a few years with the intent to remove this one when necessary. Unfortunately these are heavy decisions that need to be made. Many cities/municipalities are making the decision to remove any ash smaller than 10-12" in diameter at chest height. 

I'm attaching two documents. One is the "decision guide" that can help you make decisions regarding the future of your tree. Should you decide to replace it, I'm also including the list of trees to replace ash.

For now, keep the tree healthy and watered. Avoid additional stress. If you have additional questions, feel free to email me directly: <personal data hidden>