Mountain Ash Tree Trunk And Close Branches Are Full Of Holes With Bees

Question From: C. Raymo - CONNECTICUT
Q: I live in Canada on the East Coast (Nova Scotia.) We have a Mountain Ash that was here when we moved onto the property in Nov. 2014. It has always appeared very healthy and this year was no exception until now (mid-July 2021) we noticed there are some leaves shrivelling up the top. It's not major and it's been exceptionally hot and dry, so we just decided to water it more for a few days. I rarely water anything that is well-established in my yard. Anyhow, today I decided to cut off some suckers and lower limbs. As I was wrapped in the branches I could hear the distinct sound of bees. They got louder as I trimmed. I didn't worry too much because the garden is filled with bee friendly plants (bee balm, roses, lilies, etc.) As they started swarming around me I looked for a nest as we do have a lot of wasps and hornets around. Well, I was shocked! The entire main trunk of the tree and even some of the larger branches close to the tree is full of holes. They appear to be pretty much equally distanced apart in each direction. I remember thinking it might be from woodpeckers after ash borers but there is no damage to the bark and it appears the bees are going into the holes. Any idea of what it might be? Carpenter bees maybe? Also, is there anything I can do to save the tree? In the past few years we have lost a number of trees due to mole/vole damage (including fruit trees, a weeping birch, rhododendrons, azaleas and lilacs) and last year lost a huge magnolia to something that bored under the bark and killed it. I am at my wits end! We don't use chemicals here but I may have to consider that as we have lots thousands of dollars of trees/shrubs.

A: You need an onsite inspection from a certified arborist. To find one in your area go to and enter your zip code.Best Nancy