Bradford Pear pests

[Jeny]

What causes small holes on the trunks of trees? My Bradford has holes a little smaller than a pencil in straight rows all the way around the trunk. The rows go from the bottom branch to the ground. The holes are spaced very close together but the rows are from 1/2 inch to 4 or 5 inches apart.
I can't see any insects on the trunks causing damage.
I've had this happen to redbud trees & apple trees in my yard. Eventually, the trunk dies from the inside out & the tree dies. My pears are still healthy & I'm hoping to save them. Can anyone tell me what causes this & what I can do to stop it?

 

[JeffE]

Sounds like damage from sapsucker woodpeckers. Unfortunately, once they choose a tree to feed on, they can be difficult to deter. Common suggestions are to wrap the attacked area with hardware cloth or burlap, or apply a sticky substance such as bird tanglefoot.

 

[Pondracer]

Do they look like this? I had a sapsucker problem that eventually went away.

<img src=http://mindspear.com/yard/images/birchholes3.jpg>

<img src=http://mindspear.com/yard/images/birchholes1.jpg>