If the holes are in straight horizontal or vertical rows, the holes were caused by yellow bellied sapsuckers which migrate through the area. Unfortunately there isn’t much you can do about them. To discourage sapsuckers from feeding on a favorite tree, wrap hardware cloth or burlap around the area being damaged, or smear the bark with a commercial sticky repellent, such as “Bird Tanglefoot”. Beware, however, that other birds not responsible for the damage can also get stuck in it.

If the holes are not in straight lines, you may have wood-boring insects. Generally, borers are attracted to stressed trees, that is, young transplants, poorly sited plants or plants that are not cared for. For more information about borers, see our web page at http://www.mortonarb.org/tree-plant-advice/article/753/borers.html