Q. Noticed, about a year ago, these horizontal lines of holes on two trees in our yard; one is a maple and the other an ornamental cherry and they are both about 20 years old. The pines are unaffected. We do have woodpeckers but I don’t hear them and they don’t seem to stay on the trees long. Here is a digital picture. Violet Fischer – Dupont, WA
A. The picture you sent is classic sapsucker feeding pattern. Sapsuckers are a woodpecker that has the unique habit of boring through bark and into underlying water and nutrient conducting tissues of the tree. An analogy would be the holes we drill into sugar maples (those transplants from the northeast may have actually seen this) to capture the sap and boil it down into maple syrup. The name sapsucker is misleading since their primary food source is not the sap, but rather the insects that come to feed on the sap. Sapsuckers eat some of the sap as they feed on the insects. There are four species of sapsucker native to Washington State – Williamson’s, Yellow-bellied, Red-naped and Red-breasted. I contacted my friend Helen Engle to find out the habits and migratory patterns (Helen is an avid birder and member of Audubon and many other gardening & environmental organizations). The most likely species that you have working your trees is the Red-breasted since it is the most common. Although it is migratory there are local residents all year. Birds migrate in from further north (like Alaska) so the Local populations are replaced when they migrate further south. The sapsuckers prefer older trees and often will have favorite trees they use over and over again. This is how the neatly arranged rows accumulate. The birds are very secretive but if you are very lucky and patient you may see one. Now to the question of whether or not you should control them. Any damage to the bark that exposes the tissue below is a possible entry point for disease or insects. The bark is the trees first line of defense. That said, healthy trees would normally heal over these small holes quickly and compartmentalize the wound and stave off insects and disease. Older weaker trees may be adversely impacted with the proverbial “straw that broke the camels back”. If you feel you need to control this you can wrap the tree trunks with burlap or hardware cloth, but you will be removing a source of food for the sapsuckers or at minimum displace them to another tree.