While out in the forest, park, or even your own backyard you may have seen rows of small holes seemingly drilled into the bark of trees. These holes are not from an insect (those are more randomly spaced and usually smaller) but from a type of woodpecker called a Sapsucker (Sphyrapicus sp.). They chip away the outer layer of bark to feed on the tree’s sap. They usually prefer thinner barked trees such as birch, but can be found on conifers as well.
Damage is usually not severe enough to cause significant long term damage to the tree. Although the Birch tree I was pruning east of Seattle and is pictured here, seemed to suffer enough damage that its growth habit was altered. Instead of one central leader, lower more vertical branches began to assume dominance because of the extensive damage to the leader, giving the tree a multi-trunked vase shape.
Since it’s most often not very damaging to the tree, control is not necessary. If you feel it’s causing significant damage or just find it unsettling to see holes in your favorite tree, wrapping burlap loosely around the area or hanging brightly colored tape may discourage the sapsuckers from returning.