Woodpeckers make a living by being curious. They chip away at loose bark looking for insects that hide under loose pieces of bark in bark furrows. Generally, their excavations don't damage the living bark (periderm) or cambium beneath the dead corky outer layers of bark that serve as a protective covering for the plant beneath the bark unless they specialize in feeding on sap from holes they peck out of the living tissue (sapsuckers/ flickers). Often though, they get blamed for death of wood which has long been dead, if only for exposing the injury in search of their supper.
We have a pear tree outside our picture windows overlooking the back yard, on which we have assorted feeders that attract a plethora of woodpeckers, flickers, chickadees, nuthatches, brown creepers, and titmice, all of which are naturally curious and on the hunt for insects hidden beneath the bark. While there isn't much loose bark on the tree, the bug eaters keep pecking, and after 20 years plus, there have been no issues with the tree I could attribute to the bird's industriousness.
Al
