Question: Why does my tree have rows of holes in its trunk?
Answer: Those are caused by sapsuckers (woodpecker relatives). They are not generally harmful, nor do they suggest the presence of any harmful insects. The birds drill their holes, then return to feed on the sap days and weeks later. If they seem to be doing damage consider a sticky repellent. You may also want to hit the holes lightly with an aerosol pruning sealant to prevent pests from entering.