Question
I have recently noticed that on my Cedar Spruce tree that there are holes in the bark.  They go completely around the trunk in several places up the tree.  the holes are about 2 cm in diameter and about 4 cm apart.  They circumference the tree as if it were a string of beads strung around the tree.  Holes are only located on the trunk and only on the tree not the tree next to it which I think is some kind of poplar.  Too high for kids to have damaged the tree.  Bore hole only goes through the bark not into the tree itself.

Answer
Sounds like sap sucker damage. These are wood pecker type birds that make the holes and when insects come to eat the sap in the holes the birds return to eat the insects. They will not harm the tree. The best way to rid the tree of sap suckers is to spray the trunk where the holes are with and insecticide this will prevent the insects from coming and the birds will go away. You can use any common insecticide--malathion, sevin or ready mixed home defense sprays.