What strips the bark off of spruce trees?

[Dewey Cox]

I have an old spruce and a young pine tree that both have a lot of bark stripped off of them.
It looks like the kind of damage a porcupine makes on a willow tree.
Do porcupines eat spruce bark too?
None of the trees that usually get damage have any chewing of them, just one spruce and one little pine.
Trees look healthy otherwise, and the barkless sections are mostly around branches, as if something was chewing from on the branches.

[lone wolf]

porcupine would be my first guess

[kodiakken]

I have removed a few Prcupines out of Pine and Spruce trees. They were doing damage to them.

[bagwan]

Could be sapsucker woodpeckers. They can strip all the bark at the base of young trees.

[Red Bullets]

A porcupine will leave pellets under the trees and have distinct trails. Pretty tasty too should you need to cull one or two.