So, they’re climbing up the trunk and causing damage there rather than eating the bark at the base? Got a picture?

If the damage is significantly above the base, could be a piliated woodpecker, unless you've actually seen the porc-critter.

I once saw a porcupine about 20 feet up in a tree. Was a surprise, I didn't know they could climb, but I used my binoculars and it was definitely a porcupine.

The only times I've seen wild porcupines, they were fast asleep, about 20 ft up a tree.

Yup, they eat, and they sleep.

Many decades ago, they were a protected species in Minnesota.

The reasoning behind the protection, was that they were, one, edible and two, an animal that a person, who was lost in the woods, could harvest without a firearm, for survival purposes.

Since the days when a person lost in the woods is nbd anymore, they've multiplied and with not many predators that care to deal with such a prickly subject, have become a real nuisance, causing much destruction throughout the wild forests.

The trees in my picture were all in a little group of trees and there were 6 or 7 trees that were destroyed and all by one porcupine, during the period of a few months over winter.

My dad had a pe t porcupine