Here is another photo of a different limb

Could be damage from insects, sapsuckers, or mammals. It's hard to tell.

Thank you for your response, yeah I don't know, it's a real mystery. I thought maybe insects too, but the spots are big; an inch or more in diameter, but maybe. We can see the tree from our kitchen window and never see any animals other than the occasional squirrel or bird, so not sure about animals being the culprit.

I just don't want to lose the tree... It looks like some of the newer smaller branches are dying on the affected limbs...

I can try to get a closer and clearer pic tomorrow

I think they're bark galls but I don't know which type.

Dax