Thank you for the good photos - This is likely squirrel damage. If the damage is all relatively high in the tree, consider installing a "baffle," which is just a sheet of smooth metal (2 ft wide) wrapped around the tree at least 6 feet from the ground. Otherwise, wrapping the trunk with hardware cloth (chicken wire is too chewable) is another option. Then, depending on where this tree is located in relation to other trees, fences, or structures from which a squirrel could jump (they can leap 10' or more), some of your task to protect the tree could include trimming back neighboring trees' branches, adding a hotwire to the top of a fence, or other means to prevent the animals from getting onto this tree. 
First however, I strongly recommend contacting <personal data hidden> to make sure, given how much damage already has happened, that the tree is still going to have a chance to recover and if so, what other care you can give the tree to help it pull through.