Your original photo doesn't have anything alongside for comparison of bite-sizes.
But it does have what appears to be incisor "
try-bites" at the upper right. The marks appear to be betwixt porcupine and squirrel. (More towards porcupine—but there's no real "standard" for a measurement present).
If they are measured against your neighbor's beaver-bite bark damage, it may become clear that the incisor "
try-bites" are the smaller two of the three animals. (Clearing the beaver of tree-
assault-and-battery).
.