All of the Hybrid maple group are thinned barked trees (of which autumn blaze is one) The problem is a frost crack. Water gets in behind the bark through a small wound freezes, and expands causing this injury. The tree should be "healing" under the wounded area unless the tree is in other stresses, i.e. drought, etc. The small pieces of loose bark can be removed as the wounds can be hiding places for insects that are attracted to wood decay, carpenter ants, earwigs, etc. Be VERY careful removing ONLY the LOOSE bark, do NOT "peel" the bark back into living tissue. Use a sharp knife and LIGHTLY dissect the loose bark free. You do NOT want to place alot of force on the knife and cut into living tissue. Once the loose bark is gone the tree will heal itself, do NOT use pruning sealant. This deprives the wound of oxygen slowing the "healing" process. You have just learned the art of bark tracing. The affected areas will always be there but the tree should have no problem moving water around those areas, and it should continue to be healthy. Good Luck!