Trident maple blight?
Hi - The good news is that it is natural for Trident Maples to have bark that peels off. Trident Maples are also fairly disease resistant.
In your photo it does appear that some branches have previously been pruned off of the main stem. If the pruning was not done properly, it is possible that this could have been a possible entry into the tree for some canker diseases. I do not see any cankers in the photo, but the bark is unusually deformed.
If cankers do occur on maples, there is little that can be done to eliminate them. Branches with cankers can be pruned back with clean tools to their junction with another branch or to the main stem.
I would give the tree a chance to grow out and heal itself. If you have a dry spell in the summer, I would recommend watering to help avoid additional stress.
Thanks for the information, I'll see if it heals on its own. The pruning was done about a year ago, last winter. Could it take most of a year for this damage to show up from pruning? The tree was pretty bare where that growth is, with the bark falling off, for many months, and then this shows up several weeks ago.
It's possible that the pruning cut could be an entry for disease for a few months afterwards. It looks like some tar or other black sealant was applied to the pruning cuts. Tree sealants (tar, paints, shellac, etc.; ) do not prevent disease, decay, insect infestations or promote closing of wounds. There is actually some evidence that such sealants may actually cause harm. Leave wounds open and allow the tree’s natural defenses to work as intended.
Having said that, it looks like the tree is already starting to heal over the pruning cuts and I expect it will complete the healing in the next year or two.