I only know a tiny bit about trees, but i think the answer is basically never. Only the very outer layer of a tree grows, so the parts that were constricted during that year's growth will stay permanently that shape forever.

Cosmetically I'd guess the bark might grow in to fill the gap, but that's just a pure guess

If I had to hazard a guess I would say the tree will probably fail before it has a chance to heal. That trees a goner.

I'm hoping OP gives us an update in a couple months

It's odd; I use Sync Ultra, and while sometimes it uploads images for posts and comments just fine, at other times it simply refuses, and there doesn't seem to be a pattern to the failures or successes, so I've fallen back to Imgur during those times.

Here's a great example! Just tried to upload this copy. First try, it didn't upload and didn't even produce an error message. Second try, uploaded no trouble at all. It's bizarre.

Reminder set for three, six, nine, and twelve months out.