Significant limb damage

I have no idea what's going on here.. It's the only tree that's doing it, it is 9' tall and well established.  The split is on the top side of the branch. I don't think the freeze did it since none of the other trees are exhibiting this. any ideas  Or what I should do now? 


@roadkill I'd dab pruning paint on it and hope. Maybe got watered after dry spell, and swelling wood expanded to split bark?

@pete2000  Great article and thanks for finding that. It was after a hard freeze that I noticed it so so that could be what caused it. Now I shall be patient and just leave it alone. That article should get posted into the main library

last edited by roadkill