For one thing I know it is persistent. Last year I decided to girdle it hoping that would kill it. I cut through about 3/4 of the way on one side of the tree and then about 5 inches above that I cut through from the opposite direction about 3/4 through the diameter of the tree (not the way to girdle--you should remove the cambiam layer all the way around the tree). But this spring the tree seemed to be invigorated by the surgery I had done.
