spartacus: If the bark is peeling at the cambium layer your tree may be beyond help. What I'm saying is that if it's not just the surface of the bark but all the bark, that's bad. Prevention is the only solution. Paint the bark with a 50:50 mix of interior white latex paint diluted with water.

Update: a search seems to show this is a silver maple. So now my question is, what are those "silver maples" folks planted back in the 50s and 60s (to their regret) that had much smaller very silvery leaves, and they sprout up ALL over your yard, especially if the tree is removed? Is that one also a real "silver" maple or something else? TIA Nigell

^ Sorry, yes I was holding the piece of fallen bark up next to where it fell off for reference (as if it opened like a book). The damage was about chest-high. The bark seemed to be loose all around the opening of that hole. How far it extends beyond that, I cannot tell? Yet, the tree overall still looks healthy. I did not notice any other signs of external injury, either.. I mean, if it was a physical impact, the damage should have just been very local. And even then, I kind of doubt it would have so cleanly delaminated the bark like that? I am actually suspecting a lightning strike, now.. And in fact, there were just heavy rains all last week.. Here is a link that might be useful: Lightning strike This post was edited by blakrab on Fri, May 16, 14 at 18:04

I may be judging some peoples thoughts on here unfairly, and maybe I'm the one who's wrong. But, Not all trees are symetrical and perfect. Trees get burls,galls uneven growth if one side is shaded etc. Some times your mulch gets dog vomit fungus and your tree gets Slime Flux. It isn't all perfect, but, it's normal, and no cause to just throw it out and start new. Yes, sometimes you need to get rid of a diseased tree and start with the new, but, I just don't see this (the Op's) tree as a lost case to get rid of. This is likely why ( at least in the US) there won't be many old tree specimens to show future generations. I realize if there is an old tree near a house ready to fall it should be cut down, but, the younger generations (no I'm no crotchety old man) will just get rid of trees that are breaking down, even if they are away from buildings. In the UK, it seems they remove any rotten wood, then fence around them, so nobody will get close enough to get hurt easily. Then the tree continues to put on growth in girth, if not height, and it is a sight to behold, and of great age. I need some unicorn blood to make sure I can be around and make sure nobody cuts down my English oaks and white oaks. I'm kidding about that of course. I don't mean to be ignorant to Logan and anyone. But, trees get better with age, and don't need to be perfect, they are shaped by their environment. In the forest they don't have limbs until many feet up in the tree because of growing in the forest environment. I guess if you are in a HOA neighborhood, and all has to be perfect, you will think if it isn't perfect it has to go.