The bark is falling off my tree. Is the tree dead? Diseased? Will I have to have it removed? Please see the pics:
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Most of this looks to be old damage and I suspect it is caused by a porcupine due to:
Any tree would be stressed from this amount of damage and this seems to be born out by the thinning leaf canopy. As Kate Gregory recommends compare the amount of foliage to similar trees in the area to establish what is healthy.
If it is porcupines one control method is:
from here. You might be able to see similar damage on other trees in the area.
It is also possible that the cause is something else but we would need to know more about what kind of tree and where it is growing.
EDIT: current thinking in tree care in regards to wounds is to leave them alone and let the tree utilize it's natural defense mechanisms to close off the wound. Tar, shellac and numerous other "ideas" people have used do not appear to help the tree and could harm it by providing an area that is sealed where existing fungus/virus/bugs can live in comfort.
I had a tree service come out. They said that it's dead and is infested with pine bark beetles.