Answer: Unfortunately, any big hole in a tree trunk is always a bad sign. Whether the problem will become critical and kill the tree sooner or later on depends on the cause of the hole. Generally, holes no matter what the source originally act as conduits for infection and infestation and thus ultimately weaken the tree and make it dangerous. I would strongly suggest you consult with a professionally trained arborist about the prognosis (and safety) of this tree.
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