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Several arborists have checked it out and said it’s fine, but I still don’t trust the stability of the White Oak that sits outside my office window. Officially it’s on our neighbor’s side of the property line, so he’s the one who has hired arborists (from 2 different companies) to inspect it several times over the last couple of years.
But the hole at the base of the trunk gets bigger every year, and if you stick your arm in the smaller hole at the bottom, you can dive in up to your elbows without running into anything.
It also doesn’t give me confidence that I’ve seen chipmunks run into that hole.