Q: I have some old oak trees in my yard. I noticed in one of the knots in the tree a squirrel. It appears he has taken up home within the tree.

This is a very large tree that I want to keep for a long time. Should I be concerned?

A: I recommend that at least the area the squirrel has set up shop in be checked into.

There is obviously a cavity there, and the cavity may be large enough to reduce the strength of the tree at that point, which can increase its potential to break.

Much depends on what "targets" there are in the area. A target is defined as anything of value, such as a house, garage, passers-by, users of the area (i.e., children playing), etc.

The question to ask is, "If the tree were to fail in part or whole, what would/could it hit?"

You should contact a Certified or Registered Consulting Arborist in your area to investigate. If the cavity is in a limb, maybe just that limb needs to be removed.

If the cavity is in the trunk, the tree may need to be removed for the safety of the surrounding area. Hopefully it's a minor thing, and you will be able to keep your tree.