I posted a few pictures of this tree yesterday and while answering comments this morning decided to ask a question.

Here’s another image of the same tree; different view point, showing a large hole at the bottom of the trunk.

The trunk of this tree is completely hollow to a height of some 6 or 7 feet, possibly more. You can see through part of the trunk some distance above that. So the bark and outer layer of timber forms a kind of shell.

Various boughs have been broken or sawn off, causing the openings in the mid and upper trunk.

As the tree is still very much alive my question is, how much damage does a tree like this have to suffer before life becomes untenable?

I’m not seeking a definitive answer, since that would be too much to ask. Any knowledge would be greatly appreciated though.