I am watching a TV series named "Treehouse Masters." What they do is make houses on trees or around it getting physical support from a big strong tree, like this:
But to make the support strong, they make a big hole in the trunk of a tree
Then they put a steel beam into it, like this:
In some cases, they make more than one hole. So, does this affect the tree in any way?
If anyone makes a hole that big or even bigger but doesn't fill it with any other thing(like the beam), will the tree heal itself?
I have heard that trunk is the most important part of a tree. So I am curious to know if this act is cruel towards the trees or not.