Many a bolt have been (or is it "has" been) screwed into trees. If you look at a ropes/challenge course, you'll see countless bolts and lag going into and sometimes all the way through a tree.
What you need to be concerned with is if you are screwing into good wood. If the tree is healthy and you are screwing into a healthy part of that tree, after a few years new growth will surround the bolt and you won't be able to get it out even if you want to!
Arborists will sometimes use bolts to connect to branches together via a cable. It can be very strong...when installed by a trained arborist.
And please, use appropriate size pilot holes to avoid splitting.
So, yes, you can do it. That being said, I would like to point out that you will BE DRILLING A LARGE HOLE INTO A LIVING CREATURE. Rarely throughout history has this been considered a good thing. I discourage any such measure. Please consider if this can be done without harm to the tree. I've been in trees with cables and you could see nothing but a bunch of rotten wood around the cable, yet the rest of the branch is fine. There is no doubt in my mind that harm was brought to that tree by mankind (and I say mankind as opposed to "humankind" because I would bet it was a male, not a female, that drilled that hole into the tree).
So why a tree house? Why not a treeboat instead!
love
nick
Would you like a lanyard spliced up, or anything else for that matter??? Give me a call- 323-384-7770 or This email address is being protected from spambots. You need JavaScript enabled to view it.