We have a cottonwood tree in our back yard with a treehouse in it, I have one vertical climbing wall on one side, but we're thinking of putting an inverted wall on the other. The tree is one large tree that branches into 8 trunks about 3ft off the ground. One of the trunks is at about a 50-60° angle to the ground and about 13-15" in diameter, the guy I'm planning this with thinks that we could just build right off of the trunk, but I'm concerned about how the trunk will support the weight. It probably could support the wall, but I'm not sure. I'm wondering if it would be better to build the wall around the tree or if I'd be ok attaching it to the tree. Or if anyone else has any great suggestions?