I love stacking hammocks double and triple tall, this was only a double, but still very cool.
Hammock knot? For rope? Got a link? I've heard ropes can hurt the tree, cut into the bark.
These are hammock straps, with loops for length adjustment, like this:
That helps spread the load out so the tree is happier.
I do agree the trunk is best, usually that's all I do. But I was trying to fit 4 hammocks in here. The branches were plenty stout, plus if you keep the angle acute enough, that is, if you're hanging correctly, you can reduce the lateral load, like this:
I see way too many people with bad hang angles, not only does it make it harder to lay diagonally, or even impossible in some cases, it actually increases the load on your straps. Which if they are ropes, is worse for the tree. And if it's an old or undersized rope, they can fail. I did that once, thankfully only a few feet off the ground 😬