Originally Posted by hempies
If you cut 2x4's into 6" lengths and slip them under the chain/cable it wont dig into the tree. If the tree is a softer wood it'll help protect the branch from the rubbing and swinging of the basket.
I've seen rubber conduit used in a similar way and it's a little less noticeable from an aesthetic point of view. Either way it's probably a good idea to do something to keep it from damaging the tree enough that you expose it to disease and other things that it can normally protect itself against.