and I just bought a hammock (to hang from trees at our campsite).....
I don't want the trees harmed. We just camped at Big Basin State Park (SF Bay Area) and they have a rule against hanging anything on the trees. It's understandable. All the trees have moss on them, so you really would do aesthetic damage, at least, by hanging a hammock or clothesline from the tree.
These trees in the campgrounds have to put up with hundreds of visitors each year, and for many many years.
I bought a stand for the hammock, but it is wayyy heavier than I thought it would be. Not sure how anyone in their right mind would take the stand on a camping trip.
Not many campsites have structures that you can use for hanging a hammock....