Since even before we moved in, Amy has wanted a tree swing. Actually, Amy wants lots of tree swings, to be used for various photo shoot locations (and also for fun, I suppose).
We decided to start with one, though, right near the driveway in some nice light overlooking a clearing in the orchard/garden area.

the spot (it’s my picture, not Amy’s, so that’s why it looks bad 🙂 )
Based on some pictures of the sort of thing Amy had in mind, I built a simple seat from a piece of cedar decking. I didn’t really follow any one set of instructions, but combined guidance from stuffwedo.com, handymanhowto.com, A Beautiful Mess, this HGTV post, and Mother Earth News.

seat, from the bottom

seat top

the rope attaches to the seat with a simple double overhand knot
Then the rope went over the tree branch:
Mostly the tree swing was a trivial project, but it was fun to research and learn some knots. Decades ago I was pretty handy with knots, but have forgotten everything I knew, and am interested in re-acquiring a functional competence. I used a Cow Hitch Variant to attachment to the branch, a Double Overhand Stopper to connect the seat to its rope, and a Bowline where the main rope loops to connect to the seat rope.

knot reference, in the field
I did a bit of saftey testing:

(I tested quickly – swinging makes me feel sick in about 30 seconds.)
the kids confirmed that it works: