Have you ever climbed a tree? I hope so! Many, many childhood summer hours of mine were spent up in the branches of a big (elm?) tree in our side yard. It was huge. Well, most likely it wasn't–but from my perspective then it was! Dad, probably with the help of one or both of my older brothers, secured some flat boards (a small door?) a ways up in it.
The platform was just big enough for two children to sit on. Sometimes it was just me and our cat. Usually I was by myself, and could stretch out and imagine the hours away, enjoy whatever breeze came by, "spy" on the neighborhood, read (probably a Nancy Drew mystery), make endless plans in a spiral notebook,... Dad also secured a rope a few feet out on the lowest sturdy branch. The knotted rope was just long enough that a brother or friend could reach up and throw the end for you to catch as you stood in the crotch of the tree. Then you could swing out as Tarzan, or a pirate, or...
We moved at the end of my grade school years. I wonder if the platform and rope were still up when we left.
Our own kids enjoyed a railed platform that Benny built between some trees. It had a short slide out from one corner, and covered a sandbox. He has also put up various swings for them (and us) in several different trees over the years. One tree in particular earned the title "Swing Tree" for its just right branch, height, and location. That tree is still at the end of our driveway, but sadly the perfect branch on it succumbed a few years ago to too many ice storms.
My drawing is not of that particular tree, but it's what came out of my pencil. I don't believe this swing goes very high, but it might be just right for some very young ones. The tree is waiting for Spring and their arrival!