How to build a tree house?
What a couple of dumbasses. Use whatever wood (or fake wood) is best water and weather resistant. I built a tree house out of old oak about eleven years ago, and the thing is still there after all the rain and snow and sun, but that’s probably due to luck. If you have the extra cash, go with that fake stuff that they use for decks and patios. If you’re just doing a quick weekend job with the kids helping, use whatever wood you have, especially plywood for the walls.