Several months ago I read an interesting one page article in the back of Make Magazine about a guy who lived in a treehouse for 3 years in the 1970s. I hadn't thought about treehouses since I was a kid, but the article struck some kind of chord in me, and I started thinking about building one.
In the spring of 2006 I headed to the family farm in southern Indiana to see if I could find a suitable tree. I hiked around with my folks for a few days, and we eventually settled on a Sycamore tree that had grown out of an old stump. The tree had sprouted 5 trunks, and it looked like we could fit a good sized treehouse between them.
I wanted to put the tree up a good distance off the ground. After climbing around in trees all weekend I realized being up high in a tree was a bit more frightening than I expected. 16 feet off the ground seemed like a reasonable distance.
My dad and I measured the circumference of each trunk, and also measured the distance from each trunk to every other trunk. This allowed me to create a scale drawing of the tree at sixteen feet. I headed back to Colorado for the summer with enough information to start designing the treehouse.