Today out in the blazing 80 degree heat, I managed to get the floor up to the treehouse and get it installed. The Doug fir is about 140' tall, and is 19" in diameter at the level of the floor. I figure it's around a hundred years old or there abouts.

I used two sheets of tongue-in-groove plywood, on top of the 2x4's and 2x6's that I managed to get put up last year. It was a little bit difficult to get the hole in the middle for the tree cut right... Had to refactor both the tree bark and the cutouts on both sides. It didn't turn out exactly square as I'd hoped it would... but it should be good enough. There's only a small gap in one corner that I can fix easily.

Next it's time to cut out the trap door, and figure out how to build the stairway up to it. Then, it's walls, roof and siding. More to follow...