Treehouse floor framing with slotted tree cross beam

Tree house foundation. It's going to be 12'x16' and about 9' from the ground at it's highest. The back two uprights are tree limbs. The front two supports are trees with a an 8" tee trunk as a cross beam, slotted to allow the beam to float when the trees sway in the wind. The floor floats on the beam, wrapping around the trunks.

Done