This is a tree house base that doesn’t yet have supports built in, but is along the same lines as the tree house I’m thinking of building for the kids in a pine tree in our yard some day.

The links to my tree house designs are below:

http://www.handyfather.com/tree-house-building-angled-supports/
http://www.handyfather.com/tree-house-design/
The whole thread can be found here: http://www.newcastle-online.org/nufcforum/index.php?topic=92373.0