[Alas Babylon!]

VERY simple mortise and tenon.

I'm looking at some trees that have natural joints and other such formations I can use.

I'm looking at a post about 14 feet above ground with a strong Y joint to support a cross beam.

Like this:

[bray]

Nice. How big is the barn?

[ROCKLOBSTER]

I'm looking at some trees that have natural joints and other such formations I can use.

You need to get some Cypress "knees"....maybe somebody in the swamp can help you find some.