TraditionalTool
Addicted to ArboristSite
The stairs you posted are not too much simpler, actually. Mortising the side of the tree limb present it's own set of challenges, IMO. Ok, they look like they could be simpler, but until you get into it you really can't tell. Moving and working with a large timber as in your pic presents issues also.......wow.........and....way outa my league!
This would be a good topic for the homeowner forum.