Gary,
The sedum branches on the stripwood trunk is a good variation! It changes the look of the sedum trees. Casey's technique of adding additional branches to the sedum trees will produce yet another variation, and Val's yet another. With just those techniques, and some different colors you can do a whole forest!
BTW Casey, I agree with the undergrowth. I still have to get some new growth trees planted, then all the undergrowth.
Pete