Check out this awesome tree trunk by markus19840420 on Flickr: https://www.flickr.com/photos/71475401@N07/11644834193/in/pool-788191@N24/
Markus uses flex tubes which are flexible rods that can be bent to your will, and any piece with a hole can be attached to them. This means that the 1x1 cylinders can be slotted in, and they form the twisting trunk of the tree. The flex tubes are held in place with 1x1 modified plates with vertical clips and headlight bricks.