Thank you for your comments.
Mikechell: I run a bead of CA glue along the cambium layer of the bark and that stabilizes it MOST of the time. I find that the greener the wood, the better success I have with the bark staying intact. Also, the harder the wood (Oak, Walnut, Pear, for instance), the better the bark stays attached. The longer the log sits before turning, the more liable it is to separate, hence; "greener is better".
Aard: Never thought of that. It is possible since I turn the Candle Trees from green wood and hollow out the stem to prevent cracking.