Bonzai trees come in many shapes since they imitate bigger regular trees. You aren't going to be able to get those twisty/curvy trunks in the Bryce tree lab. It might be better to look for an actual model somewhere on the net. So far the closest I've come to something similar is the big African umbrella trees you find on the savannah. It may be possible to get a bonzai in Bryce.....hmmmmm, challenging. If anyone knows of good settings please post them.