Two years ago I dug this cork bark elm from a growing field here in Fresno. Many know him here as treecutter, I know him as Steve DaSilva. I have a large article coming soon on him at the bunker as well as what he is growing at his field.
There are many people growing material for bonsai in California. Just because they do not do mail order like Steve and Ed Clark and Glenn Van Winkle, they still perform a valuable service to the bonsai community. Many workshop teachers partake of their material yearly.
The tree I dug two years ago has performed well and this year it was transplanted into a bonsai training pot to help slow it down. It is a very aggresive grower and losing the detailing of the canopy is easy to do in a large container or the ground for that matter.