Not yet. First winter for it hear. Didn't want to make things more complicated for it so I left it alone this spring. Will probably crack open that root mass in the spring to repot in a more stable growing container.
Just jerked a white oak seedling out of my yard last week. It was a foot tall with a foot long tap root.
Which is why looking at nurseries for larger containerized natives such as willow oak is VASTLY more productive in making oak bonsai. Also, if you're looking for native oaks to collect, you're not going to find collectible white oak or red oak easily. Willow oak is very common around here and tends to have shallower roots and less of a tap root. White oaks are all tap root for the first five or six feet down. That's the way they grow. If you want one, you're probably going to have to layer it over a couple of years.
I don't fool around with oaks. We only have 2 here growing in the landscape. White and red. Both have large leaves,long internodes and as much root underground as tree above ground. They are hard to dig up and live.
