The yellow of the fresh cut wood, says "barberry", the smooth bark, not so much. I'll take your word for it.
Nice clump.
Before the clump gets growing I would prune it lower. Do it now. The largest diameter trunk should be the tallest. The smallest diameter trunk should be the shortest. Use the visual "rule of thirds". The smallest trunk should be chopped to 1/3rd the height of the largest diameter trunk. The trunks should rank in height pretty much exactly the way they rank in diameter. The ones closest to the diameter of the main trunk should be about 2/3rds the height of the main trunk, the smallest half of trunks should be closer the one third. Avoid leaving any trunk exactly one half the height of the main trunk.
These visual "rules" are just suggestions, not "absolute rules". If any trunk has a trait that it would make sense to emphasize, you should feel free to ignore the "rules", but while one might think the rules will give you "boring", because trees don't read the books, never quite cooperate with budding at exactly the right position according to the rules. So in the end, the rules will usually give you a pleasant, unique tree, even though one might think otherwise.