Not boxwood because bw is diffuse porous, the wood in the photo is ring porous.
Like others have mentioned, could well be mullberry.
Definitely bow worthy.
True boxwood, buxus reputedly does make a good bow, as written in Gaston Phoebus's Book of the Hunt from the 15thC. Never actually seen one made from boxwood though. It would be physically tougher than yew, out for a hunt in a forest.