Why would you need a tree? You always know the location of the player in x,y,z. The world is extremely regular, first you figure out the co-ordinates of what y

Why would you need a tree? You always know the location of the player in x,y,z. The world is extremely regular, first you figure out the co-ordinates of what you are hitting, then you do a direct lookup of that from the world, with like a single top-level hashtable that links to large fixed-size segments. This will be dramatically faster than any tree.