Sometimes the wood can just be crazy. Wood is by far not always the same, even in the same place, ten feet apart from each other. Sometimes I suspect wood is not very healthy wood, sometimes it gets sick and doesn't turn out real meaty like it should. Or sometimes being sick seems to turn out even better wood than it would normally... I cut a mulberry tree last summer, and I looked at it, and there was NO SAPWOOD. Only PURE HEARTWOOD, starting right under the bark. I peeled the bark off and the only thing was orange wood. The rings were super tiny. Ridiculously tiny. After letting it dry and everything, I think what is was was some decease or something making it that way, as there were parts of the tree that looked sick or something, after it dried I could see a tiny color variation between like 1/16" or maybe 1/8" of the the first couple rings with the rest of the tree, so I think it has sapwood, just orange sapwood. Either way it is very little, and the wood is very dense for mulberry, but it definitely is mulberry, as it came from a row of mulberry I have cut from for a couple years...