I was gifted a hickory stave from a friend. He cut the tree in Missouri, split the staves, and peeled the bark off last summer, sealed the back and ends immediately. I don’t know what variety of hickory, but it’s got some kind of strange looking spots on it. He text me tonight and said he started working on a stave from the same tree, and these spots all hollow underneath.
Does anyone have any experience or knowledge of these. What might have caused them? Bugs, maybe some type of disease?