The reason the wood warped ... any wood for that matter is because it did not grow straight up, it grew bent or leaning.
The term used for this is "reaction wood" and it will never be dimensionally stable.
If you put some thought to it, the wood spent its life fighting the effects of gravity and its structure when it grew was stronger on one side than the other. So the grain structure is not uniform.
Blame the tree, not the wood. My brother makes some pretty nice furniture with yellow birch. It does not take nailing well and you have to drill your holes for screws ... other than that, it makes tough furniture and cabinets.
Some links that explain it better than I did:
Understanding Reaction Wood
View attachment 190609