Iíve had some warping after jointing a board dead flat and running it through the planer. This has occurred with oak, maple and pine. Any thoughts?
You may not be letting the lumber acclimate to your shop long enough--at least a week, two if possible. Also, try planing off opposite faces more equally.
You can check for stress by cutting a clothespin-shaped sample from the lumber--many texts illustrate how to do this. Wood with drying stress should be returned to the seller.
If it were a moisture problem, then you would see warp developing after jointing and before planing.
Gene Wengert, forum technical advisor