could be the end of stave that was closer to the root,,all staves the rings are thicker and dencer on the end closest to the ground,,rings get thinner and less dence the higher up the tree you go,,,this is why you always build the bow the way it grew in the tree,, if you are making your lower limb shorter you want the root end of the stave down so your best wood will be in the lower limb,,which is stressed a little more,,,, mike