Interesting thread. I guess few members here deal with elm, cottonwood, and birch. These have to sit in the round for several months. Then, when the bark starts to fall off and the ends are checked, only then will they split rather well. If you try to split them fresh green, forget it. You will then spend most of your time using a hatchet to break strings. Birch is less revealing than cottonwood or elm because the bark clings tightly.