one is flat and the other more rounded belly,,
hickory is better flat,,yew works with the rounded belly,, I am over simplifying ,,but thats kind of the basic of it,,,,like stated above,,
depends on the wood,, if you look at the Native American D bows,, it will give you good idea of the design,,and what wood they used,,,same with English Long Bow,,
if the bows are laminated, then it changes alot,,and thats out of my area of expertise,, but others will chime in,,