I agree with moebow. I personally like birch a little better than ash, but it,too, will bend a little at times, particularly when I carry it in a bow quiver under my arm. Hickory will, too, but much less so, it seems to me. Most of the hickory I have has stayed very straight. Birch is about the same weight as ash; hickory will be heavier. Doug fir is a good compromise. Very tough and almost as tough as ash. And, I agree with Badger Arrow, Surewood makes about the best Doug fir shafts around. Can probably go with the same spine in Doug fir maybe drop down 5# or so. Probably need to drop down even more in spine if you go to spruce or cedar because they're physically lighter and recover from paradox quicker than hardwoods. Good luck.