diddo to what VB said. i always take the bark, then the light brown cambium layer and thats all for the back. if im not mistaking, the lighter wood is the more spongy for ash, therefore you would be better off removing down to the darker looking wood. on a couple of "piggy back" staves ive worked on of ash i left some spots of the "spongy" ring because when you apply a stain, it gives you darker spots on the back almost like a camo effect. im referring the rings as spongy only because i cant remember if its the early growth rings or late rings. hope i was of some help! -white wood
