As long as the sapwood is "sound", no bugs, no serious checking, it can be left in it's "whole" state. I just finished a 56" ntn sapwood bow. I removed the bark when I cut the wood and applied several coats of shelac. With the radiussed belly profile that I prefer, there is a "strip" of hardwood down the entire length of the bow with about 1/4" of sapwood showing on the belly edges. The stave started out straight and pulled into 4" of reflex as it cured. It now holds 2" of that reflex after being shot about 100 times.....it is a light weight bow though, only pulling 40#'s at 26" (true draw). I put a bull snake skin on the back and plan on using it for hunting turkeys out of my pop-up.