I've made very good bows with mulberry(red, I believe). Some were all heartwood, some had a few rings of sapwood left on the back and a few that were 50/50 sap/heart woods. As far as I know all are still shooting. On one I made the owner has a 31"+ draw length(Alan Holt for those who know him) and he gets every bit of that from any bow he shoots. Pat