a rule of thumb that I use, is if the tree grows food on it , it is most likely safe to cook with, and likely taste ok. So any kind of common fruit or nut wood in your area, including oak of course,, I buy 1/4 chords of it in my area since I dont burn wood for heat anymore. stay away from sappy woods like pine, etc. The stuff at the stores is too pricey for my blood, since I was raised cutting wood and cannot stomach to pay that much to get just a handful of it. I know many people that buy bundles at the store tho, which works for them..