Whats a good rule of thumb for cutting up trees that have been down for a while or dead trees still standing? I just bought my house and there are down oak all over the place and some solid dead ones still standing that you can tell have been there a while. I cut one up today and the inside still seems hard and it split nice but the bark is all slimey under and has a little white substance (mold?) Still safe to burn right? I will be peeling the bark before burning of coarse since its basically falling off when I split it. Thanks guys and girls!! Im guessing as long as the wood isnt mush inside its good.......