I happened upon some utility workers clearing trees. I asked what they did with the wood. They take it to an electric substation, less than a mile from my driveway. There, they dump it off and shred it up into mulch. The guys said I can take all I wanted. It is whatever they had to clear, all types of local trees, mountains of 'em! I got my insert installed first week of March. I have scrounged up about 2 cords of wood since. I'll be busting my central heat on purpose to claim "sole source of heat" burn waiver from the bureaucrats.