I'm not sure how sustainable it is at scale but I know someone who winters off a woodburning stove. They basically get their wood for free from trees that come

I'm not sure how sustainable it is at scale but I know someone who winters off a woodburning stove. They basically get their wood for free from trees that come down in their yard or people's yards that they know. They use a hydraulic woodsplitter to manage splitting all the wood.