Wood is highly ecological, since trees are a renewable resource. If you cut down a tree, another will grow in its place. And if you cut down the new tree, still another will grow. And if you cut down that tree, yet another will grow, only this one will be a mutation with long, poisonous tentacles and revenge in its heart, and it will sit there in the forest, cackling and making elaborate plans for when you come back. Wood heat is not new. It dates back to a day millions of years ago, when a group of cavemen were sitting around, watching dinosaurs rot. Suddenly, lightning struck a nearby log and set it on fire. One of the cavemen stared at the fire for a few minutes, then said: "Hey! Wood heat!" The other cavemen, who did not understand English, immediately beat him to death with stones. But the key discovery had been made, and from that day forward, the cavemen had all the heat they needed, although their insurance rates went way up.Dave Barry, "Postpetroleum Guzzler"