If you burn wood to heat your home you undoubtedly have an interest in choosing woods that are clean-burning and productive in terms of heat produced. You will get the best results and generate more heat per wood volume when burning the highest density (heaviest) wood you can find. Dense firewood will produce the highest recoverable British Thermal Units (BTUs), but all wood must be "seasoned" for optimum heat production.The seasoning process is simply a matter of allowing the wood to dry in order to lower the moisture content. Dry wood burns more efficiently, with fewer hydrocarbons going up the chimney. It's estimated that even a mildly wet log loses fully 5% of its available energy vs. burning a dry log. When burning a wet log, a considerable amount of energy is spent driving off the water, which reduces efficiency. The Best Woods to Burn by Species There are several variable properties in different wood species that affect the chances for sustainable, clean