Firewood heat by species

Every figure is from one of two university extension tables: University of Illinois Extension's firewood page and Utah State University Extension's wood-heating table. Both are for dry wood. Where the two list the same species with different values, the row shows both as a range; where only one lists it, the row carries that single figure. Real firewood is never exactly at table moisture, density varies within a species, and a cord of large rounds holds less wood than a cord of neat splits, so read the decimals as a ranking, not a promise.

Cornell Cooperative Extension puts it simply: many species drop below 20% moisture within a year of proper stacking, and oak can take two years or more. Ash has less water to lose than oak or maple, so it is usually the first hardwood ready; the species-by-species detail is in firewood seasoning time. Split it, stack it off the ground with air on the sides, and cover only the top; a fully wrapped stack traps moisture rather than shedding it.

Burning underseasoned wood costs you twice: the heat that goes into evaporating water, and the creosote that condenses in the flue.

Set the cord count above and the third column gives your total heat for each species, which is the comparison that actually decides a purchase. Then check what you are being sold is a real cord in the cord calculator.