HEAT VALUE OF DIFFERENT WOODS

Wood is usually sold by the cord, a stack of wood 4 feet by 4 feet by 8 feet, or 128 cubic feet. (The air space between logs generally accounts for about 50 cubic feet, so the solid wood in a cord is usually between 75 and 85 cubic feet). Because some woods are heavier than others, they give off more heat per cord when burned. The chart below compares the heat values of different woods (values shown are for air-dried wood).

Wood Pounds * BTUs per cord (in millions) Ash 3,440 20.0 Aspen 2,160 12.5 Beech, American 3,760 21.8 Birch, yellow 3,680 21.3 Elm, American 2,900 17.2 Hickory, shagbark 4,240 24.6 Maple, red 3,200 18.6 Maple, sugar 3,680 21.3 Oak, red 3,680 21.3 Oak, white 3,920 22.7 Pine, eastern white 2,080 13.3

*BTU stands for “British thermal unit,” a standard unit of heat equal to about 252 calories (a calorie being the quantity of heat required to raise the temperature of 1 pound of water 1 degree Fahrenheit).

Source: “The Wood Stove and Fireplace Book” (1976, Stackpole Books)