Heating Properties of Firewood by Tree Species

Heating Properties of Firewood by Tree Species

Firewood performance can differ from species to species. The type of tree you use for burning can vary widely in heat content, burning characteristics, and overall quality. I have created a table that presents several important burning characteristics for many species used in North America. The chart ranks each tree species by its density which is a good indicator of overall heating effectiveness.

Wood Characteristics Influencing Quality Heating and Ignition

Density of Wood - density is the amount of space a volume or mass of firewood occupies. The denser the wood, the less space it's given mass takes up and the greater a particular volume of firewood weighs. For an example, hickory is about twice as dense as aspen, so a cubic foot of hickory weighs approximately 50 pounds while a cubic foot of aspen weighs only about 25 pounds.

Green Vs. Dry Wood - Firewood should be dried (seasoned) to 10% to 20% moisture content for best burning performance. Much of the energy generated from burning green firewood actually goes toward evaporating the water held in the wood. Green firewood only gives off about 40% of the energy of dry firewood. To get the most heat production out of your firewood, you should season it by first cutting into short log bolts. Split these bolts and stack in a dry, well-ventilated area for at least six months before burning.

Available Heat by Wood Species - Available heat is a measure of the heat given off when wood is burnt and measured in million British Thermal Units. Hardwood trees give off more energy in BTUs than a comparable volume of softwood because it is denser. It should be noted that the volatile oils in some softwoods can increase the heat output of some species but only for a short time.

Ease of Splitting - Wood with a straight grain is easier to split than wood with a tighter more complex grain. Knots, branches, and other defects can also increase the difficulty of splitting firewood. Remember that dry wood is generally easier to split than green wood.

Ease of Igniting Firewood - Ignition ability is an important factor wood factor. Low-density wood is easier to light than denser wood. Woods with higher levels of volatile chemicals in their structure, such as conifers, will ignite and burn more readily than those with less volatile chemicals. These woods should be used to start fires where dry high-density woods will provide the heat.

Definitions of Chart Terms

  • Density - wood's dry weight per unit volume. Denser or heavier wood contains more heat per volume. Note that hickory ranks at the top of the list.
  • Green Weight - the weight in pounds of a cord of freshly cut wood before drying.
  • mmBTUs - million British Thermal Units. The wood's actual available heat measured in BTUs.
  • Coaling - wood that forms long-lasting coals are good to use in wood stoves because they allow a fire to be carried over a longer period effectively.

Wood Heating Values Chart

Common NameDensity-lbs/cu.ft.Pounds/cd. (green)Million BTUs/cd.Coaling
Black locust444,61627.9excellent
White oak445,57329.1excellent
Red oak414,88824.6excellent
White ash403,95224.2good
Sugar maple424,68525.5excellent
Yellow birch424,31220.8good
Black walnut354,58422.2good
Silver maple323,90419.0excellent
White pine23NA15.9poor
Ponderosa Pine3,60016.2fair
Eastern Red Cedar312,95018.2poor