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Wood Density and Heat of Combustion Values

With the cost of heating oil, gas, and electricity increasing, a lot more people are installing indoor wood stoves and outdoor wood burners to help offset the utility bills.

Unfortunately for a many of those who live within city limits, restrictions are being placed on what kinds of fireplaces - if any - are allowed. Some ordinances ban all forms of wood heating while others allow only compressed wood pellets.

Benjamin Franklin famously said, "He who cuts his own wood warms himself twice." Anyone who has done gone into the forest to cut down a big maple or oak tree, cut it into fireplace size logs to pile into a truck bed, then take it home and split and stack it knows what he means. I did so often as a teenager. In the last few years I have cut down a lot of trees, but it has been to clear land of clutter; sometimes I even managed to sell the logs.

Here is a table of wood properties that includes BTU values. Pretty much the exact same table is reproduced all over the Web, so here it is again here. The information has not been verified against a reputable source, so be forewarned. Presenting a single value (especially to 3 significant figures), as opposed to a range of values, is unrealistic since wood typically varies widely in density based on water/sap content, growing conditions, and processing. Therefore, numbers should be regarded as an average value.

In the following table, 1 cord = 85 ft3 (the standard cord is defined as a densely stacked 4' x 4' x 8' = 128  pile ft3, so 85 ft3 assumes 65% wood and 35% air space) is used to convert between the "Density" and "Weight of Cord" column. Be aware that the densities used for the wood species varies significantly. The densities used above is for natural dried wood where the average moisture content is approximately 20%.

Heat values of Cords with dry wood can be estimated by adding the green wood cords values with approximately 10%.

Wood
Species
Density of Dry Wood
(lb/ft3)
Weight of Dry Cord
(lb/cord)
Heat Value of Cord (Green Wood)
(MBtu/cord)
Recoverable Heat Value of Cord (Dry Wood)
(MBtu/cord)
Units Needed to Produce
1 Million (cord/Btu's)
Apple48.74,10026.518.550.054
Ash  22.3  
Aspen272,29014.710.290.097
Balsa4 - 12    
Balsam Fir26.32,23614.310.010.10
Basswood24.82,10813.59.450.106
Beech44.23,7572416.80.060
Birch  21.7  
Black Ash35.22,99219.113.370.075
Black Spruce29.22,48215.911.130.090
Boxelder32.92,79717.912.530.080
Buckeye  13.4  
Butternut  15.4  
Catalpa  16.4  
Cherry36.73,12120140.071
Chestnut  12.9  
Coffeetree  21.6  
Cottonwood24.82,10813.59.450.106
Dogwood  27.0  
Douglas Fir  26.4  
East Hop hornbeam50.24,26727.319.110.052
Elm35.93,05219.513.650.073
Hackberry38.23,24720.814.560.069
Hemlock29.22,48215.911.130.090
Hickory50.94,32727.719.390.052
Ironwood  26.0  
Jack Pine31.42,66917.111.970.084
Larch - Eastern  18.7  
Locust  27.3  
Lodgepole pine  19.3  
Maple  21.6  
Mulberry  25.8  
Norway Pine31.42,66917.111.970.084
Osage Orange  32.9  
Paper Birch37.43,17920.314.210.070
Pinon Pine  33.5  
Ponderosa Pine282,38015.210.640.094
Redcedar - east  19.8  
Red Oak44.23,7572416.80.060
Red Maple34.42,92418.713.090.076
Spruce  16.0  
Sucamore  19.5  
Sugar Maple44.23,7572416.80.060
Tamarack38.23,24720.814.560.069
Tanarack pine  21.2  
Yellow Birch43.43,68923.616.520.061
Yellow pine  22.0  
Walnut - black  21.5  
White Ash43.43,68923.616.520.061
White Oak47.24,01225.717.990.056
White Pine 26.32,23614.310.010.100
Willow  13.2  

1 ft (foot) = 0.3048 m
1 lb = 0.4536 kg
1 Btu (British thermal unit) = 1,055.06 J = 2.931x10-4 kWh = 1.055x1010 ergs = 252 cal = 0.293 watt hour


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