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)
Apple
48.7
4,100
26.5
18.55
0.054
Ash
22.3
Aspen
27
2,290
14.7
10.29
0.097
Balsa
4 - 12
Balsam Fir
26.3
2,236
14.3
10.01
0.10
Basswood
24.8
2,108
13.5
9.45
0.106
Beech
44.2
3,757
24
16.8
0.060
Birch
21.7
Black Ash
35.2
2,992
19.1
13.37
0.075
Black Spruce
29.2
2,482
15.9
11.13
0.090
Boxelder
32.9
2,797
17.9
12.53
0.080
Buckeye
13.4
Butternut
15.4
Catalpa
16.4
Cherry
36.7
3,121
20
14
0.071
Chestnut
12.9
Coffeetree
21.6
Cottonwood
24.8
2,108
13.5
9.45
0.106
Dogwood
27.0
Douglas Fir
26.4
East Hop hornbeam
50.2
4,267
27.3
19.11
0.052
Elm
35.9
3,052
19.5
13.65
0.073
Hackberry
38.2
3,247
20.8
14.56
0.069
Hemlock
29.2
2,482
15.9
11.13
0.090
Hickory
50.9
4,327
27.7
19.39
0.052
Ironwood
26.0
Jack Pine
31.4
2,669
17.1
11.97
0.084
Larch - Eastern
18.7
Locust
27.3
Lodgepole pine
19.3
Maple
21.6
Mulberry
25.8
Norway Pine
31.4
2,669
17.1
11.97
0.084
Osage Orange
32.9
Paper Birch
37.4
3,179
20.3
14.21
0.070
Pinon Pine
33.5
Ponderosa Pine
28
2,380
15.2
10.64
0.094
Redcedar - east
19.8
Red Oak
44.2
3,757
24
16.8
0.060
Red Maple
34.4
2,924
18.7
13.09
0.076
Spruce
16.0
Sucamore
19.5
Sugar Maple
44.2
3,757
24
16.8
0.060
Tamarack
38.2
3,247
20.8
14.56
0.069
Tanarack pine
21.2
Yellow Birch
43.4
3,689
23.6
16.52
0.061
Yellow pine
22.0
Walnut - black
21.5
White Ash
43.4
3,689
23.6
16.52
0.061
White Oak
47.2
4,012
25.7
17.99
0.056
White Pine
26.3
2,236
14.3
10.01
0.100
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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