Black locust firewood: BTU, weight and seasoning

Heat per cord

Black locust is a hardwood. At 20% moisture, a full cord holds about 28.1 million BTU of heat (29.6 gigajoules). Wetter wood gives less, because part of the heat goes into boiling off the water.

That ranks black locust 208th of the 558 species in our tables, from the hottest down.

Weight and density

A full cord of seasoned black locust (20% moisture) weighs about 4,570 lb (2,070 kg). Freshly cut, the same cord weighs about 5,480 lb (2,490 kg): the difference is water you don't want to burn.

Its specific gravity, a measure of density, is 0.77. Denser wood packs more heat into each cord.

Seasoning time

Split and stacked off the ground, black locust needs at least 12 months to dry to about 20% moisture.

Wood dries faster once it is split and stacked with air around it. A moisture meter on a fresh split face tells you when it is ready.

How it burns

• Ash: low
• Coals: very high
• Burn time: very long

We rate black locust 6 out of 10 as firewood: a good choice.

Similar firewood

Other species to compare with black locust:

• Honey locust: 27.5 million BTU per cord
• Willow oak: 28.1 million BTU per cord
• White oak: 27.5 million BTU per cord
• Chestnut oak: 27.4 million BTU per cord

Where these numbers come from

The heat and weight figures come from our firewood tables, worked out the same way for every species at 20% moisture. See how we calculate them.

Questions