Black spruce firewood: BTU, weight and seasoning

Heat per cord

Black spruce is a softwood. At 20% moisture, a full cord holds about 16.9 million BTU of heat (17.8 gigajoules). Wetter wood gives less, because part of the heat goes into boiling off the water.

That ranks black spruce 502nd of the 558 species in our tables, from the hottest down.

Weight and density

A full cord of seasoned black spruce (20% moisture) weighs about 2,670 lb (1,210 kg). Freshly cut, the same cord weighs about 3,630 lb (1,650 kg): the difference is water you don't want to burn.

Its specific gravity, a measure of density, is 0.45. Denser wood packs more heat into each cord.

Seasoning time

Split and stacked off the ground, black spruce needs at least 11 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: moderate
• Coals: moderate
• Burn time: moderate

We rate black spruce 1 out of 10 as firewood: it burns, but denser species give more heat for the same work.

Similar firewood

Other species to compare with black spruce:

• Engelmann spruce: 14.4 million BTU per cord
• Norway spruce: 15.2 million BTU per cord
• Red spruce: 16.3 million BTU per cord
• Sitka spruce: 15.9 million BTU per cord

Where it grows

Northern North America

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