Spanish fir firewood: BTU, weight and seasoning

Heat per cord

Spanish fir is a softwood. At 20% moisture, a full cord holds about 17.4 million BTU of heat (18.4 gigajoules). Wetter wood gives less, because part of the heat goes into boiling off the water.

That ranks Spanish fir 491st of the 558 species in our tables, from the hottest down.

Weight and density

A full cord of seasoned Spanish fir (20% moisture) weighs about 2,760 lb (1,250 kg). Freshly cut, the same cord weighs about 3,750 lb (1,700 kg): the difference is water you don't want to burn.

Its specific gravity, a measure of density, is 0.47. Denser wood packs more heat into each cord.

Seasoning time

Split and stacked off the ground, Spanish fir 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: moderate
• Coals: moderate
• Burn time: moderate

We rate Spanish fir 2 out of 10 as firewood: it burns, but denser species give more heat for the same work.

Similar firewood

Other species to compare with Spanish fir:

• Balsam fir: 15.0 million BTU per cord
• California red fir: 16.3 million BTU per cord
• Douglas fir: 19.1 million BTU per cord
• European silver fir: 15.6 million BTU per cord

Where it grows

Spain and Morocco

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