Mountain ash firewood: BTU, weight and seasoning

Heat per cord

Mountain ash is a hardwood. At 20% moisture, a full cord holds about 24.8 million BTU of heat (26.2 gigajoules). Wetter wood gives less, because part of the heat goes into boiling off the water.

That ranks mountain ash 293rd of the 558 species in our tables, from the hottest down.

Weight and density

A full cord of seasoned mountain ash (20% moisture) weighs about 4,030 lb (1,830 kg). Freshly cut, the same cord weighs about 4,840 lb (2,200 kg): the difference is water you don't want to burn.

Its specific gravity, a measure of density, is 0.68. Denser wood packs more heat into each cord.

Seasoning time

Split and stacked off the ground, mountain ash needs at least 10 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: high
• Burn time: long

We rate mountain ash 5 out of 10 as firewood: a good choice.

Similar firewood

Other species to compare with mountain ash:

• Black ash: 19.9 million BTU per cord
• Blue ash: 23.4 million BTU per cord
• European ash: 24.8 million BTU per cord
• Green ash: 23.4 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