Downy birch firewood: BTU, weight and seasoning

Heat per cord

Downy birch is a hardwood. At 20% moisture, a full cord holds about 22.8 million BTU of heat (24.1 gigajoules). Wetter wood gives less, because part of the heat goes into boiling off the water.

That ranks downy birch 344th of the 558 species in our tables, from the hottest down.

Weight and density

A full cord of seasoned downy birch (20% moisture) weighs about 3,710 lb (1,680 kg). Freshly cut, the same cord weighs about 4,450 lb (2,020 kg): the difference is water you don't want to burn.

Its specific gravity, a measure of density, is 0.62. Denser wood packs more heat into each cord.

Seasoning time

Split and stacked off the ground, downy birch needs at least 9 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 downy birch 5 out of 10 as firewood: a good choice.

Similar firewood

Other species to compare with downy birch:

• Paper birch: 22.3 million BTU per cord
• River birch: 21.5 million BTU per cord
• Silver birch: 23.4 million BTU per cord
• Yellow birch: 25.2 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