Oak (rotation 15-25 years), beech (15-20), hornbeam (15-20) and ash (10-15) are the dense coppice species: their wood holds the most heat per cubic metre, so a stack lasts longer in the stove. Ash seasons fastest, in 3-4 months, oak slowest at 18-24 months, and none of them should be burned unseasoned.
Part of Coppicing & Fuel Management
The dense hardwood coppice species: rotation, seasoning time and why density, not a higher heat per kilogram, makes them better stove fuel.
What “High Heat” Really Means
Per kilogram of dry wood, species differ little. What differs is density: a cubic metre of oak contains more wood than a cubic metre of willow. The parent lists these species for maximum heat output per log.
- Oak (Quercus): dense, long-burning, excellent coals; slow growing but large yields per stool. Rotation 15-25 years.
- Beech (Fagus): nearly equal to oak. Rotation 15-20 years.
- Ash (Fraxinus): splits easily, seasons fastest; the parent says it can be burned green. Rotation 10-15 years.
- Hornbeam (Carpinus): the densest common firewood. Rotation 15-20 years.
- Hickory, if available: outstanding fuel and edible nuts.
One caution on beech: it is generally reported to regrow from low stumps less reliably than ash, hazel or oak, and old beech is often pollarded rather than coppiced. This comes from general forestry knowledge and was not checked against a source here, so cut a few stools first and see whether they sprout before committing a coupe.
”Ash Burns Green” Needs A Correction
Ash has less water than many woods when freshly cut and seasons quickly, but it is still wet when felled. Using the net-heat formula (net = 18.5 × (1 − w) − 2.44 × w, MJ/kg) from BTU Content Compared to Wood:
- At 40% moisture (wet basis): 18.5 × 0.6 − 2.44 × 0.4 = 11.1 − 0.98 = 10.1 MJ/kg.
- At 20%: 18.5 × 0.8 − 2.44 × 0.2 = 14.8 − 0.49 = 14.3 MJ/kg.
- Burning at 40% loses (14.3 − 10.1) ÷ 14.3 = 29% of the heat, and runs a cooler fire that deposits more tar in the flue.
Treat green ash as an emergency fuel, not a normal one; the 40% moisture figure is an assumed example, and unseasoned ash can be higher.
Seasoning Times (Parent Article)
Hardwoods 12 months, oak 18-24 months, ash 3-4 months. See Seasoning & Drying.
Common Mistakes
- Planting only slow species. First cut in 15-25 years leaves a gap; mix in hazel or ash.
- Burning unseasoned oak. It is wetter than it looks and gives smoke and tar.
- Stacking oak for one season. Oak needs the longest.
Safety
Dense wood is heavy and splits hard
Large oak and beech billets are heavy to lift and split with an axe or maul; use a chopping block, keep your feet clear of the swing, and wear boots. Burning unseasoned dense wood in a closed stove produces far more carbon monoxide and chimney tar than seasoned wood (Carbon Monoxide Risks).
What’s Next
- Learn next: Seasoning & Drying — getting dense wood burnable
- Combine with: Cutting Cycles — fitting long rotations into a plan