The land a household needs for coppice fuel is its annual demand divided by the yield per hectare: 5-10 tonnes at 3-5 tonnes a hectare is 1-3.3 hectares, or about 2.5-8 acres. If the real yield is nearer the 2-3 tonnes a hectare implied by the parent article’s own worked example, the figure rises to 1.7-5 hectares, and ten families need 10-30 hectares, not the 10-20 the parent states.
Part of Coppicing & Fuel Management
Working out how much coppice a household or group needs for fuel self-sufficiency, and what that land is no longer doing.
The Parent’s Figures
The parent article says a single family needs 1-3 ha (2.5-7.5 acres) of managed coppice for complete fuel self-sufficiency, and a group of ten families needs 10-20 ha (25-50 acres), assuming efficient stoves and good woodland management.
Worked Example: Demand Over Yield
Inputs: household demand 5-10 t/yr (Household Energy Needs); the parent’s yields (hazel and oak 3-5, ash 4-7, willow 8-15 t/ha/yr); 1 ha = 2.471 acres.
| Species | Hectares: demand ÷ yield | Acres |
|---|---|---|
| Willow | 5 ÷ 15 = 0.33 to 10 ÷ 8 = 1.25 | 0.8 to 3.1 |
| Ash | 5 ÷ 7 = 0.71 to 10 ÷ 4 = 2.5 | 1.8 to 6.2 |
| Hazel or oak | 5 ÷ 5 = 1.0 to 10 ÷ 3 = 3.3 | 2.5 to 8.2 |
| Parent example yield 2-3 | 5 ÷ 3 = 1.7 to 10 ÷ 2 = 5 | 4.1 to 12.4 |
Each acre figure is the hectares times 2.471. The “parent example” row uses the 2-3 t/ha/yr implied by its 2 ha wood giving 4-6 t a year; that is lower than the parent’s own hazel and ash yields, so the true figure for a given wood is uncertain until you measure it (Yield Calculations).
Groups
For ten families the parent’s own per-family range multiplies to 10 × 1 = 10 ha to 10 × 3 = 30 ha. The 10-20 ha it states fits only the lower half of the per-family range, so use 10-30 ha unless your yield is at the top of the range. That is 25-74 acres (10 × 2.471 to 30 × 2.471).
What The Land Is Not Doing
A hectare in coppice is a hectare not growing crops or pasture. This guide gives no food yield to compare, so set the coppice area against the best use of that same ground on your own land. Coppice has an advantage on land that is too wet, steep or poor for crops, where willow, alder and hazel can grow. Fuel land also needs space for access tracks and standards, which the parent does not count; add a margin.
Method
Step 1: Fix the demand in tonnes of air-dried wood.
Step 2: Choose a yield from measurement or the low end of the table.
Step 3: Compute the hectares and add a margin for tracks, standards and poor corners.
Step 4: Compare with the land available and fill any shortfall with other fuel (Combining with Other Fuels).
Common Mistakes
- Using the best yield. A shortfall means a cold winter.
- Ignoring the start-up years. Coppice gives nothing at first.
- Counting poor land as full yield.
Safety
Short of fuel, people burn what is unsafe
If the coppice falls short, the temptation is to burn unseasoned or unknown wood, or to cut the stools early and kill them. Keep a reserve, and do not shorten the rotation to make up the gap (Cutting Cycles).
What’s Next
- Learn next: Combining with Other Fuels — closing the gap
- Combine with: Fuel Budgeting — the full plan