The Formula (So You Can Check It)
Two lines of arithmetic
- Area per tree = spacing A × spacing B. For triangular (offset) rows, multiply by 0.866.
- Trees per acre = 4,046.86 ÷ area per tree in m²
- Trees per hectare = 10,000 ÷ area per tree in m²
- Worked: 2.5 × 2.5 = 6.25 m². 4,046.86 ÷ 6.25 = 647 per acre. 10,000 ÷ 6.25 = 1,600 per hectare.
- Conversions: 1 hectare = 2.4711 acres · 1 acre = 0.4047 ha · 1 ft = 0.3048 m
Common Spacings at a Glance
| Spacing | Trees / acre | Trees / hectare | Typical use |
|---|---|---|---|
| 1.5m × 1.5m (5ft) | 1,799 | 4,444 | Very short-rotation biomass |
| 2m × 2m (6.5ft) | 1,012 | 2,500 | Firewood, charcoal, pulpwood |
| 2.5m × 2.5m (8ft) | 647 | 1,600 | Poles — the commonest commercial spacing |
| 3m × 3m (10ft) | 450 | 1,111 | Large poles, pine sawlogs |
| 10ft × 10ft | 436 | 1,076 | US / imperial standard |
| 3m × 4m | 337 | 833 | Sawlogs, agroforestry alleys |
| 4m × 4m (13ft) | 253 | 625 | Sawn timber with thinning |
| 12ft × 12ft | 302 | 747 | US sawtimber |
| 5m × 5m | 162 | 400 | Wide agroforestry, orchards, shade |
| 8m × 8m | 63 | 156 | Fruit and nut orchards |
Square vs Triangular Layout
A square grid puts every tree at the corner of a square. A triangular (offset, quincunx) layout shifts alternate rows by half a spacing, so each tree sits in the gap of the row beside it.
- Triangular fits about 15% more stems at the same tree-to-tree distance, because the packing is more efficient.
- It gives more even canopy closure and slightly better use of the ground.
- The trade-off is that it is harder to set out and harder to run machinery through in straight lines.
- Most commercial plantations use square or rectangular grids for exactly that reason. Triangular suits hand-planted, hand-managed blocks and contour planting on slopes.
Why You Order Fewer Trees Than the Grid Says
The per-acre figure assumes ground that is 100% plantable. Real land is not. Before ordering, deduct:
- Firebreaks around and sometimes through the block
- Access and extraction roads — retrofitting them later means felling trees you paid to grow
- Boundary setbacks from neighbours, roads and any watercourse
- Unplantable ground — rock, gullies, waterlogged hollows, structures
That typically comes to 5–15%. Then add back around 5% as replacement stock for the seedlings that fail in the first weeks — filling gaps promptly is the difference between roughly 80% and 95% final stocking.
Choosing a Spacing
Work backwards from the product, not from what fits:
| If you are growing | Go | Because |
|---|---|---|
| Firewood, charcoal, biomass | Tighter (2m × 2m) | You are selling volume and weight, not stem quality |
| Poles | 2.5m × 2.5m | Fast canopy closure suppresses weeds; straight stems at pole diameter |
| Sawlogs | Wider, plus thinning | Diameter needs growing space and time |
| Intercropping in early years | 3m × 4m or wider | Leaves workable alleys for two to three seasons |
| Poor or shallow soil | Wider than the book says | The site cannot carry full stocking to merchantable size |
Tighter is not more valuable. Beyond what a site can carry, extra stems compete rather than add volume, and you finish with a dense stand of thin stems buyers discount heavily. This is the most expensive misconception in smallholder forestry anywhere in the world.
Frequently Asked Questions
How many trees per acre at 2.5m x 2.5m spacing?
About 647 trees per acre, which is 1,600 per hectare. The arithmetic: 2.5 × 2.5 = 6.25 m² per tree, and 4,046.86 ÷ 6.25 = 647.
Deduct 5–15% for firebreaks, roads and setbacks before ordering, then add about 5% as replacement stock.
How do I calculate trees per acre for any spacing?
Multiply your two spacing distances to get the ground area each tree occupies, then divide 4,046.86 (square metres in an acre) by that figure.
For hectares, divide 10,000 instead. For triangular offset rows, multiply the area per tree by 0.866 first.
How many trees per acre at 10ft x 10ft?
About 436 trees per acre. 10ft = 3.048m, so each tree occupies 9.29 m², and 4,046.86 ÷ 9.29 = 436.
At 12ft × 12ft it is about 303 per acre; at 8ft × 8ft about 681.
What is the difference between square and triangular spacing?
Square puts every tree at the corner of a square. Triangular offsets alternate rows by half a spacing so each tree sits in the gap of the row beside it.
Triangular fits roughly 15% more stems at the same tree-to-tree distance and gives more even canopy closure, but it is harder to set out and harder to run machinery through. Most commercial plantations use square grids for that reason.
Does closer spacing produce more timber?
More stems, not necessarily more value. Beyond what a site can carry, trees compete with each other and you end up with a dense stand of thin stems that buyers discount heavily or refuse.
Value comes from stems reaching saleable diameter. On poorer soils in particular, wider spacing produces a more valuable crop.
How many seedlings should I actually order?
Take the grid figure, deduct 5–15% for firebreaks, access roads, boundary setbacks and unplantable ground, then add back about 5% as replacement stock for early failures.
On one acre at 2.5m × 2.5m that means ordering roughly 610 plants rather than 647. The calculator above does this for you.
Is this calculator only for eucalyptus?
No. The geometry is identical for any species anywhere — eucalyptus, pine, teak, oak, mahogany, coffee, fruit trees, oil palm.
What changes by species is which spacing you should choose, not the arithmetic that turns spacing into a stem count.