A choose-and-cut farm that plants everything at once sells everything at once and then has nothing for eight years. A sustained harvest means planting the same block every single year, and the size of that block is the harvest target divided by the density — with the total land requirement following straight from the rotation length.
3,000 trees a year at 1,200 per acre is a 2.5-acre block — and an eight-year rotation means 20 acres in production at all times.
The example
Three farm plans at different scales, each sized for a steady annual harvest.
| A | B | C | D | E | F | |
|---|---|---|---|---|---|---|
| 1 | Plan | Trees per year | Trees per acre | Rotation yrs | Acres per year | Acres in production |
| 2 | Farm A | 3,000 | 1,200 | 8 | 2.50 | 20.0 |
| 3 | Farm B | 5,000 | 1,000 | 9 | 5.00 | 45.0 |
| 4 | Farm C | 1,800 | 1,200 | 7 | 1.50 | 10.5 |
The formula
Two divisions and a multiplication, and the second column is the one that surprises people:
How it works
The rotation is what makes this different from a normal density calculation:
B2/C2is the block you plant every spring. Trees per acre comes from spacing — a 5 x 6 foot grid is roughly 1,450 per acre before roads and headlands, so 1,200 is a realistic planted density.*D2gives the land tied up. A tree takes seven to nine years to reach a sellable height, so at any moment you are holding a block for every year of the rotation.- Every one of those blocks is a different age. The oldest one is this year's harvest, the youngest one went in last month, and the rotation length is exactly the number of blocks.
- Add the loss allowance separately. This calculation sizes the ground; grossing up for seedling mortality sizes the order, and they are different numbers.
Add 10–15% for roads, turnarounds, the parking field, and the ground that is too wet to plant. The formula gives planted acres, not deeded acres.
Try it: interactive demo
Enter your annual harvest target, planting density and rotation length.
Variations
Trees standing at any moment
Multiply the annual target by the rotation. This is the inventory number an insurer or a lender will ask for.
Harvest a fixed acreage supports
Turn it around when the land is what you have: acres over rotation years, times density, is what the farm can sell annually forever.
Pitfalls & errors
Rotation length is not one number across species. Fraser fir commonly runs 8–10 years to a 7-foot tree while some pines finish in 6 — a mixed farm needs a row per species, not a blended average.
Replant the harvested block the following spring, not the same season. Stump removal and a fallow interval are normal practice, and skipping them quietly shortens your effective rotation.
Do not confuse acres in production with acres owned. The formula returns planted ground only; roads, the wreath barn, the parking field and the unplantable corners are on top of it.
Practice workbook
Frequently asked questions
What if I am starting a farm from scratch?
Does replanting into the same rows change the numbers?
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