Hectares to Acres

Reading a Hectare Timber Figure in Acres

Almost every forest statistic published outside the United States arrives in hectares. FAO forest resource assessments, Canadian and Scandinavian inventory summaries, plantation prospectuses, REDD+ and carbon project documents, EU woodland grant schemes — all of them count area in hectares and stocking per hectare. A timber buyer, woodland manager or land-trust analyst who prices stumpage in dollars per acre and thinks in stems per acre has to move that figure across before it means anything.

Conversion factor: 1 hectare = 2.471053814672 acres, so multiply hectares by 2.4711. A 25 ha plantation compartment is 61.78 acres — at a stumpage bid of $1,800 per acre that block is worth about $111,200.

Where Hectare Figures Come From

International inventory reporting

FAO's Global Forest Resources Assessment, national inventories in Canada, Sweden and Finland, and every deforestation headline are compiled in hectares, because the hectare is the standard land unit of the metric system.

Carbon and conservation projects

Carbon methodologies quote tonnes of carbon or CO₂ equivalent per hectare, and land trusts describe protected blocks the same way. A US easement deed written in acres has to reconcile with those figures.

Growth models and yield tables

European and Antipodean yield tables give mean annual increment in cubic metres per hectare per year. Converting the block area is the first step to a per-acre volume a US mill quote can use.

Mapped compartments and stand shapefiles

Forestry GIS layers usually carry a hectare attribute per compartment. Converted to acres, the same polygon table drives harvest scheduling and a per-acre bid sheet.

Turning a Compartment Area into a Bid Sheet

The block area is the multiplier behind every other number on a timber sale — volume, stems, carbon and price all hang off it.

Enter the compartment area in hectares

Type the hectare figure from the stand table or the shapefile attribute — 8.4, 25, 143.6 — and the acre value appears beside it. Spaces are ignored, and a comma decimal mark from a European report is read correctly.

Convert the per-hectare stocking separately

Stand figures move the opposite way from the area: divide a per-hectare figure by 2.4711 to get per acre. A stand at 1,600 stems/ha carries 647 stems/acre; 250 m³/ha of standing volume is 101.2 m³/acre.

Lift the acreage into the sale schedule

The copy button puts a plain number on the clipboard with no unit attached, ready for a compartment register, a cruise summary or a stumpage worksheet. Ctrl + C in a field does the same.

Send an acre figure back to a metric partner

Reporting a US property into a European fund or a carbon registry runs the other way: press the swap button (↔) and a 320-acre woodland reads as 129.5 ha.

Net versus gross woodland: a hectare figure from a mapped boundary usually includes rides, streams, rock and unstocked edges. Stocked area can be 10–20 per cent less, so a 25 ha compartment (61.78 ac) may hold only about 52 productive acres.

Stand Measures per Hectare and per Acre

The stocking, volume and carbon figures a metric forest report prints, each shown beside the per-acre equivalent a US cruise sheet or mill bid uses. One square metre per hectare of basal area is exactly 4.356 square feet per acre, which is where the odd-looking basal area numbers come from.

Stand measure	Per hectare	Per acre	Where it shows up
Establishment density	2,500 stems	1,012 stems	Conifer planting at 2 m spacing
Pole-stage stocking	1,600 stems	648 stems	Before first thinning
Retained stocking	900 stems	364 stems	After a thinning operation
Basal area, light	20 m²	87.1 ft²	Shelterwood or savanna target
Basal area, fully stocked	30 m²	130.7 ft²	Managed conifer stand
Standing volume	250 m³	101.2 m³	Mature plantation at clearfell
Mean annual increment	12 m³/yr	4.86 m³/yr	Yield class of a productive site
Carbon stock	100 t C (367 t CO₂e)	40.5 t C (148 t CO₂e)	Above-ground biomass estimate

Every row in the acre column is the hectare figure multiplied by 0.4047, because a smaller box holds proportionally less. Only the block area itself grows by 2.4711 — which is why a stand can look thinner per acre and still be the same forest.

Handling a Stand Table on This Page

Step through a compartment register

Retype each compartment area in turn — 8.4, 25, 143.6 hectares — and the acre column builds itself without any clearing or extra clicks.

Report a US woodland the metric way

Swapping the direction covers the return trip, which is what a carbon registry submission or a European buyer's data request needs.

Cruise plots and sample squares

Both dropdowns list every area unit, so a 0.04 ha sample plot or a 400 m² regeneration quadrat converts on the same screen as the compartment.

Figures a cruise sheet will accept

Results run to eight decimals for small plots, and the copy button strips the unit so the value pastes into an inventory spreadsheet unchanged.

Woodland and Timber Questions

How much error does the "a hectare is about 2.5 acres" shortcut introduce?

About 1.17 per cent too high. The true figure is 2.4711, so on a 500 ha estate the shortcut gives 1,250 acres against a true 1,235.53 — an overstatement of 14.47 acres. On a small woodlot it is invisible; on a stumpage sale priced at $1,500 an acre it is over $21,000 of imaginary timber.

How do I convert a basal area of 30 m²/ha into the square feet per acre a US forester expects?

Multiply by 4.356 — that is 130.7 ft²/ac. The factor is exact: an acre is 43,560 ft² and a hectare is 10,000 m², so one square metre in a hectare is 4.356 square feet in an acre. Going back, divide the ft²/ac figure by 4.356; a well-stocked 120 ft²/ac stand is 27.5 m²/ha.

Do metric and imperial cruise plots line up?

Not quite. The classic US fixed plot is one-tenth of an acre, which is 0.0405 ha, while metric crews normally use a round 0.04 ha plot — 0.0988 acre. The expansion factors therefore differ: 10 per acre against 25 per hectare. Prism cruising differs too: a BAF of 10 ft²/ac equals 2.296 m²/ha, whereas a metric factor of 2 m²/ha is 8.712 ft²/ac.

A carbon project reports 367 t CO₂e per hectare — what is that per acre?

148 tonnes of CO₂ equivalent per acre, from multiplying by 0.4047. That figure comes from a carbon stock of about 100 t C/ha, since carbon is converted to CO₂ equivalent by the ratio of molecular masses, roughly 3.67. Per acre the stock is 40.5 t C. Registries expect the hectare form, so keep the conversion for internal comparison only.

Why does a plantation prospectus quote area in hectares but price in dollars per acre?

Because the two halves come from different places. The area is inherited from a metric survey, GIS layer or national inventory, while the price benchmark comes from a timberland market that still trades in dollars per acre. Convert once, at the top of the sheet, and carry both figures through — a 143.6 ha estate is 354.84 acres, and mixing the two by mistake would misstate its value by a factor of nearly two and a half.