Wood

Wood is the hard, dry, fibrous, cellulose-based structural material of plants, particularly trees. Not to be confused with the dried, sawn, finished material: lumber.

Measures

Volume

A typical measure of wood is a cord. This is defined as 128 cubic feet (3.62 m³). Typically constructed as a 4 foot high, 4 foot wide, 8 foot long stack, where the logs are at least three inches in diameter, and four feet long.

Mass

• A cord of wood weighs 1-2 tons, depending on wood type, bark content, and dryness

Fuel value

• Bone dry fuel value: 18-22 MJ/kg
• Air dry fuel value: 15-17 MJ/kg

The Energy budget says 300GJ/yr for america, requiring 15-20t of wood /yr. Unlikely. :)

Production

Woodlot

Woodlot values imply sustainable harvest: a natural environment, managed with the intent to sustainably harvest wood.

• In a moderate climate, softwood forests can produce almost 9m³ per hectare. (1 cord/acre)
• In a harsher climate, hardwood forests may produce 1.5m³ per hectare. (0.16 cord/acre)

NB: The hardwood/softwood production differences are offset somewhat by the lower fuel value for softwood, so the GJ/acre/year varies somewhat less.

Clearcut

Clearcut values indicate reducing the forest completely to bare dirt or pasture, with the commensurate time to regrow the area.

• Clearcutting may produce between 11 and 110 cords per acre

See Also

• wood distillation