Festmeter

Festmeter, abbreviated fm, is a unit of volume used in forestry and timber trade to express the amount of solid timber. It represents the volume of wood material itself, usually measured in cubic meters of solid wood, independent of how the wood is cut or arranged.

By contrast, the Raummeter (rm) denotes the volume of stacked firewood, i.e., a cubic meter of wood that includes the spaces between pieces. Because wood pieces do not fit perfectly, the solid wood content inside 1 Raummeter is less than a full cubic meter.

In practice, 1 Raummeter contains roughly 0.6 to 0.7 Festmeters of solid wood, depending on factors such as log length, species, and stacking method. Equivalently, 1 Festmeter is typically about 1.4 to 1.7 Raummeters. These relationships mean that fm and rm measure different aspects of the same commodity: fm for the wood material volume, rm for the overall packed volume.

Use and scope: Festmeter is common in Germany, Austria, and other parts of Central Europe for pricing, invoicing, and inventory in the firewood and timber trades. It is not an SI unit, but it is widely understood within the timber industry and among traders. Moisture content and wood density affect weight rather than the defined solid-volume measure, so fm remains a measure of wood content rather than water content.

See also: Raummeter, Ster, Volume measurement in forestry.