Cubic meter

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Metric room dimensions for wood

The cubic meter (rm) is a measure of space for wood and the most common unit of measurement in the trade in firewood . One cubic meter (1 m³ ) corresponds to a cube with an edge length of one meter (1 m), i.e. a volume of one cubic meter (1 m³), ​​pieces of wood stacked in parallel, including the gaps in the layering.

The ster (st) (from the ancient Greek στερεός stereos , 'rigid, hard, firm') is an older southern German spatial measure, which describes a cubic meter of logs (split and layered pieces) 1 meter long. However, colloquially, a cubic meter of shorter logs is sometimes referred to as a ster. Furthermore, in today's parlance, a fathom of wood is defined as the amount of 3 stars.

The loose cubic meter (srm) corresponds to a loose amount of wood of one cubic meter.

A solid cubic meter (fm) describes a quantity of wood that contains one cubic meter of wood after subtracting the gaps.

Cubic meter

A cubic meter long logs

A cubic meter of firewood is a stack of split or unsplit pieces of wood cut to the same length. The pure proportion of wood in a cubic meter of wood depends on the shape and length of the pieces of wood and, to a lesser extent, on the care taken when stacking (putting on) and is given in solid cubic meters. Therefore, when selling, the specification in cubic meters alone is not unambiguous, but the shape and length of the pieces of wood or the specification in solid cubic meters are also required. If firewood is prepared directly in the forest, the wood is cut to length to one meter, split and stacked at a height of 1 meter so that the forester or forest owner can then easily measure the amount of wood in cubic meters by measuring the length of the stack (allowance). After measuring, the wood is sawn to the length of the stove. A cutting length of 25 cm, 33 cm or 50 cm has become common here today, corresponding to the combustion chamber of the usual fireplace and tiled stoves, wood ovens, etc.

The Bavarian State Institute for Forests and Forestry defines a cubic meter as follows, whereby the values ​​are to be understood as reference values:

  • Plywood, 100 cm long, unsplit (round pieces): approx. 0.71 fm
  • Plywood, 100 cm long, split (logs): approx. 0.63 fm
  • Logs, 33 cm long, layered: approx. 0.71 fm
  • Logs, 33 cm long, poured loosely, beech: approx. 0.50 fm
  • Logs, 33 cm long, poured loosely, spruce: approx. 0.45 fm

Bulk cubic meter

In trade and transport, proper stratification is often uneconomical, e.g. B. for split firewood or wood chips . The appropriate material is then simply poured out , which leaves significantly more air in one cubic meter of wood than with proper layering. One then speaks of the bulk cubic meter or bulk meter , unit symbol srm.

For beech logs, one cubic meter corresponds to approx. 0.5 cubic meters, for spruce logs approx. 0.45 cubic meters.

For wood chips, one cubic meter corresponds to approx. 0.4 fm.

The bulk cubic meter is not an official measure; The amount of wood contained varies depending on the density of the bed. This results from the fact that logs of different thicknesses, lengths and types of wood leave different amounts of empty space after being poured.

Conversion table

row Solid cubic meters Plywood, 100 cm,


Plywood, 100 cm,


Logs, 33 cm,


Logs, 33 cm,

poured, beech

Logs, 33 cm,

poured, spruce

1 1 fm 1.4 rm 1.6 rm 1.4 rm 2.0 srm 2.2 srm
2 0.71 fm 1 rm 1.14 rm 1 rm 1.43 srm 1.57 srm
3 0.63 fm 0.88 1 rm 0.88 rm 1.25 srm 1.38 srm
4th 0.5 fm 0.7 rm 0.8 rm 0.7 rm 1 srm 1.1 srm
5 0.45 fm 0.64 rm 0.73 rm 0.64 rm 0.91 srm 1 srm

Reading examples (line by line):

  • Row 1: 1 cubic meter of long wood results in 1.6 cubic meters of plywood, 100 cm, split after sawing to 100 cm, splitting and placing. After sawing to 33 cm and placing it, 1.4 rm billets, 33 cm, layered.
  • Row 2: 1 rm logs, 33 cm, layered, contains 0.71 scm wood. For production you need 1 rm plywood, 100 cm, unsplit or 1.14 rm plywood, 100 cm, split. When piled up, they result in 1.43 m3 (beech) or 1.57 m3 (spruce).
  • Row 3: 1 cubic meter of plywood, 100 cm, split, results in 0.88 cubic meters of logs, 33 cm, layered after sawing and placing, and contains 0.63 cubic meters of wood.
  • Row 4: 1 cubic meter of logs, 33 cm, poured, beech, results in 0.7 cubic meters of logs, 33 cm, layered, and contains 0.5 cubic meters of wood.

Regulations in Germany

In Germany until December 31, 1977, according to the implementing ordinance to the law on units in metrology of June 26, 1970, the cubic meter (abbreviation Rm ) was legally permissible as a special name for the cubic meter in "volume information for layered wood including the air spaces".

Since June 26, 1970, only the cubic meter, the liter and all decimal parts and multiples thereof are legally permissible units of volume in Germany.

Individual evidence

  1. a b Provision and sale of logs . Bavarian State Institute for Forests and Forestry.
  2. Sales dimensions . Bavarian State Institute for Forests and Forestry
  3. Firewood: log wood unit of measure .
  4. Leaflet 20 - Ratios between the room dimensions ( Memento of November 4, 2014 in the Internet Archive ), (PDF; 389 kB) Bavarian State Institute for Forests and Forestry, July 2014; accessed on August 12, 2015.
  5. Units and Time Act (PDF) in the version published on February 22, 1985 ( Federal Law Gazette I p. 408 ), last amended by Article 4, Paragraph 68 of the Act of August 7, 2013 ( Federal Law Gazette I p. 3154 ) has been.