Solid cubic meters

Metric room dimensions for wood

The solid cubic meter ( fm or  F ) is a spatial measure for round wood , i.e. usually unprocessed logs from felled trees. One solid cubic meter corresponds to one cubic meter  (m³) of solid wood, i.e. H. without gaps in the layering. For an approximately precise calculation, each individual trunk or each piece of trunk must be measured.

The corresponding dimension with gaps in stacked logs or split logs is the cubic meter  (rm, R).

Admissibility of the unit of measure

In the wood industry practice, the solid cubic meter is generally used as a measure of space.

• In the Federal Republic of Germany - according to the implementing ordinance to the law on units in metrology of June 26, 1970 - the unit "solid cubic meter" was used as a "special name" for the cubic meter in "volume information for long timber , calculated from trunk length and trunk diameter" until 31. December 1977 legally permissible. Since then, legally permissible volume units have only been cubic meters and liters, as well as the decimal smaller or multiple parts thereof designated with SI prefixes.
• In Austria the solid cubic meter is defined in the ÖNORM L 1021 measurement of round timber .
• The cubic meter is still used in the timber industry and wood industry regulations.

detection

Derived from the volume calculation of a straight circular cylinder (base area × height), the solid cubic meter is calculated as the product of the trunk length and the circular area in the middle of the trunk length (without oversize) ( Huber's formula ).

V = / 4 × d 2 × L ${\ displaystyle \ pi}$

• V: volume in solid cubic meters
• ${\ displaystyle \ pi}$: 3.1416 ( circle number )${\ displaystyle \ approx}$
• d: Diameter: In Germany, the diameter is measured in the middle of the trunk length without excess. For logs up to 19 cm without bark, measurements are taken once horizontally, for logs with a larger diameter, measurements are taken twice at right angles to each other and the two values ​​are averaged. Contrary to the rounding rule , each individual measurement is generally rounded down to whole centimeters. From this the mean is formed and rounded off again to whole centimeters.
• L: (Order) length in meters: The trunk length is rounded off to whole meters, half meters or decimeters. In addition, the trunk length must be overdimensioned by at least 1%, which is not taken into account in the measurement. Depending on the agreed measurement rule, a trunk that has an actual trunk length of 9.94 m, for example, can have an "invoiced length" of 9.0 m, 9.5 m or 9.8 m.

It must be noted and stated whether it is solid cubic meters with bark (top right) or without bark (top right). If the mean diameter was measured in bark and solid cubic meters were offset without bark, then a so-called "bark deduction" must be carried out using a table to calculate the fixed content.

The calculated volume is rounded to at least 2 decimal places. The more the trunk shape resembles a cylinder , the closer the fixed content corresponds to the actual trunk volume.

After most of the log as now in Germany with harvesters ( harvesters is worked), the volume determination and quality assessment can be found mostly in the sawmill on stationary, calibrated rather than plants. For the measurement and sorting of logs in the sawmill (plant measurement), the framework agreement for the plant measurement of logs was concluded between the German Forestry Council and the Association of the German Saw and Wood Industry (VDS) as a nationwide set of rules for automated log measurement. This replaces the joint catalog of requirements for factory surveying from 1994. The practice of surveying in the forest was essentially adopted.

Further wood measurements based on the solid meter

• Storage cubic meter (Vfm); is measured with bark, specifying the wood supply of a standing tree or a standing forest or tree population and only records the wood above the so-called solid wood border (seven centimeters in diameter, measured at the weaker end).
• Harvesting cubic meters (m³); corresponds to one cubic meter of storage minus approximately ten percent loss of bark and ten percent loss during the timber harvest. There are tree-species-specific conversion factors for converting bulk cubic meters into harvested cubic meters. The addition D. o. R. means solid wood without bark, i.e. with a diameter of at least seven centimeters.
• Layer cubic meters (Sfm); is 1 m³ stacked, short cut logs ready for the oven. Due to the short log length, there are fewer and smaller air spaces than with the cubic meter. In contrast to the bulk cubic meter, the wood is neatly stacked.

The following designation is common in the raw wood industry:

 Unit of measurement Status Measurement and billing measure F. M (with bark)  O (without bark) M (with bark)  O (without bark)
The condition is the form of delivery, the measurement and billing measure the desired output quality for further processing:

For example, FMO denotes solid cubic meters, delivered with bark, used without bark.

This information is needed for conversion factors in practice: For the weight measurement of industrial wood (i.e. grinding and pulpwood industry as well as in the bioenergy sector ), 475 kg / FMO are used for conversion for spruce / fir, 707 kg / FMO for beech (red beech) and 427 kg / FOO or 650 kg / FOO.

literature

• Horst Kramer, Alparslan Akça: Guide to forest measurement. 3rd, expanded edition. Sauerländer, Frankfurt am Main 1995, ISBN 3-7939-0830-5 .