Hardwood

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Oak wood ( Quercus robur ), with rows of pores (cross-section)

As Hardwood is wood from deciduous trees called. Deciduous trees per se are also sometimes referred to as hardwoods or hardwoods or deciduous trees.

A distinction is made between coniferous wood , the wood of coniferous trees ( conifers ) belonging to the gymnosperms include (gymnosperms), and deciduous wood, the wood of deciduous trees, all of the class of Bedecktsamer belong (Angiospermae). The reason for this differentiation is, on the one hand, the different systematic assignment of tree species to different groups of seed plants . On the other hand, the two classes of wood types differ significantly in composition, structure and properties.

Composition and structure

Composition of the cell wall in
Central European hardwoods and conifers
substance Softwood Hardwood
cellulose 42-49% 42-51%
Hemicellulose 24-30% 27-40%
lignin 25-30% 18-24% |
Extract substances 2-9% 1-10%
Minerals 0.2-0.8%
Cell types in hardwood

The chemical composition of hardwood is similar to that of softwood (see table). Cellulose makes up the largest proportion with 42-51%, while hemicellulose makes up 27-40 % and lignin 18-24%.

Hardwood shows a greater diversity in its anatomical structure than the relatively monotonous structured softwood. In contrast to coniferous wood, where the tracheids fulfill a double function (consolidation, water conduction), a functional separation has occurred in hardwoods. There are wide-lumen vessels for the transport of water and nutrients from the root to the crown, the trachea . The mechanical strengthening function is essentially taken over by the wood fibers, which can be divided into libriform fibers and fiber tracheids. In addition, vascular tracheids and vasicentric tracheids can occur as additional cells in certain types of wood; these represent an intermediate stage in the development from the tracheid to the special water-guiding element. The storage of nutrients takes place in the longitudinal parenchyma or in the ray parenchyma. The figure opposite gives an overview of the different types of cells in hardwood.

Use and meaning

Hardwood, like softwood, can be used as a building material ( timber , wood-based material , etc.), furniture wood , raw material for paper production or as an energy source ( firewood , energy wood ). Softwoods such as B. Spruces are preferred because of their rapid growth. In addition, they usually have a straighter growth and are therefore easier to process into sawn timber with less waste .

In 2007 and 2008, respectively, the proportion of hardwood in Germany was 17.1% (13.1 million m 3 ) and 22.7% (12.6 million m 3 ) of the total felling (76.7 and 55.4 respectively Million m 3 ). In contrast, the proportion of deciduous forests in the German forest area is around 41%. The proportion of beeches is 14.8%, oaks 9.6% and other deciduous trees 15.7%.

See also

literature

  • Wilhelm Nultsch : Allgemeine Botanik , Georg Thieme Verlag Stuttgart, New York, 1996, 10th edition

Web links

Individual evidence

  1. ^ A b Nultsch, Wilhelm : Allgemeine Botanik , Georg Thieme Verlag Stuttgart, New York, 1996, 10th edition
  2. ↑ (according to Holz-Lexikon)
  3. ↑ www.holzwurm-page.de: Microscopic cell structure , information on the structure of hardwood and softwood, including images, accessed on April 2, 2010
  4. ↑ Important characteristics of hardwoods ( memento of June 10, 2007 in the Internet Archive ), information including images on the microscopic structure of wood, accessed on April 2, 2010
  5. ^ Dietger Grosser : The woods of Central Europe - A microphotographic wood atlas , Springer Verlag, 1977. ISBN 3-540-08096-1
  6. ^ Forestry - Logging , accessed on April 2, 2010
  7. ↑ Forest distribution in Germany: Tree species distribution - an ecological diversity ( Memento from June 3, 2010 in the Internet Archive ), accessed on April 2, 2010
  8. ↑ www.bundeswaldinventur.de: Areas - proportion of deciduous trees is increasing , Second National Forest Inventory in 2002 (BWI2), The most important in brief , accessed on April 2, 2010