Larch wood
| Larch wood | |
|---|---|
 |
|
| Tree species | |
| origin |
Eurasia, North America |
| colour |
reddish brown to reddish brown |
| Material properties | |
| Bulk density mean | European larch 550-590 kg / m 3 |
| Raw density limit values | European larch 400–850 kg / m 3 |
| Axial shrinkage | 0.3% |
| Radial shrinkage | 3.3% |
| Tangential shrinkage | 7.8% |
| Flexural strength | 93 N / mm 2 |
| Compressive strength | 48 N / mm 2 |
| tensile strenght | 105 N / mm 2 |
| Thermal conductivity | up to 0.12 W / (m K) |
| Fuel properties | |
| Calorific value | 4.4 kWh / kg |
As larch wood is wood of different species of larch ( Larix ) denotes, as the timber is used. The approximately 20 species of larch ( Larix ) are deciduous trees and shrubs that are widespread in northern Eurasia and North America .
Larch wood is mainly used as construction and furniture wood, much less often it is used as firewood . Also of economic interest are mainly the European larch ( Larix decidua ), the Siberian larch ( Larix sibirica ) in Eurasia and North America, the Ostamerikanische ( Larix laricina ) and the Western larch ( Larix occidentalis ). There are also lower or regional significance other species, including those of the Japanese island of Honshu native Japanese larch ( Larix kaempferi ), which is partly cultivated in Europe, and bred from the European and Japanese larch hybrid larch ( Larix eurolepis ).
The age of use of the European larch is between 100 and 140 years, whereby the specimens in high altitudes are between 200 and 400 years old when unused.
Designations
The wood of the European larch can vary greatly depending on its origin and the weather conditions in its location. A distinction is made between the types of wood in particular between stone or mountain larches , which come from mountainous areas and have an even, narrow-ringed wood, and lawn or meadow larches from low-lying areas with a broad-ringed, spongy structure. All larches that are artificially grown outside of the Alps are also often referred to as lowland larches . There are also names such as alpine larch , Tatra larch , Sudetenlärche and Poland larch , which relate directly to the four original distribution areas of the European larch.
Larches with a very pronounced red color in the wood are also known as yoke or blood larch .
properties
The larch, like the pine and the Douglas fir , has a marked difference between heartwood and sapwood . The latter is light yellow to reddish, the heartwood is much darker, bright red to reddish brown. The trunk is cored for use. This means that the core is separated from the sapwood. The sapwood is only a few centimeters thick at the time of use and is not used as construction timber.
As a special feature, the heartwood has numerous pencil-thick and dark knots that are laid out early and then grown into the wood as dry nail knots . The light early wood is sharply set off in the annual rings against the darker late wood . The denser and heavier latewood content is between 1/3 and 1/4 of the annual ring width in a one to two millimeter wide annual ring. As a result, the individual annual rings are sharply demarcated from one another and form a distinctive flat structure in the tangential section and a stripe of the wood in the radial section . The resin canals can be seen as small bright points and the wood rays are very fine and barely visible.
Habit of the European larch
Trunk cross-section of the European larch
Larch wood is the heaviest and hardest wood of the European coniferous timber and is only surpassed by the rarely used yew . It has an average bulk density of 550 to 590 kg / m 3 (depending on the humidity), with the greatest density being achieved due to the high proportion of latewood in woods with an average annual ring width of one to two millimeters. Accordingly, compared to other types of softwood, larch wood has very good strength values, at the same time high toughness and low swelling and shrinking behavior. On the other hand, compared to spruce and pine , the larch often tends to twist, which influences the standing characteristics. The heartwood is weatherproof when used without contact with the ground and its durability is comparable to oak wood , especially under water . If it comes into contact with the ground, it is classified in the standard DIN EN 350-2 ( natural durability ) as less to moderately permanent.
use
Use of the wood
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Larch wood is mainly used in furniture construction and as construction wood in interior construction as well as for residential buildings, bridges and other buildings. It is offered and processed in the form of round timber, sawn timber and sliced veneer . It can be used almost anywhere where other softwoods are also used.
In house construction, larch heartwood is used for roof structures , wall and ceiling constructions, outside for house doors, garage doors, windows, facade cladding, terraces, frames and parapets as well as for large-area cladding of walls, gables, balconies or overhangs. Larch wood is also popular in the region as roof shingles . In interior work, the sapwood is used together with the heartwood for almost all wood uses due to the decorative contrast, including stairs, railings, wall cladding, doors, parquet and plank floors . In furniture construction it is used as veneer and solid wood, especially for kitchen furniture, country furniture and furniture in alpine style. Since the discussion about avoiding exotic imported woods, it has been increasingly used in interior and exterior construction as a substitute for tropical woods .
Due to its resistance to weather and chemicals, larch wood is also used for outdoor and special applications in earthworks, bridges and hydraulic engineering as well as for storage containers for liquids (vats, barrels), cooling towers and silos. A historical use was the main beams of windmill blades , for which the wood is particularly suitable due to its toughness. There are also driven piles, masts, railway sleepers and uses in railway, ship and boat construction, wooden play equipment in playgrounds, floor coverings (deckings, wooden paving), fences, palisades and other applications in which wood is to be used without impregnation . In mining , it is also used as shaft wood and for guide rails , and turned items and household items can be made from larch wood.
Energetic use
The energetic use of larch wood plays a comparatively minor role. Larch wood has a calorific value of 4.4 kWh / kg or 1700 kWh / rm and is therefore comparable to pine and Douglas fir . It is mainly used in private house fires in the form of split logs . When pellets are industrial waste ( wood chips ) including available from the larch wood production in the form of mixed pellets.
Health related use
The secondary plant matter and the biologically active flavonoid DHQ ( Taxifolin ) are obtained from certain parts of the larch trunks by means of liquid chromatography . Taxifolin is said to have a broad spectrum of activity on the human organism. In addition to the positive effects in cardiovascular diseases (vasodilator and vaso-stabilizing, lowering blood pressure), this includes the ability of reactive oxygen species (ROS) to bind , the antioxidant and anticarcinogenic properties. In addition to taxifolin, larch extract that is less purified contains oligomeric proanthocyanidins (OPC) and other polyphenols .
A patent from the University of Graz , registered in 2013, highlights the anti-inflammatory effect of the diterpenes contained in larch wood . The researchers were able to show how the use of antibiotics in animal fattening can be reduced by using finely ground sawdust as a feed additive.
Web links
swell
literature
- D. Grosser, W. Teetz: Larch . In: Local timber (loose-leaf collection) . Information service wood, wood sales fund - sales promotion fund of the German forest and wood industry, 1998, ISSN 0446-2114 .
Individual evidence
- ↑ a b c According to DIN 68364 - Characteristic values of wood species - gross density, modulus of elasticity and strength. May 2005.
- ↑ http://www.materialarchiv.ch/app-tablet/#detail/526/laerche
- ↑ [1]
- ↑ DIN EN 350-2 Durability of wood and wood products - Natural durability of solid wood - Part 2: Guide for the natural durability and impregnability of selected types of wood of particular importance in Europe; German version EN 350-2: 1994 . 1994.
- ↑ [2]
- ↑ P. Mladenka, L. Zatloukalová, T. Filipský, R. Hrdina (2010): Cardiovascular effects of flavonoids are not caused only by direct antioxidant activity. In: Free Radic Biol Med . 49: pp. 963-975. PMID 20542108 .
- ↑ New anti-inflammatory pet food supplement [3] (PDF; 139 kB) Downloaded on November 19, 2013
- ↑ Larch sawdust is supposed to keep fattening animals healthy [4] , Kleine Zeitung June 11, 2013