In the original and narrower sense, clearing is the removal of woody plants , i.e. trees or bushes , including their roots . In further detailed explanation, deforestation and the mere cases of trees ( " blow clearing ") without reforestation and the slash and burn and Schwenden ; in these cases, the tree stumps or the roots often remain in the ground.
The aim of clearing forest areas is usually to be able to use the soil for another use ( pasture , arable farming , housing development , traffic route construction ). This is the difference to clear cutting in forestry use, which is usually followed by reforestation. The Austrian Forest Act defines clearing as “the use of forest soil for purposes other than forest culture”. But clearing is also used in the areas of horticulture and viticulture (clearing of vines ). Clearing can also affect only a single tree or bush or a single rootstock.
Clearance, and in particular slash and burn, are the main cause of increasing deforestation in many countries. However, deforestation can also be a consequence of other factors (e.g. unsustainable management, drought , forest fires and storms).
Word origin and word usage
Clearing is a word formation to clear ( mnd. Clearing , mhd. Riuten, reuten , ahd. Riuten ). The variant reuten remained in the south of the German-speaking area as a dialect word well into modern times . Linguistically related is eradicate , a word formation for the outdated verb rotten (mhd. Red , subsidiary form of riuten, reuten ).
The words clearing and clearing can be related both to the affected vegetation (trees and bushes, forest and bushes are cleared) and to the land area (a piece of land, an area is cleared). The similar term deforestation , on the other hand, is always related to the land area (a country, an area is deforested). Clearance is the standard term in the historical context (see the technical term clearing time ). In particular, when naming the specific work, the word clearing and terms such as rootstock clearing or clearing device are used . The modern term deforestation is preferred when it comes to the extent of forest loss, especially when considering large-scale areas (e.g. deforestation in the Amazon region or deforestation of the earth ).
The cleared area can also be described as clearing . Numerous clearing names are a linguistic testimony to medieval clearing in Europe. Like clearing, many of them go back to Middle High German riuten , for example Reutte , Kreuth , Werningerode .
Types of clearing
In the case of a (complete) tree clearing, the trees including the tree stump (also called "stick") are cleared in one work cycle. This is possible using chaining , for example . A chain or a wire rope is stretched between two heavy bulldozers to pull out the trees and their roots. In the case of weak trees, the use of a single tractor is sufficient. This practice takes place in forests that have only an insignificant proportion of economically interesting trees.
Often only tree stumps are cleared after the trees have been felled at some point before, or a single tree stump is cleared ( rootstock clearing, stick clearing, root clearing). When clearing roots, the roots are either largely removed (complete clearing) or parts of the root wood are left in the ground (partial clearing).
The rhizome can be torn out with an excavator, leaving the long roots in the ground if they have not been exposed beforehand. Complete clearing can only be achieved with an excavator if it works with a special clearing knife . Special milling machines can mill the stump to a depth of just under one meter, but complete clearing with a milling cutter is difficult. If a stump grinder is used, it is also known as a root stock grinder .
Historically, all kinds of mechanical devices that transmitted strong leverage , for example the forest devil , and later also motorized lifting devices, such as a steam-powered lifting crane, were used to clear root stocks. Alternatively, the tractive effort was provided by a tractor. Explosives were also used.
Manual and machine clearing
With mechanical clearing, the tree trunks are felled with so-called wood harvesters (also called "harvesters"), delimbed and sawn into sections (see wood harvesting ). Above all, excavators and special cutters are used to remove the rhizomes (see above).
Felling wood with a chainsaw takes an intermediate position. The sawing work is done by the chainsaw, but it is still strenuous physical work.
Deforestation in the broader sense
The following methods do not remove the stumps or roots. It is therefore imperfect clearing and not clearing in the narrower sense.
Slash and burn
In the case of slash and burn , the cutting off and burning of the vegetation is usually combined. A biology lexicon notes that the word " clearing" is misleading because the root stocks are left in the ground.
The term Schwenden mostly describes a historical method of land reclamation. During Schwenden, the tree population was often first dried out by curling . Undergrowth and undergrowth were removed, as well as branches and again and again the newly emerging shoots ( Schneitelung ). After the tree withered, the following options were available:
- Burning down: The dried out trees are specifically burned to gain agricultural land. The fire residues ensure high-quality, fertilized soil.
- Mechanical felling of the trees in order to then cultivate fields on the area - around the stumps .
- According to the large conversation lexicon von Meyers (1905-1909), the damaged trees fell over at some point without further action.
The dictionary by Adelung (1793–1801) explains the word schwenden as “to burn down a forest to turn it into portable fields”. Duden states to schwenden : " make arable by slash and burn ". According to the German dictionary of the Brothers Grimm, Schwenden in Austria included burning, debarking, mutilating or drilling trees that were supposed to wither as a result. With reference to a Bavarian source, the meaning of the word is stated: “Remove obstructive trees, approaches to wood, bushes by hacking, drilling, peeling them off, etc. the like first makes it stand up and wither, and then put it away or burns ”. Otherwise there is a lot of variation in the assignment of methods and designations in the old sources. For example, in a Swiss spring, wasting is supposed to denote the thinning of forest, bushes or hedges by means of cuts or hewing - and guard against burning.
In laminar clearing is generally referred to surface clearance . If all the trees are cut on a larger area in a day or in a short time, it is called a clear-cutting or clear-cutting .
Smaller cleared areas are more often referred to as clearing islands (isolated, forest-free areas) or clearing lanes (clearing, for example, along rivers or other guidelines). The cleared islands are often at the beginning of extensive cultivation.
Large-scale deforestation have passed since the Neolithic occupied, including through Aulehm deposits in the river valleys and pollen analysis . Slash and burn is likely to have been predominant, as the Neolithic were hardly able to cut up and transport giant trees. After the trees had been previously ringed , which led to their death and drying out, slash and burn was easy. However, the Schwenden can only be proven in historical times.
When swiveling, the time-consuming removal of the roots was not necessary. Another advantage was the lower risk of erosion of the cleared areas, especially in sloping locations, as the roots held the soil. Hacking was possible between the tree stump . The method was unsuitable for plow farming, especially because of the heavy weight of the plows, which were not easy to move.
Many towns and villages in Central Europe originated in the respective clearing time in Rode - or clearing landscapes as a form of internal colonization . An example of this is the settlement of people in the low mountain ranges in forest-hoofed villages .
Forestry has developed from the negative consequences of clearing . Historical descriptions from Central Europe basically coincide with today's images from the tropics. However, due to technical progress and higher population density, the speed of large-scale forest destruction has increased by orders of magnitude, and the consequences for tropical primary forest communities are more permanent. Worldwide, the proportion of forest areas in the total land area is still falling.
Today, clearing activity in Europe mostly only takes place due to infrastructural construction measures and is associated with corresponding requirements for new foundations and reforestation . In other parts of the world - especially the taiga belts of Canada and Siberia , as well as the tropical forest areas - large-scale clearing is common.
Logging without clearing, i.e. removing individual trees or lots of wood, is called permanent forest construction .
- Richard B. Hilf: The forest. Forests and pastures in the past and present - Part One [Reprint]. Aula, Wiebelsheim 2003, ISBN 3-494-01331-4 .
- Hans Hausrath : History of German silviculture. From its beginnings to 1850 . Series of publications by the Institute for Forest Policy and Regional Planning at the University of Freiburg. Hochschulverlag, Freiburg im Breisgau 1982, ISBN 3-8107-6803-0 .
- Jens Lüning : Stone Age farmers in Germany. Agriculture in the Neolithic In: University research on prehistoric archeology. Volume 58, Habelt, Bonn 2000, ISBN 3-7749-2953-X , pp. 49-52.
- clearing gartenwerk-ruhr.de. Quote: "the clearing, ie the removal of plants and their roots". At the end of the text it is made clear that it is specifically about bushes, trees and root balls.
- See Duden online: clearing (meaning 1 and 2)
- See clearing in the Lexikon der Biologie, Spektrum.de (1999). The definition contains the comment "mostly [...] including the roots"; on the other hand, slash and burn is expressly included, where “including the roots” does not apply.
- The time of the major clearing in Upper Austria in the forum OoeGeschichte.at, January 24, 2009. In the info box types of clearing , the historian Roman Sandgruber writes about clearing in the 10th to the 13th / 14th. Century: "There are three types of clearing: the clearing by cutting the trees, the slash and burn by burning the trees and the deforestation [...]" These are the methods in which the stumps remain in the ground.
- Deforestation , Federal Act of July 3, 1975, which regulates forestry ( Forest Act 1975 , Austria), accessed on June 19, 2014.
- Roden vitipendium.de (collection of articles on the subject of viticulture and oenology)
- Foresters work for Deutsche Bahn in the Frankfurt city forest fnp.de, November 18, 2016. Quote: "He would like to clear the tree [...]"
- Trees stay standing fr.de, February 21, 2012. Quote: “Until further notice, no bush and no bush will be cleared”.
- Duden online: clearing and clearing
- Duden online: reuten
- Duden online: exterminate
- Winfried Schenk: Clearance historisches-lexikon-bayerns.de, February 1, 2012.
- Roman Sandgruber: The time of the great clearing in Upper Austria in the forum OoeGeschichte.at, January 24, 2009.
- Deforestation in the Amazon region - causes and initial solutions boell.de, February 28, 2008.
- Map shows deforestation in detail for the first time heise.de, November 15, 2013.
- Duden online: clearing (meaning 2)
- Example of a picture: Clearing trees in bundles when clearing forstmuseum.ch, picture database of historical timber harvest
- Picture example: Harvesting device forstmuseum.ch, picture database of historical wood harvest (mechanical lifting device with long lever arm)
- Picture example: Waldteufel for clearing stock forstmuseum.ch, picture database of historical timber harvest
- Example of a picture: "Mammut" lifting device at work forstmuseum.ch, historical timber harvesting image database (mobile tripod with 4 HP motor)
- Example of a picture: Steam plow machine forstmuseum.ch, picture database of historical wood harvesting (steam-powered crane)
- Example of a picture: Stump clearing with a tractor-mounted lifting device forstmuseum.ch, picture database of historical timber harvest
- Picture example: Drilling the hole for explosive charge in the root stump forstmuseum.ch, picture database historical timber harvest
- burn in the lexicon of biology, Spektrum.de (1999).
- Soil improvement in: Meyers Großes Konversations-Lexikon, 6th edition (1905–1909), see Schwenden there .
- Schwenden in: Johann Christoph Adelung, Grammatical-Critical Dictionary of High German Dialect (1793–1801)
- Duden online: schwenden
- schwenden in the German dictionary of the Brothers Grimm (1854–1961), see 2 b).