Forest fire

from Wikipedia, the free encyclopedia
Forest fire disaster in the Simi Valley , October 2003
Forest fire up to the treetops (USA, c. 2003)
Ground fire in a Brandenburg forest (2003)

A forest fire is a fire in a wooded area. Forest fires, together with field fires, are considered to be vegetation fires. Forest fires usually occur during dry periods and are often dangerous for humans and animals because of their high speed of spread.

For example, the term bushfire is used to refer to large fires in bush and woodlands on the Australian continent or in Africa .

causes

Worldwide, only about four percent of all forest fires (in relation to the "number" of fires, not the size of the area burned) can be traced back to natural causes. The rest is due to deliberate arson ( slash and burn , arson , for example to gain building land in a nature reserve) or negligence (carelessness, for example due to "wild" campfires , thrown cigarettes or matches). Another underestimated cause is the hot catalytic converter in cars and motorcycles parked on the forest floor. In March 2018, the brake disc of a mountain bike that had been lying on the meadow slope, heated up from a descent, ignited dry grass. In eastern Germany, a significant proportion of the fires are caused by spontaneous combustion of rotting ammunition from World War II .

It is highly unlikely that glass bottles and shards will focus the sun's rays like burning glasses and thus ignite leaves or grass , even under optimal circumstances. However, if the bottles are filled with water, they can even be ignited with a PET bottle .

More rarely, forest fires arise from natural causes such as lightning strikes or volcanic activity .

Natural forest fires

Forest fire in the Bitterroot National Forest , Montana , August 6, 2000
Forest fire near Goslar , August 11, 2003
Wammentrappe follows the fire in search of food.

Although forest fires are part of the natural dynamics, less than 5% of all forest fires in Europe have natural causes, mostly lightning strikes. In a natural landscape in Central Europe, they would only appear on a small scale and play a subordinate role. Major forest fires would be less common without humans.

The natural forests of Central Europe are mainly mixed deciduous forests of common beech and English oak . They hold more moisture in biomass, soil and air and dry out less quickly than coniferous forests. A natural forest composition is also a good protection against forest fires.

A forest fire acts as a disturbance to the ecosystem forest and allows the germination of pioneer plants . The mosaic cycle concept sees forest fires as part of the natural forest succession . It is not always sensible to absolutely prevent forest fires in large protected areas, as it interrupts the natural cycle. Such natural forest fires reduce the amount of combustible deadwood and thereby prevent them from returning too often.

In dry and warm climates, forest fires naturally play a larger role, even if they are also largely caused by humans. The dry herb and shrub layer burns down quickly without completely destroying old trees, leaving behind soil that is bare and, due to the ash, also rich in minerals in which new trees can germinate. Sequoias do not drop their seeds until after a forest fire, when there is enough space for young trees, and are thus an example of the adaptation to such "disasters" and their importance in the natural regeneration of the forest. Eucalyptus promotes forest fires due to its high flammability and benefits from them by the fact that the stumps sprout again particularly quickly, even before other plants have recovered.

The largest natural forest fires occur intermittently in the boreal coniferous forests of the north, particularly in Canada. Here they are part of the natural ecological dynamic.

development

A forest fire usually goes through three phases. It starts as wildfire on the ground that is still easy to fight. This wildfire can, especially with conifers, jump over to the treetops, which leads to the so-called treetop fire and the rapid spread of the fire. Top fires are much more difficult to fight than ground fires and easily grow into the third stage, total fire. Under the climatic conditions of Central Europe, such a full fire collapses if the ground fire that supports it can be fought down. If the vegetation in other climatic zones contains less moisture, it is very difficult to extinguish.

For the spread of a fire in the forest see also Deadman Zone .

statistics

Europe

2017 was a record year for forest fires in Europe ; more than 800,000 hectares of land were destroyed, mainly in Italy, Portugal and Spain. In 2018, 1,192 fires were registered on 181,000 hectares (see also drought and heat in Europe 2018 # forest and wilderness fires ) and in 2019, 1,233 fires were counted by the end of April that burned 30 hectares or more of land (see also heat waves in Europe 2019 # drought , Forest fires and agricultural damage ). The ten-year average for this time of year is just 115 forest fires.

Germany

In Germany , an average of around 1,000 forest fires occur each year, destroying around 500 hectares of forest. In comparison, the German forest area increased by around 48,000 ha between 2002 and 2012.

Austria

The University of Natural Resources and Life Sciences has been carrying out statistical recording of forest fires since 1993. The largest forest fire in terms of area since the end of the Second World War took place in 1947 at the Nederjoch in Telfes, Tyrol. At that time, 200 hectares of forest were destroyed. In 1961 it was 120ha in the Föhrenwald near Wiener Neustadt and around 80ha in the spring of 2014 in Absam .

In contrast to fires in the settlement area, the costs of which must be borne by the municipalities or the federal state, in the case of forest fires there are agreements with the federal government that these are borne by the Ministry of Land and Forestry . However, there are always cases where the ministry can be sued up to the highest courts in order to get out of the substitute obligations. It often takes years for even small communities to be able to reimburse their often not low remote extinguishing costs.

Fighting forest fires

From the air

Fire fighting plane in Greece, 2007
Smoke jumpers when boarding ( Idaho )

If the scene of the fire cannot be reached even with all-terrain fire engines, the most effective method of fighting forest fires is the combined use of ground troops and fire-fighting aircraft and helicopters . Trained ground troops can use hand tools such as B. Firemen keep a forest fire in check and reduce the flame length in a controlled manner. When fighting forest fires with aircraft, extinguishing water (with or without additives) is selectively thrown onto the source of the fire. Disadvantages of this method are the great dangers to the pilots and machines for fighting the fire and the lack of reworking on the sources of the fire, which can re-ignite without manual control. For example, on June 18, 2002, three people died when a fire fighting plane crashed in California .

Large fire-fighting aircraft were used twice in Germany. During the fire in the Lüneburg Heath , from 11 to 16 August 1975, Canadair CL-215 fire-fighting aircraft of the French civil defense from Marignane helped . In total, they transported 962,500 liters of water to the fire, which corresponds to 15 to 20 commute trips per day and per aircraft by a fire truck. The second use took place on 26./28. July 1983 at Knesebeck , this time with a Transall C-160 of the Luftwaffe , which had been equipped with a water tank conversion kit. The request came after the federal government had promised to release the district from the operational costs. Another request from the Transalls, which would then have been subject to a charge, was never made, and the conversion kits were scrapped after a few years.

In large, inaccessible forest areas, firefighters can parachute to the scene of the incident as so-called “ fire jumpers ” and fight the fire there. This is not very common in Europe and is also classified as critical as the fire jumpers do not have a secure way back when they land. In Germany, the Deutsche Löschflugzeug Rettungsstaffel (DLFR for short) has PZL M18 Dromader and PZL-106 Kruk fire-fighting aircraft ready to fight forest fires. The fire brigades in Austria are mainly supported by helicopters of the armed forces , especially in alpine areas . The air service installed at the fire brigade has the necessary extinguishing agents available and provides the necessary fire fighting teams.

In Germany, responsibility for disaster control lies with the federal states. Air support should therefore first and foremost be provided by the respective federal state in the form of the helicopter squadron of its state police. This ability differs from state to state. The Hessian state police improved training and equipment significantly in 2006/2007. The Saxon State Police decommissioned their last PZL W-3 Sokół in 2009 , and thus the last helicopter they had ordered with the “load hook” equipment. Since then, fire fighting operations from the air have only been possible if resources from other federal states or the federal government are brought in. The most powerful tools are the Sikorsky CH-53 of the helicopter squadron 64 of the German armed forces from Laupheim and Holzdorf , which are suitable for 5000 l fire water tanks . For reasons of cost, they are only requested if the head of operations sees other options exhausted. In 2008, the disaster control system had to pay € 7,941 per flight hour plus personnel costs.

On the ground

When fighting, a distinction is made between treetop fire and ground fire .

In the case of a ground fire, one approach is to build fire breaks . Depending on the expected maximum flame lengths, a wound strip is created in which all combustible material is removed or burned off in a controlled manner so that the forest fire cannot spread further there. However, flying sparks can cause the firebreak to jump and the ground troops endangered by fire in the rear.

Most forest fires have problems with the water supply , as the nearest water supply points are often far away. In addition, the area of ​​application is often difficult to access , especially in the mountains . You have to set up a fire extinguishing water supply over long distances . Several fire pumps are required for this. As the water but still remains only on the surface of the leaves, you have to still turn out with shovels and Fire beaters the fire or the fire water , a wetting agent admixed which the surface tension reduces the water. [Receipt?]

Such operations always require a large number of firefighters, who must also undergo specialized training in order to be able to fight fires effectively.

A very special extinguishing method is the blast hose method. This process was registered in 1996 by the developers Ries and Rosenstock under the name 2RS-System . The explosion is extinguished by using specially manufactured, plastic-coated hoses that are filled with water. The hose with a typical diameter of 25 cm is provided with an explosive cord (maximum 40 g of explosives per meter). By deploying and filling the hoses in the vicinity of the fire site or fire front, the water can be finely dispersed and brought close to the fire source by igniting the explosive devices. This can put out the fire and cool the surrounding area.

  • Fire bat of metal

  • TLF 8/18 - a fire engine suitable for fighting forest fires

  • A fire fighting vehicle (in 2010), based on the Marder AFV

  • Wet extinguisher with backpack frame for use in forest fires

  • Artificially placed counterfire in California, June 2008

Prevention and exposure

Fire watch tower on the Calvörde Rabenberg (Calvörde)
Extinguishing water pond between Oldendorf and Eschede (Lower Saxony)
The Cessna 206 H Stationair of the Lower Saxony fire brigade flight service for forest fire observation

An important aspect is the timely detection of forest fires, as the effort required to extinguish them grows exponentially over time . Therefore patrols or be fire watchtowers stationed fire guards used.

In Germany, an automated smoke detection system ( FireWatch ) has been used since 2002 for the early detection of forest fires . With the help of an optical sensor and an automatic smoke detection software, a fire is detected as early as the initial stage (smoldering fire). The method allows the detection of smoke clouds up to a distance of 15 km within an average of 4 minutes. The transmission of image sequences and coordinates to the forest fire control centers enables effective operations management. Today, 4.5 million hectares of forest are monitored worldwide with 280 sensors from the FireWatch system (as of 01/2011).

174 optical sensors of the FireWatch system alone search for smoke in all endangered forest areas in the federal states of Brandenburg , Saxony , Saxony-Anhalt , Mecklenburg-Western Pomerania and Lower Saxony during the summer months . The population is also requested to report any forest fires they see to the fire brigade immediately . Also from pilot forest fires are the repeated air traffic control to alarm centers reported to the fire department. In Lower Saxony, the fire brigade flight service of the Lower Saxony State Fire Brigade Association is also used to monitor forest fires . Similar missions by aerial observers (personnel from the fire brigade, forest administration or district offices) together with pilots of the air rescue squadron exist in Bavaria

In Germany, the risk of a forest fire is determined according to a four or five-level forest fire index, depending on the federal state. The more well-known this risk situation is, the greater the probability of preventing forest fires, but experience has shown that many arsonists are encouraged to ignite by known forest fire warnings.

In addition, appropriate water supplies are being created in areas at risk of forest fires for prevention reasons . In Lower Saxony, for example, after the forest fire disaster in 1975, extinguishing water extraction points were set up at existing lakes, fish ponds or gravel pits and extinguishing water ponds were created in particularly endangered areas in order to enable rapid and efficient water absorption by fire engines. Where there was no running water to draw water from, disused heating oil tanks were placed in the ground as extinguishing water storage tanks, each with between 20,000 and 100,000 liters of water. [Receipt?]

During the forest fire on March 23, 2014 in the Jungherrntal area, Lilienfeld , Lower Austria, machine gun ammunition and grenades that were stored or dropped from the Second World War resulted in numerous explosions, shots and flashes that hindered the extinguishing work.

Forest fire hazard and forest fire warning

Warning sign (Czech-German)

To calculate the risk of forest fires, weather values such as air temperature , relative humidity , wind speed , precipitation rate and the short-term and long-term total precipitation , as well as short-wave and long-wave radiation are used .

But not only meteorological parameters are decisive for the forest fire risk, but also the state of vegetation. Pointer plants (they indicate certain environmental conditions, such as the nitrogen content of the soil, air pollution or moisture or drought) play an important role. They are used to estimate the phenological development of the forest floor vegetation and the crown area. When the fresh greening of the ground vegetation and the foliage of the crowns are complete, the spread of the forest fires is dampened and the risk is rated lower. Not all tree species are equally susceptible to ignition. Forest fire statistics show that different stand types are threatened by forest fires to different degrees. It has therefore proven to be sensible and sufficient to assess the forest landscapes - depending on their ignition and combustibility. The hazard corrections associated with this classification are taken into account in the final assessment of the local forest fire risk.

Classification systems are for example:

  • Fire Weather Index (FWI / Indice forêt météo , IFM) from Météo-France and Meteorological Service of Canada: on meteorological parameters, index up to 30, or a six-point scale ( very low to extreme , EFFIS); underlying values ​​are Fine Fuel Moisture Code  (FFMC), Duff Moisture Code  (DMC), Drought Code  (DC), Buildup Index  (BUI), Initial Spread Index  (ISI); in addition there is the Daily Severity Rating  (DSR) and other classifications
  • Forest fire risk level (forest fire hazard class) of the EU Commission, it classified the forests of Europe in different levels of danger (three levels: A / high, B / medium, C / low risk)
  • Forest fire risk, German system of the DWD: from forest fire risk class (by area, four), forest fire risk index (WBI / M-68, four / five), forest fire risk warning level (four / five)

Warning systems (and websites):

  • Meteoalarm : for all of Europe, takes over the national warning levels in the four-level overall system green - yellow - orange - red; Field fire (grass, reed, heather fire and the like) are included under this warning level.
  • EFFIS (European Forest Fire Information System) : The common European warning system, gives the French-Canadian classification system
  • ALPFFIRS (Alpine Forest Fires) : Warning association of the Alpine region

research

Burned forest near Kastro / Thasos island
Detail of a tree burned out by a bushfire in the Okavango Delta (2019)

The Global Fire Monitoring Center in Freiburg im Breisgau has been the only European research center for collecting data in connection with forest fires since 1998. Head of this branch of the Max Planck Institute for Chemistry is Johann Georg Goldammer , who on behalf of the United Nations (UN International Strategy for Disaster Reduction (UN-ISDR)) at the Global Fire Monitoring Center (GFMC) u. a. As part of his professorship for fire ecology, he developed strategies for fighting global forest fires with the help of his research.

The “ ALP FFIRS ” ( Alpine Forest Fire Warning System ) project was carried out in the Alpine region . The aim of the project was preventive measures to reduce damage in connection with forest fires. For this purpose, a common warning system was developed for the Alpine region , taking into account the current weather conditions. The main task was to provide decision support for the authorities and fire departments. A uniform hazard index should enable the warning levels to be compared across the Alps. Project partners were 14 public institutions such as weather services, universities, regional and national authorities from the Alpine region (5 from Italy, 3 from Switzerland, 2 from Austria, 2 from Slovenia, 1 each from France and Germany).

At the University of Natural Resources and Life Sciences which was under Austrian Forest Fire Research Initiative (AFFRI - Austrian Forest Fire Research Initiative) investigated the frequency distribution and the risk of forest fires in Austria. Depending on vegetation , climate and human influence, the occurrence and behavior of forest fires in endangered forest ecosystems is to be described as a model. AFFRI pursued the two goals of identifying “hot spots” for forest fires in Austria depending on vegetation, climate and location and developing a forest fire simulator for Austrian conditions.

A publicly accessible forest fire database for Austria was created within the framework of AFFRI as well as ALP FFIRS and FIRIA . It includes all vegetation fires recorded at the University of Natural Resources and Life Sciences in Vienna, Institute for Silviculture, since 1993.

In Australia, the Bushfire Research Center studies the social, ecological and economic effects of bushfires.

In the literature

The then famous story The Forest Fire by Leopold Schefer described a huge forest fire in Canada in 1827. In Young Men in Fire (1994), Norman Maclean describes the man-gulch forest fire in Montana in 1949 , which killed 13 men.

Historic forest fires

See also

literature

  • Peter Lex: Die Rote Hefte, Booklet 26 - fighting forest fires, moor fires, heather fires . 4th, revised and expanded edition. Kohlhammer, Stuttgart, Berlin and Cologne 1996, ISBN 3-17-014033-7 , pp. 164 .
  • Ehrenfried Liebeneiner: Forest Fire Reports. From the forest , booklet 34.Schaper, Hannover 1981, 256 pp.
  • Collective of authors: Forest fire protection. The learning program for forest management, fire services and disaster control, etc. AID no. 3643. 3 CD-ROMs. Evaluation and information service for food, agriculture and forestry (AID) e. V., Bonn 2000, ISBN 3-8308-0026-6 .
  • Hans-C. King: Forest fire protection. Compendium for forest and fire services . Edition Hazard Defense; Supplement (Volume 1). Fachverlag Grimm, Berlin 2007, 197 pages, ISBN 978-3-940286-01-7 .
  • Jan Südmersen (Ed.): SER - forest and wildfire fighting , ecomed Verlag, Landsberg 2008.
  • Birgit Süssner: Die Roten Hefte, Booklet 107 - Forest and vegetation fires: prevention, preparation for operations, fighting . 1st edition. Kohlhammer, Stuttgart 2020, ISBN 978-3-17-036500-1 .
  • Hans Heinrich Ziemann: Forest fires: Tierra del Fuego California. In: Geo-Magazin. Hamburg 1979, No. 2, pp. 78-96. Informative experience report about "Hell" with an energy of 250 Hiroshima atom bombs. ISSN  0342-8311

Web links

Commons : Forest Fires  - Collection of pictures, videos and audio files

Individual evidence

  1. ↑ Jürgen Suda, Florian Rudolf-Miklau (ed.): Building and natural hazards: Handbook for constructive building protection . Springer-Verlag, Vienna 2012, ISBN 978-3-7091-0680-8 , pp. 68 ( books.google.de ).
  2. ↑ Forests in Flames , WWF Forest Fire Study, 2009, p. 4 (PDF).
  3. ↑ Vorarlberg: Overheated mountain bike brake disc causes forest fire faz.net, March 26, 2018, accessed April 8, 2018.
  4. ↑ Forest fire statistics 2018. Ministry for Rural Development, Environment and Agriculture of the State of Brandenburg (MLUL) - Landesbetrieb Forst Brandenburg and Landeskompetenzzentrum Forst Eberswalde (LFE), June 19, 2019, accessed on May 9, 2020 . (While only 11 fires could be safely assigned to the spontaneous ignition of old ammunition, these caused around 25% of the burned area.)
  5. ↑ The crux with the broken glass. University of Natural Resources and Life Sciences, Vienna, June 7, 2012, accessed on June 5, 2019 (Detailed summary of the original source: causes glass of forest fires ?, AFZ Der Wald, edition 18/2007).
  6. ↑ Christoph Drösser : Right / Right?: Glass under a magnifying glass. In: Die Zeit No. 39, September 16, 2004.
  7. ↑ a b mdr.de: Can broken glass cause forest fires? | MDR.DE. Retrieved August 26, 2019 .
  8. ↑ Forest fire through a PET bottle: test ignites the Internet. Retrieved August 26, 2019 .
  9. ^ Forest fires , WWF background information, July 2005
  10. ^ Peter Hirschberger: Forests in flames - causes and consequences of global forest fires. WWF Germany, Berlin 2012.
  11. ↑ Sam Morgan: More forest fires than in the whole of 2018. In: euractiv.de . May 16, 2019, accessed May 16, 2019 .
  12. ↑ Risk varies by region. How to avoid forest fires . In: t-online.de , April 24, 2019. Accessed April 24, 2019.
  13. ↑ National Forest Inventory 3, 2012 . Retrieved January 20, 2020.
  14. ↑ Forest fire statistics on the BOKU portal accessed on December 24, 2019
  15. ↑ After the forest fire, the Ministry of Forestry abandoned Steinbach for six years in the OÖ Nachrichten of December 23, 2019, accessed on December 24, 2019.
  16. ↑ Steffen Thomas Patzelt: Forest fire prognosis and forest fire fighting in Germany - future-oriented strategies and concepts with special consideration of fire fighting from the air ( Memento of January 31, 2012 in the Internet Archive ) Dissertation, Johannes Gutenberg University Mainz, 2008, p. 202 ff. ( PDF; 3 MB)
  17. ^ Chronicle of the Hessen Police Helicopter Squadron , accessed on January 1, 2015.
  18. ↑ The Sokol W-3A of the Saxony Police ( Memento of May 4, 2011 in the Internet Archive ), accessed in June 2011.
  19. ↑ Assistance by the Bundeswehr in the event of natural disasters or particularly serious accidents and in the context of urgent emergency aid. (PDF; 177 kB) (No longer available online.) In: Ministerialblatt des Bundesministerium der Defense (VMBl) 2008 - page 2. Federal Ministry of Defense, February 6, 2008, archived from the original on January 8, 2014 ; Retrieved July 1, 2013 .
  20. ↑ Achmed AW Khammas: Extinguishing forest fires by blasting away. In: Telepolis. August 29, 2007, accessed January 1, 2015 .
  21. ↑ Air observation in Lower Franconia and Lower Bavaria
  22. ↑ forest fire monitoring; Organization of aerial observation flights in the Bayernportal
  23. ↑ Christian Teis: District Fire Command LILIENFELD - munitions hampered fire fighting at forest fire. In: bfkdo-lilienfeld.at. March 22, 2014, accessed January 1, 2015 .
  24. ^ Lilienfeld: Explosions in forest fire. In: orf.at. March 22, 2014, accessed January 1, 2015 .
  25. ↑ Risk of forest fire. ZAMG (accessed May 4, 2016).
  26. ^ Canadian Wildland Fire Information System. cwfis.cfs.nrcan.gc.ca
  27. ↑ Susanne Kaulfuß: Legal basis for forest fire prevention waldwissen.net, accessed May 4, 2016.
  28. ↑ forest.jrc.ec.europa.eu/effis
  29. ^ Alpine Forest Fire Warning System
  30. ↑ Süddeutsche Zeitung No. 34, February 11, 2009, p. 2, by Claudia Fromme
  31. ↑ GFMC Global Fire Monitoring Center, founded October 1998.
  32. ↑ natur & kosmos interview with Johann G. Goldammer on the forest fire situation (August 29, 2000) ( Memento from July 1, 2007 in the Internet Archive )
  33. ↑ Research: Fire Ecology ( Memento from June 10, 2007 in the Internet Archive )
  34. ↑ ALP FFIRS. In: alpffirs.eu. March 12, 2014, accessed January 1, 2015 .
  35. ^ Austrian Forest Fire Research Initiative (AFFRI 1: 2008–2012); later started AFFRI 2 - research initiative forest fire
  36. ^ Forest fire :: Institute for Silviculture (WALDBAU). In: wabo.boku.ac.at. Retrieved January 1, 2015 .
  37. ^ Forest fire database Austria. In: boku.ac.at. Retrieved July 7, 2018 .
  38. ^ Norman Maclean, Young Men and Fire, excerpt. In: press.uchicago.edu. Retrieved January 1, 2015 .
  39. ^ Karl E. Weick: The collapse of sensemaking in organizations: The Mann Gulch disaster In: Administrative Science Quarterly: Volume 38, number 4, 1993; ABI / INFORM Global, p. 628.