Wildfire

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Wildfire is a general term which includes forest fires, grassland fires, bushfires, brush fires and any other vegetation fire in countryside areas.[1][2]

Wildfires occur on every continent except Antarctica. They can occur naturally, but many are caused by humans, accidentally or deliberately. Fossil records and human history show that wildfires do occur at intervals.[3][4]

Wildfires can cause extensive damage to property and human life, but they also have some beneficial effects on wilderness areas. Some plant species depend on the effects of fire for growth and reproduction,[3] although large wildfires may also have negative ecological effects.[5]

Strategies of wildfire prevention, detection, and suppression have varied over the years.[6] One of the more controversial techniques is controlled burning: permitting or lighting small fires to cut the amount of flammable material for a potential wildfire.[7][8] While some wildfires burn in remote forested regions, they can cause extensive destruction of homes and other property in the zone between developed areas and undeveloped wilderness.[7][9]

Plant adaptation[change | change source]

Two photographs of the same section of a pine forest; both show blackened bark at least halfway up the trees. The first picture is noticeably lacking in surface vegetation, while the second shows small, green grasses on the forest floor.
Ecological succession after a wildfire in a boreal pine forest next to Hara Bog, Lahemaa National Park, Estonia. The pictures were taken one and two years after the fire.

Plants in wildfire-prone ecosystems often have adaptations to their local conditions. Such adaptations include physical protection against heat, increased growth after a fire event, and flammable materials that encourage fire and eliminate competition. For example, plants of the genus Eucalyptus contain flammable oils that encourage fire and hard sclerophyll leaves that resist heat and drought. This makes them dominant over less fire-tolerant species.[10][11] Dense bark, shedding lower branches, and high water content in external structures may also protect trees from rising temperatures.[3] Fire-resistant seeds and reserve shoots that sprout after a fire encourage species preservation, as shown by 'pioneer' species, which are first to start up after a fire.

Smoke, charred wood, and heat can stimulate the germination of seeds. Smoke from burning plants promotes contains orange butenolide, which induces germination of seeds.[12][13]

Grasslands in Western Sabah, Malaysian pine forests, and Indonesian Casuarina forests are believed to have resulted from previous periods of fire.[14] The deadwood litter of Chamise (Californian greasewood shrub) is low in water content and flammable, and the shrub quickly sprouts after a fire.[3] Sequoia relies on periodic fires to reduce competition, release seeds from their cones, and clear the soil and canopy for new growth.[15] Some have adapted to, and rely on, low-intensity surface fires for survival and growth. The optimum fire frequency for Caribbean Pine in Bahamian pineyards is every 3 to 10 years. Too frequent fires favour herbaceous plants, and infrequent fires favour other tree species.[16]

Related pages[change | change source]

References[change | change source]

  1. "Federal Fire and Aviation Operations Action Plan" (PDF). National Interagency Fire Center. 2005-04-18. http://www.nifc.gov/nicc/administrative/nmac/correspond/FireOpsPlan.pdf. Retrieved 2009-06-26.
  2. Cambridge Advanced Learner's Dictionary. 2008. 3rd ed, Cambridge University Press. page 5 [1] ISBN 978-0-521-85804-5
  3. 3.0 3.1 3.2 3.3 Pyne, Stephen J. 2002. How plants use fire (and are used by it) NOVA online | accessdate = 2009-06-30
  4. Krock, Lexi (June 2002). "The World on Fire". NOVA online - Public Broadcasting System (PBS). http://www.pbs.org/wgbh/nova/fire/world.html. Retrieved 2009-07-13.
  5. Flannigan, M.D. et al. (2005). "Forest fires and climate change in the 21st century" (PDF). Mitigation and adaptation strategies for global change 11: 847. doi:10.1007/s11027-005-9020-7. https://www.firelab.utoronto.ca/pubs/2005_flannigan_wotton_etal.pdf. Retrieved 2009-06-26.
  6. "International experts study ways to fight wildfires". Voice of America (VOA) News. 2009-06-24. http://www1.voanews.com/english/news/a-13-2009-06-24-voa7-68788387.html. Retrieved 2009-07-09.
  7. 7.0 7.1 Interagency strategy for the implementation of the Federal Wildland Fire Policy, entire text
  8. National Wildfire Coordinating Group Communicator's Guide for Wildland Fire Management, entire text
  9. "Wildfires in Canada". Government of Canada. 2009-02-04. http://www.getprepared.gc.ca/knw/ris/wldf-eng.aspx. Retrieved 2009-07-09.
  10. Santos, Robert L. (1997). "Section Three: problems, cares, economics, and species". The Eucalyptus of California. California State University. http://library.csustan.edu/bsantos/section3.htm. Retrieved 2009-06-26.
  11. (PDF) Fire: the Australian experience, NSW Rural Fire Service, http://www.bushfire.nsw.gov.au/file_system/attachments/State08/Attachment_20050308_44889DFD.pdf, retrieved 2009-02-04
  12. Keeley, J.E. and C.J. Fotheringham (1997) (PDF). Trace gas emission in smoke-induced germination. 276. Science. pp. 1248–1250. http://www.werc.usgs.gov/seki/pdfs/emissions.pdf. Retrieved 2009-06-26.
  13. Flematti GR, Ghisalberti EL, Dixon KW, Trengove RD (2004). "A compound from smoke that promotes seed germination". Science 305 (5686): 977. doi:10.1126/science.1099944. PMID 15247439.
  14. Karki, Sameer (2002). "Community involvement in, and management of, forest fires in South East Asia" (PDF). Project FireFight South East Asia. Archived from the original on 2007-07-30. http://web.archive.org/web/20070730211840/http://www.asiaforests.org/doc/resources/fire/pffsea/Report_Community.pdf. Retrieved 2009-02-13.
  15. "Giant Sequoias and Fire". US National Park Service. http://www.nps.gov/archive/seki/fire/segi.htm. Retrieved 2009-06-30.
  16. "Fire management assessment of the Caribbean Pine (Pinus caribea) Forest Ecosystems on Andros and Abaco Islands, Bahamas". TNC Global Fire Initiative. The Nature Conservancy. September 2004. http://www.nature.org/initiatives/fire/files/bahamas_assessment.pdf. Retrieved 2009-08-27.