A fire regime is the pattern, frequency and intensity of the bushfires and wildfires that prevails in an area. It is an integral part of fire ecology, and renewal for certain types of ecosystems. If fires are too frequent, plants may be killed before they have matured, or before they have set sufficient seed to ensure population recovery. If fires are too infrequent, plants may mature, senesce and die, without ever releasing their seed.
The ecological need to provide an appropriate fire regime is often at odds with the principles and goals of bushfire management, which aims to manage the human and financial costs of bushfires. One of the strategies employed is frequent prescribed burns. By firing the bush at frequent, regular intervals, the bush is burnt before much fuel has built up, ensuring a low-intensity burn that is easily managed. Both the higher frequency of fire, and the low intensity, may have ecological implications; as may the tendency to burn off outside the usual bushfire season.
Bushfire is especially important in Australia, where much of the vegetation has evolved in the presence of regular fires caused by the Aboriginal practice of firestick farming. As a result of this, components of the vegetation are adapted to, and depend upon, a particular fire-regime, and their survival is affected by disruption of that fire regime.
An example is found in the many Banksia species that are both fire-sensitive and serotinous; these species are killed by fire, but fire also triggers the release of seed, ensuring population recovery. Under an ideal fire regime, a plant that recruits following a bushfire will have sufficient time to mature and build an adequately large bank of seed, before the next fire kills it and triggers seed release.
The California chaparral and woodlands ecoregion, covering a large portion of the U.S. state, is dependent on periodic natural wildfires for optimal health and renewal. The increasing rural-urban fringe interface and wildfire suppression practices of the last century have now resulted in significant environmental and human safety issues and events.
- Stephen J. Pyne. "How Plants Use Fire (And Are Used By It)". NOVA online. Retrieved 2009-06-30.
- http://www.californiachaparral.com/firenature.html Wildfire in the Chaparral . 9/29/2010
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