Wildfire

A wildfire (or forest fire, bushfire) is an unplanned, uncontrolled and unpredictable fire in an area of combustible vegetation.^[1][2] Depending on the type of vegetation present, a wildfire may be more specifically identified as a bushfire (in Australia), desert fire, grass fire, hill fire, peat fire, prairie fire, vegetation fire, or veld fire.^[3] Some natural forest ecosystems depend on wildfire.^[4] Wildfires are different from controlled or prescribed burning, which are carried out to provide a benefit for people. Modern forest management often engages in prescribed burns to mitigate fire risk and promote natural forest cycles. However, controlled burns can turn into wildfires by mistake.

Wildfires can be classified by cause of ignition, physical properties, combustible material present, and the effect of weather on the fire.^[5] Wildfire severity results from a combination of factors such as available fuels, physical setting, and weather.^[6][7][8][9] Climatic cycles with wet periods that create substantial fuels, followed by drought and heat, often proceed severe wildfires.^[10] These cycles have been intensified by climate change.^[11]: 247

Naturally occurring wildfires can have beneficial effects on those ecosystems that have evolved with fire.^[12][13][14] In fact, many plant species depend on the effects of fire for growth and reproduction.^[15] Some natural forests are dependent on wildfire.^[16] High-severity wildfires may create complex early seral forest habitat (also called snag forest habitat). These types of forest may have higher species richness and biodiversity than an unburned old forest.

Wildfires can severely impact humans and their settlements. Effects include for example the direct health impacts of smoke and fire, as well as destruction of property (especially in wildland–urban interfaces), and economic losses. There is also the potential for contamination of water and soil.

Wildfires are a common type of natural disaster in some regions, including Siberia (Russia), California (United States), British Columbia (Canada), and Australia.^{[17][18][19][20]} Areas with Mediterranean climates or in the taiga biome are particularly susceptible. At a global level, human practices have made the impacts of wildfire worse, with a doubling in land area burned by wildfires compared to natural levels.^[11]: 247 Humans have impacted wildfire through climate change (e.g. more intense heat waves and droughts), land-use change, and wildfire suppression.^[11]: 247 The carbon released from wildfires can add to carbon dioxide concentrations in the atmosphere and thus contribute to the greenhouse effect. This creates a climate change feedback.^[21]: 20