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- An uncontrolled fire in combustible vegetation that occurs in the countryside or a wilderness area. Other names such as brush fire, bushfire, forest fire, desert fire, grass fire, hill fire, peat fire, vegetation fire, and veldfire may be used to describe the same phenomenon depending on the type of vegetation being burned. A wildfire differs from other fires by its extensive size, the speed at which it can spread out from its original source, its potential to change direction unexpectedly, and its ability to jump gaps such as roads, rivers and fire breaks. Wildfires are characterized in terms of the cause of ignition, their physical properties such as speed of propagation, the combustible material present, and the effect of weather on the fire.
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| Abstract from DBPedia | A wildfire, forest fire, bushfire, wildland fire or rural fire is an unplanned, uncontrolled and unpredictable fire in an area of combustible vegetation starting in rural and urban areas. Some forest ecosystems in their natural state depend on wildfire. Depending on the type of vegetation present, a wildfire can also be classified more specifically as a bushfire (in Australia), desert fire, grass fire, hill fire, peat fire, prairie fire, vegetation fire, or veld fire. Wildfires are distinct from beneficial uses of fire, called controlled burns, though controlled burns can turn into wildfires. Fossil charcoal indicates that wildfires began soon after the appearance of terrestrial plants approximately 419 million years ago during the Silurian period. The occurrence of wildfires throughout the history of terrestrial life invites conjecture that fire must have had pronounced evolutionary effects on most ecosystems' flora and fauna. Earth's carbon-rich vegetation, seasonally dry climates, atmospheric oxygen, and widespread lightning and volcanic ignitions create good conditions for fires. Wildfires are often classified by characteristics like cause of ignition, physical properties, combustible material present, and the effect of weather on the fire. Wildfire behavior and severity result from a combination of factors such as available fuels, physical setting, and weather. Climatic cycles that include wet periods that create substantial fuels and then are followed by drought and heat often proceed severe wildfires. These cycles are made worse by heat waves and droughts caused by climate change. Wildfires can cause damage to property and human life, although naturally occurring wildfires may have beneficial effects on native vegetation, animals, and ecosystems that have evolved with fire. High-severity wildfire creates complex early seral forest habitat (also called "snag forest habitat"), which often has higher species richness and diversity than an unburned old forest. Many plant species depend on the effects of fire for growth and reproduction. Wildfires in ecosystems where wildfire is uncommon or where non-native vegetation has encroached may have strongly negative ecological effects. Similarly, human societies can be severely impacted by fires, including direct health impacts of smoke, destruction of property, especially in wildland–urban interfaces, economic and ecosystem services losses, and contamination of water and soil. There are also significant indirect or second-order societal impacts from wildfire, such as demands on utilities to prevent power transmission equipment from becoming ignition sources, and the cancelation or nonrenewal of homeowners insurance for residents living in wildfire-prone areas. Wildfires are among the most common forms of natural disaster in some regions, including Siberia, California, and Australia. Areas with Mediterranean climates or in the taiga biome are particularly susceptible. At a global level, human practices have made wildfires worse than naturally would happen, with a doubling in land area burned by wildfires when compared to natural levels. Humans have contributed to major factors to increased wildfires, increased heat and dry periods due to climate change and other more direct human activities, such as land-use change and wildfire suppression. Since records started at the beginning of the 20th century, wildfires have steadily declined. The increase in severity of fires creates a positive feedback loop by releasing naturally sequestered carbon back into the atmosphere, increasing the atmosphere's greenhouse effect contributing to climate change. Modern forest management taking an ecological perspective engages in controlled burns to mitigate this risk and promote natural forest life cycles.山火事（やまかじ、英語：wildfire）とは、自然界における火災の日本語での総称。山でなく、平坦な土地の森林や草原で発生・延焼する場合も含み、その対象に応じて森林火災（しんりんかさい）、山林火災（さんりんかさい）、林野火災（りんやかさい）、原野火災（げんやかさい）などともいう。乾燥や強風といった条件が重なると火災旋風に発展することもある。 近代になって地球温暖化が進行するにつれ頻度および規模が増大しており、各地で大きな被害を出しているほか、山火事の多発が地球の大気中で温暖化ガスである二酸化炭素（CO2）を増やしたり、北極と南極の氷や永久凍土の融解を促したりして温暖化を加速させる一因になる。 (Source: http://dbpedia.org/resource/Wildfire) |
