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The Yellowstone fires of 1988 together formed the largest wildfire in the recorded history of Yellowstone National Park in the United States. Starting as many smaller individual fires, the flames quickly spread out of control with increasing winds and drought and combined into one large conflagration, which burned for several months. The fires almost destroyed two major visitor destinations and, on September 8, 1988, the entire park was closed to all non-emergency personnel for the first time in its history. Only the arrival of cool and moist weather in the late autumn brought the fires to an end. A total of , or 36 percent of the park was affected by the wildfires. Thousands of firefighters fought the fires, assisted by dozens of helicopters and fixed-wing aircraft which were used for water and fire retardant drops. At the peak of the effort, over 9,000 firefighters were assigned to the park. With fires raging throughout the Greater Yellowstone Ecosystem and other areas in the western United States, the staffing levels of the National Park Service and other land management agencies were inadequate for the situation; over 4,000 U.S. military personnel were soon brought in to assist in fire suppression efforts. The firefighting effort cost $120 million ($ in ). No firefighters died while fighting Yellowstone fires, though there were two fire-related deaths outside the park. Before the late 1960s, fires were generally believed to be detrimental for parks and forests, and management policies were aimed at suppressing fires as quickly as possible. However, as the beneficial ecological role of fire became better understood in the decades before 1988, a policy was adopted of allowing natural fires to burn under controlled conditions, which proved highly successful in reducing the area lost annually to wildfires. In contrast, in 1988, Yellowstone was overdue for a large fire, and, in the exceptionally dry summer, the many smaller "controlled" fires combined. The fires burned discontinuously, leaping from one patch to another, leaving intervening areas untouched. Large firestorms swept through some regions, burning everything in their paths. Tens of millions of trees and countless plants were killed by the wildfires, and some regions were left looking blackened and dead. However, more than half of the affected areas were burned by ground fires, which did less damage to hardier tree species. Not long after the fires ended, plant and tree species quickly reestablished themselves, and natural plant regeneration has been highly successful. The Yellowstone fires of 1988 were unprecedented in the history of the National Park Service, and many questioned existing fire management policies. Media accounts of mismanagement were often sensational and inaccurate, sometimes wrongly reporting or implying that most of the park was being destroyed. While there were temporary declines in air quality during the fires, no adverse long-term health effects have been recorded in the ecosystem and contrary to initial reports, few large mammals were killed by the fires, though there has been a reduction in the number of moose which has yet to rebound. Losses to structures were minimized by concentrating firefighting efforts near major visitor areas, keeping property damage down to $3 million ($ as of ). ==Fire management policy development in the United States== (詳細はwhite settlements moved further west into drier areas, the first large scale fires were encountered. Range fires on the Great Plains and forest fires in the Rocky Mountains were far larger and more destructive than what had ever been seen in the east. A number of catastrophic fire events over the years greatly influenced fire management policies. The worst loss of life in United States history due to a wildfire occurred in 1871 when the Peshtigo Fire swept through Wisconsin, killing more than 1500 people. The Santiago Canyon Fire of 1889 in California and especially the Great Fire of 1910 in Montana and Idaho contributed to the philosophy that fire was a danger that needed to be suppressed. The Great Fire of 1910 had burned , destroyed a number of communities and killed 86 people, and this event prompted various land management agencies to emphasize wildfire suppression. U.S. Government land agencies, including the National Park Service, generally followed the fire management policies established by the U.S. Forest Service, which oversees the majority of the nation's forestlands. Before the middle of the 20th century, most forest managers believed that fires should be suppressed at all times. By 1935, the U.S. Forest Service's fire management policy stipulated that all wildfires were to be suppressed by 10 A.M. the morning after they were first spotted. Fire fighting crews were established throughout public lands, and generally staffed by young men during fire seasons. By 1940, firefighters known as smokejumpers would parachute out of airplanes to extinguish flames in remote locations. By the beginning of World War II, over 8,000 fire lookout towers had been constructed in the United States. Though many have been torn down due to increased use of airplanes for fire spotting, three are still used each year in Yellowstone. Firefighting efforts were highly successful, with the area burned by wildfires reduced from an annual average of during the 1930s, to between and by the 1960s.〔 The need for lumber during World War II was high and fires that destroyed timberland were deemed unacceptable. In 1944, the U.S. Forest Service developed an ad campaign to help educate the public that all fires were detrimental, using a cartoon black bear named Smokey Bear. This iconic firefighting bear can still be seen on posters with the catchphrase "Only you can prevent forest fires".〔 Early posters of Smokey Bear misled the public into believing that western wildfires were predominantly human-caused. In Yellowstone, human-caused fires average between 6 to 10 annually, while 35 wildfires are ignited by lightning.〔 Some researchers, as well as some timber companies and private citizens, understood that fire was a natural state of affairs in many ecosystems. Fire would help clean out the understory and dead plant matter, allowing economically important tree species to grow with less competition for nutrients. Native Americans would often burn woodlands to reduce overgrowth and increase grasslands for large prey animals such as bison and elk. As early as 1924, environmentalist Aldo Leopold argued that wildfires were beneficial to ecosystems, and were necessary for the natural propagation of numerous tree and plant species. Over the next 40 years, increasing numbers of foresters and ecologists concurred about the benefits of wildfire to ecosystems. In 1963, a group of ecologists consulted by the National Park Service released a report recommending that wildfires should be allowed to periodically burn to restore the environmental balance in parks. The Wilderness Act of 1964 helped to address the role of fire as a natural part of ecosystems.〔 By 1968, the National Park Service had adjusted its fire management policies to reflect changing attitudes. The service determined that fires that started naturally (by lightning) would be permitted to burn if they posed little risk to human life and property. The service also decreed that under prescribed conditions, controlled burns would be deliberately set to restore balance to ecosystems.〔 Fire ecology became better understood after many forests had aged to maturity and were overdue for a large scale burn. From 1972, the National Park Service began allowing natural fires in Yellowstone to burn under controlled conditions. Fires of this type were referred to as ''prescribed natural fires''. Between 1972 and 1987, a total of 235 prescribed natural fires burned a relatively small under the directives of the new policy. Of these, only 15 spread to more than . The five years prior to 1988 were much wetter than normal and this may have reduced the area of the fires during that period. The prescribed natural fire policy appeared to be an effective way to manage fires, especially in the Yellowstone region. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Yellowstone fires of 1988」の詳細全文を読む スポンサード リンク
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