Minnich R A
Science. 1983 Mar 18;219(4590):1287-94. doi: 10.1126/science.219.4590.1287.
In spite of suppression efforts, severe wildfires burn large areas of southern California grassland, coastal sage scrub, and chaparral. Such large burns may not have been characteristic prior to the initiation of fire suppression more than 70 years ago. To compare controlled with uncontrolled areas, wildfires of southern California and adjacent northern Baja California were evaluated for the period 1972 to 1980 from Landsat imagery. Fire size and location, vegetation, year, and season were recorded. It was found that suppression has divergent effects on different plant communities depending on successional processes, growth rates, fuel accumulation, decomposition rates, and length of flammability cycles. These variables establish feedback between the course of active fires, fire history, spatial configuration of flammable vegetation, and fire size. Suppression has minimal impact in coastal sage scrub and grassland. Fire control in chaparral reduces the number of fires, not burned hectarage; fires consequently increase in size, spread rate, and intensity and become uncontrollable in severe weather conditions. The Baja California chaparral fire regime may serve as a model for prescribed burning in southern California.
尽管有灭火行动，但严重的野火仍烧毁了南加州的大片草原、沿海鼠尾草灌丛和矮橡树林。在70多年前开始实施灭火行动之前，如此大面积的火灾可能并不常见。为了比较控制区和非控制区，利用陆地卫星图像对1972年至1980年期间南加州和邻近的北下加利福尼亚州的野火进行了评估。记录了火灾面积和位置、植被、年份和季节。研究发现，根据演替过程、生长速度、燃料积累、分解速度和易燃周期的长度，灭火对不同植物群落有不同的影响。这些变量在活跃火灾的进程、火灾历史、易燃植被的空间配置和火灾规模之间建立了反馈。灭火对沿海鼠尾草灌丛和草原的影响最小。矮橡树林的火灾控制减少了火灾次数，但并未减少烧毁的公顷数；因此，火灾的规模、蔓延速度和强度增加，在恶劣天气条件下变得无法控制。下加利福尼亚州的矮橡树林火灾模式可作为南加州规定燃烧的一个模型。
