Using Size-Frequency Distributions to Analyze Fire Regimes in Florida
Using Size-Frequency Distributions to Analyze Fire Regimes in Florida
复制标题
使用尺寸频率分布分析佛罗里达州的火灾状况
DOI：
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发表时间：
2004
期刊：
影响因子：
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通讯作者：
K. Abt
中科院分区：
文献类型：
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作者：
T. Holmes;J. Prestemon;J. M. Pye;D. Butry;D. Mercer;K. Abt
天然森林生态系统中的野火具有幂律分布的特征。在本文中，我们评估了野火政权在人类占主导地位的景观是否也符合幂律分布。我们的案例研究集中在佛罗里达，一个国家的快速人口增长和随之而来的森林生态系统和自然火灾制度的快速变化的野火。研究发现，所有的火灾规模频率分布都符合幂律分布，但幂律分布是分段线性的。一个扭结的幂律分布发生在约640公顷的flatwoods火灾和约290公顷的沼泽火灾。超过这些水平，火灾“爆炸”成灾难性的政权。如果扭结代表火灾对灭火工作免疫的水平，我们预计扭结的位置将在极端火灾年份发生在较小的火灾规模，因为燃料的可燃性增加和灭火资源的相对稀缺。我们发现这一结果为三个四个极端火灾年在flatwoods生态系统和所有四个极端火灾年在沼泽。这些结果表明，灾难性的火灾可能是不可能的，以防止和抑制在极端火灾年的努力可能是最好的战略领域，减少燃料的连通性。关键词：火制度，灭火，佛罗里达，幂律分布，自组织，大小频率分布。引用：Holmes，T. P.，J.P. Prestemon，J.M. Pye，D.T. Butry，D.E.美世和K.L. ABT. 2004.用大小频率分布分析佛罗里达的火灾状况。R.T.第88-94页Engstrom，K.E.M. Galley，and W.J. de Groot（eds.）.第22届高大木材火灾生态学会议论文集：温带，北方和山地生态系统的火灾。Tall Timbers Research Station，Tallahassee，FL.大型交互式自然系统的动力学，如发生在佛罗里达雪崩和地震中的灾难性野火（巴克和陈1991）。自组织临界性是一个整体理论，它解释了一个动态系统的全球特征，该系统的面积在至少半个世纪内被烧毁（巴内特和参数总结了Brenner 1992年的相对数量）。仅在佛罗里达东北部，就发生了约100起小型和大型事件。202，430公顷的自我组织焚烧和生产的经济生态系统的一个关键特征是，小规模的财产损失至少为6亿美元（Butry等人，2001年）。系统不能用来预测大规模的地震，尽管最近有一些经验证据。相反，随着时间的推移，大规模的行为出现，灾难性的野火季节在佛罗里达是relatand空间，从动态的相互作用艾德到厄尔尼诺-南方涛动现象之间的系统部分。（Brenner 1991，Prestemon等人2002），火灾状态随时间和行为的自组织临界尺度特征的广泛引用的例子是“沙堆模型”（例如，Kauffman空间并没有得到很好的理解。1995年人口统计）。在这个模型中，沙粒在城市-荒地界面持续增加，它变成了一堆放在桌子上。随着时间的推移，越来越重要的是要了解沙堆的性质增长和雪崩的许多大小的发生，荒地火灾制度，以及他们是如何受到偶尔的灾难性雪崩，carhuman行动，如荒地碎片，ries沙子离开桌子到下面的地板.但是，规定的燃烧和灭火。灾难性的雪崩是由相同的最近试图表征森林火灾制度的事件，导致较小的雪崩，增加了已经开发使用的理论称为“selfa一粒沙子。在这个模型中，一个灾难性的原因是有组织的临界性（Drossal and Schwabl 1992）。不需要引发灾难性的后果。这个理论也被用来描述雪崩是一个分支过程，
Wildfire regimes in natural forest ecosystems have been characterized with power–law distributions. In this paper, we evalu ated whether wildfire regimes in a human-dominated landscape were also consistent with power–law distributions. Our case study focused on wildfires in Florida, a state with rapid population growth and consequent rapid alteration of forest ecosys tems and natural fire regimes. We found that all fire size–frequency distributions evaluated in this study were consistent with power–law distributions, but the power–law distributions were piece-wise linear. A kink in the power–law distributions occurred at about 640 ha for flatwoods fires and at about 290 ha for swamp fires. Above these levels, fires “exploded” into a catastrophic regime. If the kink represents the level at which fires become immune to fire suppression effort, we would expect that the location of the kink would occur at smaller fire sizes during extreme fire years due to the increased flammability of fuels and the relative scarcity of fire suppression resources. We found this result for three of four extreme fire years in flatwoods ecosystems and for all four extreme fire years in swamps. These results suggest that catastrophic fires may not be pos sible to prevent and that suppression efforts during extreme fire years may be best applied to strategic areas that decrease the connectivity of fuels. keywords: fire regime, fire suppression, Florida, power–law distributions, self-organization, size–frequency distribution. Citation: Holmes, T.P., J.P. Prestemon, J.M. Pye, D.T. Butry, D.E. Mercer, and K.L. Abt. 2004. Using size–frequency distri butions to analyze fire regimes in Florida. Pages 88–94 in R.T. Engstrom, K.E.M. Galley, and W.J. de Groot (eds.). Proceed ings of the 22nd Tall Timbers Fire Ecology Conference: Fire in Temperate, Boreal, and Montane Ecosystems. Tall Timbers Research Station, Tallahassee, FL. INTRODUCTION dynamics of large interactive natural systems such as The catastrophic wildfires that occurred in Florida avalanches and earthquakes (Bak and Chen 1991). during the summer of 1998 were the worst in terms Self-organized criticality is a holistic theory that explains the global features of a dynamic system with of area burned in at least a half-century (Barnett and parameters that summarize the relative number of Brenner 1992). In northeast Florida alone, approxismall and large events. A key feature of self-orga mately 202,430 ha burned and produced economic nized systems is that the small-scale properties of a losses of at least $600 million (Butry et al. 2001). system cannot be used to predict large-scale behavAlthough there is some recent empirical evidence ior. Rather, large-scale behavior emerges over time that catastrophic wildfire seasons in Florida are relatand space, resulting from the dynamic interactions ed to the El Niño–Southern Oscillation phenomenon between parts of the system. (Brenner 1991, Prestemon et al. 2002), the broadA widely cited example of self-organized critical scale characteristics of fire regimes over time and behavior is the “sandpile model” (e.g., see Kauffman space are not well understood. As human populations 1995). In this model, grains of sand are persistently increase in the urban–wildland interface, it becomes placed in a pile on the top of a table. Over time, the increasingly important to understand the nature of sandpile grows and avalanches of many sizes occur, wildland fire regimes and how they are affected by with an occasional catastrophic avalanche that carhuman actions such as fragmentation of wildlands, ries sand off the table to the floor below. However, prescribed burning, and fire suppression. catastrophic avalanches are initiated by the same Recent attempts to characterize forest fire regimes event that causes smaller avalanches—the addition of have been developed using a theory known as “selfa grain of sand. In this model, a catastrophic cause is organized criticality” (Drossal and Schwabl 1992). not required to induce a catastrophic effect. This theory has also been used to describe the An avalanche is a branching process that causes