Litter is the predominant fuel that drives surface fire behavior in most fire-prone forest and woodland ecosystems. The flammability of litter is driven by fuel characteristics, environmental factors, and the interactive effects of the two. Solar radiation can influence litter flammability through its effect on fuel moisture and temperature. The direct influence of radiative heating on flammability, however, is poorly understood and the interactive effects of forest structure, composition, fuels, and micrometeorology may have fine-scale ecological consequences in fire-dependent ecosystems. In this study, we measured laboratory flammability of two dominant southeastern USA litter fuels—Pinus palustris Mill. and Quercus stellata Wangenh.—and evaluated the interactive effects of fuel moisture and infrared radiation. Heating of litter fuels increased their flammability primarily through enhanced litter drying. Heated litter quickly became more flammable than unheated litter when fuels were undergoing drying after saturation, a result of more rapid moisture loss. Litter mass did not change the effect of heating on drying rates, but heavier fuels burned with greater flammability. Interactions among surface fuels, overstory structure, and solar heating may be important in understanding fine-scale heterogeneity in both fire behavior and effects, with strong implications toward increasing the effectiveness of prescribed burning.

中文翻译：

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辐射加热通过影响燃料水分而迅速增加垃圾的可燃性

乱扔垃圾是导致大多数易燃森林和林地生态系统中地表火灾行为的主要燃料。垃圾的易燃性受燃料特性，环境因素以及二者的相互作用影响。太阳辐射会通过影响燃油湿度和温度来影响垃圾的可燃性。然而，人们对辐射加热对可燃性的直接影响了解甚少，森林结构，成分，燃料和微气象学的相互作用可能会在依赖火的生态系统中产生小规模的生态后果。在这项研究中，我们测量了美国东南部两种主要的凋落物燃料-Pinus palustris Mill的易燃性。和Quercus stellata Wangenh。并评估了燃料水分和红外辐射的相互作用。垫料燃料的加热主要通过提高垫料干燥来增加其可燃性。当燃料在饱和后进行干燥时，加热的垃圾会比未加热的垃圾迅速变得更易燃，这是水分流失更快的结果。垃圾质量不会改变加热对干燥速率的影响，但燃烧较重的燃料则具有更大的可燃性。地表燃料，高层建筑结构和太阳能加热之间的相互作用对于理解火灾行为和后果中的精细异质性可能很重要，这对于提高指定燃烧的有效性具有重要意义。垃圾质量不会改变加热对干燥速率的影响，但燃烧较重的燃料则具有更大的可燃性。表面燃料，高层建筑结构和太阳能加热之间的相互作用可能对理解火灾行为和后果中的细微尺度异质性很重要，对提高规定燃烧的有效性具有重要意义。垃圾质量不会改变加热对干燥速率的影响，但燃烧较重的燃料则具有更大的可燃性。地表燃料，高层建筑结构和太阳能加热之间的相互作用对于理解火灾行为和后果中的精细异质性可能很重要，这对于提高指定燃烧的有效性具有重要意义。