Instituto de Diversidad y Ecología Animal (IDEA), CONICET-UNC and Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba, Córdoba, Argentina.
Instituto de Altos Estudios Espaciales "Mario Gulich", Comisión Nacional de Actividades Espaciales-Universidad Nacional de Córdoba, Falda del Cañete, Córdoba, Argentina.
PLoS One. 2018 Oct 4;13(10):e0204889. doi: 10.1371/journal.pone.0204889. eCollection 2018.
Fuel moisture content (FMC) is an important fuel property for assessing wildfire hazard, since it influences fuel flammability and fire behavior. The relationship between FMC and fire activity differs among land covers and seems to be a property of each ecosystem. Our objectives were to analyze pre-fire FMC among different land covers and to propose a wildfire hazard classification for the Sierras Chicas in the Chaco Serrano subregion (Argentina), by analyzing pre-fire FMC distributions observed for grasslands, shrublands and forests and using percentiles to establish thresholds. For this purpose, we used a fire database derived from Landsat imagery (30 m) and derived FMC maps every 8 days from 2002 to 2016 using MODIS reflectance products and empirical equations of FMC. Our results indicated that higher FMC constrains the extent of wildfires, whereas at lower FMC there are other factors affecting their size. Extreme and high fire hazard thresholds for grasslands were established at FMC of 55% and 67% respectively, at 72% and 105% for forests and at 106% and 121% for shrublands. Our FMC thresholds were sensitive to detect extreme fire hazard conditions during years with high fire activity in comparison to average conditions. The differences in the distributions of pre-fire FMC among land covers and between ecosystems highlighted the need to locally determine land cover-specific FMC thresholds to assess wildfire hazard. Our wildfire hazard classification applied to FMC maps in an operational framework will contribute to improving early warning systems in the Sierras Chicas. However, moisture alone is not sufficient to represent true fire hazard in Chaco forests and the combination with other variables would provide better hazard assessments. These operational wildfire hazard maps will help to better allocation of fire protective resources to minimize negative impact on people, property and ecosystems. To the best of our knowledge, this is the first study analyzing pre-fire FMC over several fire seasons in a non-Mediterranean ecosystem, aiming at assessing wildfire hazard.
燃料水分含量（FMC）是评估野火危险的重要燃料特性，因为它影响燃料的可燃性和火灾行为。FMC 与火灾活动之间的关系因土地覆盖类型而异，似乎是每个生态系统的特性。我们的目标是分析不同土地覆盖类型的预燃 FMC，并通过分析观察到的草原、灌木和森林的预燃 FMC 分布，使用百分位数来建立阈值，为查科塞拉诺次区域（阿根廷）的奇卡山脉提出野火危险分类。为此，我们使用了源自 Landsat 图像（30 米）的火灾数据库，并使用 MODIS 反射率产品和 FMC 的经验方程，每 8 天从 2002 年到 2016 年生成 FMC 地图。我们的结果表明，较高的 FMC 限制了野火的范围，而在较低的 FMC 下，还有其他因素影响其规模。草地的极端和高火灾危险阈值分别设定为 FMC 的 55%和 67%，森林为 72%和 105%，灌木为 106%和 121%。与平均条件相比，我们的 FMC 阈值在火灾活动高的年份能够敏感地检测到极端火灾危险条件。不同土地覆盖类型和生态系统之间的预燃 FMC 分布差异突出表明，需要根据当地情况确定特定土地覆盖类型的 FMC 阈值，以评估野火危险。我们将 FMC 阈值应用于操作框架中的 FMC 地图，将有助于改善奇卡山脉的早期预警系统。然而，仅湿度不足以代表查科森林的真实火灾危险，与其他变量结合将提供更好的危险评估。这些操作野火危险地图将有助于更好地分配防火资源，以最大程度地减少对人员、财产和生态系统的负面影响。据我们所知，这是第一项在非地中海生态系统中分析多个火灾季节的预燃 FMC 的研究，旨在评估野火危险。
