Fuelscape datasets for wildfire risk assessment in the sagebrush biome (270m)

The foundation of quantitative wildfire hazard or risk assessment is a current-condition fuelscape (i.e., fuel and terrain layers), ideally updated to account for recent disturbances and calibrated to reflect the fire behavior potential observed in recent historical wildfire events. This data publication provides the fuelscape generated for a wildfire risk assessment focused on the sagebrush biome of the western United States (US). The data depict ca. 2020 fuel conditions, after customization, to better reflect expected fire behavior in sagebrush ecosystems, including influences from exotic annual grass (e.g., cheatgrass) invasion and conifer (e.g., pinyon, juniper) encroachment. These data are presented as used for biome-wide geospatial fire modeling at a 270-meter resolution. The work was conducted using simulation units called “pyromes,” which represent areas of relatively homogenous contemporary fire regimes. The sagebrush biome is represented by 31 pyromes, covering about 450 million acres in total area. Fuelscapes for the 31 pyromes are included in this data product as separate multiband GeoTIFFs. The bands of each GeoTIFF store eight layers of data that describe terrain (aspect, elevation, slope), tree canopy (cover, height, base height, bulk density), and surface fuel (FBFM40). These data form the Landscape (LCP) file commonly used by US wildland fire behavior modeling systems (e.g., FlamMap, FSPro, FSim). Each fuelscape dataset includes a 30-kilometer buffer to avoid truncating the simulated fires at pyrome boundaries. A shapefile and geopackage containing the boundaries and size of each pyrome are also included.In the western United States, hundreds of thousands of acres of highly imperiled sagebrush ecosystems are lost or degraded each year as a result of altered wildfire regimes. In response to these wildfire threats, extensive fuel treatment investments have been proposed throughout the region. Regional-scale assessment of wildfire risk offers a consistent means of evaluating threats to valued resources and assets, thereby facilitating the most cost-effective investments in management activities that can mitigate those risks. We used a large-fire simulation system (FSim) to estimate the probabilistic components of wildfire risk across the sagebrush biome, which includes portions of 13 western states. This publication includes the customized fuelscape data used for that fire-modeling work.

定量野火致灾因子或风险评估的基础是现状燃料景观（fuelscape），即燃料图层与地形图层，理想情况下应更新以反映近期干扰事件，并校准以匹配近期历史野火事件中观测到的火行为潜力。本数据集出版物提供了针对美国西部蒿灌丛生物群区（sagebrush biome）的野火风险评估所用的燃料景观数据。该数据刻画了约2020年经定制优化后的燃料状况，以更精准地反映蒿灌丛生态系统中的预期火行为，包括外来一年生草本（如旱雀麦（cheatgrass））入侵与针叶树（如矮松、杜松（juniper））侵占。这些数据以270米分辨率的全生物群区地理空间火灾模拟所用数据形式呈现。本研究采用名为火区单元（pyromes）的模拟单元，这类单元代表具有相对均一现代火制度的区域。蒿灌丛生物群区共包含31个火区单元，总覆盖面积约4.5亿英亩。本数据产品为31个火区单元分别提供了多波段GeoTIFF格式的燃料景观数据。每个GeoTIFF文件包含8个数据图层，分别描述地形（坡向、海拔、坡度）、林冠层（郁闭度、高度、基部高度、体积密度）以及地表燃料（FBFM40）。这些数据构成了美国野外火行为模拟系统（如FlamMap、FSPro、FSim）常用的LCP文件（Landscape）。每个燃料景观数据集均附带30千米缓冲区，以避免模拟火灾在火区单元边界处被截断。本产品还附带了包含各火区单元边界与面积的形状文件（shapefile）和地理包（geopackage）。
在美国西部，每年都有数十万英亩高度濒危的蒿灌丛生态系统因火制度改变而丧失或退化。针对这些野火威胁，该区域已提出大量燃料处理投资方案。野火风险的区域尺度评估可为评估珍贵资源与资产所面临的威胁提供统一方法，从而助力制定成本效益最优的管理活动投资方案，以缓解相关风险。本团队采用大型火灾模拟系统（FSim）估算了覆盖13个西部州的蒿灌丛生物群区野火风险的概率组分。本出版物包含了此次火灾模拟工作所用的定制化燃料景观数据。