美国西海岸国家森林火灾内生物量损失估算：基于清查数据的含不确定性推断

中文摘要 AI 辅助

野火正在重塑美国西部森林，然而野火影响的估算往往依赖于过火面积汇总或卫星衍生的严重程度指标，这些指标并未直接量化森林生物量的变化或其不确定性。我们将美国森林清查与分析样地测量数据与年度30米树冠覆盖数据相结合，采用贝叶斯时空建模框架，估算华盛顿州、俄勒冈州和加利福尼亚州国家森林系统土地上火灾内活体地上生物量（AGB）的变化及森林死亡面积。该模型同时表示活体森林的存在与否以及以活体森林为条件的AGB，从而能够在像素尺度上对火灾前和火灾后的状况进行后验预测估计。将该方法应用于2000年至2022年的6,239场火灾，分析估计野火相关的AGB损失为9,530万公吨，森林死亡面积为239万公顷，其中最大的总体影响发生在2020年。像素级估计揭示了火灾边界内显著的空间异质性，包括总过火面积、森林死亡面积和相关生物量损失之间的巨大差异。这种基于清查数据、具有不确定性意识的方法提供了一个可扩展的框架，用于在保留火灾内空间细节的同时，量化跨广泛区域的干扰对森林碳的影响。

英文摘要

Wildfire is reshaping forests in the western United States (US), yet estimates of wildfire impacts often rely on burned-area summaries or satellite-derived severity metrics that do not directly quantify changes in forest biomass or their uncertainty. We combine US Forest Inventory and Analysis plot measurements with annual 30 m tree canopy cover data in a Bayesian spatio-temporal modeling framework to estimate within-fire changes in live aboveground biomass (AGB) and forest mortality area across National Forest System lands in Washington, Oregon, and California. The model represents both live forest presence or absence and AGB conditional on live forest, allowing posterior predictive estimates of pre- and post-fire conditions at the pixel scale. Applied to 6,239 fires from 2000 to 2022, the analysis estimates 95.3 million Mg of wildfire-associated AGB loss and 2.39 million ha of forest mortality area, with the largest aggregate impacts occurring in 2020. Pixel-level estimates reveal substantial spatial heterogeneity within fire perimeters, including large differences between total burned area, forest mortality area, and associated biomass loss. This inventory-informed, uncertainty-aware approach provides a scalable framework for quantifying forest carbon impacts of disturbance across broad regions while retaining within-fire spatial detail.

发表机构

• Michigan State University（密歇根州立大学）
• South Dakota School of Mines & Technology（南达科他矿业理工学院）
• USDA Forest Service, Pacific Northwest Research Station（美国农业部林务局，太平洋西北研究站）
• Northern Research Station, United States Department of Agriculture Forest Service（美国农业部林务局北方研究站）
• USDA Forest Service, Rocky Mountain Research Station（美国农业部林务局，落基山研究站）

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