Assessing climate change impacts on live fuel moisture and wildfire risk using a hydrodynamic vegetation model

作者：Wu Ma, Lu Zhai, Alexandria L. Pivovaroff, J. K. Shuman, Polly C. Buotte, Junyan Ding, Bradley Christoffersen, Ryan Knox, Max A. Moritz, Rosie A. Fisher, Charles D. Koven, Lara M. Kueppers, Chonggang Xu · 发表于：Biogeosciences · 年份：2021 · DOI：10.5194/bg-18-4005-2021 · 被引用次数：43 · 研究领域：Fire effects on ecosystems、Plant Water Relations and Carbon Dynamics、Tree-ring climate responses

Abstract. Live fuel moisture content (LFMC) plays a critical role in wildfire dynamics, but little is known about responses of LFMC to multivariate climate change, e.g., warming temperature, CO2 fertilization, and altered precipitation patterns, leading to a limited prediction ability of future wildfire risks. Here, we use a hydrodynamic demographic vegetation model to estimate LFMC dynamics of chaparral shrubs, a dominant vegetation type in fire-prone southern California. We parameterize the model based on observed shrub allometry and hydraulic traits and evaluate the model's accuracy through comparisons between observed and simulated LFMC of three plant functional types (PFTs) under current climate conditions. Moreover, we estimate the number of days per year of LFMC below 79 % (which is a critical threshold for wildfire danger rating of southern California chaparral shrubs) from 1960 to 2099 for each PFT and compare the number of days below the threshold for medium and high greenhouse gas emission scenarios (RCP4.5 and 8.5). We find that climate change could lead to more days per year (5.2 %–14.8 % increase) with LFMC below 79 % between the historical (1960–1999) and future (2080–2099) periods, implying an increase in wildfire danger for chaparral shrubs in southern California. Under the high greenhouse gas emission scenario during the dry season, we find that the future LFMC reductions mainly result from a warming temperature, which leads to 9.1 %–18.6 % reduction in LFMC...