B080-0008
Post-fire recovery of ecosystem productivity in Arctic and boreal forests of Alaska

Monday, 14 December 2020
Poster
Nima Madani1, Nicholas Parazoo2, John Kimball3, Abhishek Chatterjee4, Jennifer Watts5, Sassan Saatchi1, Arthur Endsley6, Torbern Tagesson7, Zhihua Liu8, Brendan M Rogers9, Liang Xu1, Jonathan Wang10, Troy Magney11 and Charles E Miller12, (1)NASA Jet Propulsion Laboratory, Pasadena, CA, United States, (2)University of California Los Angeles, JIFRESSE, Los Angeles, CA, United States, (3)University of Montana, Numerical Terradynamic Simulation Group, W.A. Franke College of Forestry & Conservation, Missoula, MT, United States, (4)USRA, Greenbelt, MD, United States, (5)Woods Hole Research Center, Falmouth, MA, United States, (6)University of Montana, Missoula, United States, (7)Lund University, Lund, Sweden, (8)University of Montana, Missoula, MT, United States, (9)University of California Irvine, Irvine, CA, United States, (10)Boston University, Earth and Environment, Boston, MA, United States, (11)University of California Davis, Plant Sciences, Davis, CA, United States, (12)Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, United States
Abstract:
Large fires are significantly increasing in the boreal and arctic biomes of Alaska. While recent studies indicate positive gross primary productivity (GPP) trends in undisturbed parts of artic boreal biomes, less is known about the impact of wildfires on productivity of these ecosystems. Here, we used a remote sensing-based light use efficiency (LUE) model to analyze the impact of large fires that occurred between 2000-2015 on ecosystem GPP. In order to better understand the GPP dynamics in Alaska, we used a suite of ancillary datasets from remote sensing and reanalysis including vegetation optical depth (VOD), land surface temperature (LST), soil moisture (SM), atmospheric vapor pressure deficit (VPD), and above ground biomass. We also obtained regional CO2 flux tower data airborne solar induced fluorescence (SIF) data from the Chlorophyll Fluorescence Imaging Spectrometer (CFIS) over Alaska. We found higher than average summer LST and VPD condition at burned sites, which also coincided with lower than average SM. Our results indicated that wildfires significantly influence ecosystem productivity and it takes 2-3 years for the ecosystems to show a recovery signal. While, the GPP dynamics show an increasing trend in early growing season with the rate of 1 Tg C yr-1, our analysis do not provide an evidence of increasing carbon uptake in the late growing season. Our results confirm that warmer-than-average years provide favorable climate conditions for plant photosynthesis, but the increase in temperatures also increases the risk of wildfire occurrences. While current productivity models are rely heavily on climate data, we suggest models could emphasize more on the impact of disturbance on ecosystem productivity.
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