Projecting Future Fire Regimes in a Semiarid Watershed of the Inland Northwestern United States: Interactions Among Climate Change, Vegetation Productivity, and Fuel Dynamics

Abstract Fire regimes are influenced by both exogenous drivers (e.g., increases in atmospheric CO2 and climate change) and endogenous drivers (e.g., vegetation and soil/litter moisture), which constrain fuel loads and fuel aridity. Herein, we identified how exogenous and endogenous drivers can inter...

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Main Authors: Jianning Ren, Erin J. Hanan, John T. Abatzoglou, Crystal A. Kolden, Christina (Naomi) L. Tague, Maureen C. Kennedy, Mingliang Liu, Jennifer C. Adam
Format: Article
Language:English
Published: Wiley 2022-03-01
Series:Earth's Future
Subjects:
Online Access:https://doi.org/10.1029/2021EF002518
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author Jianning Ren
Erin J. Hanan
John T. Abatzoglou
Crystal A. Kolden
Christina (Naomi) L. Tague
Maureen C. Kennedy
Mingliang Liu
Jennifer C. Adam
author_facet Jianning Ren
Erin J. Hanan
John T. Abatzoglou
Crystal A. Kolden
Christina (Naomi) L. Tague
Maureen C. Kennedy
Mingliang Liu
Jennifer C. Adam
author_sort Jianning Ren
collection DOAJ
description Abstract Fire regimes are influenced by both exogenous drivers (e.g., increases in atmospheric CO2 and climate change) and endogenous drivers (e.g., vegetation and soil/litter moisture), which constrain fuel loads and fuel aridity. Herein, we identified how exogenous and endogenous drivers can interact to affect fuels and fire regimes in a semiarid watershed in the inland northwestern United States throughout the 21st century. We used a coupled ecohydrologic and fire regime model to examine how climate change and CO2 scenarios influence fire regimes. In this semiarid watershed, we found an increase in burned area and burn probability in the mid‐21st century (2040s) as the CO2 fertilization effect on vegetation productivity outstripped the effects of climate change‐induced fuel decreases, resulting in greater fuel loading. However, by the late‐21st century (2070s), climatic warming dominated over CO2 fertilization, thus reducing fuel loading and burned area. Fire regimes were shown to shift from flammability‐ to fuel‐limited or become increasingly fuel‐limited in response to climate change. We identified a metric to identify when fire regimes shift from flammability‐ to fuel‐limited: the ratio of the change in fuel loading to the change in its aridity. The threshold value for which this metric indicates a flammability versus fuel‐limited regime differed between grasses and woody species but remained stationary over time. Our results suggest that identifying these thresholds in other systems requires narrowing uncertainty in exogenous drivers, such as future precipitation patterns and CO2 effects on vegetation.
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spelling doaj.art-ebdfac24adcf4079a66f1bea3ad13c562022-12-22T01:34:03ZengWileyEarth's Future2328-42772022-03-01103n/an/a10.1029/2021EF002518Projecting Future Fire Regimes in a Semiarid Watershed of the Inland Northwestern United States: Interactions Among Climate Change, Vegetation Productivity, and Fuel DynamicsJianning Ren0Erin J. Hanan1John T. Abatzoglou2Crystal A. Kolden3Christina (Naomi) L. Tague4Maureen C. Kennedy5Mingliang Liu6Jennifer C. Adam7Department of Civil & Environmental Engineering Washington State University Pullman WA USADepartment of Natural Resources and Environmental Science University of Nevada Reno NV USAManagement of Complex Systems University of California Merced CA USAManagement of Complex Systems University of California Merced CA USABren School of Environmental Science & Management University of California Santa Barbara CA USASchool of Interdisciplinary Arts and Sciences Division of Sciences and Mathematics University of Washington Tacoma WA USADepartment of Civil & Environmental Engineering Washington State University Pullman WA USADepartment of Civil & Environmental Engineering Washington State University Pullman WA USAAbstract Fire regimes are influenced by both exogenous drivers (e.g., increases in atmospheric CO2 and climate change) and endogenous drivers (e.g., vegetation and soil/litter moisture), which constrain fuel loads and fuel aridity. Herein, we identified how exogenous and endogenous drivers can interact to affect fuels and fire regimes in a semiarid watershed in the inland northwestern United States throughout the 21st century. We used a coupled ecohydrologic and fire regime model to examine how climate change and CO2 scenarios influence fire regimes. In this semiarid watershed, we found an increase in burned area and burn probability in the mid‐21st century (2040s) as the CO2 fertilization effect on vegetation productivity outstripped the effects of climate change‐induced fuel decreases, resulting in greater fuel loading. However, by the late‐21st century (2070s), climatic warming dominated over CO2 fertilization, thus reducing fuel loading and burned area. Fire regimes were shown to shift from flammability‐ to fuel‐limited or become increasingly fuel‐limited in response to climate change. We identified a metric to identify when fire regimes shift from flammability‐ to fuel‐limited: the ratio of the change in fuel loading to the change in its aridity. The threshold value for which this metric indicates a flammability versus fuel‐limited regime differed between grasses and woody species but remained stationary over time. Our results suggest that identifying these thresholds in other systems requires narrowing uncertainty in exogenous drivers, such as future precipitation patterns and CO2 effects on vegetation.https://doi.org/10.1029/2021EF002518fire regimesclimate changefuel aridityfuel loadingvegetationfire regime modeling
spellingShingle Jianning Ren
Erin J. Hanan
John T. Abatzoglou
Crystal A. Kolden
Christina (Naomi) L. Tague
Maureen C. Kennedy
Mingliang Liu
Jennifer C. Adam
Projecting Future Fire Regimes in a Semiarid Watershed of the Inland Northwestern United States: Interactions Among Climate Change, Vegetation Productivity, and Fuel Dynamics
Earth's Future
fire regimes
climate change
fuel aridity
fuel loading
vegetation
fire regime modeling
title Projecting Future Fire Regimes in a Semiarid Watershed of the Inland Northwestern United States: Interactions Among Climate Change, Vegetation Productivity, and Fuel Dynamics
title_full Projecting Future Fire Regimes in a Semiarid Watershed of the Inland Northwestern United States: Interactions Among Climate Change, Vegetation Productivity, and Fuel Dynamics
title_fullStr Projecting Future Fire Regimes in a Semiarid Watershed of the Inland Northwestern United States: Interactions Among Climate Change, Vegetation Productivity, and Fuel Dynamics
title_full_unstemmed Projecting Future Fire Regimes in a Semiarid Watershed of the Inland Northwestern United States: Interactions Among Climate Change, Vegetation Productivity, and Fuel Dynamics
title_short Projecting Future Fire Regimes in a Semiarid Watershed of the Inland Northwestern United States: Interactions Among Climate Change, Vegetation Productivity, and Fuel Dynamics
title_sort projecting future fire regimes in a semiarid watershed of the inland northwestern united states interactions among climate change vegetation productivity and fuel dynamics
topic fire regimes
climate change
fuel aridity
fuel loading
vegetation
fire regime modeling
url https://doi.org/10.1029/2021EF002518
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