TY - JOUR

T1 - Large loss and rapid recovery of vegetation cover and aboveground biomass over forest areas in Australia during 2019–2020

AU - Qin, Yuanwei

AU - Xiao, Xiangming

AU - Wigneron, Jean-Pierre

AU - Ciais, Philippe

AU - Canadell, Josep G.

AU - Brandt, Martin

AU - Li, Xiaojun

AU - Fan, Lei

AU - Wu, Xiaocui

AU - Tang, Hao

AU - Dubayah, Ralph

AU - Doughty, Russell

AU - Crowell, Sean

AU - Zheng, Bo

AU - Moore, Berrien

N1 - Funding Information: This study is supported in part by research grants from NASA Geostationary Carbon Cycle Observatory (GeoCarb) Mission (GeoCarb Contract # 80LARC17C0001 ), NSF ( IIA-1946093 ), NASA Land Use and Land Cover Change program ( NNX14AD78G ) and NASA Science Team for the OCO Missions ( 80NSSC21K1077 ). JGC thanks the support from the Australian National Environmental Science Program-Climate Systems Hub. We thank the four reviewers for their time and effort in the review process and their comments and suggestions are invaluable for us to improve the manuscript. Publisher Copyright: © 2022 Elsevier Inc.

PY - 2022

Y1 - 2022

N2 - Australia experienced multi-year drought and record high temperatures, and massive forest fires occurred across the southeast in 2019 and early 2020. In the fire-affected forest areas, understory and often tree canopies were burned, and in-situ observations in late 2020 reported rapid vegetation recovery, including grasses, shrubs, and tree canopies from burned-but-not-dead eucalyptus trees. Considering the strong fire resilience and resistance of eucalyptus trees and above-average rainfall in 2020, we assessed how much and how quickly vegetation structure and biomass changed from loss to post-fire and drought recovery in 2020 for all forest areas in Australia. Here, we analyzed space-borne optical, thermal, and microwave images to assess changes in the structure and function of vegetation using four vegetation indices (VIs), leaf area index (LAI), solar-induced chlorophyll fluorescence (SIF), gross primary production (GPP), and aboveground biomass (AGB). We found that all eight variables show large losses in 2019, driven by fires and climate (drought and high temperature), but large gains in 2020, resulting from the high resilience of most trees to fire and rapid growth of understory vegetation under wet condition in 2020. In 2019, the forest area has an AGB loss of 0.20 Pg C, which is ~15% of the pre-fire AGB. Attribution analyses showed that both fire and climate (prior and co-occurring severe drought and record high temperatures) are responsible for the AGB loss in 2019, approximately 0.09 Pg C (fire) and 0.11 Pg C (climate), respectively. In 2020, the forest area has a total AGB gain of 0.26 Pg C, composed of 0.22 Pg C from fire-affected forest area and 0.04 Pg C from fire-unaffected forest area. Fire-adapted Eucalyptus forests and above-average annual precipitation in 2020 brought by a moderate La Niña drove the recovery of vegetation cover, productivity, and AGB. The results from this study shows the potential of multiple sensors for monitoring and assessing the impacts of fire and climate on the forest areas in Australia and their post-fire recovery.

AB - Australia experienced multi-year drought and record high temperatures, and massive forest fires occurred across the southeast in 2019 and early 2020. In the fire-affected forest areas, understory and often tree canopies were burned, and in-situ observations in late 2020 reported rapid vegetation recovery, including grasses, shrubs, and tree canopies from burned-but-not-dead eucalyptus trees. Considering the strong fire resilience and resistance of eucalyptus trees and above-average rainfall in 2020, we assessed how much and how quickly vegetation structure and biomass changed from loss to post-fire and drought recovery in 2020 for all forest areas in Australia. Here, we analyzed space-borne optical, thermal, and microwave images to assess changes in the structure and function of vegetation using four vegetation indices (VIs), leaf area index (LAI), solar-induced chlorophyll fluorescence (SIF), gross primary production (GPP), and aboveground biomass (AGB). We found that all eight variables show large losses in 2019, driven by fires and climate (drought and high temperature), but large gains in 2020, resulting from the high resilience of most trees to fire and rapid growth of understory vegetation under wet condition in 2020. In 2019, the forest area has an AGB loss of 0.20 Pg C, which is ~15% of the pre-fire AGB. Attribution analyses showed that both fire and climate (prior and co-occurring severe drought and record high temperatures) are responsible for the AGB loss in 2019, approximately 0.09 Pg C (fire) and 0.11 Pg C (climate), respectively. In 2020, the forest area has a total AGB gain of 0.26 Pg C, composed of 0.22 Pg C from fire-affected forest area and 0.04 Pg C from fire-unaffected forest area. Fire-adapted Eucalyptus forests and above-average annual precipitation in 2020 brought by a moderate La Niña drove the recovery of vegetation cover, productivity, and AGB. The results from this study shows the potential of multiple sensors for monitoring and assessing the impacts of fire and climate on the forest areas in Australia and their post-fire recovery.

KW - Carbon

KW - Climate change

KW - Fire

KW - Forest

KW - Forest recovery

KW - Remote sensing

U2 - 10.1016/j.rse.2022.113087

DO - 10.1016/j.rse.2022.113087

M3 - Journal article

AN - SCOPUS:85130893785

VL - 278

JO - Remote Sensing of Environment

JF - Remote Sensing of Environment

SN - 0034-4257

M1 - 113087

ER -