Mechanistic Processes Controlling Persistent Changes of Forest Canopy Structure After 2005 Amazon Drought

Shi, Mingjie; Liu, Junjie; Zhao, Maosheng; Yu, Yifan; Saatchi, Sassan

doi:10.1002/2017jg003966

Cited by 4 publications

(4 citation statements)

References 70 publications

(106 reference statements)

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“…The relative importance of NPPmediated lagged effects in responses to climatic anomalies has also been inferred on from in situ and continental-scale measurements (Sherry et al, 2008;Detmers et al, 2015;Wolf et al, 2016). Our findings also suggest that tracking the long-term evolution of tropical ecosystem canopy cover (Saatchi et al, 2013;Shi et al, 2017) and reducing the process-level uncertainties associated with foliar C dynamics relationships to meteorological and disturbance forcings (discussed in Sect. 3.3) are potentially critical for advancing process-level understanding of tropical NBE IAV.…”

Section: Concurrent and Lagged Effects On The Tropical C Balancesupporting

confidence: 74%

Lagged effects regulate the inter-annual variability of the tropical carbon balance

et al. 2020

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Abstract. Inter-annual variations in the tropical land carbon (C) balance are a dominant component of the global atmospheric CO2 growth rate. Currently, the lack of quantitative knowledge on processes controlling net tropical ecosystem C balance on inter-annual timescales inhibits accurate understanding and projections of land–atmosphere C exchanges. In particular, uncertainty on the relative contribution of ecosystem C fluxes attributable to concurrent forcing anomalies (concurrent effects) and those attributable to the continuing influence of past phenomena (lagged effects) stifles efforts to explicitly understand the integrated sensitivity of a tropical ecosystem to climatic variability. Here we present a conceptual framework – applicable in principle to any land biosphere model – to explicitly quantify net biospheric exchange (NBE) as the sum of anomaly-induced concurrent changes and climatology-induced lagged changes to terrestrial ecosystem C states (NBE = NBECON+NBELAG). We apply this framework to an observation-constrained analysis of the 2001–2015 tropical C balance: we use a data–model integration approach (CARbon DAta-MOdel fraMework – CARDAMOM) to merge satellite-retrieved land-surface C observations (leaf area, biomass, solar-induced fluorescence), soil C inventory data and satellite-based atmospheric inversion estimates of CO2 and CO fluxes to produce a data-constrained analysis of the 2001–2015 tropical C cycle. We find that the inter-annual variability of both concurrent and lagged effects substantially contributes to the 2001–2015 NBE inter-annual variability throughout 2001–2015 across the tropics (NBECON IAV = 80 % of total NBE IAV, r = 0.76; NBELAG IAV = 64 % of NBE IAV, r = 0.61), and the prominence of NBELAG IAV persists across both wet and dry tropical ecosystems. The magnitude of lagged effect variations on NBE across the tropics is largely attributable to lagged effects on net primary productivity (NPP; NPPLAG IAV 113 % of NBELAG IAV, r = −0.93, p value < 0.05), which emerge due to the dependence of NPP on inter-annual variations in foliar C and plant-available H2O states. We conclude that concurrent and lagged effects need to be explicitly and jointly resolved to retrieve an accurate understanding of the processes regulating the present-day and future trajectory of the terrestrial land C sink.

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Section: Concurrent and Lagged Effects On The Tropical C Balancesupporting

confidence: 74%

Lagged effects regulate the inter-annual variability of the tropical carbon balance

et al. 2020

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“…The results also show that our fourth hypothesis, expecting higher importance of precipitation and VPD to resilience in grassland than in other VTs, is testable. The post-disturbance biotic factor determined slow recovery of the forest ecosystems was also identified by Shi et al (2017), which performed numerical simulations based on the 2005 Amazonian drought with the Community Land Model (CLM), revealing the limited influence of environmental factors to the forest recovery. The random forest feature importance study shows that hydraulics are influenced almost equally by water supply (i.e., precipitation) and demand across (i.e., VPD).…”

Section: Discussionmentioning

confidence: 99%

Ecosystem leaf area, gross primary production, and evapotranspiration responses to wildfire in the Columbia River Basin

Shi,

Mcdowell,

Huang

et al. 2024

Preprint

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Wildfires impact the provision of ecosystem services and are increasing in intensity, frequency, and spatial area globally. The rate of vegetation recovery after fire plays a major role in the recovery of ecosystem services, but such recovery rates are poorly understood. Here we used remotely sensed data products from the Moderate Resolution Imaging Spectroradiometer (MODIS) to quantify the resistance and resilience of leaf area index (LAI), gross primary production (GPP), and evapotranspiration (ET) to 138 wildfires across the Columbia River Basin of the Pacific Northwest in 2015. Increasing burn severity caused lower resistance and resilience for all three variables. Resistance and resilience were highest in grasslands, intermediate in woodlands, and lowest in needleleaf evergreen forests, consistent with adaptation of these vegetation types to fire. LAI had consistently lower resistance and resilience than GPP and ET, which is consistent with physical and physiological mechanisms that compensate for reduced LAI.Resilience was influenced by precipitation, vapor pressure deficit (VPD), and burn severity across all three vegetation types, however, burn severity played a more minor role in grasslands.Increasing wildfire severity will reduce the resistance and resilience and lengthen the recovery time of vegetation structure and fluxes with climate change, with significant consequences on the provision of ecosystem services and complications for model predictions.

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“…We find that the remaining states (labile C, wood C, fine root C and litter C) explain < 0.2 PgC/yr variability of ΔNBE LAG across all regions. The gradual increase of ΔNBE LAG across all tropical regions ( Figure 6) is 525 jointly attributable to changes in soil C and foliar C, while plant-available water exhibits no substantial trend: these results suggest that tracking the long-term evolution of tropical ecosystem canopy cover (Saatchi et al, 2013;Shi et al, 2017) and reducing the process-level uncertainties associated with foliar C dynamics relationships to meteorological forcings (discussed in 3.4) are potentially critical for advancing quantitative understanding of tropical NBE IAV. We also note that, while our analysis focused on the ΔNBE LAG sensitivity to year-to-year ecosystem states changes, the magnitude of ΔNBE CON is also in 530 principle dependent on time-varying ecosystem states (Figure 2).…”

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confidence: 90%

Lagged effects dominate the inter-annual variability of the 2010–2015 tropical carbon balance

Bloom

Bowman

Liu

et al. 2020

Preprint

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Inter-annual variations in the tropical land carbon (C) balance are a dominant component of the global atmospheric CO2 growth rate. Currently, the lack of quantitative knowledge on processes controlling net tropical ecosystems C balance on inter-annual timescales inhibits accurate understanding and projections of land-atmosphere C exchanges. In particular, uncertainty on the 20 relative contribution of ecosystem C fluxes attributable to concurrent meteorological forcing anomalies (concurrent effects) and those attributable to the continuing influence of past phenomena (lagged effects) stifles efforts to explicitly understand the integrated sensitivity of tropical ecosystem to climatic variability. Here we present a conceptual framework-applicable in principle to any meteorology-forced land biosphere model-to explicitly quantify net biospheric exchange (NBE) as the sum of anomaly-induced concurrent changes and climatology-induced lagged changes to terrestrial ecosystem C states (NBE = 25 NBE CON + NBE LAG ). We apply this framework to an observation-constrained analysis of the 2010-2015 tropical C balance:we use a data-model integration approach (CARDAMOM) to merge satellite-retrieved land-surface C observations (leaf area, biomass, solar-induced fluorescence), soil C inventory data and satellite-based atmospheric inversion estimates of CO2 and CO fluxes to produce a data-constrained analysis of the 2010-2015 tropical C cycle. We find that the inter-annual variability of lagged effects explains the majority of NBE inter-annual variability (IAV) throughout 2010-2015 across the tropics (NBE LAG 30 IAV = 112% of NBE IAV, r = 0.87) relative to concurrent effects (NBE CON IAV = 54% of total NBE IAV, r = 0.03) and the dominance of NBE LAG IAV persists across both wet and dry tropical ecosystems. The magnitude of lagged effect variations on NBE across the tropics is largely attributable to lagged effects on net primary productivity (NPP; NPP LAG IAV 88% of NBE LAG IAV, r = -0.99, p-value<0.05), which emerge due to the dependence of NPP on inter-annual variations in canopy C mass and

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Mechanistic Processes Controlling Persistent Changes of Forest Canopy Structure After 2005 Amazon Drought

Cited by 4 publications

References 70 publications

Lagged effects regulate the inter-annual variability of the tropical carbon balance

Lagged effects regulate the inter-annual variability of the tropical carbon balance

Ecosystem leaf area, gross primary production, and evapotranspiration responses to wildfire in the Columbia River Basin

Lagged effects dominate the inter-annual variability of the 2010–2015 tropical carbon balance

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