A first assessment of the impact of the extreme 2018 summer drought on Central European forests

Basic and Applied Ecology, Journal Year: 2020, Volume and Issue: 45, P. 86 - 103

Published: April 29, 2020

In 2018, Central Europe experienced one of the most severe and long-lasting summer drought heat wave ever recorded. Before 2003 millennial was often invoked as example a "hotter drought", classified event in for last 500 years. First insights now confirm that 2018 climatically more extreme had greater impact on forest ecosystems Austria, Germany Switzerland than drought. Across this region, mean growing season air temperature from April to October 3.3°C above long-term average, 1.2°C warmer 2003. Here, we present first assessment heatwave European forests. response event, ecologically economically important tree species temperate forests showed signs stress. These symptoms included exceptionally low foliar water potentials crossing threshold xylem hydraulic failure many observations widespread leaf discoloration premature shedding. As result stress, caused unprecedented drought-induced mortality throughout region. Moreover, unexpectedly strong drought-legacy effects were detected 2019. This implies physiological recovery trees impaired after leaving them highly vulnerable secondary impacts such insect or fungal pathogen attacks. consequence, triggered by events is likely continue several Our indicates common are waves previously thought. occur frequently with progression climate change, might approach point substantial ecological economic transition. also highlights urgent need pan-European ground-based monitoring network suited track individual mortality, supported remote sensing products high spatial temporal resolution track, analyse forecast these transitions.

Language: Английский

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From the comfort zone to crown dieback: Sequence of physiological stress thresholds in mature European beech trees across progressive drought

The Science of The Total Environment, Journal Year: 2020, Volume and Issue: 753, P. 141792 - 141792

Published: Aug. 21, 2020

Language: Английский

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Representation of Plant Hydraulics in the Noah‐MP Land Surface Model: Model Development and Multiscale Evaluation

Journal of Advances in Modeling Earth Systems, Journal Year: 2021, Volume and Issue: 13(4)

Published: Feb. 6, 2021

Abstract Plants are expected to face increasing water stress under future climate change. Most land surface models, including Noah‐MP, employ an idealized “big‐leaf” concept regulate and carbon fluxes in response soil moisture through empirical hydraulics schemes (SHSs). However, such have been shown cause significant uncertainties simulations. In this paper, we present a novel plant scheme (PHS) for Noah‐MP (hereafter, Noah‐MP‐PHS), which employs big‐tree rather than big‐leaf concept, wherein the whole‐plant hydraulic strategy is considered, root‐level acquisition, stem‐level conductance capacitance, leaf‐level anisohydricity capacitance. Evaluated against plot‐level observations from mature, mixed hardwood forest at University of Michigan Biological Station compared with default Noah‐MP‐PHS better represents improves simulations, especially during periods dry conditions. also asymmetrical diel simulation gross primary production low able reproduce different patterns transpiration, stem storage root uptake 2‐week dry‐down period two species contrasting behaviors, i.e., “cavitation risk‐averse” red maple risk‐prone” oak. Sensitivity experiments capacitance show that enables nocturnal recharge, affects use efficiency, provides important buffer relieve xylem

Language: Английский

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Mutually inclusive mechanisms of drought‐induced tree mortality

Global Change Biology, Journal Year: 2022, Volume and Issue: 28(10), P. 3365 - 3378

Published: March 5, 2022

Unprecedented tree dieback across Central Europe caused by recent global change-type drought events highlights the need for a better mechanistic understanding of drought-induced mortality. Although numerous physiological risk factors have been identified, importance two principal mechanisms, hydraulic failure and carbon starvation, is still debated. It further remains largely unresolved how local neighborhood composition affects individual mortality risk. We studied 9435 young trees 12 temperate species planted in diversity experiment 2013 to assess traits, dynamics, pest infestation, height competition influence Following most extreme since record 2018, one third these died. Across species, safety margins (HSMs) were negatively shift towards higher sugar fraction non-structural carbohydrate (NSC) pool positively associated with Moreover, infested bark beetles had risk, taller lower Most interactions beneficial, although effects highly species-specific. Species that suffered more from drought, especially Larix spp. Betula spp., tended increase survival probability their neighbors vice versa. While severe tissue dehydration marks final stage mortality, we show interrelated series other, mutually inclusive processes. These include shifts NSC pools driven osmotic adjustment and/or starch depletion as well infestation are modulated size identity its neighbors. A holistic view accounts multiple causes required improve predictions trends forest dynamics identify beneficial combinations.

Language: Английский

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The Possible Role of Non-Structural Carbohydrates in the Regulation of Tree Hydraulics

International Journal of Molecular Sciences, Journal Year: 2019, Volume and Issue: 21(1), P. 144 - 144

Published: Dec. 24, 2019

The xylem is a complex system that includes network of dead conduits ensuring long-distance water transport in plants. Under ongoing climate changes, embolism major and recurrent cause drought-induced tree mortality. Non-structural carbohydrates (NSC) play key roles plant responses to drought frost stress, several studies putatively suggest their involvement the regulation transport. However, clear picture on NSCs hydraulics has not been drawn date. We summarize current knowledge during formation subsequent hydraulic recovery. drought, sugars are generally accumulated parenchyma sap. At drought-relief, functionality restored an osmotically driven process involving wood parenchyma, sap phloem compartments. By analyzing published data stem NSC contents under drought/frost stress relief, we found build-up positively correlated depletion, magnitude post-stress recovery consumption soluble sugars. These findings close relationship between carbohydrate dynamics. call for more experiments dynamics controlled field conditions.

Language: Английский

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Wood density predicts mortality threshold for diverse trees

New Phytologist, Journal Year: 2020, Volume and Issue: 229(6), P. 3053 - 3057

Published: Nov. 30, 2020

In the past decades, drought-induced forest die-off has been recorded on every forested biome, exerting great effects biodiversity and ecosystem functions (Allen et al., 2010; Hartmann 2018; Brodribb 2020). A general understanding of vulnerability to damage due climate is lacking, because our limited variation in lethal water potential (Ψlethal) trees. Achieving this critical goal requires a reliable proxy for Ψlethal that can be used characterize many species community. Tree (Ψ), which shapes tree hydraulic conductance uptake from soil, robust direct indicator physiological stress (Steppe, 2018). The threshold Ψ beyond trees are unable recover drought, even after year rewatering (Brodribb & Cochard, 2009; Choat, 2013). face along with decreasing soil availability, gradually drops (i.e. becomes more negative), inducing xylem cavitation loss conductivity (Sperry 2002). When falls below Ψlethal, spreads widely within conduits, eventually, die excessive dehydration cells (McDowell 2008; Körner, 2019). recent data synthesis showed dehydrated experienced > 60% conductivity, suggesting ubiquitous failure mortality (Adams 2017). However, technical problems associated measuring plants undergoing tissue damage, leading not quantified across species, despite its importance predicting response vegetation drought (Choat Blackman 2019; McDowell determination particularly time- labor-consuming. Quantification typically done by monitoring recovery potted exposure different degrees stress. This approach may take months years experiments Kursar 2009), decades studies examining natural events (Breshears 2016). Added challenge identifying death during as opposed seasonal or transient leaf deciduousness (Wolfe Therefore, we need explore understand drought. Based previous few studies, useful associations between have observed Urli If these emerge constitutive feature plants, then curve data, now available hundreds (Maherali 2004; Choat 2012; McCulloh 2019), could provide important insights into two drawbacks currently limit broad application Ψlethal; first, relationship yet generalized diverse species; second, technique laborious technically challenging. respect wood density (dry weight per fresh volume sapwood) offer an alternative. Wood thought essential index tolerance (Hacke 2001; Greenwood 2017), correlation easily measured trait never tested before. present study, values 59 were compiled published journal articles. We aimed investigate (1) at level biomes (2) correlations functional traits believed related tolerance. hypothesized was lower (more negative) P50 P88 (Ψ 50% 88% respectively), higher density. First, extracted Where possible, P50, P88, obtained same source location all species. For location-specific found, mean via searching literature datasets, ignoring intra-specific traits. final dataset included three biomes, i.e. tropical, subtropical, temperate forests. Specifically, there 14 gymnosperms seven genera, families, 45 angiosperms 36 21 families (Supporting Information Table S1). Across assessed, ranged −1.5 MPa (Populus balsamifera, angiosperm) −14.7 (Callitris columellaris, gymnosperm) (Fig. 1). significantly (mean value: −8.2 MPa) than −6.0 (Student's t-test: t = 2.33, P < 0.05), line findings drought-tolerant 2012). There no significant difference subtropical −1.83, 0.09), while forests had less negative (−4.4 those tropical (−6.7 (−7.0 (ANOVA: F 4.32, 0.05; Fig. differences among might result climatic seasonality (Liu 2021), most here being seasonally dry example, angiosperm having Barro Colorado Island Panama, pronounced 4-month season (Kursar 2009). As evergreens, they exposed low availability period season, probable evolutionary selection resistance. By contrast, deciduous (Table S1), usually do experience regularly humid growing season. Hence subtropical/tropical evergreen These imply climate, especially rainfall seasonality, matters shaping plant tolerance, investigations needed draw complete picture global scale. linearly correlated (R2 0.75, 0.001; 2a), slope 1 (standardized major axis test: 0.43), represents good predictor gymnosperms. raises question: how remaining? answer lie leaves (or needles), commonly resistant stems (Choat, Indeed, four close stem but importantly, 95% point situation runaway likely completely disconnect stem, rapidly causing Regarding angiosperms, always 2a,b), closer P88. explains why so operated safety margin, lowest under conditions It also strengthens idea margin provides meaningful metric describing (Urli Highly found both 0.50, 0.001) 0.43, 0.01) 2c). properties storage transport, resistance Hoffmann 2011). study forest, osmotic full turgor (De Guzman 2021). reported denser globe (Fu Meinzer, providing clear evidence high able retain thus survive Ψ. On scale, tend rates (Nardini 2013; Taken together, suggests density, trait, considered angiosperms. should noted given 2c), similar Hacke al. (2001). reflect contrasting characteristics types Of particular relevance distinct anatomy inter-conduit pits (torus-margo pits) vs (simple bordered pits). Given pit determining (Lens 2011), it surprising see time takes reach determines survival droughts, therefore models aim predict must include parameter (Blackman Our results variations conclusion Ψlethal. Although first step, work expand sample diversity confirm generality patterns here. Drought-induced widespread only presented small number biomes. Besides, primarily came seedlings saplings, mature field poorly represented. multiple life stages Pinus edulis, showing Nonetheless, shown change age (Rosner 2014), hold regardless stage. sum, suggest quite hard measure, predicted using trait. advance prediction changing climate. authors thank editor reviewers their constructive suggestions comments earlier version manuscript. supported National Natural Science Foundation China (31825005 31800336), Guangdong Basic Applied Research (2020A1515010688), Key Special Project Introduced Talents Team Southern Marine Engineering Laboratory (Guangzhou; GML2019ZD0408), Institution South Sea Ecology Environmental Engineering, Chinese Academy Sciences (ISEE2018YB01). declare competing interests. XL QY conceived idea, analyzed drafted manuscript, XL, QY, HL TJB contributed substantially revisions. All S1. S1 Full sources study. Please note: Wiley Blackwell responsible content functionality any Supporting supplied authors. Any queries (other missing material) directed New Phytologist Central Office. publisher supporting information content) corresponding author article.

Language: Английский

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SurEau: a mechanistic model of plant water relations under extreme drought

Annals of Forest Science, Journal Year: 2021, Volume and Issue: 78(2)

Published: June 1, 2021

Abstract Key message A new process-based model, SurEau , is described. It predicts the risk of xylem hydraulic failure under drought. Context The increase in drought intensity due to climate change will accentuate tree mortality. But very few models are currently able predict this mortality risk. Aims We describe operating principle a mechanistic model that computes water balance, relations, and hydraulics plant extreme Methods based on formalization key physiological processes response stress. hydric functioning at core which focuses both flows (i.e., hydraulic) pools hydric) using variable conductances. considers elementary flow from soil atmosphere through different organs described by their symplasmic apoplasmic compartments. For each organ, symplasm pressure-volume curve apoplasm its vulnerability cavitation. evaluated mature oak trees exposed Results On tested trees, captures well observed level embolism. sensitivity analysis reveals embolism strongly determined air VPD traits such as cuticular transpiration, resistance cavitation, leaf area. Conclusion offers opportunities evaluate how species or genotypes respond future climatic conditions.

Language: Английский

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Global ecosystem-scale plant hydraulic traits retrieved using model–data fusion

Hydrology and earth system sciences, Journal Year: 2021, Volume and Issue: 25(5), P. 2399 - 2417

Published: May 10, 2021

Abstract. Droughts are expected to become more frequent and severe under climate change, increasing the need for accurate predictions of plant drought response. This response varies substantially, depending on properties that regulate water transport storage within plants, i.e., hydraulic traits. It is, therefore, crucial map traits at a large scale better assess impacts. Improved understanding global variations in is also needed parameterizing latest generation land surface models, many which explicitly simulate processes first time. Here, we use model–data fusion approach evaluate spatial pattern across globe. integrates model with data sets derived from microwave remote sensing inform ecosystem-scale regulation. In particular, both soil moisture vegetation optical depth (VOD) X-band Japan Aerospace Exploration Agency (JAXA) Advanced Microwave Scanning Radiometer Earth Observing System (EOS; collectively AMSR-E). VOD proportional content and, closely related leaf potential. addition, evapotranspiration (ET) Atmosphere–Land Exchange Inverse (ALEXI) used as constraint derive The compared independent sources based ground measurements. Using K-means clustering method, build six functional types (HFTs) distinct trait combinations – mathematically tractable alternatives common assigning values types. averaged by HFTs rather than (PFTs) improves ET estimation accuracies majority areas and/or this study will contribute improved parameterization hydraulics large-scale models prediction ecosystem

Language: Английский

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The uncertain role of rising atmospheric CO2 on global plant transpiration

Earth-Science Reviews, Journal Year: 2022, Volume and Issue: 230, P. 104055 - 104055

Published: May 12, 2022

As CO2 concentration in the atmosphere rises, there is a need for improved physical understanding of its impact on global plant transpiration. This knowledge gap poses major hurdle robustly projecting changes hydrologic cycle. For this reason, here we review different processes by which atmospheric affects transpiration, several uncertainties related to complex physiological and radiative involved, gaps be filled order improve predictions Although high degree certainty that rising will exact nature remains unclear due interactions between climate, key aspects morphology physiology. The interplay these factors has substantial consequences not only future climate vegetation, but also water availability needed sustaining productivity terrestrial ecosystems. Future transpiration response enhanced are expected driven availability, evaporative demand, processes, emergent disturbances increasing temperatures, modification physiology coverage. Considering universal sensitivity natural agricultural systems argue reliable projections an issue highest priority, can achieved integrating monitoring modeling efforts representation effects next generation earth system models.

Language: Английский

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Key technologies improvements promote the economic-environmental sustainability in wheat production of China

Journal of Cleaner Production, Journal Year: 2024, Volume and Issue: 443, P. 141230 - 141230

Published: Feb. 13, 2024

Language: Английский

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