Climate Change Risks to Global Forest Health: Emergence of Unexpected Events of Elevated Tree Mortality Worldwide

Annual Review of Plant Biology, Journal Year: 2022, Volume and Issue: 73(1), P. 673 - 702

Published: March 1, 2022

Recent observations of elevated tree mortality following climate extremes, like heat and drought, raise concerns about change risks to global forest health. We currently lack both sufficient data understanding identify whether these represent a trend toward increasing mortality. Here, we document events sudden unexpected drought in ecosystems that previously were considered tolerant or not at risk exposure. These underscore the fact may affect forests with force future. use as examples highlight current difficulties challenges for realistically predicting such uncertainties future condition. Advances remote sensing technology greater availably high-resolution data, from field assessments satellites, are needed improve prediction responses change. Expected final online publication date Annual Review Plant Biology, Volume 73 is May 2022. Please see http://www.annualreviews.org/page/journal/pubdates revised estimates.

Language: Английский

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Extreme heat increases stomatal conductance and drought‐induced mortality risk in vulnerable plant species

Global Change Biology, Journal Year: 2021, Volume and Issue: 28(3), P. 1133 - 1146

Published: Nov. 6, 2021

Tree mortality during global-change-type drought is usually attributed to xylem dysfunction, but as climate change increases the frequency of extreme heat events, it necessary better understand interactive role stress. We hypothesized that some drought-stressed plants paradoxically open stomata in heatwaves prevent leaves from critically overheating. experimentally imposed (>40°C) and stress onto 20 broadleaf evergreen tree/shrub species a glasshouse study. Most well-watered avoided lethal overheating, exacerbated thermal damage heatwaves. Thermal safety margins (TSM) quantifying difference between leaf surface temperature critical temperature, where photosynthesis disrupted, identified vulnerability Several mechanisms contributed high tolerance avoidance damaging temperatures-small size, low osmotic potential, mass per area (i.e., thick, dense leaves), transpirational capacity, access water. Water-stressed had smaller TSM, greater crown dieback, fundamentally different stomatal heatwave response relative plants. On average, closed decreased conductance (gs ) heatwave, droughted did not. Plant with gs , either due isohydric behavior under water deficit or inherently opened increased temperatures. The current paradigm maintains close before hydraulic thresholds are surpassed, our results suggest may dramatically increase (over sixfold increases) even past their turgor loss point. By actively increasing at temperatures, can be driven toward more rapidly than has been previously recognized. inclusion TSM responses could improve ability predict tree future droughts.

Language: Английский

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Drought legacies and ecosystem responses to subsequent drought

Global Change Biology, Journal Year: 2022, Volume and Issue: 28(17), P. 5086 - 5103

Published: May 24, 2022

Climate change is expected to increase the frequency and severity of droughts. These events, which can cause significant perturbations terrestrial ecosystems potentially long-term impacts on ecosystem structure functioning after drought has subsided are often called 'drought legacies'. While immediate effects have been comparatively well characterized, our broader understanding legacies just emerging. Drought relate all aspects functioning, involving changes at species community scale as alterations soil properties. This consequences for responses subsequent drought. Here, we synthesize current knowledge underlying mechanisms. We highlight relevance legacy duration different processes using examples carbon cycling composition. present hypotheses characterizing how intrinsic (i.e. biotic abiotic properties processes) extrinsic timing, severity, frequency) factors could alter resilience trajectories under scenarios recurrent events. propose ways improving their implications needed assess longer-term droughts functioning.

Language: Английский

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Tropical tree mortality has increased with rising atmospheric water stress

Nature, Journal Year: 2022, Volume and Issue: 608(7923), P. 528 - 533

Published: May 18, 2022

Language: Английский

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Compound climate events increase tree drought mortality across European forests

The Science of The Total Environment, Journal Year: 2021, Volume and Issue: 816, P. 151604 - 151604

Published: Nov. 12, 2021

Climate change can lead to the simultaneous occurrence of extreme droughts and heat waves increasing frequency compound events with unknown impacts on forests. Here we use two independent datasets, a compiled database tree drought mortality ICP-Forest level I plots, study hot summers, elevated vapour pressure deficit (VPD), dry years forest defoliation across Europe. We focused background rates, studied their co-occurrence summers years. In total, 143 out 310 Europe, i.e. 46% cases, corresponded rare characterized by Over past decades, summer temperature increased in most sites severe resulted not observed before 1980s. From plots identified 291 (1718 trees) 61 (128 where mortality, respectively, were caused drought. The analyses these showed that 34% 27% cases climate events, respectively. Background rates Europe period 1993-2013 presented higher values regions VPD more steeply rose, increased. steady increase temperatures Southern Eastern may favor conditions. Giving both, local intense are linked such expect an European over next decades.

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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European beech dieback after premature leaf senescence during the 2018 drought in northern Switzerland

Plant Biology, Journal Year: 2022, Volume and Issue: 24(7), P. 1132 - 1145

Published: Sept. 14, 2022

During the particularly severe hot summer drought in 2018, widespread premature leaf senescence was observed several broadleaved tree species Central Europe, European beech (Fagus sylvatica L.). For beech, it is yet unknown whether evoked a decline towards mortality or trees can recover longer term. In this study, we monitored crown dieback, and secondary damage symptoms 963 initially live that exhibited either normal 2018 three regions northern Switzerland from to 2021. We related multiple climate- stand-related parameters. Cumulative continuously increased up 7.2% 1.3% 2021 for with respectively. Mean dieback surviving peaked at 29.2% 2020 8.1% 2019 senescence, Thereafter, showed first signs of recovery. Crown more pronounced recovery slower growing on drier sites, larger trees. The presence bleeding cankers 24.6% 10.7% bark beetle holes 22.8% 14.8% Both occurred frequently had higher proportions and/or 2018. Our findings demonstrate context-specific differences reflecting importance regional local climate soil conditions. Adapting management increase forest resilience gaining importance, given expected further dry sites Switzerland.

Language: Английский

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The impacts of rising vapour pressure deficit in natural and managed ecosystems

Plant Cell & Environment, Journal Year: 2024, Volume and Issue: 47(9), P. 3561 - 3589

Published: Feb. 13, 2024

An exponential rise in the atmospheric vapour pressure deficit (VPD) is among most consequential impacts of climate change terrestrial ecosystems. Rising VPD has negative and cascading effects on nearly all aspects plant function including photosynthesis, water status, growth survival. These responses are exacerbated by land-atmosphere interactions that couple to soil govern evolution drought, affecting a range ecosystem services carbon uptake, biodiversity, provisioning resources crop yields. However, despite global nature this phenomenon, research how incorporate these into resilient management regimes largely its infancy, due part entanglement trends with those other co-evolving drivers. Here, we review mechanistic bases at spatial scales, paying particular attention independent interactive influence context environmental changes. We then evaluate consequences within key contexts, resources, croplands, wildfire risk mitigation natural grasslands forests. conclude recommendations describing could be altered mitigate otherwise highly deleterious rising VPD.

Language: Английский

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A joint framework for studying compound ecoclimatic events

Nature Reviews Earth & Environment, Journal Year: 2023, Volume and Issue: 4(5), P. 333 - 350

Published: April 18, 2023

Language: Английский

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The role of height‐driven constraints and compensations on tree vulnerability to drought

New Phytologist, Journal Year: 2023, Volume and Issue: 239(6), P. 2083 - 2098

Published: July 23, 2023

Summary Frequent observations of higher mortality in larger trees than smaller ones during droughts have sparked an increasing interest size‐dependent drought‐induced mortality. However, the underlying physiological mechanisms are not well understood, with height‐associated hydraulic constraints often being implied as potential mechanism driving increased drought vulnerability. We performed a quantitative synthesis on how key traits that drive plant water and carbon economy change tree height within species assessed implications different compensations may interacting (hydraulic failure, starvation and/or biotic‐agent attacks) affecting vulnerability to drought. While xylem tension increases height, taller present range structural functional adjustments, including more efficient use transport greater uptake storage capacity, mitigate path‐length‐associated drop potential. These adaptations allow withstand episodic stress. Conclusive evidence for height‐dependent failure starvation, their coupling defence pest pathogen dynamics, is still lacking. Further research needed, particularly at intraspecific level, ascertain specific conditions thresholds above which hinders survival under

Language: Английский

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