Evidence map›Paper›PMID 42623274›Full record

ArticleTree physiology2026

Elevated CO2 buffers negative impacts of heat stress on short-term growth adjustments of 180-year-old Quercus robur.

Anna Gardner, Angus R MacKenzie, Muhammad S Amjad, Stefan Krause, Joshua Larsen, Susan Quick, Klaske van Wijngaarden, Alice Gauthey

Abstract read
In one paragraph

Article in Tree physiology, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

0numbers the graph read from it
0cells of the map it votes in
0citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

0 citing papers in PubMed.

No citing paper in PubMed yet.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

8 authors.

Anna GardnerSchool of Biological Sciences, University of Birmingham, Edgbaston B15 2TT, UK.ORCID 0000-0002-4625-9769
Angus R MacKenzieBirmingham Institute of Forest Research, University of Birmingham, Edgbaston B15 2TT, UK.
Muhammad S AmjadBirmingham Institute of Forest Research, University of Birmingham, Edgbaston B15 2TT, UK.
Stefan KrauseBirmingham Institute of Forest Research, University of Birmingham, Edgbaston B15 2TT, UK.
Joshua LarsenBirmingham Institute of Forest Research, University of Birmingham, Edgbaston B15 2TT, UK.
Susan QuickBirmingham Institute of Forest Research, University of Birmingham, Edgbaston B15 2TT, UK.ORCID 0000-0003-4239-5285
Klaske van WijngaardenBirmingham Institute of Forest Research, University of Birmingham, Edgbaston B15 2TT, UK.
Alice GautheyBirmingham Institute of Forest Research, University of Birmingham, Edgbaston B15 2TT, UK.ORCID 0000-0002-4432-8249

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

Rising atmospheric carbon dioxide (CO2) concentration are a primary driver of global warming and are expected to be associated with more frequent droughts, greater temperatures and increased vapour pressure deficit (VPD). These factors are all key drivers of tree mortality. Whilst elevated CO2 (eCO2) enhances photosynthesis (Anet) and intrinsic water-use efficiency (iWUE), its capacity to mitigate heat stress in mature trees under field conditions remains poorly understood. We investigated the effects of eCO2 on the physiological and growth responses of mature Quercus roburL. (~180 years old) at a forest Free Air Carbon Enrichment (FACE) experiment. We combined measurements of tree growth, canopy conductance and leaf gas exchange, together with leaf morphological traits, collected during a naturally occurring heat events (>32 °C), to assess whether eCO2 buffered the impacts of extreme heat events (>32 °C). The leaf-level measurements also enabled us to determine whether the physiological enhancements previously observed during the early years of Birmingham Institute of Forest Research FACE were maintained following prolonged exposure to CO2. After 8 years of CO2 enrichment (+150 p.p.m. above ambient), eCO2-grown trees showed increased iWUE (+33%), driven by increased Anet (+26.1%) and modest reductions in stomatal conductance (-11.1%), with no significant changes in stomatal anatomy. Elevated CO2 increased the sensitivity of canopy-level conductance to VPD during heat events, indicating stronger stomatal regulation under high atmospheric demand in eCO2 compared with ambient CO2-grown trees. Heat stress reduced tree growth in both conditions, but the reduction was less pronounced under eCO2, suggesting partial mitigation of heat stress effects. These findings indicate that eCO2 can confer partial physiological buffering against heat stress in mature Q. robur, enhancing resilience without compromising structure. Shifts in water use highlight the importance of integrating CO2-climate interactions when predicting forest responses to future climate extremes.

Indexed as

Carbon DioxideHeat-Shock ResponseQuercusHot TemperaturePhotosynthesisPlant LeavesPlant TranspirationTreesCarbon Dioxideclimate changeleaf gas exchangephotosynthesistree ecophysiologywater use efficiency

Identifiers

PMID42623274
PMCPMC13669954

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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.