Mixed-species forests are proposed to enhance tree resistance and resilience to drought. However, growing evidence shows that tree species richness does not consistently improve tree growth responses to drought. The underlying mechanisms remain uncertain, especially under unprecedented multiyear droughts. We used a network of planted tree diversity experiments to investigate how neighborhood tree diversity and species' functional traits influence individual tree responses to drought. We analyzed tree cores (948 trees across 16 species) from nine young experiments across Europe featuring tree species richness gradients (1-6 species), which experienced recent severe droughts. Radial growth response to drought was quantified as tree-ring biomass increment using X-ray computed tomography. We applied hydraulic trait-based growth models to analyze single-year drought responses across all sites and site-specific responses during consecutive drought years. Growth responses to a single-year drought were partially explained by the focal species' hydraulic safety margin (representing species' drought tolerance) and drought intensity, but were independent of neighborhood species richness. The effects of neighborhood functional diversity on growth responses shifted from positive to negative with increasing drought duration during a single growing season. Tree diversity effects on growth responses strengthened during consecutive drought years and were site-specific with contrasting directions (both positive and negative). This indicates opposing diversity effects pathways under consecutive drought events, possibly resulting from competitive release or greater water consumption in diverse mixtures. We conclude that tree diversity effects on growth under single-year droughts may differ considerably from responses to consecutive drought years. Our study highlights the need to consider trait-based approaches (specifically, hydraulic traits) and neighborhood scale processes to understand the multifaceted responses of tree mixtures under prolonged drought stress. This experimental approach provides a robust framework to test biodiversity-ecosystem functioning (BEF) relationships relevant for young, planted forests under increased drought stress.

AgroParisTech INRAE UMR Silva Université de Lorraine Nancy France

Chair of Geobotany Faculty of Biology University of Freiburg Freiburg Germany

Chair of Silviculture Faculty of Environment and Natural Resources Institute of Forest Sciences University of Freiburg Freiburg Germany

CIRAD INRAE Institut Agro IRD Eco and Sols Univ Montpellier Montpellier France

Consiglio Nazionale Delle Ricerche Istituto per la Bioeconomia CNR IBE Sassari Italy

Department of Biological Sciences Royal Holloway University of London Surrey UK

Department of Forest and Soil Sciences Institute of Forest Ecology University of Natural Resources and Life Sciences Vienna Austria

Department of Forest Protection and Wildlife Management Faculty of Forestry and Wood Technology Mendel University in Brno Brno Czech Republic

Earth and Life Institute Université Catholique de Louvain Louvain la Neuve Belgium

Forest and Nature Lab Department Environment Ghent University Melle Gontrode Belgium

Forest Science Department University of São Paulo ESALQ Piracicaba Brazil

French Environment and Energy Management Agency Angers France

Huanjiang Agriculture Ecosystem Observation and Research Station of Guangxi Guangxi Key Laboratory of Karst Ecological Processes and Services Huanjiang Observation and Research Station for Karst Ecosystems Chinese Academy of Sciences Huanjiang China

Hydrology Section GFZ Helmholtz Centre for Geosciences Potsdam Germany

IAFES Division CMCC Centro Euro Mediterraneo sui Cambiamenti Climatici Sassari Italy

INRAe Ecologie Des Forêts Méditerranéennes Avignon France

INRAE University of Bordeaux Cestas France

Key Laboratory of Agro Ecological Processes in Subtropical Region Institute of Subtropical Agriculture Chinese Academy of Sciences Changsha China

School of Integrative Plant Science Cornell University Ithaca New York USA

UGent Center for 10 Ray Tomography Ghent University Ghent Belgium

UGent Radiation Physics Department of Physics and Astronomy Faculty of Sciences Ghent University Ghent Belgium

UGent Woodlab Laboratory of Wood Technology Department of Environment Faculty of Bioscience Engineering Ghent University Ghent Belgium

Zobrazit více v PubMed

Agnew, C. T. 2000. “Using the SPI to Identify Drought.” Drought Network News 12, no. 1: 6–12.

Aldea, J. , Ruiz‐Peinado R., Del Río M., et al. 2022. “Timing and Duration of Drought Modulate Tree Growth Response in Pure and Mixed Stands of Scots Pine and Norway Spruce.” Journal of Ecology 110, no. 11: 2673–2683. 10.1111/1365-2745.13978. DOI

Anderegg, L. D. L. , Anderegg W. R. L., and Berry J. A.. 2013. “Not all Droughts Are Created Equal: Translating Meteorological Drought Into Woody Plant Mortality.” Tree Physiology 33, no. 7: 701–712. 10.1093/treephys/tpt044. PubMed DOI

Anderegg, W. R. L. 2015. “Spatial and Temporal Variation in Plant Hydraulic Traits and Their Relevance for Climate Change Impacts on Vegetation.” New Phytologist 205, no. 3: 1008–1014. 10.1111/nph.12907. PubMed DOI

Anderegg, W. R. L. , Klein T., Bartlett M., et al. 2016. “Meta‐Analysis Reveals That Hydraulic Traits Explain Cross‐Species Patterns of Drought‐Induced Tree Mortality Across the Globe.” Proceedings of the National Academy of Sciences of the United States of America 113, no. 18: 5024–5029. 10.1073/pnas.1525678113. PubMed DOI PMC

Anderegg, W. R. L. , Konings A. G., Trugman A. T., et al. 2018. “Hydraulic Diversity of Forests Regulates Ecosystem Resilience During Drought.” Nature 561, no. 7724: 538–541. 10.1038/s41586-018-0539-7. PubMed DOI

Anderegg, W. R. L. , Schwalm C., Biondi F., et al. 2015. “Pervasive Drought Legacies in Forest Ecosystems and Their Implications for Carbon Cycle Models.” Science 349, no. 6247: 528–532. 10.1126/science.aab1833. PubMed DOI

Anderegg, W. R. L. , Trugman A. T., Badgley G., Konings A. G., and Shaw J.. 2020. “Divergent Forest Sensitivity to Repeated Extreme Droughts.” Nature Climate Change 10, no. 12: 1091–1095. 10.1038/s41558-020-00919-1. DOI

Bartlett, M. K. , Klein T., Jansen S., Choat B., and Sack L.. 2016. “The Correlations and Sequence of Plant Stomatal, Hydraulic, and Wilting Responses to Drought.” Proceedings of the National Academy of Sciences of the United States of America 113, no. 46: 13098–13103. 10.1073/pnas.1604088113. PubMed DOI PMC

Bastos, A. , Ciais P., Friedlingstein P., et al. 2020. “Direct and Seasonal Legacy Effects of the 2018 Heat Wave and Drought on European Ecosystem Productivity.” Science Advances 6, no. 24: eaba2724. 10.1126/sciadv.aba2724. PubMed DOI PMC

Bastos, A. , Orth R., Reichstein M., Ciais P., Viovy N., and Zaehle S.. 2021. Increased Vulnerability of European Ecosystems to Two Compound Dry and Hot Summers in 2018 and 2019. Earth Syst Dynam.

Bates, D. , Mächler M., Bolker B., and Walker S.. 2015. “Fitting Linear Mixed‐Effects Models Using lme4.” Journal of Statistical Software 67, no. 1: 1–48. 10.18637/jss.v067.i01. DOI

Bauhus, J. , Forrester D. I., and Pretzsch H.. 2017. “From Observations to Evidence About Effects of Mixed‐Species Stands.” In Mixed‐Species Forests, edited by Pretzsch H., Forrester D. I., and Bauhus J., 27–71. Springer Berlin Heidelberg.

Beguería, S. , Latorre B., Reig F., and Vicente‐Serrano S. M.. 2022. SPEI Global Drought Monitor. https://spei.csic.es/map/.

Beguería, S. , and Vicente‐Serrano S. M.. 2017. Package ‘spei’. Calculation of the Standardised Precipitation‐Evapotranspiration Index.

Bello, J. , Hasselquist N. J., Vallet P., Kahmen A., Perot T., and Korboulewsky N.. 2019. “Complementary Water Uptake Depth of Quercus Petraea and DOI

Benavides, R. , Valladares F., Wirth C., Müller S., and Scherer‐Lorenzen M.. 2019. “Intraspecific Trait Variability of Trees is Related to Canopy Species Richness in European Forests.” Perspectives in Plant Ecology, Evolution and Systematics 36: 24–32. 10.1016/j.ppees.2018.12.002. DOI

Bertness, M. D. , and Callaway R.. 1994. “Positive Interactions in Communities.” Trends in Ecology & Evolution 9, no. 5: 191–193. 10.1016/0169-5347(94)90088-4. PubMed DOI

Beugnon, R. , Le Guyader N., Milcu A., et al. 2024. “Microclimate Modulation: An Overlooked Mechanism Influencing the Impact of Plant Diversity on Ecosystem Functioning.” Global Change Biology 30, no. 3: e17214. 10.1111/gcb.17214. PubMed DOI

Biondi, F. , and Qeadan F.. 2008. “A Theory‐Driven Approach to Tree‐Ring Standardization: Defining the Biological Trend From Expected Basal Area Increment.” Tree‐Ring Research 64, no. 2: 81–96. 10.3959/2008-6.1. DOI

Björklund, J. , Arx G., Nievergelt D., et al. 2019. “Scientific Merits and Analytical Challenges of Tree‐Ring Densitometry.” Reviews of Geophysics 57, no. 4: 1224–1264. 10.1029/2019RG000642. DOI

Blondeel, H. , Guillemot J., Martin‐StPaul N., et al. 2024. “Tree Diversity Reduces Variability in Sapling Survival Under Drought.” Journal of Ecology 112, no. 5: 1164–1180. 10.1111/1365-2745.14294. DOI

Bontemps, J.‐D. , Hervé J.‐C., and Dhôte J.‐F.. 2010. “Dominant Radial and Height Growth Reveal Comparable Historical Variations for Common Beech in North‐Eastern France.” Forest Ecology and Management 259, no. 8: 1455–1463. 10.1016/j.foreco.2010.01.019. DOI

Bose, A. K. , Doležal J., Scherrer D., et al. 2024. “Revealing Legacy Effects of Extreme Droughts on Tree Growth of Oaks Across the Northern Hemisphere.” Science of the Total Environment 926: 172049. 10.1016/j.scitotenv.2024.172049. PubMed DOI

Brodribb, T. J. , and Holbrook N. M.. 2003. “Stomatal Closure During Leaf Dehydration, Correlation With Other Leaf Physiological Traits.” Plant Physiology 132, no. 4: 2166–2173. 10.1104/pp.103.023879. PubMed DOI PMC

Bunn, A. G. 2008. “A Dendrochronology Program Library in R (dplR).” Dendrochronologia 26, no. 2: 115–124. 10.1016/j.dendro.2008.01.002. DOI

Bunn, A. G. , Korpela M., Biondi F., et al. 2023. dplR: Dendrochronology Program Library in R. Version R Package Version 1.7.6. https://CRAN.R‐project.org/package=dplR.

Cailleret, M. , Jansen S., Robert E. M. R., et al. 2017. “A Synthesis of Radial Growth Patterns Preceding Tree Mortality.” Global Change Biology 23, no. 4: 1675–1690. 10.1111/gcb.13535. PubMed DOI

Camarero, J. J. , and de Andrés E. G.. 2024. “Deciphering Carbon Source‐Sink Dynamics in Masting Tree Species Using Tree‐Ring Isotopes.” Tree Physiology 44, no. 3: tpae026. 10.1093/treephys/tpae026. PubMed DOI PMC

Camarero, J. J. , Gazol A., Linares J. C., et al. 2021. “Differences in Temperature Sensitivity and Drought Recovery Between Natural Stands and Plantations of Conifers Are Species‐Specific.” Science of the Total Environment 796: 148930. 10.1016/j.scitotenv.2021.148930. PubMed DOI

Cardinale, B. J. , Wright J. P., Cadotte M. W., et al. 2007. “Impacts of Plant Diversity on Biomass Production Increase Through Time Because of Species Complementarity.” Proceedings of the National Academy of Sciences of the United States of America 104, no. 46: 18123–18128. 10.1073/pnas.0709069104. PubMed DOI PMC

Castagneri, D. , Vacchiano G., Hacket‐Pain A., DeRose R. J., Klein T., and Bottero A.. 2022. “Meta‐Analysis Reveals Different Competition Effects on Tree Growth Resistance and Resilience to Drought.” Ecosystems 25, no. 1: 30–43. 10.1007/s10021-021-00638-4. DOI

Cervellini, M. , Zannini P., Di Musciano M., et al. 2020. “A Grid‐Based Map for the Biogeographical Regions of Europe.” Biodiversity Data Journal 8: e53720. 10.3897/BDJ.8.e53720. PubMed DOI PMC

Choat, B. , Jansen S., Brodribb T. J., et al. 2012. “Global Convergence in the Vulnerability of Forests to Drought.” Nature 491, no. 7426: 752–755. 10.1038/nature11688. PubMed DOI

Colangelo, M. , Camarero J. J., Borghetti M., Gazol A., Gentilesca T., and Ripullone F.. 2017. “Size Matters a Lot: Drought‐Affected Italian Oaks Are Smaller and Show Lower Growth Prior to Tree Death.” Frontiers in Plant Science 8: 135. 10.3389/fpls.2017.00135. PubMed DOI PMC

de Boeck, H. J. , Bloor J. M. G., Kreyling J., et al. 2017. “Patterns and Drivers of Biodiversity–Stability Relationships Under Climate Extremes.” Journal of Ecology 106, no. 3: 890–902. 10.1111/1365-2745.12897. DOI

de Micco, V. , Carrer M., Rathgeber C. B. K., et al. 2019. “From Xylogenesis to Tree Rings: Wood Traits to Investigate Tree Response to Environmental Changes.” IAWA 40, no. 2: 155–182. 10.1163/22941932-40190246. DOI

de Mil, T. , and van den Bulcke J.. 2023. “Tree Core Analysis With X‐Ray Computed Tomography.” Journal of Visualized Experiments 2023: 65208. 10.3791/65208. PubMed DOI

de Mil, T. , Vannoppen A., Beeckman H., van Acker J., and den Bulcke J.. 2016. “A Field‐To‐Desktop Toolchain for X‐Ray CT Densitometry Enables Tree Ring Analysis.” Annals of Botany 117, no. 7: 1187–1196. 10.1093/aob/mcw063. PubMed DOI PMC

Decarsin, R. , Guillemot J., Le Maire G., et al. 2024. “Tree Drought‐Mortality Risk Depends More on Intrinsic Species Resistance Than on Stand Species Diversity.” Global Change Biology 30, no. 9: e17503. 10.1111/gcb.17503. PubMed DOI

Del Campo, A. D. , Otsuki K., Serengil Y., Blanco J. A., Yousefpour R., and Wei X.. 2022. “A Global Synthesis on the Effects of Thinning on Hydrological Processes: Implications for Forest Management.” Forest Ecology and Management 519: 120324. 10.1016/j.foreco.2022.120324. DOI

Del Río, M. , Schütze G., and Pretzsch H.. 2014. “Temporal Variation of Competition and Facilitation in Mixed Species Forests in Central Europe.” Plant Biology 16, no. 1: 166–176. 10.1111/plb.12029. PubMed DOI

Depauw, L. , de Lombaerde E., Dhiedt E., et al. 2024. “Enhancing Tree Performance Through Species Mixing: Review of a Quarter‐Century of TreeDivNet Experiments Reveals Research Gaps and Practical Insights.” Current Forestry Reports 10, no. 1: 1–20. 10.1007/s40725-023-00208-y. DOI

DeSoto, L. , Cailleret M., Sterck F., et al. 2020. “Low Growth Resilience to Drought Is Related to Future Mortality Risk in Trees.” Nature Communications 11, no. 1: 545. 10.1038/s41467-020-14300-5. PubMed DOI PMC

Dietrich, V. , Skiadaresis G., Schnabel F., et al. 2024. “Identifying the Impact of Climate Extremes on Radial Growth in Young Tropical Trees: A Comparison of Inventory and Tree‐Ring Based Estimates.” Dendrochronologia 86: 126237. 10.1016/j.dendro.2024.126237. DOI

D'Orangeville, L. , Maxwell J., Kneeshaw D., et al. 2018. “Drought Timing and Local Climate Determine the Sensitivity of Eastern Temperate Forests to Drought.” Global Change Biology 24, no. 6: 2339–2351. 10.1111/gcb.14096. PubMed DOI

Duchesne, L. , Houle D., Ouimet R., Caldwell L., Gloor M., and Brienen R.. 2019. “Large Apparent Growth Increases in Boreal Forests Inferred From Tree‐Rings Are an Artefact of Sampling Biases.” Scientific Reports 9, no. 1: 6832. 10.1038/s41598-019-43243-1. PubMed DOI PMC

Etzold, S. , Sterck F., Bose A. K., et al. 2022. “Number of Growth Days and Not Length of the Growth Period Determines Radial Stem Growth of Temperate Trees.” Ecology Letters 25, no. 2: 427–439. 10.1111/ele.13933. PubMed DOI PMC

Fernández‐de‐Uña, L. , Martínez‐Vilalta J., Poyatos R., Mencuccini M., and McDowell N. G.. 2023. “The Role of Height‐Driven Constraints and Compensations on Tree Vulnerability to Drought.” New Phytologist 239, no. 6: 2083–2098. 10.1111/nph.19130. PubMed DOI

Fichtner, A. , Härdtle W., Li Y., Bruelheide H., Kunz M., and von Oheimb G.. 2017. “From Competition to Facilitation: How Tree Species Respond to Neighbourhood Diversity.” Ecology Letters 20, no. 7: 892–900. 10.1111/ele.12786. PubMed DOI

Fichtner, A. , Schnabel F., Bruelheide H., et al. 2020. “Neighbourhood Diversity Mitigates Drought Impacts on Tree Growth.” Journal of Ecology 108, no. 3: 865–875. 10.1111/1365-2745.13353. DOI

Forrester, D. I. 2014. “The Spatial and Temporal Dynamics of Species Interactions in Mixed‐Species Forests: From Pattern to Process.” Forest Ecology and Management 312: 282–292. 10.1016/j.foreco.2013.10.003. DOI

Forrester, D. I. 2017. “Ecological and Physiological Processes in Mixed Versus Monospecific Stands.” In Mixed‐Species Forests, edited by Pretzsch H., Forrester D. I., and Bauhus J., 73–115. Springer Berlin Heidelberg. 10.1007/978-3-662-54553-9_3. DOI

Forrester, D. I. 2019. “Linking Forest Growth With Stand Structure: Tree Size Inequality, Tree Growth or Resource Partitioning and the Asymmetry of Competition.” Forest Ecology and Management 447: 139–157. 10.1016/j.foreco.2019.05.053. DOI

Forrester, D. I. , and Bauhus J.. 2016. “A Review of Processes Behind Diversity—Productivity Relationships in Forests.” Current Forestry Reports 2, no. 1: 45–61. 10.1007/s40725-016-0031-2. DOI

Forrester, D. I. , Bonal D., Dawud S., et al. 2016. “Drought Responses by Individual Tree Species Are Not Often Correlated With Tree Species Diversity in European Forests.” Journal of Applied Ecology 53, no. 6: 1725–1734. 10.1111/1365-2664.12745. DOI

Forrester, D. I. , and Pretzsch H.. 2015. “Tamm Review: On the Strength of Evidence When Comparing Ecosystem Functions of Mixtures With Monocultures.” Forest Ecology and Management 356: 41–53. 10.1016/j.foreco.2015.08.016. DOI

Gao, S. , Liu R., Zhou T., et al. 2018. “Dynamic Responses of Tree‐Ring Growth to Multiple Dimensions of Drought.” Global Change Biology 24, no. 11: 5380–5390. 10.1111/gcb.14367. PubMed DOI

Gazol, A. , Camarero J. J., Sánchez‐Salguero R., et al. 2020. “Drought Legacies Are Short, Prevail in Dry Conifer Forests and Depend on Growth Variability.” Journal of Ecology 108, no. 6: 2473–2484. 10.1111/1365-2745.13435. DOI

Gazol, A. , Camarero J. J., Sangüesa‐Barreda G., et al. 2020. “Tree Species Are Differently Impacted by Cumulative Drought Stress and Present Higher Growth Synchrony in Dry Places.” Frontiers in Forests and Global Change 3: 573346. 10.3389/ffgc.2020.573346. DOI

Gazol, A. , Fajardo A., and Camarero J. J.. 2023. “Contributions of Intraspecific Variation to Drought Tolerance in Trees.” Current Forestry Reports 9, no. 6: 461–472. 10.1007/s40725-023-00199-w. DOI

Gessler, A. , Bottero A., Marshall J., and Arend M.. 2020. “The Way Back: Recovery of Trees From Drought and Its Implication for Acclimation.” New Phytologist 228, no. 6: 1704–1709. 10.1111/nph.16703. PubMed DOI

Gillerot, L. , Forrester D. I., Bottero A., Rigling A., and Lévesque M.. 2021. “Tree Neighbourhood Diversity Has Negligible Effects on Drought Resilience of European Beech, Silver Fir and Norway Spruce.” Ecosystems 24, no. 1: 20–36. 10.1007/s10021-020-00501-y. DOI

Göransson, H. , Bambrick M. T., and Godbold D. L.. 2016. “Overyielding of Temperate Deciduous Tree Mixtures is Maintained Under Throughfall Reduction.” Plant and Soil 408, no. 1–2: 285–298. 10.1007/s11104-016-2930-1. DOI

Grossiord, C. 2019. “Having the Right Neighbors: How Tree Species Diversity Modulates Drought Impacts on Forests.” New Phytologist 228, no. 1: 42–49. 10.1111/nph.15667. PubMed DOI

Grossiord, C. , Granier A., Gessler A., Jucker T., and Bonal D.. 2014. “Does Drought Influence the Relationship Between Biodiversity and Ecosystem Functioning in Boreal Forests?” Ecosystems 17, no. 3: 394–404. 10.1007/s10021-013-9729-1. DOI

Grossiord, C. , Granier A., Gessler A., Pollastrini M., and Bonal D.. 2013. “The Influence of Tree Species Mixture on Ecosystem‐Level Carbon Accumulation and Water Use in a Mixed Boreal Plantation.” Forest Ecology and Management 298: 82–92. 10.1016/j.foreco.2013.03.001. DOI

Grossiord, C. , Granier A., Ratcliffe S., et al. 2014. “Tree Diversity Does Not Always Improve Resistance of Forest Ecosystems to Drought.” Proceedings of the National Academy of Sciences of the United States of America 111, no. 41: 14812–14815. 10.1073/pnas.1411970111. PubMed DOI PMC

Grossiord, C. , Sevanto S., Bonal D., et al. 2019. “Prolonged Warming and Drought Modify Belowground Interactions for Water Among Coexisting Plants.” Tree Physiology 39, no. 1: 55–63. 10.1093/treephys/tpy080. PubMed DOI

Grote, R. , Gessler A., Hommel R., Poschenrieder W., and Priesack E.. 2016. “Importance of Tree Height and Social Position for Drought‐Related Stress on Tree Growth and Mortality.” Trees 30, no. 5: 1467–1482. 10.1007/s00468-016-1446-x. DOI

Guerrero‐Ramírez, N. R. , Craven D., Reich P. B., et al. 2017. “Diversity‐Dependent Temporal Divergence of Ecosystem Functioning in Experimental Ecosystems.” Nature Ecology & Evolution 1, no. 11: 1639–1642. 10.1038/s41559-017-0325-1. PubMed DOI PMC

Guillemot, J. , and Martin‐StPaul N.. 2024. “Tree Growth Strategies Mediate Drought Resistance in Species‐Diverse Forests.” Tree Physiology 44, no. 11: tpae141. 10.1093/treephys/tpae141. PubMed DOI

Guisset, C. , Dendoncker M., Vincke C., and Ponette Q.. 2024. “Drought Timing, Intensity, and Consecutiveness Have More Influence on Douglas Fir Growth Response Than Site Conditions and Stand Density in European Temperate Climate.” Forest Ecology and Management 569: 122177. 10.1016/j.foreco.2024.122177. DOI

Haberstroh, S. , and Werner C.. 2022. “The Role of Species Interactions for Forest Resilience to Drought.” Plant Biology 24, no. 7: 1098–1107. 10.1111/plb.13415. PubMed DOI

Hajek, P. , Link R. M., Nock C. A., et al. 2022. “Mutually Inclusive Mechanisms of Drought‐Induced Tree Mortality.” Global Change Biology 28, no. 10: 3365–3378. 10.1111/gcb.16146. PubMed DOI

Hari, V. , Rakovec O., Markonis Y., Hanel M., and Kumar R.. 2020. “Increased Future Occurrences of the Exceptional 2018–2019 Central European Drought Under Global Warming.” Scientific Reports 10, no. 1: 12207. 10.1038/s41598-020-68872-9. PubMed DOI PMC

Hartmann, H. , Bastos A., Das A. J., et al. 2022. “Climate Change Risks to Global Forest Health: Emergence of Unexpected Events of Elevated Tree Mortality Worldwide.” Annual Review of Plant Biology 73: 673–702. 10.1146/annurev-arplant-102820-012804. PubMed DOI

Hegyi, F. 1974. “A Simulation Model for Managing Jack‐Pine Stands Simulation.” In Growth Models for Tree and Stand Simulation, edited by Fries J., vol. 30 (Research Notes, 30), 74–90.

Huang, M. , Wang X., Keenan T. F., and Piao S.. 2018. “Drought Timing Influences the Legacy of Tree Growth Recovery.” Global Change Biology 24, no. 8: 3546–3559. 10.1111/gcb.14294. PubMed DOI

Jacobs, K. , Bonal D., Collet C., Muys B., and Ponette Q.. 2021. “Mixing Increases Drought Exposure Through a Faster Growth in Beech, but Not in Oak.” Forest Ecology and Management 479: 118593. 10.1016/j.foreco.2020.118593. DOI

Jucker, T. , Bouriaud O., Avacaritei D., and Coomes D. A.. 2014. “Stabilizing Effects of Diversity on Aboveground Wood Production in Forest Ecosystems: Linking Patterns and Processes.” Ecology Letters 17, no. 12: 1560–1569. 10.1111/ele.12382. PubMed DOI

Jucker, T. , Grossiord C., Bonal D., Bouriaud O., Gessler A., and Coomes D. A.. 2017. “Detecting the Fingerprint of Drought Across Europe's Forests: Do Carbon Isotope Ratios and Stem Growth Rates Tell Similar Stories?” Forest Ecosystems 4, no. 1: 24. 10.1186/s40663-017-0111-1. DOI

Jucker, T. , Koricheva J., Finér L., Bouriaud O., Iacopetti G., and Coomes D. A.. 2020. “Good Things Take Time—Diversity Effects on Tree Growth Shift From Negative to Positive During Stand Development in Boreal Forests.” Journal of Ecology 108, no. 6: 2198–2211. 10.1111/1365-2745.13464. DOI

Jump, A. S. , Ruiz‐Benito P., Greenwood S., et al. 2017. “Structural Overshoot of Tree Growth With Climate Variability and the Global Spectrum of Drought‐Induced Forest Dieback.” Global Change Biology 23, no. 9: 3742–3757. 10.1111/gcb.13636. PubMed DOI

Kambach, S. , Allan E., Bilodeau‐Gauthier S., et al. 2019. “How Do Trees Respond to Species Mixing in Experimental Compared to Observational Studies?” Ecology and Evolution 9, no. 19: 11254–11265. 10.1002/ece3.5627. PubMed DOI PMC

Kannenberg, S. A. , Maxwell J. T., Pederson N., D'Orangeville L., Ficklin D. L., and Phillips R. P.. 2019. “Drought Legacies Are Dependent on Water Table Depth, Wood Anatomy and Drought Timing Across the Eastern US.” Ecology Letters 22, no. 1: 119–127. 10.1111/ele.13173. PubMed DOI

Kannenberg, S. A. , Novick K. A., Alexander M. R., et al. 2019. “Linking Drought Legacy Effects Across Scales: From Leaves to Tree Rings to Ecosystems.” Global Change Biology 25, no. 9: 2978–2992. 10.1111/gcb.14710. PubMed DOI

Kannenberg, S. A. , Schwalm C. R., and Anderegg W. R. L.. 2020. “Ghosts of the Past: How Drought Legacy Effects Shape Forest Functioning and Carbon Cycling.” Ecology Letters 23, no. 5: 891–901. 10.1111/ele.13485. PubMed DOI

Körner, C. 2019. “No Need for Pipes When the Well is Dry‐a Comment on Hydraulic Failure in Trees.” Tree Physiology 39, no. 5: 695–700. 10.1093/treephys/tpz030. PubMed DOI

Laliberté, E. , and Legendre P.. 2010. “A Distance‐Based Framework for Measuring Functional Diversity From Multiple Traits.” Ecology 91, no. 1: 299–305. 10.1890/08-2244.1. PubMed DOI

Laliberté, E. , Legendre P., and Shipley B.. 2014. Package ‘FD’. Measuring Functional Diversity From Multiple Traits, and Other Tools for Functional Ecology. R Package Version 1.0‐12. Version 1.0‐12. PubMed

Lehmann, M. M. , Vitali V., Schuler P., Leuenberger M., and Saurer M.. 2021. “More Than Climate: Hydrogen Isotope Ratios in Tree Rings as Novel Plant Physiological Indicator for Stress Conditions.” Dendrochronologia 65: 125788. 10.1016/j.dendro.2020.125788. DOI

Lempereur, M. , Martin‐StPaul N. K., Damesin C., et al. 2015. “Growth Duration is a Better Predictor of Stem Increment Than Carbon Supply in a Mediterranean Oak Forest: Implications for Assessing Forest Productivity Under Climate Change.” New Phytologist 207, no. 3: 579–590. 10.1111/nph.13400. PubMed DOI

Leuschner, C. , Jungkunst H. F., and Fleck S.. 2009. “Functional Role of Forest Diversity: Pros and Cons of Synthetic Stands and Across‐Site Comparisons in Established Forests.” Basic and Applied Ecology 10, no. 1: 1–9. 10.1016/j.baae.2008.06.001. DOI

Liu, X. , Huang Y., Chen L., et al. 2022. “Species Richness, Functional Traits and Climate Interactively Affect Tree Survival in a Large Forest Biodiversity Experiment.” Journal of Ecology 110, no. 10: 2522–2531. 10.1111/1365-2745.13970. DOI

Lloret, F. , Keeling E. G., and Sala A.. 2011. “Components of Tree Resilience: Effects of Successive Low‐Growth Episodes in Old Ponderosa Pine Forests.” Oikos 120, no. 12: 1909–1920. 10.1111/j.1600-0706.2011.19372.x. DOI

Loreau, M. , Barbier M., Filotas E., et al. 2021. “Biodiversity as Insurance: From Concept to Measurement and Application.” Biological Reviews 96, no. 5: 2333–2354. 10.1111/brv.12756. PubMed DOI PMC

Loreau, M. , and Hector A.. 2001. “Partitioning Selection and Complementarity in Biodiversity Experiments.” Nature 412, no. 6842: 72–76. 10.1038/35083573. PubMed DOI

Lüdecke, D. , Bartel A., Schwemmer C., Powell C., Djalovski A., and Titz J.. 2024. Package ‘sjPlot’. R Package Version 2.8.16. https://strengejacke.github.io/sjPlot/.

Lv, P. , Rademacher T., Huang X., Zhang B., and Zhang X.. 2022. “Prolonged Drought Duration, Not Intensity, Reduces Growth Recovery and Prevents Compensatory Growth of Oak Trees.” Agricultural and Forest Meteorology 326: 109183. 10.1016/j.agrformet.2022.109183. DOI

Maestre, F. T. , Callaway R. M., Valladares F., and Lortie C. J.. 2009. “Refining the Stress‐Gradient Hypothesis for Competition and Facilitation in Plant Communities.” Journal of Ecology 97, no. 2: 199–205. 10.1111/j.1365-2745.2008.01476.x. DOI

Mahecha, M. D. , Bastos A., Bohn F. J., et al. 2024. “Biodiversity and Climate Extremes: Known Interactions and Research Gaps.” Earth's Future 12, no. 6: e2023EF003963. 10.1029/2023EF003963. DOI

Martínez‐Vilalta, J. , and Garcia‐Forner N.. 2017. “Water Potential Regulation, Stomatal Behaviour and Hydraulic Transport Under Drought: Deconstructing the Iso/Anisohydric Concept.” Plant, Cell & Environment 40, no. 6: 962–976. 10.1111/pce.12846. PubMed DOI

Martin‐StPaul, N. , Delzon S., and Cochard H.. 2017. “Plant Resistance to Drought Depends on Timely Stomatal Closure.” Ecology Letters 20, no. 11: 1437–1447. 10.1111/ele.12851. PubMed DOI

Mas, E. , Cochard H., Deluigi J., et al. 2024. “Interactions Between Beech and Oak Seedlings Can Modify the Effects of Hotter Droughts and the Onset of Hydraulic Failure.” New Phytologist 241, no. 3: 1021–1034. 10.1111/nph.19358. PubMed DOI

Mas, E. , Vilagrosa A., Morcillo L., Saurer M., Valladares F., and Grossiord C.. 2024. “Drought Effects in Mediterranean Forests Are Not Alleviated by Diversity‐Driven Water Source Partitioning.” Journal of Ecology 112: 14387. 10.1111/1365-2745.14387. DOI

Masschaele, B. , Dierick M., van Loo D., et al. 2013. “HECTOR: A 240 kV Micro‐CT Setup Optimized for Research.” Journal of Physics: Conference Series 463: 12012. 10.1088/1742-6596/463/1/012012. DOI

McDowell, N. G. , Sapes G., Pivovaroff A., et al. 2022. “Mechanisms of Woody‐Plant Mortality Under Rising Drought, CO DOI

Messier, C. , Bauhus J., Sousa‐Silva R., et al. 2022. “For the Sake of Resilience and Multifunctionality, Let's Diversify Planted Forests!” Conservation Letters 15, no. 1: e12829. 10.1111/conl.12829. DOI

Moreno, M. , Simioni G., Cochard H., et al. 2024. “Isohydricity and Hydraulic Isolation Explain Reduced Hydraulic Failure Risk in an Experimental Tree Species Mixture.” Plant Physiology 195, no. 4: 2668–2682. 10.1093/plphys/kiae239. PubMed DOI PMC

Müller, L. M. , and Bahn M.. 2022. “Drought Legacies and Ecosystem Responses to Subsequent Drought.” Global Change Biology 28, no. 17: 5086–5103. 10.1111/gcb.16270. PubMed DOI PMC

Muñoz‐Sabater, J. , Dutra E., Agustí‐Panareda A., et al. 2021. “ERA5‐Land: A State‐of‐the‐Art Global Reanalysis Dataset for Land Applications.” Earth System Science Data 13, no. 9: 4349–4383. 10.5194/essd-13-4349-2021. DOI

Nehrbass‐Ahles, C. , Babst F., Klesse S., et al. 2014. “The Influence of Sampling Design on Tree‐Ring‐Based Quantification of Forest Growth.” Global Change Biology 20, no. 9: 2867–2885. 10.1111/gcb.12599. PubMed DOI

Paquette, A. , Hector A., Castagneyrol B., et al. 2018. “A Million and More Trees for Science.” Nature Ecology & Evolution 2, no. 5: 763–766. 10.1038/s41559-018-0544-0. PubMed DOI

Pardos, M. , Del Río M., Pretzsch H., et al. 2021. “The Greater Resilience of Mixed Forests to Drought Mainly Depends on Their Composition: Analysis Along a Climate Gradient Across Europe.” Forest Ecology and Management 481: 118687. 10.1016/j.foreco.2020.118687. DOI

Pebesma, E. , and Bivand R.. 2023. Spatial Data Science. Chapman and Hall/CRC.

Plaga, B. N. E. , Bauhus J., Smith A. R., Pereira M. G., and Forrester D. I.. 2024. “Drought‐Related Mortality Modifies Mixing Effects on Light Absorption and Growth in Mono‐Specific and Mixed Stands of DOI

Powers, J. S. , Vargas G G., Brodribb T. J., et al. 2020. “A Catastrophic Tropical Drought Kills Hydraulically Vulnerable Tree Species.” Global Change Biology 26, no. 5: 3122–3133. 10.1111/gcb.15037. PubMed DOI

Pritzkow, C. , Williamson V., Szota C., Trouvé R., and Arndt S. K.. 2020. “Phenotypic Plasticity and Genetic Adaptation of Functional Traits Influences Intra‐Specific Variation in Hydraulic Efficiency and Safety.” Tree Physiology 40, no. 2: 215–229. 10.1093/treephys/tpz121. PubMed DOI

R Core Team . 2023. R: A Language and Environment for Statistical Computing. R Foundation for Statistical Computing. https://www.R‐project.org/.

Rakovec, O. , Samaniego L., Hari V., et al. 2022. “The 2018–2020 Multi‐Year Drought Sets a New Benchmark in Europe.” Earth's Future 10, no. 3: e2021EF002394. 10.1029/2021EF002394. DOI

Ratcliffe, S. , Wirth C., Jucker T., et al. 2017. “Biodiversity and Ecosystem Functioning Relations in European Forests Depend on Environmental Context.” Ecology Letters 20, no. 11: 1414–1426. 10.1111/ele.12849. PubMed DOI

Ruffault, J. , Martin‐StPaul N. K., Rambal S., and Mouillot F.. 2013. “Differential Regional Responses in Drought Length, Intensity and Timing to Recent Climate Changes in a Mediterranean Forested Ecosystem.” Climatic Change 117, no. 1–2: 103–117. 10.1007/s10584-012-0559-5. DOI

Ruffault, J. , Pimont F., Cochard H., Dupuy J.‐L., and Martin‐StPaul N.. 2022. “SurEau‐Ecos v2.0: A Trait‐Based Plant Hydraulics Model for Simulations of Plant Water Status and Drought‐Induced Mortality at the Ecosystem Level.” Geoscientific Model Development 15, no. 14: 5593–5626. 10.5194/gmd-15-5593-2022. DOI

Sachsenmaier, L. , Schnabel F., Dietrich P., et al. 2024. “Forest Growth Resistance and Resilience to the 2018–2020 Drought Depend on Tree Diversity and Mycorrhizal Type.” Journal of Ecology 112: 14360. 10.1111/1365-2745.14360. DOI

Sanchez‐Martinez, P. , Mencuccini M., García‐Valdés R., et al. 2023. “Increased Hydraulic Risk in Assemblages of Woody Plant Species Predicts Spatial Patterns of Drought‐Induced Mortality.” Nature Ecology & Evolution 7, no. 10: 1620–1632. 10.1038/s41559-023-02180-z. PubMed DOI PMC

Scherer‐Lorenzen, M. , Schulze E.‐D., Don A., Schumacher J., and Eberhard W.. 2007. “Exploring the Functional Significance of Forest Diversity: A New Long‐Term Experiment With Temperate Tree Species (BIOTREE).” Perspectives in Plant Ecology, Evolution and Systematics 9, no. 2: 53–70. 10.1016/j.ppees.2007.08.002. DOI

Schnabel, F. , Barry K. E., Eckhardt S., et al. 2024. “Neighbourhood Species Richness and Drought‐Tolerance Traits Modulate Tree Growth and δ PubMed DOI

Schnabel, F. , Beugnon R., Yang B., et al. 2024. “Tree Diversity Increases Forest Temperature Buffering.” bioRxiv. 10.1101/2023.09.11.556807. PubMed DOI PMC

Schnabel, F. , Liu X., Kunz M., et al. 2021. “Species Richness Stabilizes Productivity via Asynchrony and Drought‐Tolerance Diversity in a Large‐Scale Tree Biodiversity Experiment.” Science Advances 7, no. 51: eabk1643. 10.1126/sciadv.abk1643. PubMed DOI PMC

Schnabel, F. , Purrucker S., Schmitt L., et al. 2022. “Cumulative Growth and Stress Responses to the 2018‐2019 Drought in a European Floodplain Forest.” Global Change Biology 28, no. 5: 1870–1883. 10.1111/gcb.16028. PubMed DOI

Schuldt, B. , Buras A., Arend M., et al. 2020. “A First Assessment of the Impact of the Extreme 2018 Summer Drought on Central European Forests.” Basic and Applied Ecology 45: 86–103. 10.1016/j.baae.2020.04.003. DOI

Schwarz, J. , Skiadaresis G., Kohler M., et al. 2020. “Quantifying Growth Responses of Trees to Drought—A Critique of Commonly Used Resilience Indices and Recommendations for Future Studies.” Current Forestry Reports 6, no. 3: 185–200. 10.1007/s40725-020-00119-2. DOI

Searle, E. B. , Chen H. Y. H., and Paquette A.. 2022. “Higher Tree Diversity is Linked to Higher Tree Mortality.” Proceedings of the National Academy of Sciences of the United States of America 119, no. 19: e2013171119. 10.1073/pnas.2013171119. PubMed DOI PMC

Senf, C. , Buras A., Zang C. S., Rammig A., and Seidl R.. 2020. “Excess Forest Mortality is Consistently Linked to Drought Across Europe.” Nature Communications 11, no. 1: 6200. 10.1038/s41467-020-19924-1. PubMed DOI PMC

Serrano‐León, H. , Nitschke R., Scherer‐Lorenzen M., and Forrester D. I.. 2022. “Intra‐Specific Leaf Trait Variability of PubMed DOI

Shovon, T. A. , Auge H., Haase J., and Nock C. A.. 2024. “Positive Effects of Tree Species Diversity on Productivity Switch to Negative After Severe Drought Mortality in a Temperate Forest Experiment.” Global Change Biology 30, no. 3: e17252. 10.1111/gcb.17252. PubMed DOI

Skiadaresis, G. , Leban J.‐M., Schnabel F., et al. 2025. “Interacting and Dynamic Effects of Species and Structural Diversity Promote Annual Woody Biomass Production in a Tropical Tree Diversity Experiment.” Forest Ecology and Management 593: 122844. 10.1016/j.foreco.2025.122844. DOI

Slette, I. J. , Post A. K., Awad M., et al. 2019. “How Ecologists Define Drought, and Why We Should Do Better.” Global Change Biology 25, no. 10: 3193–3200. 10.1111/gcb.14747. PubMed DOI

Smith‐Martin, C. M. , Muscarella R., Ankori‐Karlinsky R., et al. 2023. “Hydraulic Traits Are Not Robust Predictors of Tree Species Stem Growth During a Severe Drought in a Wet Tropical Forest.” Functional Ecology 37, no. 2: 447–460. 10.1111/1365-2435.14235. DOI

Soliveres, S. , Smit C., and Maestre F. T.. 2015. “Moving Forward on Facilitation Research: Response to Changing Environments and Effects on the Diversity, Functioning and Evolution of Plant Communities.” Biological Reviews of the Cambridge Philosophical Society 90, no. 1: 297–313. 10.1111/brv.12110. PubMed DOI PMC

Song, Y. , Poorter L., Horsting A., Delzon S., and Sterck F.. 2022. “Pit and Tracheid Anatomy Explain Hydraulic Safety But Not Hydraulic Efficiency of 28 Conifer Species.” Journal of Experimental Botany 73, no. 3: 1033–1048. 10.1093/jxb/erab449. PubMed DOI PMC

Taylor, A. R. , Gao B., and Chen H. Y. H.. 2020. “The Effect of Species Diversity on Tree Growth Varies During Forest Succession in the Boreal Forest of Central Canada.” Forest Ecology and Management 455: 117641. 10.1016/j.foreco.2019.117641. DOI

Toïgo, M. , Vallet P., Tuilleras V., et al. 2015. “Species Mixture Increases the Effect of Drought on Tree Ring Density, but Not on Ring Width, in DOI

Torres‐Ruiz, J. M. , Cochard H., Delzon S., et al. 2024. “Plant Hydraulics at the Heart of Plant, Crops and Ecosystem Functions in the Face of Climate Change.” New Phytologist 241, no. 3: 984–999. 10.1111/nph.19463. PubMed DOI

Trogisch, S. , Liu X., Rutten G., et al. 2021. “The Significance of Tree‐Tree Interactions for Forest Ecosystem Functioning.” Basic and Applied Ecology 55: 33–52. 10.1016/j.baae.2021.02.003. DOI

Tumajer, J. , and Treml V.. 2019. “Disentangling the Effects of Disturbance, Climate and Tree Age on Xylem Hydraulic Conductivity of PubMed DOI PMC

Urgoiti, J. , Messier C., Keeton W. S., Belluau M., and Paquette A.. 2023. “Functional Diversity and Identity Influence the Self‐Thinning Process in Young Forest Communities.” Journal of Ecology 111: 2010–2022. 10.1111/1365-2745.14158. DOI

van de Peer, T. , Verheyen K., Ponette Q., Setiawan N. N., and Muys B.. 2018. “Overyielding in Young Tree Plantations Is Driven by Local Complementarity and Selection Effects Related to Shade Tolerance.” Journal of Ecology 106, no. 3: 1096–1105. 10.1111/1365-2745.12839. DOI

van den Bulcke, J. , Boone M. A., Dhaene J., et al. 2019. “Advanced X‐Ray CT Scanning Can Boost Tree Ring Research for Earth System Sciences.” Annals of Botany 124, no. 5: 837–847. 10.1093/aob/mcz126. PubMed DOI PMC

van den Bulcke, J. , Wernersson E. L. G., Dierick M., et al. 2014. “3D Tree‐Ring Analysis Using Helical X‐Ray Tomography.” Dendrochronologia 32, no. 1: 39–46. 10.1016/j.dendro.2013.07.001. DOI

van Kampen, R. , Fisichelli N., Zhang Y.‐J., and Wason J.. 2022. “Drought Timing and Species Growth Phenology Determine Intra‐Annual Recovery of Tree Height and Diameter Growth.” AoB Plants 14, no. 3: plac012. 10.1093/aobpla/plac012. PubMed DOI PMC

Vannoppen, A. , Boeckx P., de Mil T., et al. 2018. “Climate Driven Trends in Tree Biomass Increment Show Asynchronous Dependence on Tree‐Ring Width and Wood Density Variation.” Dendrochronologia 48: 40–51. 10.1016/j.dendro.2018.02.001. DOI

Verheyen, K. , Vanhellemont M., Auge H., et al. 2016. “Contributions of a Global Network of Tree Diversity Experiments to Sustainable Forest Plantations.” Ambio 45, no. 1: 29–41. 10.1007/s13280-015-0685-1. PubMed DOI PMC

Vicente‐Serrano, S. M. , Beguería S., and López‐Moreno J. I.. 2010. “A Multiscalar Drought Index Sensitive to Global Warming: The Standardized Precipitation Evapotranspiration Index.” Journal of Climate 23, no. 7: 1696–1718. 10.1175/2009JCLI2909.1. DOI

Vilonen, L. , Ross M., and Smith M. D.. 2022. “What Happens After Drought Ends: Synthesizing Terms and Definitions.” New Phytologist 235, no. 2: 420–431. 10.1111/nph.18137. PubMed DOI PMC

Visser, H. , van der Maaten‐Theunissen M., and van der Maaten E.. 2023. “BAI BAI Bias—An Evaluation of Uncertainties in Calculating Basal Area Increments From Cores.” Dendrochronologia 78: 126066. 10.1016/j.dendro.2023.126066. DOI

Vitali, V. , Schuler P., Holloway‐Phillips M., et al. 2024. “Finding Balance: Tree‐Ring Isotopes Differentiate Between Acclimation and Stress‐Induced Imbalance in a Long‐Term Irrigation Experiment.” Global Change Biology 30, no. 3: e17237. 10.1111/gcb.17237. PubMed DOI

Vlassenbroeck, J. , Masschaele B., Dierick M., et al. 2007. “Recent Developments in the Field of X‐Ray Nano‐ and Micro‐CT at the Centre for X‐Ray Tomography of the Ghent University.” Microscopy and Microanalysis 13: 184–185. 10.1017/S1431927607077379. DOI

Wang, M. , Calders K., Verbeeck H., et al. 2024. “Exploring the Influence of Tree Species Richness on Vertical Structure Variability in Young Plantations Using Terrestrial Laser Scanning.” Forest Ecology and Management 554: 121662. 10.1016/j.foreco.2023.121662. DOI

Wu, X. , Liu H., Li X., et al. 2018. “Differentiating Drought Legacy Effects on Vegetation Growth Over the Temperate Northern Hemisphere.” Global Change Biology 24, no. 1: 504–516. 10.1111/gcb.13920. PubMed DOI

Zang, C. S. , Buras A., Esquivel‐Muelbert A., Jump A. S., Rigling A., and Rammig A.. 2020. “Standardized Drought Indices in Ecological Research: Why One Size Does Not Fit All.” Global Change Biology 26, no. 2: 322–324. 10.1111/gcb.14809. PubMed DOI

Zapater, M. , Hossann C., Bréda N., Bréchet C., Bonal D., and Granier A.. 2011. “Evidence of Hydraulic Lift in a Young Beech and Oak Mixed Forest Using DOI

Zhang, S. , Landuyt D., Verheyen K., and de Frenne P.. 2022. “Tree Species Mixing Can Amplify Microclimate Offsets in Young Forest Plantations.” Journal of Applied Ecology 59, no. 6: 1428–1439. 10.1111/1365-2664.14158. DOI

Zscheischler, J. , and Fischer E. M.. 2020. “The Record‐Breaking Compound Hot and Dry 2018 Growing Season in Germany.” Weather and Climate Extremes 29: 100270. 10.1016/j.wace.2020.100270. DOI