Astigarraga, JulenCalatayud, JoaquínRuiz-Benito, PalomaMadrigal-González, JaimeTijerín-Triviño, JuliánZavala, Miguel A.Andivia Muñoz, EnriqueHerrero, Asier2025-05-222025-05-222025Astigarraga, J., Calatayud, J., Ruiz-Benito, P., Madrigal-González, J., Tijerín-Triviño, J., Zavala, M. A., Andivia, E., & Herrero, A. (2025). Forest structural diversity modulates tree growth synchrony in response to climate change. Forest Ecology and Management, 579, 122505. https://doi.org/10.1016/j.foreco.2025.1225050378-112710.1016/j.foreco.2025.122505https://hdl.handle.net/20.500.14352/120398This study was funded by the Oñati Town Council (Basque Country, Spain). JA, PRB and MAZ acknowledge funding from the CLIMB-FOREST Horizon Europe project (No 101059888) that was funded by the European Union. Views and opinions expressed are however those of the author only and do not necessarily reflect those of the European Union. The European Union cannot be held responsible for them. JA was supported by the FPI fellowship of the Department of Education of the Basque Government. PRB and JTT were supported by the Community of Madrid Region under the framework of the multi-year Agreement with the University of Alcalá (Stimulus to Excellence for Permanent University Professors, EPU-INV/2020/010). JA, PRB, JTT, MAZ and AH were funded by the Spanish State Research Agency (AEI, subproject LARGE, No PID2021–123675OB-C41). EA was supported by the grant PID2019–110470RA-100 (ADAPTAMIX) funded by MCIN/AEI/10.13039/501100011033. AH was supported by the Basque Government funding that supported FisioKlima-AgroSosT (IT1682–22) research group.Following centuries of deforestation, many industrialized countries have experienced an increase in forest area and biomass due to changes in land- and forest-use since the mid-20th century. At the same time, the impacts of climate change on forests are aggravating, but the interplay between past land- and forest-use (i.e. land- and forest-use legacies) and climate change in tree growth remains elusive. Tree growth synchrony, defined as the coincident increase in annual tree growth between different tree individuals over time, represents a comprehensive ecological measure of the level of environmental stress faced by forests, and consequently, can assess forest vulnerability to global change. Here using network theory and generalized linear mixed models, we tested whether tree size heterogeneity, resulting from different land- and forest-use legacies (i.e. recently-established, long-established, recently-pruned pollards and old-pruned pollards), modulated tree growth synchrony in response to heatwaves frequency synchrony between 1970 and 2020. We analyzed tree growth data from European beech (Fagus sylvatica L.) stands with different histories of forest management at the species’ low-latitude margin. We found increased tree growth synchrony under more frequent heatwaves and late spring frosts, and reduced precipitation. Interestingly, tree growth synchrony in response to heatwave frequency was modulated by tree size heterogeneity, with the highest synchrony observed in stands with low tree size heterogeneity, mainly found in recently-established forests. Conversely, stands with high tree size heterogeneity did not show important changes in synchrony with increasing heatwaves frequency. Our results highlight the importance of maintaining structurally diverse forests to mitigate the negative effects of climate change on forest productivity, and thereby, increase forest resilience to future forest climate risks.engAttribution-NonCommercial 4.0 Internationalhttp://creativecommons.org/licenses/by-nc/4.0/journal article1872-7042https://doi.org/10.1016/j.foreco.2025.122505https://www.sciencedirect.com/science/article/pii/S0378112725000131open access574581.5582.47551.58630Climatic stressDendroecologyForest managementForest structureLand-and forest-use legaciesNetwork theoryEcología (Biología)Fisiología vegetal (Biología)Medio ambiente natural2417.13 Ecología Vegetal2410.05 Ecología Humana2417 Biología Vegetal (Botánica)2502 Climatología3106 Ciencia Forestal