Severe droughts limit tree growth and forest productivity worldwide, a phenomenon which is expected to aggravate over the next decades. However, how drought intensity and climatic conditions before and after drought events modulate tree growth resilience remains unclear, especially when considering the range-wide phenotypic variability of a tree species. We gathered 4632 Aleppo pine (Pinus halepensis Mill.) tree-ring width series from 281 sites located in 11 countries across the Mediterranean basin, representing the entire geographic and bioclimatic range of the species. For each site and year of the period 1950–2020, we quantified tree-growth resilience and its two components, resistance and recovery, to account for the impact of drought and the capacity to recover from it. Relative drought intensity of each year was assessed using SPEI (Standardized Precipitation Evapotranspiration Index), a climatic water deficit index. Generalized additive mixed models were used to explore the non-linear relationships between resilience and its two components and drought intensity, preceding and following years climatic conditions. We found that P. halepensis radial growth was highly dependent on the SPEI from September of the previous year to June of the current year. Trees growing under more arid bioclimates showed higher inter-annual growth variability and were more sensitive to drought, resulting in an increased response magnitude to pre-, during and post-drought conditions. In contrast to our expectations, drought intensity only slightly affected resilience, which was rather negatively affected by favorable preceding conditions and improved by favorable following conditions. Resilience and its components are highly dependent on preceding and following years climatic conditions, which should always be taken into account when studying growth response to drought. With the observed and predicted increase in drought frequency, duration and intensity, favorable conditions following drought episodes may become rare, thus threatening the future acclimation capacity of P. halepensis in its current distribution.

The authors are grateful to F. Lebourgeois for his helpful suggestions regarding the methodological framework used in this study. We also thank K. Villsen for English proofreading. LV, BP and MC were supported by the French Ministry of Ecological Transition and Territorial Cohesion (DGALN-DEB; project RESIMED) and by the OHM bassin minier de Provence; LV by the French Ecole Doctorale des Sciences de l'Environnement (ED251 ; Aix Marseille Université); VB, CT and TB by the Department of Forest Health of the French Ministry of Agriculture; CR, VB and CT by a grant overseen by the French National Research Agency (ANR) as part of the "Investissements d'Avenir" program (ANR-11-LABX-0002-01, Lab of Excellence ARBRE); TB by the CNRS [EC2CO CITRYX project] and the LABEX OTMED [n° ANR-11LABX- 0061]; SB by the ERA-NET WaterWorks2015 Cofunded Call [INNOMED project] and FA210/16/PIRAGUA, co-funded by the European Regional Development Fund (ERDF) through the Interreg V Spain-France-Andorre Programme [POCTEFA 2014-2020] of the EU; FB by the iuFOR Institute Unit of Excellence of the University of Valladolid co-financed by Junta de Castilla and León (Spain) and the European Regional Development Fund [Projects CLU-2019-01 and CL-EI-2021-05]; XSM by a JdC-F contract (FJC2021-047175-I) from the Spanish ministry of science and innovation; KC by the Slovenian Research Agency ARRS [program P4-0015]; ADF by the Italian Ministry of Instruction, University and Research (MIUR) “Department of excellence” (Law 232/2016) and FISR-MIUR project “Italian Mountain Lab”; MD by the Chief Scientist of the Israeli Ministry of Agriculture and Rural Development, and the Israel Forest Service (KKL); EG and MR by the EU project ForMAT (Sensitivity of tree-growth to climate change and growth modeling from past to future) [contract ENV4-CT97-0641]; DS by the Research Committee of the University of Patras (Karatheodori Research project); TV by the Spanish Ministry of Economy, Industry and Competitivity [AGL2012-40098-C03] and the Spanish Ministry for Science and Innovation [FJC2018-036673-I to T.V.].

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