Climatic Suitability from MaxEnt Models Reflects Growth Performance in European Forest Trees

Species distribution models (SDMs) are widely used to define climatic constraints on species ranges, yet their ability to reflect demographic processes remains poorly understood. We integrated annually calibrated SDMs (1981-2005) with tree-ring width data from 15 European forest species in the Iberian Peninsula to evaluate if climatic suitability mirrors tree growth, particularly for populations at their climatic tolerance limits. Our results show that higher suitability consistently relates to reduced growth decline, acting as a reliable proxy for forest vigor. Notably, interannual variability in climatic suitability was positively associated with growth, suggesting that climatic fluctuations may enhance physiological resilience. We also found that Mediterranean species exhibit higher growth sensitivity to climatic suitability changes than Eurosiberian species. These findings demonstrate that SDMs can capture functional constraints beyond mere presence, positioning annual climatic suitability as a key predictor of radial growth and offering valuable insights for forest management under climate change.