Tree Age Modulates Climate Sensitivity across a Latitudinal Aridity Gradient in Central Siberia

Climate change is altering boreal forest dynamics, but the influence of tree age on climate sensitivity remains poorly understood, particularly in the vast forests of Siberia. This study investigates the climate-growth relationships of Pinus sylvestris L. across an 850 km latitudinal gradient of increasing temperature and aridity in Central Siberia. We sampled 121 trees from uneven-aged stands at three sites, grouping them into distinct age classes. We developed tree-ring width chronologies and analyzed their response to monthly climate data, and temporal shifts in climate sensitivity. Our results reveal a shift from temperature-limited growth in the north to moisture-limited growth in the south. The climate response varies significantly with tree age; older trees tend to respond to earlier seasonal cues. We conclude that tree age is a critical factor modulating climate sensitivity, and that future projections of forest growth must incorporate age-specific responses to improve accuracy under changing climate scenarios.