Distinct spatial patterns in climate-growth relationships, vegetation and resilience indices of Black pine (Pinus nigra J.F. Arnold) from its northern and southern distribution range

Abstract

As climate change intensifies, trees face heightened drought risks, impacting future forest composition. This study compares the climate sensitivity and resilience of black pine (Pinus nigra) across its north-south distribution range, guiding adaptive forest management amidst changing environmental conditions. Tree-ring cores from 211 P. nigra trees across seven sites in northern distribution (Slovenia) and three different sites in southern distribution range (Western Turkey), including the subspecies P. nigra subsp. nigra and P. nigra subsp. pallasiana, were analyzed. We investigated climate-growth dynamics, evaluating temperature and precipitation correlations with tree-ring width indices, and analyzed resilience indices. Leveraging remote sensing data, disparities in surface reflectance and photosynthetic activity were assessed. Our findings reveal distinct climate-growth patterns between southern and northern P. nigra populations, with precipitation predominantly shaping growth in the south and both precipitation and temperature influencing growth in the north. Given the site-specific conditions of each population, resilience indices further suggest that P. nigra subsp. pallasiana exhibits stronger drought tolerance. Sites in the northern range show the lowest resistance due to precipitation limitation. Temperature-limited sites demonstrate the highest resilience, indicating potential long-term effects of drought on tree growth. Our findings enhance our understanding of the climate-growth responses and resilience mechanisms in two subpopulations of Pinus nigra in Southern Europe.