Climate warming induced pervasive growth decline in Chinese pine populations of the Loess Plateau, China

Introduction: Carr.) responds to these climatic shifts across the Loess Plateau, a region highly sensitive to environmental changes. Methods: We synthesized tree-ring width chronologies from 60 sites spanning major geomorphological units of the Loess Plateau. To evaluate the impact of rapid warming, we compared climate-growth relationships between two distinct periods: the pre-warming phase (1901-1960) and the post-warming phase (1961-2012). Results: Before 1960, when warming and drying were not pronounced, radial growth generally increased across regions, primarily limited by moisture while temperature had a modest stimulatory effect. After 1960, as warming and aridification strengthened, growth declined across all geomorphological units. Moisture limitation intensified, and higher temperatures shifted from a weak benefit to a clear suppressive influence. Spatially, the southern Loess Plateau showed the highest sensitivity to both growing- and non-growing-season climate, while the western and eastern regions were less sensitive and primarily influenced by non-growing-season conditions. Discussion: The spatially heterogeneous responses identified in this tree-ring dataset underscore the complex impact of recent warm-dry trends on forest ecosystems. These findings are crucial for improving our understanding of forest dynamics in semi-arid regions and can guide adaptive forest management strategies to sustain ecosystem functioning under ongoing aridification of the Loess Plateau.