Tree rings reveal spatial differences in temperature changes between the Altai and Tianshan Mountains over the past 289 years

The Altai and Tianshan Mountains in Xinjiang, located in northwest China, are considered important natural boundaries in Asia. However, the scarcity of long-term meteorological data in these regions has hindered a comprehensive understanding of historical climate variations and their influences on ecology. This study constructed a new tree-ring width chronology of Larix sibirica in the Altai Mountains. Correlation analysis results showed that the average minimum temperature from June to July (Tmin₆₇) was significantly positively correlated with the tree-ring width chronology and was the primary limiting factor for tree radial growth Based on these findings, the Tmin₆₇ for the Altai Mountains from 1730 to 2018 was reconstructed and the warmest and coldest years occurred in 2012 and 1743, respectively. In the past decade, the Tmin₆₇ in the Altai Mountains has risen by 0.86 °C compared to pre-industrial levels. The summer North Atlantic Oscillation (NAO) was found to have an inverse effect on temperature variations in the Altai Mountains. This is the first reconstruction of summer minimum temperatures in the Altai Mountains of central Asia based on a standardized tree-ring width chronology of L. sibirica. Additionally, the combined influences of geographical features and environmental factors contribute to substantial differences in temperature changes between the Altai and Tianshan Mountains. These not only enhance our understanding of past temperature fluctuations but also for projecting future temperature changes through climate modeling.