Tree-ring based climate reconstruction and growth-climate analysis of Pinus kesiya Royle ex Gordon in Doi Khuntan National Park, northern Thailand

<br />Tree-ring analysis isavaluable tool for understanding long-term climate patterns and their influence ontree growth. This study investigates the climate–growth relationships ofKhasi pine (<i>Pinus kesiya </i>Royle ex Gordon) inDoi Khuntan National Park, northern Thailand (at elevations of850 to1035 m a.s.l.), toreconstruct past climate and inform forest management. Using 48 cross-dated increment cores, wedeveloped an83-year chronology (1936–2018). Standard dendrochronological methods and regression models were applied. The radial growth of<i>P. kesiya</i> was primarily influenced bymoisture availability, showing significant positive correlations with March rainfall (<i>r</i>=0.39, <i>P</i><0.01) and April–July relative humidity (<i>r</i>=0.45, <i>P</i><0.01). Growth was negatively correlated with April–July mean temperature (<i>r</i>=–0.47, <i>P</i><0.01), indicating that warmer wet seasons induce stress. False-rings served ascomplementary intra-annual drought proxies, linked tocool-dry transitional periods. Multiple regression models explained 40.6% ofradial growth variance and 65.6% offalse-ring frequency variance. Reconstructed climate series revealed significant warming trends since the 1930s, most pronounced inApril extreme minimum temperature, which increased by+0.98 C over the study period (Mann-Kendall test, <i>P</i><0.01). These findings highlight the vulnerability ofmontane pine forests toincreasing temperatures and atmospheric dryness, providing amulti–proxy baseline for climate change adaptation.