J. For. Sci., X:X | DOI: 10.17221/78/2025-JFS

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

Kritsadapan Palakit ORCID...¹, Khwanchai Duangsathaporn¹, Nathsuda Pumijumnong ORCID...², Supasit Sriarkarin ORCID...¹, Thanyaporn Bungbai¹, Pichit Lumyai ORCID...¹

¹ Department of Forest Management, Faculty of Forestry, Kasetsart University, Bangkok, Thailand

² Faculty of Environment and Resource Studies, Mahidol University, Nakhon Pathom, Thailand

Tree-ring analysis is a valuable tool for understanding long-term climate patterns and their influence on tree growth. This study investigates the climate–growth relationships of Khasi pine (Pinus kesiya Royle ex Gordon) in Doi Khuntan National Park, northern Thailand (at elevations of 850 to 1 035 m a.s.l.), to reconstruct past climate and inform forest management. Using 48 cross-dated increment cores, we developed an 83-year chronology (1936–2018). Standard dendrochronological methods and regression models were applied. The radial growth of P. kesiya was primarily influenced by moisture availability, showing significant positive correlations with March rainfall (r = 0.39, P < 0.01) and April–July relative humidity (r = 0.45, P < 0.01). Growth was negatively correlated with April–July mean temperature (r = –0.47, P < 0.01), indicating that warmer wet seasons induce stress. False-rings served as complementary intra-annual drought proxies, linked to cool-dry transitional periods. Multiple regression models explained 40.6% of radial growth variance and 65.6% of false-ring frequency variance. Reconstructed climate series revealed significant warming trends since the 1930s, most pronounced in April extreme minimum temperature, which increased by +0.98 °C over the study period (Mann-Kendall test, P < 0.01). These findings highlight the vulnerability of montane pine forests to increasing temperatures and atmospheric dryness, providing a multi–proxy baseline for climate change adaptation.

Keywords: dendrochronology; false ring; intra-annual ring; Khasi pine; montane forest

Received: November 4, 2025; Revised: March 18, 2026; Accepted: March 18, 2026; Prepublished online: April 17, 2026