Pine growth variation and climate change: Opportunities for dendroclimatology in central Thailand
Pichit Lumyai and Khwanchai Duangsathaporn
This study investigated the relationships between tree growth and climatic data in Pinus merkusii using dendrochronological techniques. The aim was to demonstrate the opportunities for climatic reconstruction in central Thailand. A sample of 48 cores collected from 24 trees was subjectively selected from the Phutoei National Park in Suphan Buri province in central Thailand. A 229-year tree-ring chronology was built from 1779 to 2007 and was correlated with climatic data collected at the Suphan Buri Meteorological Station. The chronology indicated a high positive correlation (P<0.01) with the present and previous year average temperature and the current year temperature in October. The annual ring width chronology of merkus pine could be divided into three segments of A.D. 1779-1839, 1840-1992 and 1993-2007 based on their growing patterns. The averages of annual ring width indices in these three segments were 1.13, 0.86 and 1.63 cm, respectively. From 229 years of October temperature data reconstructed from the annual ring width index, the results showed a high fluctuation of temperature with the mean temperature in October being 27.750 °C. The trend of reconstructed temperature in 1779-1839 increased to 27.84 °C and gradually decreased to a stable temperature of 27.68 °C in 1840-1992. In 1993-2007, the temperature rapidly increased to 28.17 °C. In addition, nomalous events occurring in some growing years illustrated increased temperature fluctuations revealing a cycle of 2.5-5, 57, 76 and 114 years, respectively.