Chronological Study of Quercus Persica Growth Ring Response to Climatic Variables of Precipitation and Temperature in Zagros Forests (A Case Study of Dena Region)

Plant species, including trees, react to environmental changes throughout their lives. One method of studying the response of trees to climatic variables is dendroclimatology. In this study, the effect of precipitation and temperature on annual growth of rings was investigated through extracting eighteen growth samples from 9 intact trees in Seesakht site of Dena region, located in Central Zagros Mountains (Iran). Counting and measuring annual rings were performed applying LINTAB5 measuring device that is equipped with the TSAP software. Time series of growth curves was standardized applying residual chronology and calibrated applying precipitation and temperature data of Hana weather station. Analyzing chronological relationships of site with precipitation and temperature pointed to the significant and positive impact of precipitation before growing season and its negative impact during the growing season in some months on annual growth rings. Also, temperatures in the months before and during the growing season had a significant and meaningful impact on the growth of rings. It can be concluded that Quercus Persica has the greatest sensitivity to the mean and the maximum mean of temperature at the onset of the growing season and colder months of the year. In other words, it is more accustomed to the warmer conditions before the start of the growing season and due to its higher sensitivity, EPS and SNR values, this species is suitable for dendroclimatology studies. Finally, a multiple regression model was fitted on the variables.