200 Years Tree-ring Reconstruction of Maximum Temperature in Koliak, Nowshahr

One way to reconstruction of climatic variables, especially temperature, is dendroclimatogy or the use of trre-ring width chronology. There is no tree-ring based reconstruction of long term temperature in Caspian Ecosystem. In this research, temperature was reconstructed using Fagus Orientalis tree-ring chronology collected from high elevated regions of Koliak (Nowshahr). To this target, a correlation between annual tree ring width with meteorological variables in local and global scales was considered. Correlation analysis showed that the reduction of maximum temperature is a limiting factor of tree growth, particularly in the period March-September. So, the average of March-September maximum temperature based on data measured at Nowshahr’s station was reconstructed. The results of temperature reconstruction showed that this region has experienced very cold years more than very warm ones in two past centuries. Also 1900th, 1950-1970 and 1830th, 1930-1950 were the warmest and coldest periods, respectively. Besides, the significant effect of negative NAO on temperature rising in the early months of growth period was revealed. Reconstructed temperatures of this research like the results of other researchers in Eastern Mediterranean didn’t show the warming trend in recent years.