l. poursartip

Gole of this study was to analyze relationships between the annual variability of the Quercus cataneifolia and Quercus macranthera tree-ring chronologies and the variability of the main climatic parameters in Caspian forests. The study areas represented by a forestry ecosystem located from west to east of Caspian forests in north of Iran. 6 sites were slected from Gilan (cool and moist)، Mazandaran (moist with moderate winters) and Golestan (warm and arid) provinences. The measurements of the cores were made with the LINTAB device and TSAP program. The Principal Component Analysis (PCA) was applied to the time-series of the treerings indices as well as to the residual time-series of the monthly precipitation and temperature derived from 6 meteorological stations located near to the study regions. The results of ring width variation (111 years of data) showed that 30. 2% of the total variance of tree-rings chronologies could be attributed to the common variability of the climatic parameters: Finally، results have shown that 30. 2% of variance has a significant and positive correlation with June precipitation in both species and in all sites. Precipitation in spring is an important factor to all physiological activities of tree، like cambium activation. Results have shown that this area has a good potential to reconstruct past climate.