Relationship between oak's tree-ring width and climatic indices (in regional and global scales) in Javanroud region, Kermanshah

Nadi, Mehdi; Bazrafshan, Javad; Pourtahmasi, Kambiz; Najafi Harsini, Fatemeh

Relationship between oak's tree-ring width and climatic indices (in regional and global scales) in Javanroud region, Kermanshah

Document Type : Complete scientific research article

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Abstract

In this study, the correlation of some climatic indices with the tree-ring index of Quercus infectoria was investigated in Javanroud region of Kermanshah Province. The climatic data was prepared from meteorological stations of region (temperature, precipitation, Standardized Precipitation Index (SPI)) and global grid point data from NOAA site (temperature, precipitation, Palmer Drought severity Index (PDSI)) in Asia, Europe, Africa and Oceania. Based on the meteorological station data the results showed that the air temperature had a negative effect on growth of trees in this region. The effect of maximum temperature in comparison to minimum temperature was more significant representing the dominant effect of heat stress on the freezing stress in trees growth in this area. Also temperature and precipitation of a few months before and after the growth period had most impacts on tree growth while the temperature at the beginning of the growing season has no significant effect on tree growth. The highest correlation coefficients of tree ring with the SPI were derived from the 5-8 time scales with the final months of June to August, respectively. Analysis based on the global grid point data showed that there is significant correlation between tree ring widths and precipitation of some parts in the world. Also, it was revealed that significant correlated boundaries (next to the study area) corresponded to intrusion paths of the Sudan and the Mediterranean air masses from the west and the pluvial air masses from northeastern of Iran.

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