Effect of climate on Oak (Quercus macranthera) annual tree-ring chronologies at tree line of hyrcanian forest

Document Type : Complete scientific research article

Abstract

Trees with high mortality, can record environmental change on their annual ring widths. Therefore, at this study focused on effect of climate variables (Precipitation and Temperature) on annual growth of oak in the north of Iran. At recently study, samples supplied from 12 old oak trees. Tree ring widths are measuring by LINTAB measurement table. Cross-dating done with between core samples and maximum and minimum GLK rate obtained as a 62 and 52 respectively. After recording of tree ring widths, individual and finally mean of chronology are standard. We supplied a chronology for Quercus castanaifoli with 276 (1734-2010) year. Statistical analysis show that sensitive, Signal-to-noise, Expressed Population Signal are 0.24, 0.85 and 6/15 respectively. Climate and growth analysis was done by using Response Function and results show that March and July Temperature are negative effect on tree ring growth. Investigate of pointer years indicated time interval negative event years are minimum 2 years and maximum 8 years. Length of wet and dry years probably occurred in region are 2 or 3 years. Results of this study are useful for management of drought years at futures and applied for forest and reforestation management in the region.

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