effects of climate variables (temperature and precipitation) on the width of rings-growth in persian coppice oak in the central zagros (case study: khoramabad)

abstract       1   most tree characteristics such as annual growth ring are influenced by climatic changes. dendroclimatology, a branch of dendrochronology science, studies the effects of climate parameters such as temperature and precipitation on the characteristics of annual growth ring. to carry out this research, 30 quercus persica coppice trees were selected in oak forest in khorramabad, lorestan, iran. we supply trees samples with disk format. tree ring samples were taken to the laboratory and were prepared there by the handle cutter. annual growth rings were measured by binocolar and lintab measurement table and tsap software. cross dating was performed among samples by tsap software. seven tree samples were deleted due to unsuitable cross dating. chronology of the site was prepared by arstan. temperature and precipitation data were collected from climatology station and their effects on annual growth ring were examined. the results indicated that precipitation and temperature had positive and negative effects on trees growth, respectively because of the arid and semi arid climate. most positive and significant effect of precipitation was recognized in october and may but that of temperature was determined in september, october, november, december, july and august.