Effects of climate variables (temperature and precipitation) on annual growth of Zelkova carpinifolia

Plants such as tree species respond to their surrounding environmental variations over their biological life cycle. One of the techniques to study the tree response to environmental conditions is dendrochronolog. In this study, 20 samples were prepared from 10 Zelkova carpinifolia trees in Badleh-Sari area. The effects of climate variables (precipitation and temperature) on annual rings of Zelkova carpinifolia trees were examined. Samples rings cross-date was determined using dendrochronological method. Also a chronology of 78 years period was made (1932-2012 AD). Mean Sensitivity (MS), mean correlation coefficient between the samples (trees), EPS and SNR, were determined as 20%, 0.5, 0.88 and 4.11 respectively. Analysis of the relationship between growth and climate over the period of 1951 – 2005, using response function (RF) showed that temperature did not significantly affect growth but total precipitation in February had positive effect (r = 0.45 p <0.001) on the growth of Zelkova carpinifolia. Analysis of trees growth response to precipitation in February showed that precipitation in the periods 1976–1994 had significant impact on the growth. However, in recent years (2011-2006) the rate of effectiveness of the precipitation on tree growth was decreased. Finally it could be mentioned that Zelkova can be a useful tree species for dendroclimatological purposes in terms of high rate of MS, EPS and SNR.