تأثیر جهت دامنه، اقلیم (دما و بارندگی) و خاک بر پهنای دوایر سالیانه گونه زغال‌اخته در جنگل‌های ارسباران (شمال غرب ایران)

Cornalian cherry (Cornus mas L.) is a native woody species in Arasbaran, N.W. Iran. It commonly grows as a wild tree on the forest edges and in forest openings areas. In this study, the influence of physiographic and environmental factors such as aspect, climate (temperature, precipitation) and physical and chemical properties of soil on the tree ring width of Cornalian cherry was examined and statistically analyzed. Totally, 48 trees at four aspects (north, east, west and south), 12 trees in each one, were randomly selected, and a 2 cm thick disk was taken at 10 cm height above ground for each stem. For soil analysis, a soil sample was taken from 0 to 30 cm of depth just next to those stems in which the discs had been got in each aspect (totally 48 samples). After scanning the disks, the width of growth rings was measured using Image-j software. Comparison of tree ring width average in different aspects using Duncan's multiple comparison showed that there was significant difference between average widths in different aspects (α=0.05). The tree ring width in the east aspect had the most growth (1.34 mm) compared to others. The relationship between the rings width and climate conditions (precipitation and temperature) was shown using Pearson's correlation. It was found that there was a significant positive relationship between the annual ring width and temperature in northern and eastern aspects and between the width of the annual rings and precipitation in the southern aspect. Soil results also showed that CaCo3% (28.8), clay% (45), NH4+ (57.3 mg/kg), NO3- (12 mg/kg) and exchangeable Ca (22.9 cmol/kg) were significantly higher in the east compared to other aspects. Eventually, using cornellian cherry as a multi-purposes species suggested the possibility of rehabilitating degraded forest stands in Arasbaran region, which is located in the eastern aspect.