The potential of Juniperus foetidissima Willd. tree and Juniperus oblonga M.B. shrub for dendroclimatology in Arasbaran forests

Despite the importance of Arasbaran forests, no dendrochronological research has been conducted in this region, yet. In this study, for the first time, the potential of two juniper species, Juniperus foetidissima and J. oblonga was evaluated to be used in dendroecology. The first and the second species are respectively in the form of trees and shrubs in Arasbaran forests. Twenty-five trees of each species were samples and the sample preparation, ring width measurements, cross-dating, and construction of tree-ring chronology were performed according to the standard procedures. Developed tree-ring chronologies for juniper tree and shrub covered around 60 and 40 years, respectively. The statistics for evaluating the qualities of chronologies i.e. mean sensitivity (MS), signal-to-noise ratio (SNR), and expressed population signal (EPS) proved the capability of both species to study climate-growth relationships and reconstruction of climate. The relations between radial growth and climatic factors showed that both species have similar responses to climate: high temperature before the growing season promoted the growth while a warm spring reduced growth rate. Rainfall before the growing season had no meaningful effect on growth while spring precipitation strongly stimulated the radial growth. Overall, given the good distribution of juniper species in Arasbaran forest, the success of the developing ring-width series for studied junipers and its strong relationship with climate factors, these species can be used for dendroecological studies. For extending the length of tree ring chronology, juniper logs of old local buildings can also be used.