Factors affecting the radial growth of Juniperus foetidissima Willd. and J. excelsa M. Bieb. in central Anatolia

Abstract

Central Anatolia is one of the semi-arid regions of Turkey that does not offer very suitable conditions for the growth of trees. Tree growth is a process controlled by genetic, environmental and climatic factors. Trees record these signals, which provide valuable scientific data for dendrochronological research. We used raw annual tree-ring width (taken from trees under the age of 100 years) as one of the dendrochronological parameters to compare Juniperus foetidissima and J. excelsa in terms of affecting factors. We compared the annual tree-ring width of both species considering species, locations and research sites of the altitude range of 677–1 400 m a.s.l.. Environmental signals (longitude and latitude, altitude, slope, exposure, human impact and nearest settlement distance), as well as climatic factors (precipitation, temperature, moisture) affecting growth were examined. Results indicate that there is an obvious difference in raw annual tree-ring widths depending on species. J. foetidissima differs from J. excelsa in wider annual tree-ring widths and preferences to a low slope and altitude. While the annual tree-ring width of J. excelsa did not respond to the environmental signals, the annual tree-ring width of J. foetidissima was notably correlated with longitude, latitude, altitude and slope. The most remarkable variables affecting the growth of both species were summer temperatures and moisture.