Altitudinal effect on Crimean pine (Pinus nigra J.F. Arnold subsp. pallasiana (Lamb.) Holmboe) sapling morphology in north-western Türkiye

ABSTRACT Sapling morphological characters are one of the important tools for assessing the adaptive potential of a tree species to a changing environment, and so to climate change. In the study, the morphological characters of stems and needles of Crimean pine (Pinus nigra J.F. Arnold subsp. pallasiana (Lamb.) Holmboe) saplings growing in different altitudes were examined to assess the altitudinal variability. For this purpose, a total of 45 saplings and 900 needle (one- and two-year old) samples from Karabük Province of north-western Türkiye were investigated. Significant differences were observed in the morphological characters, i.e. needle length (NL), needle width (NW), needle thickness (NT), sheath length (SL), number of rows of stomata (NR), number of stomata per cm (NS), and root collar diameter (RD) of the saplings among three altitude classes (560, 756 and 968 m). RD and needle dimensions, including stomatal density, increased with altitude. Besides, there were significant differences of the needle characters between one and two years of needles, except NW and NT located in high altitude class. It was concluded that Crimean pine saplings from different altitudes can be separated from each other on the basis of the morphological characters of needles.