Morphological Variability of the Assimilation Apparatus of Pinus sylvestris L. within the Teberda National Biosphere Reserve

Pine forests are widespread in the Karachay-Cherkess Republic, in particular, in the Teberdinsky National Biosphere Reserve, mainly in its northern part. The variability 0 of pine morphological parameters is associated with the ecological and geographical features of the species’ habitat, which is especially important for the Caucasus Mountains. The purpose of this research has been to study the morphological variability of pine in the mountainous conditions of the Karachay-Cherkess Republic based on the morphometric parameters of needles and shoots. The collection of needles and shoots has been carried out using the standard methods. According to the data obtained, the longest pine needles are found in the gorge of the Gonachkhir River (1671 m above sea level), and the shortest – in the gorge of the Daut River (1900 m above sea level). A decrease in the length of the needles with altitude has been recorded. No change in the width has been observed. The needle packing index, on the contrary, increases with altitude. The length of the shoot in the samples of Pinus sylvestris ranges from 22.00 mm (Arkhyz and Daut-2 samples) to 28.94 mm (Teberda and Daut-1 samples) and correlates with the altitude of the habitats. The weight of the freshly collected pine needles in the study area has varied from 4.43 g (Teberda) to 6.06 g (Daut-1); when dried, the weight of 100 pairs of needles has decreased in all the samples by 2 times and has ranged from 2.23 g (Teberda) to 2.00 g (Gonachkhir). No correlation of the weight with the terrain altitude has been found. The lifespan of pine needles growing at different altitudes in the Karachay-Cherkess Republic is on average 2–3 years; 4–year-old needles have been found in small quantities in Teberda (1 %) and Dzhamagat (4 %).The results of this research are the first data on the morphological variability of the needles and shoots of Pinus sylvestris L., growing at different altitudes for the Western Caucasus, in particular for the Karachay-Cherkess Republic. The obtained data on the variability of the pine assimilation apparatus in the Western Caucasus complements and confirms the conclusions of other scientists about the increase in the size and weight of needles, as well as a decrease in their life expectancy when moving from north to south. They will be useful in assessing the phenotypic variability of coniferous forests.