Pinus sibirica Du Tour in the Conditions of Introduction by the Example of the Polar-Alpine Botanical Garden-Institute

Abstract

The study has been conducted at the Polar-Alpine Botanical Garden-Institute, the northernmost botanical garden in Russia (67°38′ N). The aim of this work has been a comprehensive analysis of the condition of Siberian stone pine trees (Pinus sibirica Du Tour) during their introduction in the Arctic. The condition of 8 specimens of the species cultivated at the experimental plot in the town of Apatity has been examined. Their phenological development has been analyzed: the swelling and breaking of the vegetative buds, the end of the elongation and maturation of the needles, the beginning and end of growth of the annual shoots, the lignification of the shoots, the beginning and end of pollen dispersion. The degree of lignification of the annual shoot, the winter hardiness, the habit, the shootforming capacity, the height increment, the generative development and the reproduction in the plantation have also been assessed. The risk of a tree falling has been determined by considering its surroundings and exposure to wind. The root zones, the butts, the trunks, the crown bases, the boughs and the crowns have been examined for the presence of hollows, cracks, decomposition, fungal fruit bodies, damage, weak forks, dead branches, etc. The application of an approach combining the analysis of seasonal development, viability and risk of tree fall is promising for a comprehensive and objective assessment of the condition of Siberian stone pine trees by morphological and phenological characteristics during the introduction to the Arctic zone of the Russian Federation. The phenological rhythm of the studied trees corresponds to the environmental conditions during the introduction to the Polar-Alpine Botanical Garden-Institute named after N.A. Avrorin. Vegetation begins in late May. By the end of August the annual shoots lignify, which indicates the readiness of the plants for the winter period. The close timing of the onset of phenophases and their low variation may indicate a low dependence of the seasonal development of Siberian stone pine on weather conditions during the introduction to the central part of the Kola Peninsula. The trees are winter-hardy, retain the life form inherent to the species, have a high shoot-forming capacity and annual height increment. They reach the generative stage of development. For their propagation in the plantation, it is necessary to attract seed material from other regions. The trees are monocormic, unimucronate and bimucronate. They are characterized by dense crowns. Their apical and lateral shoots are developed. In rare cases, the increment of lateral shoots is reduced. The V-shaped forks have been noted on the stems and a hollow in the butt area has been found on one of the trees. An additional instrumental examination is needed to determine the effect of diseases or pathogens on the stability of the trees.