The influence of climatic factors on the vegetative development of introduced Pinus pumila (Pall.) Regel at the Polar-Alpine Botanical Garden-Institute

Abstract

The article describes the vegetative development of introduced Pinus pumila (Pall.) Regel that grow in the experimental area of the Polar-Alpine Botanical Garden and Institute (the surroundings of the town Apatity). It gives the generalized over several years dates of the beginning of the main vegetative phenophases, the duration of the lateral shoot linear growth and needles, the sum of active and effective temperatures above 5 and 10 °C. To identify interrelations between phenodates and climatic factors, a correlation analysis was carried out (Spearman’s rank correlation coefficient was used). The sum of effective temperatures above 10 °C and the sum of precipitation varies greatly from year to year. Medium, strong and very strong correlations were found between: the dates of the beginning of various phenophases and the dates of a stable transition through 0, 5, 10 °C; sums of active and effective temperatures; average temperature and air humidity for 5, 10 and 30 days before the beginning of the phenophase; the date of isolation of а wintering apical bud in the last growing season and the environmental conditions preceding its isolation. The length of shoots and needles was measured for 2016-2021. Significant correlations between the length of shoots and needles and phenodates and selected climatic factors were not found.