Variability of Morphostructural Features of Uneven-Aged Spruce in the North of Arkhangelsk Region

Abstract

Large age variability and diverse morphometric structure are inherent to taiga spruce forests. Valuation parameters of tree stands under certain site conditions depend on these characteristics. The research purpose is to study the variability of morphostructural parameters of unevenaged spruce stands in order to identify the features of their growth and development in the north of Arkhangelsk region. The research objects are fresh blueberry spruce forests of the Plesetsk (63ºN, 40ºE), Pinega (64…65ºN, 43…44ºE) and Onega (64ºN, 38ºE) populations of Arkhangelsk region. Samplings on the study plots were formed out of 25 relatively young and middle-aged trees coming into seeding stage. Sizes of trunk and crown, sizes and num-ber of needle covered side shoots, length and limit age of needles in a lower part of crown, length and weight of 10 mature cones in air dry condition and diameter quotient of their seed scales were determined in these trees. The levels of character individual variability were estimated using the empirical scale of S.А. Mamaev. A tendency to reduce the individ-ual variability of trunk height and diameter at a height of 1.3 m, and crown total length and diameter in the elder age group of trees (g₂) in comparison with the younger one (g₁) has been found in different populations. Probably, this is due to the higher sensitivity of young trees to the action of environmental factors. The correlations between trunk diameter and age within the samplings of middle-aged (r = 0.82...0.92; p<0.05) and young (r = = 0.48...0.89; p<0.05) generative trees were established. Positive correlation between crown diameter and age (r = 0.40...0.62) of the represented populations were revealed only in the elder age group of trees (g₂). In the Pinega population, a greater number of intraverticillate shoots are formed in young generative trees (g₁); in the Onega population the shoots are formed in middle-aged trees (g₂). Longer needles in the lower part of crown are formed in middle-aged trees. The length of shoots is significantly less and life expectancy of needles is longer in younger spruce trees (g₁) in comparison with middle-aged trees (g₂) of the Onega population. The levels of individual variability of length and weight of cones correspond to the limits established by S.А. Mamaev for spruce growing in the Urals. It was found that length and weight of cones in the Pinega population are on average significantly less in comparison with the Onega and Plesetsk populations.
Funding: The research was carried out within the framework of the state assignment of N. Laverov Federal Center for Integrated Arctic Research (state registration no. АААА-А18-118011690221-0).

For citation: Tarkhanov S.N., Pinaevskaya E.A. Variability of Morphostructural Features of Uneven-Aged Spruce in the North of Arkhangelsk Region. Lesnoy Zhurnal [Forestry Journal], 2019, no. 2, pp. 56–66. DOI: 10.17238/issn0536-1036.2019.2.56