A climatic signal associated with the tree-ring width and the optical density of the wood (Blue Intensity) has been evaluated in two related pine species, European black pine ( Pinus nigra Arnold) and Turkish pine ( Pinus brutia Ten), growing on the southern coast of the Crimean Peninsula. The influence of the cumulative effect of moisture deficiency on the radial growth and lignification processes in the latewood of the studied species has been shown. The specific reaction of P. nigra growing in mountain areas to a long-term drought has been revealed. The prospect for use of the Blue Intensity index for dendroclimatic studies on the territory of the Crimean Peninsula has been demonstrated.

Climate change is most evident on the periphery of species distribution ranges. Using four tree-ring chronologies, we identified the most important climatic factors influencing the radial growth of black pine growing along an altitudinal gradient on the eastern slope of Mount Ai-Petri (Crimean Peninsula), at the northernmost part of its range. The relationship between tree-ring widths and climate was determined using response function analysis. Results from transects moving up the slope demonstrated an increase in the correlation between radial growth and the hydrothermal coefficient: from an almost complete absence of any correlation at the lowest elevation to 0.6 at the top. Furthermore, this variation in response was not only caused by differences in climatic variables, but also changed with topography, soil, and bedrock features. The ongoing climate aridization, now typically observed in the region, may lead to a decrease in the stability and persistence of black pine stands, especially in the upper part of the slope.

Climate change is most evident on the periphery of species distribution ranges. Using four tree-ring chronologies, we identified the most important climatic factors influencing the radial growth of black pine growing along an elevational transect on the eastern slope of Mount Ai-Petri (Crimean Peninsula), at the northernmost part of its range. The relationship between tree-ring width and climate was determined using response function analysis. Results indicate an increase in correlation between radial growth and hydrothermal data along the transect: from a near absence of any correlation at the lowest elevation to r = 0.6 at the top. This change in response was not only caused by differences in climatic variables, but also related to topography, soil, and bedrock features. The currently ongoing aridization may lead to a decrease in the stability and persistence of black pine stands only in the upper parts of Mount Ai-Petri.

Eleven stands of Scots pine (Pinus sylvestris L.) from the city of Ekaterinburg and its surroundings were sampled and analyzed using dendrochronological methods to detect the effects of climate, biotic and anthropogenic factors on the annual growth of trees. Tree-ring chronologies were developed for six sites within the city and for five control sites. All chronologies were highly and positively correlated before the 1940s. However, after this period, there was a significant decrease in the correlation among chronologies from urban and rural sites. Divergence lasted about 20 years. This firstly has an anthropogenic cause, mainly due to the evacuation in 1941 of more than 60 industrial factories to Sverdlovsk (now Ekaterinburg), which generated a significant increase in air pollution. Environmental pollution seems to negatively affect tree growth. In the early 1950s, trees in the region also suffered from severe droughts. The results of climate and historical data analysis suggest that the trees on urban sites were weakened by both climate and air pollution factors, which led to a massive nun moth (Lymantria monacha L.) infestation of trees. Defoliation led to a drastic reduction in tree-ring width and, in some cases, to the complete loss of annual rings. The recovery period lasted 10–15 years on average. Rural populations were much less affected by the insect outbreak. After urban populations of pine recovered in the 1960s, radial growth of urban and rural populations became synchronized again.

The study presents results of the influence of recreational impact on the radial growth of Scots pine (Pinus sylvestris L.) in old-growth stands at the sites with the V stage of recreational degradation on the territory of organized and unorganized recreation and undisturbed areas. Over the 100 years, no negative recreation-driven changes in the radial growth were found. There is a significant increase in the tree-ring width and the number of absent rings in the chronologies from active recreation sites. A linear relationship was found between the number of absent rings and Palmer's drought severity index. Under summer drought conditions, lake proximity may mitigate the negative effects of recreation on stands even at sites with V stage of recreational degradation.

It has recently become a matter of discussion whether it is correct to use regional tree-ring chronologies in spatiotemporal climate reconstructions, since natural and climatic conditions in the regions may be heterogeneous, varying on different scales (from micro to global). We have studied the response of tree-ring width to climate in Scots pine (Pinus sylvestris L.) growing in the steppe zone, in insular pine forest of the Southern Urals and ribbon pine forests of Altai. Regional features and differences between the corresponding tree-ring chronologies obtained in the season of tree-ring formation (May–July) and spatiotemporal asynchrony in the long-term dynamics of tree-ring width in the study regions have been revealed.

Pinus brutia var. pityusa (Steven) Silba (Calabrian pine) is considered a vulnerable species because of reductions in its population sizes linked to habitat decline in recent decades. Global warming alongside the collateral modification of precipitation regimes may markedly affect the distribution ranges of this species. In this dendroecological study, we identified the most influential climatic factors affecting the radial growth of P. brutia on the norther n and easter n coasts of the Black Sea among the norther n refugia of this species. Chronologies from five sites located on the Crimea Peninsula and the Caucasian coast and exposed to varying climatic conditions were used in this analysis. The study of environmental factors controlling the growth ofP. brutia trees in the coastal populations of Crimea and the Caucasus revealed that within the longitudinal transect, which encompasses a specific range of climatic conditions, correlations between climate and the growth of P. brutia under analogous orographic conditions are similar. Aridisation of the dry Crimean climate in 1981-2012 led to an increase in the tree growth response. In the same period, populations ofP. brutia trees growing in the subtropical climate of the Black Sea coast exhibited a weakened growth response to the point of disappearance. The norther n populations of P. brutia, which are at the climatic limit of the species' distribution, are exposed to a high risk of increasing climate aridisation. Ou r findings could provide use f u l information for further research on the effects of climate change on Black Sea coastal forest ecosystems.

Within the ecotone of the upper limit of woody vegetation on the southeastern macroslope of the Khibiny Mountain ridge (Kola Peninsula), the spatial and age structure, as well as features of the phytomass accumulation of spruce–birch stands, were studied. Analysis revealed that there was a manifold increase in the density and productivity of forest stands in the last century, and the upper border of the woodlands and dense forests has moved considerably higher into the mountains. All of this happened against the background of an increase in early summer temperatures and a longer growing season in the area in the 20th century. Our data will help simulate the response of mountain ecosystems in the region to future climate change.

In many regions climate warming has caused shifts of the upper and polar boundaries of woody vegetation and changes in the structure and composition of tree stands.Regions whose vegetation has not experienced large-scale anthropogenic impacts have attracted particular interest of researchers assessing the natural dynamics of stands.This work is devoted to the study of the age and morphological structure of the tree layer of mixed woodlands and forests on the Eastern spur of the Molebny Kamen' ridge (Northern Urals).The study is based on the quadrat sampling method and tree-ring analysis.The tree-line ecotone shows significant changes in the composition and morphological and age structure of forest stands that have occurred in this region since the mid-twentieth century, with the rising summer temperatures and increasing winter precipitation.Climatic response analysis, contained in 4 generalized tree-ring chronologies constructed for the Siberian larch, Siberian pine, Siberian fir and Siberian spruce, suggests that radial growth of the trees is mostly influenced by spring and early summer growing conditions.The results of the study can be used in forestry and forest management activities.

This paper presents a dendroclimatic analysis of Siberian larch trees sampled along a latitudinal 260-km transect located in the Polar Urals, Russia. Three standardised chronologies were built over a length of 230–293 years using 79 individual tree-ring chronologies collected in the southern, middle and northern parts of the Polar Urals. Bootstrapped correlation functions showed that the annual growth of the larches was mainly influenced by the air temperatures in June and July. The relative role of the temperatures increased from south to north. Daily air temperature data analysis revealed that the duration of the growing season in the northern part of the Polar Urals is 24 days less than that in the southern part. At the present time, air temperatures exceeded threshold of 8°C, 5 days earlier than it did in the beginning of the 20th century. In response to the increase in the duration of the growing season and the changing winter conditions in the Polar Urals over the last 130 years, radial growth–temperature relationships in larches have weakened; this effect was strongly pronounced in the southern part of the Polar Urals.

На примере горы Дальний Таганай (хр. Таганай, Южный Урал) проведено выделение типов верхних границ леса на основе ведущего экологического фактора, влияющего на морфометрические характеристики ели сибирской (Picea obovata Ledeb.). Крутизна склонов и экспозиция оказывают влияние на распределение экологических факторов (солнечной радиации, осадков и ветра), что в свою очередь ведет к изменению условий произрастания и формированию разных экологических типов верхних границ леса. Следовательно, температура – основной, но не единственный фактор, влияющий на динамику верхней границы леса. Выделено четыре типа границ: термическая, курумная, ветровая и снеговая. На каждой границе дано детальное описание растительного покрова. Показаны различия между границами по геофизическим и топографическим характеристикам склонов, растительному покрову, морфометрическим характеристикам деревьев и их годичному приросту. Наиболее протяженной оказалась курумная граница, наименее протяженной – снеговая

На фоне наблюдаемого потепления климата во многих регионах отмечается смещение верхней и полярной границ распространения древесной растительности, изменение структуры и состава древостоев. Особый интерес вызывают регионы, растительность которых не испытывала масштабных антропогенных воздействий, что позволяет оценить естественную динамику древостоев. Данная работа посвящена изучению возрастной и морфологической структуры древесного яруса смешанных редколесий и лесов на восточном отроге хребта Молебный Камень (Северный Урал). В основу исследования положены методы пробных площадей и древесно-кольцевого анализа. В экотоне верхней границы древесной растительности отмечены существенные изменения состава, морфологической и возрастной структуры древостоев, произошедшие на фоне повышения летних температур и увеличения количества зимних осадков, наблюдаемых в данном районе со второй половины ХХ в. Анализ климатического отклика, содержащегося в четырех обобщенных древесно-кольцевых хронологиях, построенных по лиственнице сибирской, сосне сибирской, пихте сибирской и ели сибирской, показал, что на радиальный прирост изученных деревьев наибольшее влияние оказывают весенние и раннелетние условия произрастания. Полученные данные могут быть использованы при проведении лесохозяйственных и лесоустроительных работ

Relationships between stem diameter and phytomass of trees and their parts (single- and multistemmed growth forms) have been studied at different altitudinal levels of the present-day upper treeline ecotone on the Iremel’ Massif, the Southern Urals. The time course of changes in the structure and phytomass of birch–spruce stands during the past centuries has been reconstructed. It is shown that the expansion of forests to the mountains in this period has occurred against the background of rise in summer and winter temperatures and increase in the amount of solid precipitation in the Southern Urals.