Home – Home – Jornals – Siberian Journal of Forest Science 2025 number 6

Greenhouse gas emissions have significantly changed the global climate. An increase in the frequency, duration, and severity of drought and heat stress associated with climate change can fundamentally alter the composition, structure, and biogeography of forests in many regions. Of particular concern is the potential increase in tree shrinkage associated with the physiological stress caused by climate change and interaction with other related processes such as insect infestations and forest fires. Despite the noted risks, existing forecasts of tree shrinkage and forest death are based on models that lack functionally realistic physiological mechanisms. It has become obvious that the current understanding of the physiological responses of trees to drought remains very insufficient, and additional basic knowledge is needed to make realistic forecasts of forest loss in the face of rapid climate change. A hydraulic concept has been applied to quantify the mechanisms of tree death, and based on it, different responses to drought of isohydric and anisohydric species have been shown. The presented analysis of the global vulnerability of world forests to hot droughts in the Anthropocene has shown that it is greatly underestimated, including forests in regions with sufficient moisture. In general, despite the ongoing discussions and research regarding many specific mechanisms of forest death, the enormous efforts that the research community has made to clarify these mechanisms have allowed us to obtain significant physiological data indicating an increased vulnerability of forests to death during hot droughts.

The results of a study of the intraseasonal radial growth of Gmelin larch ( Larix gmelinii (Rupr.) Rupr.) trees growing in a cryogenic larch forest on an anthropogenically modified site (the edge of a seasonal road) and on a natural forest site without anthropogenic disturbances are presented. Continuous measurements of radial growth during the season were conducted on experimental trees using DR-26A point dendrometers during the 2017-2019 seasons, which differed significantly in terms of weather conditions. The dynamics of intra-seasonal growth of the annual ring of an individual tree was characterized by a set of maximum daily values. Using the Pearl-Reed approximating logistic equation ( R ² = 68-99 %), the main phenological characteristics of tree ring seasonal growth for each tree were determined: the dates of the start and end of the growth season, duration of three stages of the growth season (in days), and the maximum growth intensity (mm/day) during the second stage. It was found that the tree ring width of the annual ring (TRW) is determined by the maximum intensity during the second stage of seasonal growth ( R = 78-97 %). In the anthropogenically modified site, the TRW is significantly wider than in the control area, regardless of the weather conditions during the season. The tree rings formed in the trees on the control site in 2019 was narrower than those in 2018, while they were wider in the anthropogenically modified site. The opposite trends are interpreted based on previously obtained relationships between radial increments and climatic factors (Benkova et al., 2024). The maximum intensity of tree ring growth during the season and TRW in the experimental sites are determined by weather conditions at different stages of xylogenesis. In the anthropogenically altered site, this is the period preceding the growth season (early May), when the weather conditions pre-determine the value of maximum intensity of tree ring growth associated with the stage of formation of new tracheids. In the control site, this is the later period (late May to middle June), when the weather conditions directly affect the process of new tracheid formation.

Trees are an important component of the urban landscape, a source of biodiversity and an important element in creating a comfortable environment. In urban conditions, trees are exposed to a wide range of stress factors that negatively affect their vital state and appearance. Regular observations are necessary to promptly assess the condition of the trees and their care. This is especially true for Arctic cities, where the range of tree stands is lower and their condition is more depressed. Combining visual and instrumental examination of a tree increases the accuracy of assessments, allows you to identify the volume of wood with varying degrees of destruction, assess the accident rate and make an informed decision on the appointment of support measures or removal. In 2024, the condition of tree stands in the Akademgorodok Park in Apatity, Murmansk Oblast was assessed using Siberian fir ( Abies sibirica Ledeb.). The categories of tree condition were determined using visual and instrumental methods using the Resistograph model R650-EA device, a number of health measures were recommended.

In recent decades, climate change has had a marked impact on ecosystems around the world. One of the most obvious effects of climate change is the marked transformations in stands of the upper forest limit. Studies show that climatic changes, particularly increases in mean annual temperatures and changes in precipitation regimes, are leading to significant shifts in vegetation zones. This paper is the first to analyze the dynamics of forest stands in the forest reserve Yenganepe on the western macro-slope of the Polar Urals. The variability of average morphometric indices of forest stands depending on altitude is shown. Despite the fact that individual trees of Siberian spruce ( Picea obovata Ledeb.), within the studied ecotone appeared in the early XIX century, the greatest changes in stand density occurred in the 30-60s of the XX century. The density of stands since the beginning of the XX century increased 12 times at the limit of individual trees distribution in tundra and up to 35-30 times in sparse forests and dense spruce forest. The dynamics of the studied stands differs significantly from the previously shown changes in the upper forest limit in the Subarctic.

A study of Scots pine ( Pinus sylvestris L.), Siberian spruce ( Picea obovata Ledeb.), and blue spruce ( Picea pungens Engelm.) tree samples in the parks of the city of Krasnoyarsk was conducted to select the most urban-tolerant forms. Morphological parameters of the stem and crown, as well as crown condition, were measured. Water-holding capacity of needles was used to assess tree drought tolerance. The most informative traits characterizing tree resilience to urban conditions, habit, and gas-cleaning capacity were selected for correlation analysis. Significant differences in the nature of multiple correlations between traits were found in the compared species within each park, as well as between samples of the same species from different parks across the city. A comparative analysis of correlation coefficients showed that the magnitude and direction of the relationship can serve as an additional significant criterion for selecting trees not only based on direct but also indirect traits. The results of correlation and discriminant analyses showed that tree breeding approaches should differ across the city, including due to the varying ages of tree stands. It is likely that, given increased air pollution and negative correlations between resistance traits and tree growth, a compromise between resistance and productivity is needed for urban tree breeding. Three evergreen coniferous species with the best traits were selected for further selection and use in urban landscaping.

This article identifies key distinguishing characteristics of the Canadian forest sector organization and compares the Canadian and Russian approaches to forest relations. It also focuses on current challenges facing forest sector authorities in these countries. The key distinguishing feature of the Canadian approach to forest sector organization is its high level of federalization. Each province has its own forest legislation, but a flexible system of leasing relations is a common feature. An analysis of Canadian forest legislation is conducted using the province of British Columbia as an example. This province is Canada’s leading forest region, accounting for more than a third of Canada’s total logging volume. Compared to the Russian forest sector, the Canadian sector demonstrates greater stability in both legislative changes and economic indicators. From 2002 to 2017, logging volume in Russia was significantly lower than in Canada, but since 2018, the countries have become comparable in this indicator. Indicators such as the area of forest damaged by fires and the volume of reforestation over the same period in both countries are subject to sharp fluctuations. Leasehold arrangements, adopted as the primary instrument for forest sector development, are one of the reasons for the limited interest of private capital. Lessees have insufficient incentive to voluntarily invest in forest areas beyond the minimum required by the lease terms. This problem is common to both the Canadian and Russian forestry sectors.

The intensity and duration of vegetative growth of plants determines their biological productivity, which in turn depends on various environmental factors and the climatic conditions of the growing region. Therefore, identifying patterns of seasonal growth in coniferous trees is essential for determining the type and timing of measures aimed at increasing the productivity of forest stands, especially in regions of introduction. Since research data are scarce in the south of Western Siberia and are of interest for generalizing the results of introduction, the aim of this study was to identify patterns of seasonal growth of two- and five-needle pine species of the genus pines ( Pinus L.) within the residential area of the city of Omsk. This article examines the climatic conditions of Omsk during the seasonal shoot growth period of model trees and constructs a climatic diagram of the G. Walter modification according to Bagnoul-Gossen for April-June 2024 and 2025. A study based on data from the Omsk Hydrometeorological Center examined the dynamics of seasonal shoot growth in two-needle pine trees: mountain pine ( Pinus mugo Turra), Scots pine ( Pinus sylvestris L.) and jack pine ( Pinus banksiana Lamb.), and five-needle pine trees: white pine ( Pinus strobus L.) and Siberian stone pine ( Pinus sibirica Du Tour).