No 1 (2025)

Every year, vast areas of forests burn down during fires all over the world. The literature contains contradictory data on the effects of fires on individual components of ecosystems, in particular on soils. This necessitates the study of the aftermath of fires in different climatic and soil conditions. The aim of this work is studying the consequences of a ground fire on the properties of phaeozems of the Khamyshinsky district forestry unit of the Adygea Republic 4 years after the impact. The chemical (CEC, hydrolytic acidity, pH, organic carbon and active carbon content) and biological (activity of catalase, dehydrogenases, invertase, urease, phosphatase) properties of post-pyrogenic soils on one fully and two partially burnt areas have been studied. The ground fire did not cause significant changes in the composition of the forest stand for burnt areas No. 2 (1159 m above sea level) and No. 3 (1359 m above sea level), while the burnt area No. 1 (651 m above sea level) was characterised by completely charred trees, abundant growth of pontic rhododendron, and poorly developed herbaceous vegetation. A 51% decrease in catalase activity compared to the control was found in the three areas. The activity of dehydrogenases and urease in post-pyrogenic soils exceeded the control values by an average of 62%. The activity of invertase and phosphatase varied depending on the study area. In general, there was a tendency toward an increase in the activity of these enzymes. At the same time, a high spatial variation in the activity of soil dehydrogenases and invertase was found for burnt-out area No. 1. There also was an increase in hydrolytic acidity by an average of 43% compared to the control values. The CEC, the content of organic and active carbon differs to a lesser extent from the control values 4 years after the fire. The acidity index (pH) of the area devoid of grassy vegetation reaches 5.8, with control having pH of 4. Notably, higher values of the CEC correspond to higher pH values. Factor analysis showed that changes in the enzymatic activity of post-pyrogenic phaeozem are associated with the peculiarities of the soils’ chemical properties. The activity of hydrolases (urease, phosphatase) is closely related to the content of organic carbon, and the activity of other enzymes – to the CEC, hydrolytic acidity and pH. The content of active carbon changes insignificantly and does not affect the enzymatic activity.

On the territory of 8 planning quarters of the state natural reserve “Bushkovsky forest”, located on the north-eastern border of hemiboreal broadleaved-coniferous forests, a structural description of four groups of plantations was performed: linden with spruce and birch, spruce-birch-linden, elm-linden and birch-linden stands. The multi-species composition was made up of small-leaved linden, spruce, pine, fir, elm, Norway maple, ash, birch, aspen and grey alder. Linden was found to have a high ontogenesis polyvariance under conditions of low insolation and high humidity of the environment. The following life forms were described: single-trunk, coppice-forming, clump-forming, multi-trunk trees and facultative trailing shrub. The categories of tree vitality were defined and indices of forest stand condition were established. The average index value was found to be 0.9: individuals were described as “healthy”, although with values close to the lower limit. Most of the stands were two-storey with promising specimens of broadleaved species, such as maple and elm, gradually entering the first storey. Natural regrowth was assessed in different communities. The most resource-intensive in terms of development was the elm and maple undergrowth. The vitality index of the elm undergrowth never went lower than 91%; all individuals were sustainable and evenly distributed. In 71% of the coenoses, the undergrowth of this category had medium density values. Maple undergrowth was sustainable and healthy, with a vitality index surpassing 87%. It was evenly distributed in 62% of stands, 67% of coenoses had average density of its regrowth. Regarding spruce, the undergrowth was found to be weakened in 86% of cases, the minimal vitality index was 33%. Only in 10% of all stands has this species reached medium undergrowth density. The linden undergrowth was determined to be the most unreliable in terms of development: 71% of individuals had questionable vitality, while 29% were wilting. Only in 10% of the coenoses, linden trees grow in quantities slightly exceeding two thousand per hectare; in other cases, it was defined as scarce, numbering up to one and a half thousand. The data obtained can be used to analyse the dynamics of coenoses development and their transformations monitoring near the borders of their natural distribution area.

Organic matter decomposition is a key process in the carbon cycle that controls the rate of carbon dioxide emission, carbon accumulation in the soil, and the availability of mineral elements for plants. Changes in the forest stand’s composition during secondary succession result in changes in the quality of litter, which affects the rate and depth of its transformation. We analysed how the chemical structure of the L-horizons of litter changes from October to August at different stages of secondary succession in typical forest ecosystems of Western Siberia’s middle taiga using IR spectrometry and elemental analysis. It turned out that the structure of organic matter in the L-horizons was transformed to the largest degree at intermediate stages of succession (in an aspen forest with a dark coniferous second storey), while at previous (monodominant aspen forests) and subsequent successional stages (mixed and dark coniferous forests), changes were less pronounced. These changes include a decrease in the proportion of relatively easily decomposable components (cellulose and carbohydrates) and accumulation of aromatic compounds and polyesters that are more recalcitrant to decomposition. Aspen forest with the dark coniferous second storey and dark coniferous forest turned out to be the objects with the highest difference in terms of changes in the litter’s elemental composition: the ratio of total carbon to nitrogen over the period from October to August increased the least in the former and the most in the latter. This combination of IR spectrometry and elemental analysis results can be explained by differences in the efficiencies of depolymerisation of nitrogen-containing compounds in litter. In general, the obtained results show that litter transformation during decomposition does not always depend only on its initial quality, even in closely located ecosystems where physical conditions are virtually identical. The functioning of the microbial community may be the cause of these differences in transformation at different stages of succession.

The condition and structure of the stand formed over 40 years after high-intensity, even, gradual logging in the fish spawning protection zone of Lake Onega were studied. In the test plots laid out in 1982 before logging in a relatively uneven-aged mixed spruce forest of the vaccinium type of forest of III–IV quality class with a wood stock of about 220 m³ ha^–1, the proportion of spruce was 40%, and the density of medium and large spruce undergrowth was about 1 thousand trees ha^–1. As a result of logging, the reserve decreased by 50–70%, and the proportion of spruce in it was 60–65%. By 2023, stepped-closed mixed stands with a predominance of spruce and a total reserve of 250-300 m³ ha^–1 were formed on the logging site. Half of the available stock is concentrated in the lower part of the canopy, under which there are more than 3 thousand trees ha^-1 of spruce undergrowth. The spatial variability of density, stock, species composition of the stand and natural regeneration in the context of ensuring the sustainability of the stand is studied. Data on the dynamics of increment, large woody debris, age structure of the stand and undergrowth are analysed. The role of the technological network in the formation of heterogeneity of the stock, increment, species composition and undergrowth was clarified. The species composition and projective cover of the living ground cover as an indicator and factor of the dynamics of the stand are studied. Statistical relationships between the structural elements of the phytocoenosis are revealed, contributing to the understanding of its development and stability. The correspondence of the stand formed after felling to the main criteria for identifying biologically valuable forests is shown. Based on the results of the analysis of the obtained data and literary sources, a conclusion was made about the prospects of continuing selective management in the interests of further growth and sustainability of the spruce forest and the performance of its protective functions.

The relevance of the study is determined by the need to study the state of forest ecosystems in conditions of changing anthropogenic pressure and the practical significance of improving the monitoring system for sustainable forest management. The dynamics of the intake of pollutants with atmospheric precipitation, their accumulation in the soil and tree layer (using the example of an edificator species – Pinus sylvestris L.)with prolonged anthropogenic impact on forest ecosystems, as well as during the period of a sharp reduction in atmospheric emissions in the impact zone of the Pechenganikel smelter (Nickel village, Murmansk region). The studies were carried out in the period from 1991 to 2021 on the test areas of permanent monitoring plots located in pine forests at various distances from the source of atmospheric emissions (7, 14, 44 km). Between 1991 and 2020, the annual volume of industrial emissions of SO2, Ni and Cu into the atmosphere decreased. In December 2020, the release of pollutants into the atmosphere practically stopped due to the Pechenganikel metallurgical smelter being shut down. First of all, a sharp reduction in the emissions of pollutants into the atmosphere led to a change in the composition of snow and rainwater, the concentrations of pollutants (Ni, Cu, Co, Pb и Cd) in them approached regional background values. However, the concentrations of heavy metals and sulfur in the soil are still significantly higher than in typical forest ecosystems of the Murmansk region, due to the long period required for soil regeneration and self-purification.

This 12-month long study explores the litterfall production and decomposition at four different sites in tropical dry forests of East Nusa Tenggara, Indonesia. The total litterfall, leaf litter and branch litter production values were found to be significantly different (p < 0.05) at all sites. The production of total litterfall, leaf litter, and branch litter was greater in Binafun (2778.125 g∙m^–2∙year^–1 and 2453.125 g∙m^–2∙yr^–1) and Bonmuti (300.437 g∙m^–2∙yr^–1). The annual mean litterfall decomposition rate followed the order of Binafun < Letkole < Bonmuti < Oelbanu (p < 0.05), which positively correlated with the monthly mean precipitation, mean humidity, and mean temperature. The turnover rate calculation indicated that the forest floor was replaced every year with a turnover time of 1.083 years.