Species Composition Of Stands Research Articles

Vliv způsobu hospodaření, druhové skladby a fluktuace cen dříví na ekonomický výsledek lesního hospodaření

The aim of this paper was to assess the influence of the silvicultural system (clear-cut and shelterwood), species composition of forest stands, in relation to the fluctuation of raw wood prices, on the economic results of forest management. Model analyses were performed on the example of the conditions of the CZU Forests, specifically for the third forest vegetation zone, SLT 3K. The input to the model evaluation was: data on the growth and production of the investigated tree species in the given site conditions from growth tables, the costs of forestry measures were derived from standards, the assortment was carried out on the basis of assortment tables, the prices of assortments of raw wood were taken from the data of the Czech Statistical Office for 2015 and 2019. The synthetic result of the model evaluations was the gross profit of forest production per hectare and year. The results of the analysis prove the economic advantage and greater stability of the shelterwood silvicultural system, especially with regard to lower silvicultural costs, higher volume of timber production and mutual compensation of the decrease and increase in the prices of raw wood of the evaluated tree species.

Comprehensive analysis of gap formation in the canopy of an old-growth broadleaved forest

We performed a quantitative and qualitative assessment of the dynamics of gap formation in the canopy of intact old-growth polydominant broadleaved forest in a permanent sample area in the Kaluga Zaseki Nature Reserve. Digital elevation models were obtained from aerial survey data of the forest in 2018 and 2021, from which gap diagrams of several elevation classes were constructed. The resulting schematics were expertly analyzed using orthophotomosaic survey data and gap areas were estimated. We conducted a sample ground survey of gaps and regression analysis of the relationship between relative gap area and stand species composition from the primary enumeration data. It was shown that the phenophase at the time of the survey can significantly change the estimate of gap areas, and the height of the stand in the gap cannot serve as a reliable indicator of its age. It was also found that aerial photography reveals a more complex gap structure than ground-based surveys.

Are western European oak forests man-made constructs? The pedoanthracological perspective

Fagus sylvatica L. is among the most competitive trees in European temperate deciduous forests on well-drained but not too dry soils and is known to be a major species in the mature stages of natural succession over large areas. However, even under favourable conditions, it is often sporadic or even absent from present-day stands whereas Quercus spp. are dominant. Based on written sources, the predominance of Quercus spp. has been identified as a potential heritage of historical management. To test the hypothesis that past human practices caused the replacement of Fagus by Quercus spp. on well-drained soils, we carried out a soil charcoal analysis on current mature Quercus spp. stands in 19 forest sites of the Lorraine Plateau in northeastern France. ‘Mega-charcoal’ assemblages were extracted from soil trenches and taxonomically identified. Our results, based on more than 5600 charcoal pieces, identified 19 taxa and showed the presence of Quercus and Fagus in all sites. Quercus was dominant, followed by Carpinus and Fagus, as it is today in the on-site forests, except for Fagus, which is not observed in any of the studied stands. Other taxa, such as Prunus, Populus, Betula, were present at lower abundances, occurring in only a few sampling sites. The 71 radiocarbon dates indicated that i) a Fagus forest had been in place during the Bronze Age, without any dated oak pieces found; ii) Quercus became common from the end of the Bronze Age, iii) and was mixed with Fagus from the middle of the Iron Age. These results provide a new evidence that historical forest management in western Europe caused the replacement of Fagus by Quercus, and therefore the manipulation of forest stand species composition started during the Bronze Age.

ГИС-анализ влияния типа землепользования на современное разнообразие лесонасаждений в национальном парке «Кенозерский»

The problem of agricultural land abandonment is a worldwide problem. In the forest zone, the transformation of fallow lands is associated with afforestation and the formation of so-called secondary forest growths. Postagrogenic forests reflect the agricultural history of fallow areas, which imprint the "mute" realities of time and the social order of their development. The type of previous land use creates sufficiently stable factors, which in the process of natural overgrowth are weakly changed by natural factors and affect the emerging forests. In the key area of Kenozersky National Park (middle taiga forest region), located in the Plesetsk District of the Arkhangelsk region, we traced, according to the 1861 boundary plans, the regularities of evolution of land use areas of different categories during forest overgrowth. We assessed the area, tree species and typological structure of modern forests according to the 2014 forest inventory and traced the connection between the transformation of agro-ecosystems into forests and the history of the use of these lands after the land survey. As of the year when the boundary plans were drawn up, more than half of the territory of the key site was under agrarian influence (arable land, perelogs, haymaking, etc.). After 160 years a forest massif was formed (97 % of the territory), in which a part of hayfields was preserved. First of all, perelogs and hayfields were overgrown with forests (99 and 85 %, respectively). The allocation characterization of taxation descriptions of forest stands showed that bilberry and oxalis type pine forests were formed more often (89,7; 81,0; 78.5 %, respectively) on abandoned arable lands, perelogs and hayfields. All formed stands, classified as bilberry and oxalis type pine forests during forest inventory, have rather high productivity (I–II quality classes) and mixed composition. Forests of lower quality classes (III and IV) were rewealed in the formation of bilberry forest type. At present about 70 % of the bilberry and oxalis type pine forests on the 1861 boundary plan, formed on arable land, are dominated by birch (more than 3 units), about 10 % – by gray alder; the share of stands dominated by aspen is high. Reduced soil fertility on swidden plots ensured a more stable position of pine in the composition of emerging stands (60 % of pine-dominated stands). The character of tree species composition in stands formed on hayfields corresponds to lands with high soil fertility, which indicates the formation of hayfields on abandoned arable land. The studies have demonstrated significant differentiation of derived forest landscapes, sometimes hidden due to the widespread growth of the main forest-forming species and the formation of zonal-type forests. Intralandscape differentiation associated with the history of agricultural development has been preserved for more than 100 years and requires close study. For citation: Kozykin A.V., Nakvasina E.N. GIS-analysis of the Influence of the Land Use Type on the Current Diversity of Forest Plantations in the Kenozersky National Park. Lesnoy Zhurnal = Russian Forestry Journal, 2023, no. 5, pp. 27–41. (In Russ.). https://doi.org/10.37482/0536-1036-2023-5-27-41

Comparison of alien Robinia pseudoacacia stands with native forest stands across different taxonomic groups

There is much knowledge about the impact of non-native Robinia pseudoacacia on native ecosystems, but mostly it is related to one group of organisms. In this article, we provide an analysis of the impact of R. pseudoacacia on the surrounding biota with a broader scope in a model area with homogeneous abiotic conditions compared and analysed by the twin plots method. Microclimatic conditions and the changes in the species composition of vegetation, terrestrial gastropods, carabid beetles, bats, and acoustic diversity were analysed. The planted Robinia stands were always brighter and warmer and had lower canopy closure than the control plots in the native floodplain forest. More nitrogen and phosphorus were recorded in the soil of the Robinia stands. The floristic composition changed the most based on the planting of Robinia trees. Compared to those in the adjacent floodplain forest, more heliophilous neophytes, archaeophytes and grasses were found. Assemblages of gastropods and carabid beetles were less affected by the planting of Robinia trees and more by the microclimatic conditions of the studied locality. The number of recorded bats and acoustic diversity were higher in native floodplain forests due to food and shelter options.All results show that the planting of Robinia trees changes the microclimatic conditions and species composition of forest stands. The warmer and less humid environment under Robinia stands is not desirable in the face of ongoing climate change. The alien (including invasive) and ruderal plant species in the understorey are supported due to the more favourable brighter conditions and nitrogen fixation in the soil. Additionally, the other groups of organisms react negatively to changes under Robinia trees in terms of microclimatic conditions, food and shelter sources. Therefore, forest managers, policy-makers and conservation workers should choose stratified management when deciding whether and where to plant R. pseudoacacia.

Evaluation of species-specific tree density and height interpreted from airborne digital stereo imagery in young boreal stands in Northwestern Ontario

Monitoring silviculture through accurate assessment of the density and height of trees in young (10–25 years) stands is a critical component of sustainable forest management. Reporting species composition and height of young stands that regenerate after harvest and renewal treatments ensures planned targets have been achieved. In the boreal regions of Ontario, operational assessment of young stand conditions is conducted using qualitative visual and/or higher cost quantitative plot-based field assessments. High resolution three-dimensional digital imagery can be collected using manned aircraft across large forest management areas for stereo-photo interpretation. Our objective was to evaluate the accuracy of stereo-photo interpretation of species-specific tree counts and height in plots in digital imagery, and the effect of resolution on interpretation accuracy. Digital imagery (7-cm and 10-cm resolution) was acquired across nine stands representing common regeneration types. Prior to imagery acquisition, marked plots were established and assessed in the field; 177 plots were used in the analysis. Higher resolution imagery improved accuracy of total and conifer tree counts and conifer heights. Interpreted counts of white birch trees and height estimates of deciduous stems were not accurate using the leaf-off imagery, and interpreters could not differentiate spruce from fir.

Application of Near-Infrared Spectroscopy to Detect Modification of the Cation Exchange Properties of Soils from European Beech and Silver Fir Forest Stands in Poland.

This study investigated changes in the composition of the cation exchange capacity of soil samples caused by the acid leaching of soil cations under laboratory conditions. Furthermore, near-infrared (NIR) spectroscopy was used to evaluate the properties of forest soils. The potential influence of the species composition of stands (beech and fir) was also investigated. Eighty soil samples from the topsoil of plots located in central Poland were analyzed. Soil samples were leached 0 (non-leached), 5, 10, and 15 times and then analyzed to determine the contents of cations (Al3+, Ca2+, K+, and Mg2+), the total carbon content, and the pH. From NIR spectra obtained by scanning 54 samples and measurement results for soil sample properties, a calibration model was developed. The model was validated using 26 independent samples. The results showed that acid leaching decreased the pH of soil solutions and the carbon content. The amounts of Al3+, Ca2+, K+, and Mg2+ decreased with an increasing number of leaching treatments, but most leaching had occurred after five treatments. Data analysis showed that leaching with hydrochloric acid depleted alkaline cations and Al3+ in the soil, which reduced the stability of organic matter, causing its release. Modification of ion exchange properties is observable based on the analysis of the NIR spectra. Good calibration results were achieved for all tested parameters (R2C ≥ 0.89). The best validation results were obtained for Al3+ and C contents under fir stands, and for the pH and Al3+ content of soils under beech stands (R2V > 0.8). However, the differences between the measured and estimated mean values of the investigated soil were relatively small (no significant difference, p > 0.05). The species composition of stands (beech and fir) had no impact on the developed mathematical models. Soil assessment using NIR spectroscopy allowed calibration models to be obtained, which were successfully used to calculate soil properties at a much lower cost and in a much shorter time compared with other laboratory methods. The results of the paper affirmed that using a relatively small number of samples (3-4) to calculate an average of soil content properties provided satisfactory results.

An updated ecological assessment of floral and faunal communities of mangrove habitats in Tolo Harbour and Channel, Hong Kong

Mangrove forests are coastal habitats of ecological and socio-economic importance, and those in Hong Kong have been found to support high species diversity. Located in northeastern Hong Kong, the mangroves in the Tolo Harbour and Channel (the Tolo area), like many mangrove communities in Hong Kong, have suffered from considerable threat due to rapid coastal development. To provide up-to-date ecological information on the species composition and diversity of major mangrove stands in the Tolo area and advise conservation priorities, surveys were conducted to investigate spatial and temporal variations in species composition of epibenthic and arboreal organisms and to quantify tree diversity in mangrove stands covering inner to outer Tolo areas. A total of 127 species/taxa were recorded in the Tolo area of which 51 were gastropods and 34 were crustaceans. Species richness was higher in the inner Tolo area associated with larger mangrove stands than the outer Tolo area. Mangrove tree communities varied spatially whereas epibenthic and arboreal communities varied both spatially and seasonally. Outer Tolo mangroves had more crab species than inner Tolo area, whereas mangrove stands in Plover Cove and inner Tolo Channel areas were richer in species and had taller mangrove trees as well as presence of endemic species. Priority should be given to conserve mangrove stands in Plover Cove and inner Tolo Channel areas in order to conserve the ecological value of the Tolo area. The present dataset could serve as a baseline for future environmental monitoring and management programmes on the mangrove habitats in the Tolo area.

Quantitative and qualitative assessment of pine seedlings under controlled undergrowth disturbance: Fire and soil scarification

Scots pine (Pinus sylvestris L.) is the most widespread forest tree species in Central Europe. The range of Scots pine depends on the influence of forest management on stand species composition, as the potential for the natural regeneration of Scots pine monocultures is smaller than the current range of the species. To achieve regeneration, pine requires specific ecological conditions, including adequate soil preparation. The literature notes that the effective natural regeneration of pine requires fire or mixing the organic soil layer with the mineral layer. This hypothesis was critically evaluated carrying out work with the main objective of comparing the germination and growth dynamic of pine seedlings in two variants, simulating fire or soil scarification against natural conditions. The research focused on analyzing the growth of pine seedlings from germination to the final number of seedlings, which remained unchanged until the end of the experiment. The evaluation was carried out in soil monoliths from Kampinos National Park (KNP), in which seeds from a homogeneous mother stand were planted. The quantitative and qualitative characteristics of the seedlings were statistically evaluated, including analyses of their root system characteristics. The results confirmed the positive effect of mixing an organic and mineral layer at the germination stage and during the subsequent growth of the pine. The seedlings had a high survival rate (65.3%). However, the positive effect of fire on the regenerative capacity of pine could not be confirmed; the number of obtained seedlings (29.5%) was significantly lower than in the control variant. In addition, the “fire variant” was characterized by high seedling mortality immediately after germination. Root systems were important for the survival of the seedlings, the development of which was affected by the tested variant. The analyses performed may have implications for the development of research on the possible natural regeneration of Pines after natural disturbances. Additional topic that needs further research is the response of seedling root systems to changes in soil conditions.

Dynamique spatio-temporelle de la forêt de mangrove dans la province de Trat en Thaïlande

In the United Nations 2021–2030 ecosystem restoration programme, coastal ecosystems such as mangroves are listed as a priority for biodiversity restoration. Therefore, understanding mangrove species diversity and changes over time are essential to predict ecosystem health, viability and resilience to changing climatic and human pressures. However, when considering future conservation ambitions and policies for mangroves, it is also crucial to understand the effects of conservation interventions. To address these concerns, we needed to develop reliable inventory methods for mangrove forests, spatialised predictions of biodiversity and good practices for using Earth observation data. In this study, we investigated the gaps in knowledge concerning the spatial organisation, intertidal zones and the recent history of mangroves in Thailand's Trat province. We investigated the impacts on forest diversification of environmental parameters, such as topography, and of human interventions such as stand rehabilitation or plantations. We were able to integrate historical multi-satellite data, current ecological data and micro-topographic measurements to establish the status and describe the spatial organisation of the mangrove forests in the Province of Trat. Using the method described in this study, we were able to overcome the technical limitations of monitoring protocols and thus develop a powerful decision-support system to assess the recovery period of mangrove forests, their structural growth and the species composition of plantations and natural native stands over three decades. Our study also identifies the main influencing factors that compromise the quality of Earth observation data, and proposes specific best practices for monitoring mangrove ecosystems. In addition, we developed the ARMA tool (Automatic Regrowth Monitoring Algorithm) and summarized functional indicators (secondary succession) by type of stand. ARMA can identify the years of planting, recovery period, age and structural development of rehabilitated mangroves compared to adjacent natural and naturally regenerating mangroves. We believe that our study makes a significant contribution to research on mangrove biodiversity, as it has several potential applications for forest restoration planning and management. It can therefore be a useful tool to measure and assess biodiversity and thereby improve ecosystem-based mangrove forest management.

Which soil properties affect soil mite (Acari, Mesostigmata) communities in stands with various shares of European ash (Fraxinus excelsior L.)?

European ash (Fraxinus excelsior L.) is an important tree species and a critical component of European forests. Its share has gradually decreased due to the global climate crisis or fungal diseases. Therefore, it may influence dependent plant communities and soil organisms. Hence, we aimed to describe soil properties among different habitats where ash may grow and assess how these habitats affect abundance, species richness, and diversity of soil mite (Mesostigmata) communities. The study was conducted in eight stands (western Poland) grouped in four habitats differing in terms of soil conditions and stand species composition. Stands represented: (1) optimal habitats for ash growth with >90 % ash in the tree layer, (2) optimal habitats without ash in the tree layer, (3) suboptimal habitats with >60 % ash and co-dominance of Quercus robur L., and (4) transformed habitats with >60 % ash and co-dominance of Pinus sylvestris L. Soil environments within the research plots (circular plot area in each stand = 400 m2) were characterized by the description of the soil profile and 17 soil parameters provided for each of 72 soil samples. Mesostigmatid mites were extracted from 72 additionally collected samples into Berlese-Tullgren funnels, then mounted on slides and classified to species or genus levels.In total, 362 mites were classified into 39 taxa. The most numerous taxa were Paragamasus sp. (13.0 % of all mites), Oodinychus ovalis (C. L. Koch) (11.3 %), and Paragamasus runcatellus (Berlese) (8.6 %). We found that decreasing nitrate‑nitrogen was accompanied by increasing mite abundance, species richness, and diversity. Furthermore, mesostigmatid mite abundance and species richness increased with increasing soil pH. Although soil moisture, pH of forest litter, magnesium, calcium, potassium, total nitrogen, and C/N mass ratio differed between all habitats, they did not affect Mesostigmatid abundance, species richness, and diversity. Nevertheless, analysis of variance conducted for the Canonical Correspondence Analysis model showed that habitat and pH of forest litter significantly impacted the community species composition of mesostigmatid mites. Our study provides a better understanding of the habitat requirements of soil mesostigmatid mites and, therefore, leads to improving the use of mesostigmatid mite taxa as effective bioindicators of soil and environmental quality.

Monitoring resistance and resilience using carbon trajectories: Analysis of forest management-disturbance interactions.

A changing climate is altering ecosystem carbon dynamics with consequences for natural systems and human economies, but there are few tools available for land managers to meaningfully incorporate carbon trajectories into planning efforts. To address uncertainties wrought by rapidly changing conditions, many practitioners adopt resistance and resilience as ecosystem management goals, but these concepts have proven difficult to monitor across landscapes. Here, we address the growing need to understand and plan for ecosystem carbon with concepts of resistance and resilience. Using time series of carbon fixation (n=103), we evaluate forest management treatments and their relative impacts on resistance and resilience in the context of an expansive and severe natural disturbance. Using subalpine spruce-fir forest with a known management history as a study system, we match metrics of ecosystem productivity (net primary production, g C m-2 year-1 ) with site-level forest structural measurements to evaluate (1) whether past management efforts impacted forest resistance and resilience during a spruce beetle (Dendroctonus rufipennis) outbreak, and (2) how forest structure and physiography contribute to anomalies in carbon trajectories. Our analyses have several important implications. First, we show that the framework we applied was robust for detecting forest treatment impacts on carbon trajectories, closely tracked changes in site-level biomass, and was supported by multiple evaluation methods converging on similar management effects on resistance and resilience. Second, we found that stand species composition, site productivity, and elevation predicted resistance, but resilience was only related to elevation and aspect. Our analyses demonstrate application of a practical approach for comparing forest treatments and isolating specific site and physiographic factors associated with resistance and resilience to biotic disturbance in a forest system, which can be used by managers to monitor and plan for both outcomes. More broadly, the approach we take here can be applied to many scenarios, which can facilitate integrated management and monitoring efforts.

Factors influencing the diversity of deadwood, a crucial microhabitat for many rare and endangered saproxylic organisms

Deadwood (DW) is a crucial component of habitats, with both its volume and diversity considered critical for saproxylic organisms. Deadwood position, thickness, snag height, species composition, and decay stage were studied in the context of eight factors characterizing habitats, stands, and management types. A multivariate multiple regression model was used to analyze data from 29,098 sample plots.Deadwood diversity (a 5-dimensional dependent variable) was found to strongly depend on DW volume in a given area and on the species composition of the stand. A less pronounced effect was exerted by site fertility and moisture, the age and DBH structure of the stand, and terrain type. The model also revealed that the location of the stand in managed or unmanaged areas did not have a direct impact on deadwood diversity, with stand features being more important.Analysis of individual qualitative characteristics showed that DW thickness was affected by the same seven factors as DW diversity. DW position and decay stage were influenced by four factors: site fertility and moisture as well as stand age and species composition. In addition to the species composition of stands, DW species composition was positively influenced by more fertile and moist sites and a more varied DBH structure of stands. A significant negative effect was identified for high DW volume, which indicates that the deadwood accumulated in a stand tends to be derived from the tree species that was most vulnerable to mortality at a given time. Snag height variation was influenced by such stand characteristics as age, DBH structure, and species composition; the other significant factors were DW volume and terrain type. The diversity levels of individual DW characteristics were significantly and positively correlated, which means that all of them often revealed high or low diversity at the same time.Our study showed that forests with low DW volume additionally face the problem of DW quality. Thus, efforts to increase DW volume should be focused on those DW characteristics that are lacking (large trees, species diversity, and height variation of snags). DW diversity is lower in younger stands, with little DBH variation, and in forests which are more easily accessible, located mostly in the lowlands, and growing on less fertile and dry or mesic sites.

Prescribed Browsing by Goats Shows Promise in Controlling Multiflora Rose in a Deciduous Forest at the Erie National Wildlife Refuge in Northwestern Pennsylvania

Multiflora rose (Rosa multiflora [MFR]) is an invasive, nonnative plant that has invaded many temperate forests across the eastern United States, often outcompeting native plants for sunlight and other resources. Herbicides can control MFR, but they can also reduce nontarget plant species and threaten aquatic ecosystems. In a black cherry-red maple forest in the Erie National Wildlife Refuge in Pennsylvania, the US Fish and Wildlife Service introduced prescribed goat-browsing as an exploratory control method. In four treatments, browsed, browsed/herbicide, cut/herbicide, and an unmanaged reference, we evaluated preliminary effects of these treatments on MFR and non-MFR herbaceous vegetation. For MFR, the browsed treatment had 56% lower leaf/stem mass ratios and 35% shorter stem lengths than the reference; the leaf/stem ratio in the cut/herbicide treatment was 55% lower than the reference. Stem density was not reduced because goats did not kill the MFR plants in this first year of treatment. The herbicide treatment had fewer non-MFR plants than the reference treatment. Light levels at ground level did not differ among the treatments. Overall, 33% of trees in the browsed treatment were affected by the goats, with 9% being completely girdled; red maple and ironwood were the most commonly browsed species. Preliminary results suggest that goats can be an effective control for MFR, however long-term success will be best evaluated after consecutive treatment seasons. Goats may increase tree mortality and shift tree species composition in stands dominated by trees with high browsing rates, but effects on diverse stands may be less pronounced.

The impact of forest naturalness and tree species composition on soil organic carbon content in areas with unnatural occurrence of Norway spruce in the Czech Republic

Climate change has increased attention paid in the research to forest soils and tree species composition, in respect to the potential for carbon sequestration. It is known that forest stands are able to store soil organic carbon (SOC), but little is known about the effect of forest naturalness on SOC content. This is important in relation of dying of unnatural spruce stands. It is necessary to determine a suitable composition of tree species which will replace them. This research is based on 248 plots with oak, beech, and spruce stands and mixtures of these species, with measured values of SOC. Our results show that autochthonous and mixed stands, in terms of tree species composition, in the study area had a higher SOC content than allochthonous and pure stands. In addition, it was found that autochthonous oak and beech stands, especially in mixtures, had a higher SOC content than allochthonous spruce stands (monocultures). On the basis of the presented results, it is possible to optimize the future tree species composition of stands in the study area, which currently have an allochthonous representation of spruce, to provide better function of carbon sequestration and resistance to climate change.

Polycyclic aromatic hydrocarbons accumulation in soil horizons of different temperate forest stands

AbstractPollution due to polycyclic aromatic hydrocarbons (PAHs) is a serious environmental issue. The aim of this study was to determine the effect of stand species composition on PAH content. The research covered the stand soils of the Rybnik Forest District, which experiences some of the highest deposition of industrial emissions in Europe. Pine, pine–oak and oak stands growing in the same soil conditions were selected for the study. Samples for further analyses were collected from the organic, humus mineral and mineral soil horizons. The organic C and N concentrations, pH, alkaline cation content, microbiological biomass of C and N, soil enzyme activity, soil organic matter (SOM) fractions and PAH content were determined. The oak stand soils were characterised by the lowest accumulation of PAHs (2936.0 μg kg−1) with high biochemical activity expressed by enzyme activity (dehydrogenases, N‐acetyl‐β‐d‐glucosaminidase, phosphatase) and high microbiological biomass. In contrast, pine stand soils are acidified; hence, SOM decomposition is slowed, resulting in a high accumulation of PAHs (3805.0 μg kg−1). A strong correlation (r = 0.825) between PAH accumulation and SOM free light fraction (fLF) C concentration was noted. The stand species composition plays an important role in shaping the quality and quantity of SOM and soil acidification, which is reflected in the microbial activity and PAH accumulation in forest soils. Such accumulation in forest soils is related to the fractional composition of SOM, which is due to the influence of species composition through the supplied biomass.

Post-fire tree regeneration in forests of the Tikhvin Ridge, North-West Russia

We assessed the effect of ground fires on the success of advanced regeneration of tree species on gentle hilly ridges of terminal moraines of the North-Eastern part of the Leningrad Region. To study the juvenile generation of tree species, we carried out a reconnaissance survey of transects in the forest areas affected by wildfires. The forest stands were 10–12 years old. The stem numbers and heights of the regenerating tree species were recorded. The correlation analysis was used to determine the degree of influence of external factors on forest regeneration, including soil conditions and the burnt area size. We found differences in the species composition of stands with a predominance of deciduous and coniferous species depending on soil and hydrological conditions. We also found a relationship between soil factors and spruce and pine regeneration size in stands with a predominance of coniferous and deciduous species. The soil granulometric composition influenced proportions of coniferous and deciduous trees in post-fire stands. Using the knowledge obtained about the stand composition, we can forecast the future development of forest stands and prescribe the optimal forest management regimes.

Influence of Forest Environment Factors on Ornithocomplexes of the Valleys of the Large Tributaries of the Ob River (Western Siberia)

Western Siberia is an interesting polygon for studying the patterns of territorial variability of zonal forest formations and their animal population. Forests covering more than 60% of the territory are undergoing significant anthropogenic transformation due to the activities of the oil-and-gas industry, large-scale deforestation and fires. All this makes it very relevant to study the spatial differentiation of ornithocomplexes, as well as natural and anthropogenic environmental factors that determine it. The data was collected during the period of 1996-2010 using the route bird census method in 64 landscape forest plots with a total length of over a thousand km, in the valleys of large tributaries of the Ob River (the Chulym, Ket, Vasyugan and Tym Rivers). The total abundance of birds, the composition of the dominant species in terms of population density, and the species richness depending on the zoning (middle and southern taiga subzones), the species composition of tree stands, the terrain, and the degree of anthropogenic transformation of the environment by forest cutting and fires of forest ornithocomplexes, are discussed.

The Effects of Natural and Economic Factors on the Financial Performance of Forest Management Units: The Example of Forest Districts of the State Forests National Forest Holding from Eastern Poland

Given the changing market conditions and uncertainty arising from climate change, forest management tends to focus on the financial functioning of forest holdings. The objective of this work is to study the financial performance of forest districts using ratio analysis, synthetic financial indicators, as well as the relationship between synthetic indicators and forest district categories defined in terms of forest site type, site fertility, compatibility stand species composition, species composition, harvesting system, harvesting intensity, fragmentation of forest complexes and management difficulty level. The study material consists of financial documentation from 82 forest districts of the State Forests National Forest Holding (SFNFH) in eastern Poland from the years 2015–2019 and 2005–2009 (for comparison purposes). Synthetic indicators were calculated using two sets of financial ratios as well as two variants of accounting data. In the study period, forest districts were found to differ in terms of their financial performance, which was affected by the natural and economic factors. The synthetic indicators were significantly higher (p > 0.05) for forest districts operating on low-fertility lowland sites, those managing stands with dominant pine, and those implementing a clearcutting regeneration system. The findings concerning the effects of selected natural and economic factors on the financial condition of forest districts may be used for financial planning and management by SFNFH, in particular in decision-making processes to optimize forest management. The applied methods may stand as a basis for the construction of a sectoral evaluation tool.

Tree species composition and soil properties in pure and mixed beech-conifer stands drive soil fungal communities

Soil fungi, especially the functional guilds of saprotrophs and symbiotrophs, play a central role in ecosystem processes such as decomposition and plant nutrient acquisition. Fungal communities are influenced by soil properties and management strategies such as tree species selection. Yet, the implications of the enrichment of temperate forests consisting of tree species in their native range with non-native tree species on soil fungal diversity and their functional groups are unknown. Here, we studied fungal communities in 40 plots (2500 m2 size per plot) located in two regions differing in site conditions (nutrient content, soil moisture and climate) in forests composed of European beech, spruce and Douglas-fir (non-native) and mixtures of beech with either spruce or Douglas-fir. We hypothesized that fungal community structures are driven by soil properties and tree species composition, generally resulting in higher fungal diversity in mixed than in mono-specific forests. We further hypothesized that Douglas-fir has a negative effect on ectomycorrhizal fungal species richness compared to native species, whereas saprotrophic fungal richness is unaffected. Fungal DNA barcoding and dissimilarity analyses showed significant separation of fungal communities between nutrient-rich and nutrient-poor regions and among forest types. Mycorrhizal species richness did not vary with forest type, but the relative abundance of mycorrhizal species was lower in Douglas-fir and mixed beech-Douglas-fir forests than in spruce or beech-spruce mixture forests. Conifer forests contained higher relative abundances of saprotrophic fungi than mono-specific beech forests. Among 16 abundant fungal orders in the soil, two containing saprotrophic fungi (Tremellales and Hymenochaetales) were enriched in conifer forests, regardless of site conditions and tree species mixture. The other fungal orders, including those dominated by mycorrhizal fungi (Russulales, Boletales, Atheliales and Cantharellales) showed variable patterns depending on site conditions and tree species. Our results show the impact of tree species composition and soil properties on soil fungi. The response of fungal guilds and taxa to forest types and soil properties can potentially influence nutrient fluxes.