Forestry and Forest Melioration

Centenary of the founder of Ukrainian forestry science – Professor P.S. Pasternak

V. P. Tkach — 2025-12-29

This manuscript commemorates the centenary of the birth of Professor Petro S. Pasternak, an Honored Forester of Ukraine and an outstanding Ukrainian scientist. Through his original scientific ideas, profound knowledge, and influential publications, he made a substantial contribution to forestry and silviculture, forest soil science, forest typology, protective afforestation, and forest ecology. His analytical thinking, broad erudition, logical and precise scientific reasoning, and clarity of presentation distinguished him as an exceptional scholar. Owing to his innate intelligence, leadership qualities, remarkable memory, diligence, ability to engage in scientific debates and defend his views, and personal integrity, Professor Pasternak earned deep respect among colleagues, students, and collaborators.

Professor Petro Pasternak was born on 23 February 1925 in the town of Skvyra, Kyiv region. In September 1942, he volunteered for military service and took part in combat operations. After demobilization in 1946, he entered the Kyiv Forestry Institute, graduated in 1950, and subsequently pursued postgraduate studies at the Forest Institute of the Ukrainian Academy of Sciences.

In December 1953, Petro Pasternak defended his PhD thesis entitled “The Impact of Caragana on Forest Soil Fertility” and continued his career at the Forest Institute as a junior and later senior researcher. From 1953 onwards, his research focused on forest regeneration in the Ukrainian Carpathians and on increasing forest productivity and resilience. In 1956, he was appointed Director of the Transcarpathian Forest Research Station of the Ukrainian Research Institute of Forestry and Forest Melioration (URIFFM). In 1964, he became the first Director of the Carpathian Branch of URIFFM in Ivano-Frankivsk. There, he initiated research into the causes of catastrophic windstorms and windbreaks, as well as the biological cycles of matter in forest ecosystems. A central component of his work was a comprehensive study of the relationships between forest types and soil formation, leading to the classification of morphological and physicochemical soil properties in relation to forest types.

In August 1968, Petro Pasternak was appointed Director of URIFFM. To address emerging environmental challenges, he established the first forest ecology laboratory in Ukraine, which investigated the impacts of air pollution, uncontrolled recreation, and other anthropogenic pressures on forest health and water resources, and developed measures to prevent or mitigate their adverse effects. From the earliest days following the Chernobyl nuclear accident, research programs under his leadership were launched to address a wide range of problems in radioactively contaminated regions of Ukraine. These studies assessed radionuclide distribution and migration pathways in forest ecosystems and provided recommendations for forest management under radioactive contamination. Professor Pasternak was the first in Ukraine to initiate forest monitoring as a distinct scientific discipline. He founded a scientific school of forest ecologists; under his supervision, more than 30 researchers defended their dissertations and later became leading scientists in forestry and related fields. His scientific interests encompassed a wide range of theoretical and applied issues, including interactions among tree species in different forest types, forest vegetation and forestry zoning, forest management based on zonal-typological and program-targeted principles, sustainable forest use and ecosystem protection under anthropogenic pressure, and the establishment of agroforestry and reclamation plantations, particularly on former agricultural lands.

4 Figs., 17 Refs.

Seasonal dynamics of English oak acorns infestation by carpophagous insects in forest shelter belts in Kharkiv region

V. M. Us — 2025-12-29

Introduction

English oak (Quercus robur L.) is one of the most common forest-forming species in Ukraine. Its proportion in the forest fund of Ukraine makes up 27%. and it is also widely represented in forest shelter belts and urban green spaces. Recently, the health of oak stands has deteriorated in many regions due to climate change and significant anthropogenic impact. To restore the existing oak stands and establish new ones, it is necessary to harvest a sufficient quantity of high-quality acorns in the stands with the best growth and health, in permanent forest seed plots and seed plantations. However, oak fruiting is irregular, and acorns are infested by carpophagous insects, whose species composition, prevalence, and harmfulness vary among regions and stands. Until recently, few studies were devoted to oak carpophagous insects in Ukraine. Interest in this group increased following the detection of the invasive acorn moth, Blastobasis glandulella (Riley, 1871) (Blastobasidae), which inhabits not only Quercus acorns but also fruits of Juglans and Aesculus. In eastern Ukraine, in addition to the above-mentioned alien species, three indigenous species of acorn pests have been identified: Curculio glandium Marsh., 1802 (Coleoptera: Curculionidae); Cydia splendana (H?bner, 1799) and Cydia amplana (H?bner, 1799) (Lepidoptera: Tortricidae). Their prevalence varied among regions (Chernihiv, Poltava, and Kharkiv) and among specific biotopes. Differences in seasonal development and timing of possible acorn infestation among these species complicate the planning and implementation of effective protection measures.

This research aimed to study the timing of acorn infestation by carpophagous insects and their composition during the growing season.

Materials and Methods

The research was carried out in forest shelter belts dominated by early-flushing English oak within the territory of the Educational, Scientific and Production Center “Dokuchaevske Experimental Field” of the State Biotechnological University (SBTU) (49°89' N, 36°45' E). Beginning in the first decade of April, trees were regularly inspected to determine the dates of the development of vegetative and generative organs of oaks and to record the presence of carpophagous insects. After budburst, the size of the leaves and shoots was recorded, and subsequently, acorn length and diameter were measured weekly using a caliper. Following the first detection of acorn infestation by carpophagous insects (first decade of July) and until acorn fall at the end of October, 100 acorns were collected weekly, their diameter and length were measured, each acorn was dissected and examined for presence of entry holes, cracks, and carpophagous insect eggs or larvae.

Results and Conclusions

The oak vegetation began 15 days earlier than the long-term dates. The size of the leaves reached its maximum in the second decade of May, and the length of the shoots in the third decade of May. Acorn growth lasted from the third decade of May to the first decade of September, with a total of 2,149.7 °C of active temperatures. Among 1,200 acorns analyzed from the second decade of July to the end of October, 38.5% were inhabited by insects, in particular 23.4% by acorn weevil, 12.2% by tortricids, and 2.9% by acorn moth. Among acorns with larvae (462 specimens), 60.8% were inhabited by weevils, 31.6% by tortricids, and 7.6% by acorn moths. Acorn weevils inhabited acorns from the first decade of July, when acorn length did not exceed 10 mm. Cydia sp. infestation began in the third decade of July, whereas acorn moth infestation was first recorded in the first decade of August. Despite the accelerated hardening of the acorn shell beginning in the second decade of July, carpophagous insects were able to penetrate acorns through natural cracks and holes gnawed by other insect species.

6 Figs., 27 Refs.

Dynamics of pathological processes in Ukrainian forests in 2018–2024

I. M. Ustskyi — 2025-12-29

Introduction

The main objective of forest pathological monitoring is to develop a comprehensive assessment of the forest pathological situation both at the level of individual forestry units and at the national scale. Analysis of the temporal dynamics of forest pathological processes, their relationships with mensurational and geographical characteristics of stands, and the influence of negative environmental factors enables the prediction of their occurrence and spread and provides a basis for planning appropriate forest management measures. This study aimed to assess the extent and identify trends in the spread of pathological processes in Ukrainian forests during the period 2018–2024, based on summarized observations conducted by forestry specialists and specialized forest protection services.

Materials and Methods

The study focused on forest stands in Ukraine in which pathological processes were recorded. The system for assessing forest pathological conditions was based on routine observations carried out by forestry specialists and forest protection services. The database included stands exhibiting pathological tree dieback that required the implementation of sanitary measures. Factors initiating pathological processes were identified based on characteristic symptoms and types of damage. Data collection and summarization were performed using the online Forest Pathology Monitoring system and Microsoft Excel software. Correlation analysis was applied to identify trends in the spread of pathological processes. The extent of pathological processes was quantified by the area of forest stands in which they were observed.

Results and Conclusions

An analysis of data from the “Forest Pathology Monitoring” portal for the period 2018 and 2021–2024 showed that 34–53% of total area of affected by stand dieback of the main species was occupied by Scots pine (Pinus sylvestris L.), followed by oak (Quercus robur L.; 25–38%), ash (Fraxinus excelsior L.; 5–9%), spruce (Picea abies (L.) Karst.; 5–10%), and black locust (Robinia pseudoacacia L.; 4–6%). A decreasing trend in the extent of pathological processes was observed in pine stands, whereas an increasing trend was recorded in oak stands. The largest areas of dieback in oak, ash, and black locust were concentrated in forests managed by the Tsentralnyi Regional Office, where a clear upward trend was observed from 2018 to 2024. Dieback of spruce forests was mainly concentrated in the Carpathian region, where its extent also tended to increase during the study period. The proportion of oak stands experiencing dieback increased in the Tsentralnyi, Pivnichnyi, Karpatskyi, and Slobozhanskyi Regional Offices, while a decrease was recorded in the Poliskyi, Podilskyi, and Stolychnyi Regional Offices. The proportion of ash stands affected by dieback increased in the Tsentralnyi Regional Office but decreased in the Podilskyi, Poliskyi, and, since 2021, Pivnichnyi Regional Offices. A reduction in the proportion of drying spruce stands was observed in the Poliskyi and Stolychnyi Regional Offices, whereas an increase occurred in the Karpatskyi, Podilskyi, and Tsentralnyi Regional Offices. The highest proportion of black locust stands with deteriorating health was recorded in the forests of the Tsentralnyi Regional Office, with a steady increase observed from 2021 to 2024. A similar upward trend was also noted in the Slobozhanskyi Regional Office. Compared to the 2018 survey, the total area affected by pathological processes increased to 111% in 2021, but subsequently declined to 81%, 57%, and 58% in 2022, 2023, and 2024, respectively. The decline is primarily attributed to incomplete data resulting from limited access to monitoring in areas affected by military operations.

7 Figs, 3 Tables, 27 Refs.

Experience in introducing the most promising exotic coniferous species in the Carpathian region

M. M. Sishchuk — 2025-12-29

Introduction

The introduction of exotic tree species aims to utilize species, their forms, climatic types, and varieties that have undergone preliminary testing under local conditions and demonstrated promise in one or more economically valuable traits, such as resistance to anthropogenic stress, high productivity, wood quality, durability, early and abundant fruiting, phyto-ameliorative capacity, and ornamental value. Forest ecosystems can better adapt to changing environmental conditions and continue to provide ecological, social, and economic functions when high-quality seeds and planting material of promising introduced species are used in reforestation and afforestation.

The aim of this study was to assess the current level of coniferous species introduction in the Ukrainian Carpathians, analyze growth characteristics of selected species, and evaluate their potential for practical forestry applications.

Materials and Methods

The introduction of coniferous species in the Carpathian region was studied using the authors’ original research with previous scientific findings from the Laboratory of Reforestation and Selection of the Ukrainian Research Institute of Mountain Forestry (UkrRIMF). The analysis also incorporated legislative and regulatory frameworks, financial and departmental records, and both the domestic and international experience in plant introduction and its effective application.

Results.

Experience in artificial reforestation aimed at increasing the productivity of newly established forest plantations in the Carpathians demonstrates the important role of introduced coniferous species, including Pseudotsuga menziesii, grand fir, white fir, balsam fir, European and Japanese larches, Weymouth pine, yellow pine, black pine, as well as Siberian and Korean stone pines. Studies conducted by the Laboratory of Forest Restoration and Selection of UkrRIMF across all forest management department units in the Carpathians indicate that, by 2024, plantations with introduced coniferous species cover 199.7 ha, accounting for an average of 12.0% of forest plantation projects and involving two non-native species for forest plantation. The larges areas of introduced species were recorded in the Ivano-Frankivsk region (120.2 ha; 21.2%), followed by the Zakarpattia region (32.9 ha; 5.5%). Smaller areas were observed in the Chernivtsi (27.1 ha; 10%) and Lviv (19.5 ha; 8.9%) regions. Among the introduced species, European larch (Larix decidua) was the most widespread, covering 109.2 ha in Ivano-Frankivsk, 32.9 ha in Zakarpattia, 24.0 ha in Chernivtsi, and 19.5 ha in Lviv, for a total of 185.6 ha (11.2%). In contrast, Pseudotsuga menziesii occupied only 14.1 ha (0.8%) of the forest plantation area.

Conclusions

The experience of growing 12 species of five genera of four subfamilies of the Pinaceae in the Ukrainian Carpathians region was considered. In the area, 11 species are introduced: Pinus koraiensis, P. sibirica, P. nigra, P. ponderosa, P. strobus, Picea pungens, Larix kaempferi, Pseudotsuga menziesii, Abies balsamea, A. concolor, A. grandis. Larix decidua is a native species in the Transcarpathian region, and from the Ciskarpattia and further east, an introducer. The introduction of Ps. menziesii, L. decidua and L. kaempferi is at the stage of naturalization. Their fast growth, productivity, early and abundant seed production, resistance to pathogens and phytophagous insects have been confirmed. There are objects of a permanent forest seed base. The introduction of A. balsamea, A. grandis and P. koraiensis is at the stage of adaptation; there are no permanent forest seed base objects. P. strobus is recommended to be used in forest crops on southern slopes (800 m above sea level) up to 10–15%, as well as in recreational and health forests and in horticultural and park management, providing fencing or protection from vertebrate pests with repellents.

2 Tables, 26 Refs.

Features of the formation of self-seeded Scots pine forests on abandoned agricultural lands in Eastern Polissia and the northeastern part of the Left-Bank Forest-Steppe of Ukraine

A. M. Zhezhkun — 2025-12-29

Introduction

In the Polissia and Forest-Steppe regions of Ukraine, a substantial area of agricultural land (arable fields, meadows, and pastures) has been withdrawn from agricultural use. As a result, during recent decades, natural regeneration processes have led to the formation of self-seeded forests of various compositions on abandoned lands adjacent to existing forest stands. The natural overgrowth of former agricultural lands with woody vegetation and the formation of self-seeded forests occur through seed dispersal from neighbouring parent stands. The study aimed to identify the characteristics of natural self-afforestation processes on abandoned agricultural lands and to assess the feasibility of preserving self-seeded forests in Eastern Polissia and the northeastern part of the Left-Bank Forest-Steppe of Ukraine.

Materials and Methods

The research was conducted in young pine stands up to 27 years of age that developed on abandoned agricultural lands under fresh relatively poor and relatively fertile site conditions. To determine average stand parameters of naturally regenerated forests, sample plots (SPs) were established using standard forestry methods. Within the SPs, all tree species were recorded individually, and their age, diameter, Kraft class, and health condition category were determined. To assess the spatial distribution of Scots pine natural regeneration depending on location and distance from parent stand edges, transects were laid perpendicular to the forest edge. Accounting plots measuring 5 x 5 m were established at 20 m intervals, within which Scots pine regeneration was inventoried.

Results

On abandoned agricultural lands adjacent to pine forest stands, active natural regeneration under fresh relatively poor and relatively fertile site conditions resulted in the formation of self-seeded forests dominated by Pinus sylvestris L., with admixtures of Betula pendula Roth., Pyrus communis L., and Malus sylvestris (L.) Mill.

Natural Scots pine regeneration extended 100–250 m from the edge of parent stands. Tree distribution was uneven, forming clusters with high stem density.

Analysis of age structure showed that uneven-aged Scots pine stands developed on former agricultural lands. Continuous natural afforestation generally lasted up to 15 years, followed by a period of approximately 5 years with almost no emergence of new pine seedlings. As a result of the prolonged afforestation period, self-seeded forests exhibited heterogeneous distributions of trees by age, diameter, and height.

During the first 10-year period, the growth rate of self-seeded pine stands was somewhat reduced due to strong competition from herbaceous vegetation. In the first age class, medium-density stands of site quality class I were formed, with a growing stock of 22–47 m³·ha^-1 and no signs of weakening (health condition index I_c = 1.24–1.39).

In the second age class, following canopy closure and the formation of typical forest phytocoenosis, Scots pine growth rate increased markedly. At the age of 13–23 years, naturally regenerated pine stands with a birch admixture, growing under fresh relatively poor site conditions on former agricultural lands, corresponded to site quality class I^b. These stands exhibited a relative density of stocking exceeding 1 and a growing stock of 165–275 m³·ha^-1, nearly 2.4 times higher than that of fully stocked pine stands of natural origin. Under such conditions, stand health deteriorated due to increased natural mortality among trees of lower diameter classes.

Conclusions

The most effective natural regeneration occurred within 100–150 m wide strips of abandoned farmland located on the leeward side of prevailing westerly winds adjacent to seed-source pine stands. Under fresh relatively poor and relatively fertile site conditions, the average density of 5–27-year-old self-seeded stands ranged from 2,000 to 2,800 stems·ha^-1, generally corresponding to site quality class I or higher. Growth rates accelerated after canopy closure and the establishment of a typical forest microenvironment. The growing stock of 13-year-old high-density self-seeded pine forests in fresh relatively poor pine site types on abandoned farmland exceeded that of fully stocked naturally regenerated pine stands by nearly 2.4 times. However, excessive stand density may lead to deterioration in tree health, emphasizing the need for timely tending felling to reduce competitive stress, improve growth conditions, and promote the development of productive and stable stands with the desired composition and structure appropriate to the forest site type.

3 Figs., 5 Tables, 21 Refs.

Health condition of natural oak stands in the Left-Bank Forest-Steppe of Ukraine

M. Н. Rumіantsev — 2025-12-29

Introduction

In recent years, several regions of Ukraine have experienced forest weakening and dieback, including oak forests, primarily due to the combined effects of abiotic, biotic, and anthropogenic factors. Assessing the health condition of forests, particularly natural oak stands in the Left-Bank Forest-Steppe of Ukraine, is therefore essential for predicting stand decline and for improving forest management practices aimed at enhancing stand resilience and productivity. The aim of this study was to analyze the dynamics of the health condition of coppice-origin and natural seed-origin oak stands and to assess the degree of their degradation under the influence of various environmental and anthropogenic factors.

Materials and Methods

The health condition of oak trees was evaluated on four permanent and 32 temporary sample plots established in natural oak stands of different ages in the Sumy and Kharkiv regions, following standard forestry and forest inventory methods

The studied stands were 85–200 years old, with a relative density of stocking of 0.5–0.9. The proportion of oak in the first canopy layer ranged from 40% to 100%, and stand origin included both coppice and natural seed regeneration. Stand health and damage intensity were characterized using the mean health condition index (І_с). Tree health was classified according to the condition category scale defined in the Sanitary Forests Regulations in Ukraine.

Results

On permanent sample plots, the mean health condition index of natural oak stands ranged from 1.27 to 1.81, while that of oak trees specifically ranged from 1.59 to 1.82. These stands were classified as “healthy” and “weakened”, with damage intensity assessed as “none” to “low”. A slight deterioration in health condition was observed with increasing stand age.

A relationship was identified between stand health condition and species composition. The poorest health condition (І_с = 1.81) occurred in nearly pure oak stands with only a minor admixture (up to 5% of growing stock) of common ash. Increasing the proportion of associated species (common ash, small-leaved lime, and Norway maple) to 50–60% improved stand health (І_с = 1.27–1.54). Oak trees in health categories 1 and 2 predominated, accounting for 86–92% of the total trees.

On temporary sample plots, the mean health condition index ranged from 1.65 to 2.56 for stands overall and from 2.02 to 2.94 for oak trees. These stands were classified as “weakened” to “severely weakened”, with damage intensity increasing from “low” to “moderate” with stand age, depending on species composition. Stands with 80% oak trees exhibited better health (І_с = 1.65–2.43) than those with 90% oak trees (І_с = 1.89–2.56). The proportion of standing dead trees was low, not exceeding 16% of the total oak growing stock.

Conclusions. Natural oak stands in the Left-Bank Forest-Steppe of Ukraine were generally characterized by a relatively good health condition. In stands of various ages and compositions, trees in health condition categories 1 and 2 predominated, accounting for more than 80% of all trees, while the proportion of standing dead trees remained low. Overall, these findings indicate no clear evidence of oak stand degradation in the region. To further improve the health and stability of oak stands, targeted tending and sanitary felling should be implemented, with a focus on optimizing stand composition and enhancing resilience.

3 Figs., 3 Tables, 28 Refs.

Silvicultural efficiency of cultivation regimes for artificial pine stands in the Northern Steppe of Ukraine

O. M. Tarnopilska — 2025-12-29

Introduction

The optimal intensity and periodicity of thinning during tending fellings, as well as the resulting stand density, remain subjects of debate in silviculture. The effect of heavy thinning – particularly during tending – on the growth, resilience, and productivity of planted pine stands have not been sufficiently studied. The aim of the study was to assess the effect of thinning intensity and frequency during tending fellings on the growth, productivity, resilience, and differentiation of planted pine stands in the Northern Steppe of Ukraine, using the Izyum steppe forest as a case study.

Materials and Methods

The experiment was initiated in 1983 in the Chervonooskil Forestry (compartment 66) of the Izium Forestry Management Unit, Branch “Slobozhanskyi Forest Office” of the State Specialized Forest Enterprise “Forests of Ukraine”. The study was conducted in 31-year-old planted pine stands growing in fresh relatively poor forest site conditions. The experimental design included one linear-selective cleaning (weeding) at 17 years of age, one thinning at 31 years, and one thinning at 50 years. Mensuration characteristics, stand health condition, and tree growth classes were assessed using standard forestry methods. Stand resistance to wind, ice, and wet snow damage was evaluated using the relative slenderness ratio (H/D). The maximum (boundary) H/D value for dominant trees, which indicating stand resistance, ranged from 80 to 110. Statistical analysis was performed using analysis of variance (ANOVA).

Results

In 57-year-old stands subjected to different cultivation regimes, stand density ranged from 1,818 to 670 stems ha^-1. Mean diameter varied from 16.5 to 23.4 cm, mean height from 18.0 to 20.9 m, stand basal area from 38.7 to 27.0 m² ha^-1, and stand volume from 371 to 259 m³ha^-1. Relative density of stocking ranged from 0.9 to 0.6, and the relative slenderness ratio from 116 to 89. The dominant Kraft class was II, and stand health was assessed as “weakened” (І_с = 2.0). Within 7 years after thinning, current volume increment ranged from 8.2 to 4.6 m³ha^-1·year^-1, while mortality in the densest stands reached 9.4–15.0 m³ha^-1. As stand density decreased, the number of trees in Kraft classes I and II ranged from 512 to 301 stems ha^-1. Correspondingly, mean diameter was 18.7–23.5 cm, mean height was 19.5–20.9 m, the basal area was 25–30 m² ha^-1, and the stand volume ranged from 267 to 271 m³ha^-1.

Conclusions

In planted pine stands of the Northern Steppe of Ukraine, the number of thinning operations can be reduced by increasing thinning intensity, provided that stand density and resilience are carefully controlled at all development stages. Less frequent but more intensive thinning reduces mechanical interventions and promotes faster formation of resilient and productive stands. However, thinning intensity must be adapted to actual stand conditions to avoid excessive reduction in resistance to windthrow, snow damage and pest outbreaks. Moderate thinning (18% of stand volume) and heavy thinning (28–30%), reducing stand density to 1,600–1,200 stems?ha^-1, increased mean diameter by 5–34% and mean height by 6–11%, and enhanced resistance to physical stress, as indicated by a reduction in the relative slenderness ratio (H/D) to 96–101, without a significant decrease in total stand volume. Moderate and heavy thinning (22–28% of stand volume), reducing stand density to approximately 1,000–700 stems ha^-1, resulted in a 33–42% increase in mean diameter and further improvement in stand resilience (H/D reduced to 89–96), while maintaining total stand volume over the long term. The results of the study should be considered when developing regulatory guidelines for the management of planted pine forests.

6 Figs., 3 Tables, 34 Refs.

Monitoring of secondary Norway spruce stands condition in the Zacharovanyi Krai National Nature Park

I. F. Shyshkanynets — 2025-12-29

Introduction

The problem of Norway spruce forest dieback in the Ukrainian Carpathians is evident. In the Zacharovanyi Krai National Nature Park (hereinafter referred to as the NNP), secondary Norway spruce forests occupy 380.2 hectares, representing 6.6% of the forest-covered area. Studies on the condition of secondary spruce stands in the NNP began in 2020, when nine permanent sample plots (PSPs) were established. It was found that the age of quantitative maturity of secondary spruce stands occurs at 50–55 years, which is approximately five years earlier than reported in studies conducted in the 1980s. According to current regulatory documents, the maturity age of secondary spruce stands is 61–70 years.

Thіs study aimed to identify trends in changes in the health condition of secondary Norway spruce (Picea abies (L.) H. Karst.) stands in beech-type forests within the Zacharovanyi Krai National Nature Park.

Materials and Methods

Repeated assessments were conducted on the permanent sample plots established in 2020. Detailed descriptions of the study sites and methods are provided in Shyshkanynets et al. (2021). In 2025, remeasurements were carried out on six PSPs (2, 4, 5, 6, 7, and 8). Plots 1, 3, and 9 were not remeasured because the tree stands there were identical to those of PSP 2.

Results

A pronounced deterioration in the health condition of secondary spruce stands was observed. In 2020, the average proportion of dead spruce trees across the sample plots was 63.5%, increasing to 85.8% in 2025. Excluding PSP 5, the proportion of dead spruce trees reached 97.0%. In PSPs 2 and 8, all spruce trees were dead (health condition index = 6.0), while in PSPs 4, 6, and 7, dead spruce trees were recorded sporadically (the spruce health condition index = 5.7–5.9). The average age of spruce trees on the studied sample plots ranged from 55 to 72 years. In 2025, the proportion of broken dead trunks (with stem height greater than or equal to 1.3 m) accounted for 35–45%, indicating advanced stand degradation.

As a result of dieback, complete mortality of spruce stands occurred in sites that had a pure spruce composition (100%) in 2020 (PSPs 2 and 9). In the stands with a spruce proportion of 70–80%, in 2020 (PSPs 7 and 8), sparse beech forests developed, with relative densities of stocking of 0.3 and 0.2, respectively. In sites with spruce accounting for only 30–40% in 2020 (PSPs 4 and 6), the tree stand changed to a beech-dominated one with an admixture of maple, which is typical for beech-type forests.

Conclusions

The proportion of dead spruce trees increased from 63.5% in 2020 to 97.0% in 2025, indicating mass dieback and degradation of secondary spruce stands at the age of maturity (60–70 years) under the influence of abiotic and biotic factors. In areas formerly occupied by pure spruce stands, successional processes involving pioneer species (birch, rowan, etc.) and spruce regeneration are underway. In secondary spruce stands with a beech proportion of 20–30%, sparse beech forests have formed, accompanied by pioneer species and spruce undergrowth. Where the parent stand contained six or more units of beech, no pronounced succession changes were observed.

1 Fig., 2 Tables, 13 Refs.

Methods for mitigating and minimizing forest fire risks in the Ukrainian forest management system

T. M. Portyanko — 2025-12-29

Introduction

Forest fires have become an increasingly critical threat to the ecological stability, biodiversity and socio-economic resilience of Ukraine’s forest ecosystems. The intensification of extreme weather events, prolonged droughts and rising temperatures – highlighted in IPCC and UNEP assessments – has amplified fire danger, particularly in continental regions of Eastern Europe. Ukrainian forests, especially pine stands in Polissya and the Left-Bank region, face accumulating fuel loads, expanding WUI (wildland–urban interface) areas and greater anthropogenic pressure. Although Ukrainian legislation provides a regulatory basis for forest-fire prevention, its practical implementation remains inconsistent, fragmented and insufficiently integrated into forest-management systems. The study aimed to systematize contemporary methods for preventing and minimizing forest fire risks and to substantiate the possibilities for their adaptation to the conditions of forest management in Ukraine.

Materials and Methods

This study applies a structured literature-review methodology following PRISMA and ROSES guidelines, ensuring systematic identification, screening and inclusion of relevant sources. The dataset encompasses international documents (FAO, UNEP, IPCC reports; EFFIS datasets), Ukrainian regulations (Resolutions No. 610–612, National Fire Danger Scale, Fire Safety Rules), and peer-reviewed articles from Scopus, Web of Science and Google Scholar (2000–2024). Sources were categorised into six thematic blocks: climatic drivers of wildfire risk; structural characteristics of forest stands; fuel-load management practices; application and regional adaptation of the Fire Weather Index; GIS-based monitoring and remote sensing; and risk-based management approaches aligned with ISO 31000. Screening was based on relevance, scientific validity and applicability to Ukrainian forest-management conditions.

Results

The analysis shows that systematic fuel-load reduction – mechanical thinning, sanitary logging and prescribed burning – is the most consistently effective method of reducing wildfire intensity and preventing crown-fire development. International case studies demonstrate long-term positive effects of coordinated fuel-management programmes, while Ukrainian data confirm the need for similar measures, particularly in pine-dominated ecosystems. The Fire Weather Index remains the dominant tool for operational assessment of fire danger; however, without regional calibration, it may distort risk levels under Ukrainian climatic and forest-type conditions. GIS-supported monitoring, combined with satellite observations (Sentinel, Landsat, MODIS) and automated early-warning systems, significantly improves the accuracy of risk mapping and early detection. The study highlights the growing influence of infrastructure-related ignition sources – especially power-line corridors and transportation networks – within WUI zones, where the concentration of human assets greatly increases potential losses. Integration of ISO 31000 principles offers a structured pathway for identifying vulnerabilities, prioritising risk-reduction measures and transitioning from reactive suppression to preventive planning.

Conclusions

An effective forest-fire prevention and mitigation system in Ukraine should be built upon several key components: systematic and science-based fuel-load reduction; regionally adapted fire-danger indices; expansion of GIS, remote-sensing and automated early-warning technologies; enhanced management of infrastructure-related risks, especially within WUI zones; and strengthened inter-agency cooperation involving forest authorities, emergency services and local communities. Embedding ISO 31000 risk-management principles into strategic and operational forest planning will enable more proactive, evidence-based decision-making and increase the resilience of Ukrainian forest ecosystems to intensifying climate-driven wildfire threats.

22 Refs.

Methodological aspects of forest soil monitoring organisation in Ukraine

S. P. Raspopina — 2025-12-29

Introduction

The ICP Forests program is the most well-known forest monitoring program in the region of the United Nations Economic Commission for Europe. It provides, among other components, the monitoring of forest soils. In Ukraine, the Ukrainian Research Institute of Forestry and Forest Melioration named after G.M. Vysotsky has been the national coordinating center for forest monitoring within the framework of the ICP Forests program for over 30 years.

The national legislative and regulatory framework and Ukraine's international obligations provide for the monitoring and national inventory of forests (since 2021), which includes a component for the assessment of forest soils. At present, forest soils are largely overlooked by systematic research, leading to a critical information deficit concerning their condition and the dynamics of their forest-growing properties in the face of numerous adverse environmental factors. This study aimed to analyse the main methodological principles, current requirements, and key challenges associated with the implementation and organisation of forest soil monitoring in Ukraine within the framework of the ICP Forests Programme.

Results

The main principles, methodological aspects, and problems of organizing forest soil monitoring at all stages of its implementation are presented in accordance with the requirements of the ICP Forests program, which provides for observations at Level I and II monitoring sites, according to the list of mandatory and optional soil indicators. Level I soil monitoring is mainly focused on obtaining basic information about the chemical state of the soil and its changes over time. Level II monitoring includes an expanded range of soil studies on permanent plots, which, together with studies of other forest components, provide an opportunity to comprehensively assess the overall state of the forest ecosystem. Soil studies consist of several stages: 1) field studies (using the FAO field soil survey methodology (2006) with the determination of the taxonomic name of the soil in accordance with the International Standard for Soil Taxonomic Classification (World Reference Base for Soil Resources, WRB)), 2) analytical (measurement of key soil parameters using recommended standardized methods), 3) verification of results in laboratory intercalibration tests.

The development and functioning of forest soil monitoring requires addressing a range of tasks, the most important of which include:

Strengthening the legal, institutional, and technical framework for forest and soil monitoring, including clear regulatory provisions and modernization of laboratory capacities.
Advancing scientific and methodological support through harmonization of national and WRB soil classifications, digitalization of monitoring systems, and integration into forestry education programs.
Ensuring stable financial support via dedicated national funding and international donors (GEF, FAO, World Bank).

Conclusions

Establishing a functional system of forest soil monitoring is essential for informed and sustainable forest management in Ukraine, particularly under post-war recovery conditions, climate change, and EU integration. Stable financial support through national programs and international donors (GEF, FAO, World Bank) will ensure the continuity of monitoring and provide the knowledge base necessary to maintain forest ecosystem resilience and productivity.

3 Tables, 14 Refs.

Effectiveness of fertilizer application during containerized english oak seedling cultivation in the South-Eastern Forest-Steppe of Ukraine

M. Н. Rumіantsev — 2025-12-29

Introduction

Ensuring optimal mineral nutrition during seedling cultivation is essential for enhancing resistance to biotic and abiotic stress factors and improving the quality of planting material. The application of mineral and complex fertilizers represents an effective approach to achieving these objectives. Studies on fertilizer use in the cultivation of English oak (Quercus robur L.) seedlings provide a scientific basis for developing intensive technologies for producing high-quality stress-resistant planting material.

The aim of this research was to evaluate biometric parameters, the air-dry aboveground biomass, root system biomass, and the yield of standard-quality one-year-old containerized English oak seedlings under different fertilization regimes.

Materials and Methods

The effectiveness of root and foliar fertilization with solutions of Partner Standart, Rokohumin, Rost Kontsentrat, Master, Help Rost, Brexil Multi, Nutrivant Plus, and Rosasol on biometric parameters, biomass accumulation, and yield of standard-quality one-year-old English oak containerized seedlings was investigated in 2023.

Ten experimental treatments with different fertilizer types and concentrations, along with an unfertilized control, were established. During the growing season, two applications of fertilizer solutions were carried out either through root fertilization (irrigation) or foliar fertilization (spraying).

Fertilizer effectiveness was assessed based on biometric characteristics, biomass parameters, and the proportion of standard-quality seedlings. Differences between treatments and the control were tested for statistical significance using Student’s t-test at a 5% significance level.

Results. The greatest mean seedling height (35.8 cm) was recorded following root fertilization with Partner 20:20:20 at a concentration of 3 g·l^-1, while the lowest height (29.1 cm) was observed with root application of Master 20:20:20 at 2.5 g·l^-1.

The largest mean root collar diameter (4.7 mm) was achieved with root fertilization using Master 6:3:6 at 5 ml·l^-1^-?, whereas the smallest diameter (3.9 mm) was observed in treatments with root fertilization using Partner 35:10:10 and Partner 20:20:20 at 3 g·l^-1.

The highest mean air-dry aboveground biomass (3.2 g) resulted from foliar fertilization with Rosasol at 1.5 g·l^-1, while the lowest value (1.9 g) occurred following root fertilization with Master 20:20:20 at 2.5 g·l^-1.

Maximum mean root biomass (9.9 g) was obtained with root fertilization using Help Rost at 3.5 ml·l^-1, whereas the minimum value (3.3 g) was recorded with Partner 20:20:20 applied at 3 g·l^-1.

The proportion of standard-quality containerized seedlings in all fertilized treatments (86–100%) exceeded that of the control (82%). Seedling condition in both experimental and control treatments was assessed as good, with a low incidence of disease (5–10%).

Conclusions. Compared with the control, fertilization increased seedling height by 18–45%, root collar diameter by 25–52%, air-dry aboveground biomass by 86–218%, and root biomass by 5–213%.

The proportion of standard-quality one-year-old containerized oak seedlings was consistently higher in all fertilized treatments (86–100%) than in the unfertilized control (82%).

The results demonstrate the effectiveness of applying Partner Standart, Rokohumin, Rost Kontsentrat, Master, Help Rost, Brexil Multi, Nutrivant Plus, and Rosasol fertilizers – used in accordance with the manufacturers’ recommendations – for intensifying the growth of containerized English oak seedlings. These fertilization practices can be recommended for seedling cultivation in open-ground nurseries and for producing high-quality planting material for reforestation and afforestation in the south-eastern Forest-Steppe of Ukraine.

4 Figs, 1 Table, 27 Refs.