Forestry and Forest Melioration

Features of the growth of English oak forest plantations established with different planting materials in Kharkiv Forest Research Station

2025-03-07T19:15:26+02:00

Introduction

Artificial reforestation does not always enhance the quality and reproductive success of biologically sustainable and productive forest stands. One approach to addressing this challenge is the establishment of artificial plantations using containerised seedlings, which have several advantages over bare-root seedlings. Consequently, the use of containerised seedlings is being increasingly integrated into silvicultural practices.

The study aimed to compare the growth performance, survivability, and preservation rates of five-year-old English oak plantations established using containerised seedlings grown on substrates of different compositions and those established with bare-root seedlings.

Materials and Methods

The research was conducted on a permanent multivariate research site within the Pivdenne forestry of the Kharkiv Forest Research Station in fresh maple-lime oak forest. The plantations were established in July 2016 using containerised seedlings cultivated on substrates composed of medium loamy soil, peat, and fresh sawdust in different proportions.

The survivability, preservation, and growth parameters of the experimental plantations were compared to those of plantations of the same age established with bare-root seedlings.

Data from measurements and observations of experimental plantations were analysed using descriptive statistics in MS Excel. The statistical significance of differences between control and experimental variants was assessed at the 5% significance level.

Results

The composition of the substrate used for containerised oak seedlings significantly influenced their biometric parameters. Seedlings grown on a substrate containing medium loamy soil and peat in 3:1 or 2:1 ratio (by volume) exhibited the greatest height and root collar diameter. This substrate composition is recommended for growing English oak seedlings in agrofibre containers at the Kharkiv Forest Research Station.

Plantations established with containerised seedlings exhibited higher survivability (91–98% vs. 85%) and preservation rates (83–89% vs. 78%) compared to those established with bare-root seedlings.

At five years of age, all plantation variants established with containerised seedlings demonstrated superior growth parameters compared to those established with bare-root seedlings, with differences of up to 32% in height, 53% in diameter, and 33% in height increment. The highest growth parameters at five years were recorded for English oak plants in the ‘Soil + peat (3:1)’ variant, while the lowest values were observed in the ‘Soil + sawdust (2:1)’ variant.

Conclusions

The findings of the study should be used in future revisions to the regulatory document “On the approval of the Instruction on Design, Technical Acceptance, Accounting, and Quality Assessment of Forestry Objects”, specifically regarding normative survivability and quality indicators for plantations established with containerised seedlings when transplanted to forested areas, including the density of the main species.

2 Figs., 2 Tables, 11 Refs.

Diversity of grass vegetation in field shelterbelts transformed into silvoarable agroforestry plantings in the Right-Bank Forest-Steppe of Ukraine

2025-03-07T19:29:00+02:00

Introduction

More than half of Ukraine’s agroforestry fund consists of 60–70-year-old shelterbelts. As these shelterbelts age, their condition deteriorates, and in the absence of silvicultural management, forest edges encroach into adjacent fields, leading to an increase in their width. This expansion results in a more open structure, reducing their amelioration efficiency. To enhance their protective functions, reducing their width is recommended. One potential solution to this issue is the transformation of existing shelterbelts into silvoarable agroforestry plantings. Such transformation leads to several ecological changes, particularly in the aboveground vegetation cover.

The aim of the study was to assess changes in species and quantitative composition, as well as the prevalence of herbaceous vegetation in shelterbelts that were transformed into linear silvoarable agroforestry plantings.

Materials and Methods

The research was conducted in the northern part of the Right-Bank Forest-Steppe across six sample plots in both wide and transformed shelterbelts. The species composition and degree of projective cover of the aboveground vegetation were analyzed using1?1 m² survey plots with tenfold replication. Phytodiversity of the living aboveground cover was assessed using several ecological indices, including Shannon’s species diversity index, Pielou’s evenness index, and Simpson’s diversity index. The collected data were statistically processed to determine mean values and associated errors.

Results

In classical shelterbelts, the dominance of sylvatic species, along with high projective cover, creates a stable microclimatic environment with high species diversity, which is the result of an environment close to forest phytocoenoses. However, in transformed shelterbelts, ruderal species replace forest vegetation, leading to the formation of agrobiocoenotic plant communities. This suggests that in older shelterbelts with diverse species composition, anthropogenic succession is driving a transition from forest biocenosis to agroforestry ecosystems, accompanied by distinct coenotic changes. An analysis of the coenotic structure of aboveground vegetation revealed that both classical and transformed shelterbelts are characterised by the dominance of sylvatic and ruderal species. However, in classical shelterbelts, sylvatic species accounted for a higher proportion (39.0–49.4%) compared to ruderal species (20.3–42.0%). In contrast, transformed shelterbelts exhibited a clear dominance of ruderal vegetation (22.1-41.3%) over forest species (17.3–31.7%). This shift is attributed to increased light penetration, the dispersal of forest litter, the loss of forest-like microenvironments, and the more open, wind-exposed structure of transformed shelterbelts. In classical shelterbelts, species diversity is influenced by light availability and structural characteristics of the shelterbelts. However, species richness was significantly lower in classical shelterbelts compared to those transformed into silvoarable agroforestry systems.

Conclusions

The transformation of shelterbelts into linear plantings of the silvoarable agroforestry system accelerates successional changes in the aboveground vegetation, leading to desilvatization of herbaceous species and a decline in species diversity. Consequently, transformed shelterbelts experience intensified synanthropization, and are characterised by an increased presence and adaptation of ruderal and meadow vegetation.

3 Figs., 2 Tables, 30 Refs.

Survival and growth characteristics of forest pine plantations established with different planting stock types in the south-eastern part of the Left-Bank Forest-Steppe of Ukraine

2025-03-07T19:40:50+02:00

Introduction

The planting of forest stands remains predominant among the various methods of restoring pine forests in the country. In the Kharkiv region, no recent research has been conducted on the growth characteristics of Scots pine plantations established using different planting technologies and planting stock types. This gap in research highlights the relevance of the present study.

The aim of this research was to evaluate the growth and survival rates of two- and three-year-old Scots pine plantations established using different planting methods and planting stock types in fresh infertile and fresh relatively infertile pine site types. The goal was to determine the optimal technology for establishing pine stands in the south-eastern part of the Left-Bank Forest-Steppe of Ukraine.

Materials and Methods

The study was conducted at the Branch “Zhovtneve Forestry” of the State Specialized Forest Enterprise “Forests of Ukraine” (Merefianske forest district) and Kharkiv Forest Research Station (Derhachivske and Lypetske forest districts) in fresh infertile pine site types and fresh relatively infertile pine site types. Measurements and assessments of growth indicators – height, height increment, root collar diameter – and survivability- were performed on two- and three-year-old Scots pine plantations established using different planting methods, planting stock types, and stand compositions.

The survivability in the second and third years of cultivation was determined as the ratio of the number of viable plants at the time of assessment to the initial number of planting spots, expressed as a percentage.

The collected data were analysed using mathematical statistics in MS Excel. The significance of the difference between control and experimental variants was tested using Student's t-test at a 5% significance level.

Results

Two-year-old plantations in the Merefianske forest district. It was found that pure plantations in fresh relatively infertile pine site types established by hand planting exhibited higher growth rates compared to pure plantations established by mechanised planting, mixed plantations, and pure plantations in fresh infertile pine site types. This differences in growth parameters were as follows: height – 1%, 4%, and 12%; height increment – 4%, 5%, and 8%; and root collar diameter –7%, 9%, and 16%, respectively.

The highest survival rate was recorded for pure plantations in fresh relatively infertile pine site types established by hand planting, while the lowest (80%) was observed in plantations in fresh infertile pine site types established by hand planting.

Three-year-old plantations in Merefianske forest district. The results showed that pure plantations in fresh relatively infertile pine site types established by hand planting exhibited higher growth rates compared to pure plantations established by mechanised planting, mixed plantations, and pure plantations in fresh infertile pine site types. This differences in growth parameters were as follows: height—4%, 3%, and 10%; height increment—6%, 8%, and 15%; and root collar diameter—4%, 6%, and 11%, respectively.

The highest survival rate (80%) was recorded in pure plantations in fresh relatively infertile pine site types established by hand planting, while the lowest (77%) was observed in plantations in fresh infertile pine site types established by hand planting.

Two-year-old plantations in Derhachivske forest district. The research results indicate that plantations in fresh relatively infertile pine site types established using containerised seedlings exhibited higher growth rates compared to those planted with bare-root seedlings. The differences observed were 13% in height and 15% in both height increment and root collar diameter.

Additionally, plantations established with containerised seedlings demonstrated a higher survivability (88%) compared to those planted with bare-root seedlings (82%).

Three-year-old plantations in Lypetske forest district. The research results show that plantations in fresh fairly infertile pine site types established with containerised seedlings exhibited superior growth rates compared to those planted with bare-root seedlings. The differences recorded were 28% in height, 21% in height increment, and 16% in root collar diameter.

Plantations established with containerised seedlings also exhibited higher survivability (85%) compared to those planted with bare-root seedlings (80%).

Conclusions

To enhance the technology of pine plantation establishment in the study region, the broader use of containerised planting stock is recommended for pine forest restoration. Additionally, expanding the proportion of mixed plantations, particularly those established using mechanised method, is advised.

5 Tables, 18 Refs.

Emerald ash borer: Risk-based strategies to pest management

2025-03-10T10:01:51+02:00

Introduction

The emerald ash borer (EAB, Agrilus planipennis), a highly invasive beetle native to northeast Asia, poses a severe threat to ash trees (Fraxinus spp.) in forests, urban areas, and agricultural landscapes. Since its introduction to North America in the 1990s, EAB has caused significant ecological and economic damage. Its spread to Europe, including Russia and Ukraine, has intensified these challenges. This review examines EAB’s impact, identification, and management strategies to mitigate its spread and minimize damage.

Materials and Methods

This review is grounded in an extensive analysis of publications in scientific journals worldwide, with a primary focus on the identification and management strategies for the EAB, as well as our previously published scientific papers addressing EAB and ash dieback in Ukraine.

Results

Regulation and monitoring. EAB is classified as a quarantine pest in Ukraine and is subject to regulatory control under EU regulations, with controls on ash material movement. Localized eradication measures, such as the felling and burning of infested trees, are implemented alongside phytosanitary monitoring. However, the ongoing military conflict presents significant challenges to containment efforts in some regions.

Spread and detection. EAB spreads both naturally (at a rate of up to 20 km per year) and through human activities, such as the transport of infested wood. First officially detected in Ukraine’s Luhansk region in 2019, EAB has since expanded into Kharkiv and Kyiv. Monitoring is coordinated by the State Service of Ukraine for Food Safety and Consumer Protection (SSUFSC) and its regional departments. These entities rely on visual inspections, pheromone traps, and sentinel trees for detection. Key visual symptoms of infestation include crown dieback, epicormic shoots, thinning crowns, and increased woodpecker activity. Surveys prioritize high-risk areas, such as shelterbelts, forest edges, declining ash stands, urban parks, and wood-processing sites. Pheromone traps and girdled trap trees are deployed to capture adult EAB, with adjustments made for local conditions.

EAB-specific symptoms include D-shaped exit holes, serpentine larval galleries, and characteristic canopy decline. Detection tools include prism and multifunnel traps baited with specific attractants such as (3Z)-hexenol. Girdled trap trees, though cost-effective, are destructive and suited for delimitation efforts. Sentinel trees show promise for early detection. Differentiating EAB damage from ash dieback (Hymenoscyphus fraxineus) is essential for accurate diagnosis.

Response framework. The SSUFSC oversees response efforts based on EAB contingency plans and EPPO standards. Upon confirmation of an infestation, quarantine zones are established, and infested trees are felled and destroyed. Regional SSUFSC departments coordinate with landowners to halt tree harvesting and restrict the movement of potentially infested materials.

Post-confirmation strategies include containment through selective felling, insecticide applications, biological control, and public awareness campaigns. Eradication aims to remove all infested trees within a specific radius, though its success depends on early detection and limited spread.

Eradication or Containment Strategies. Eradication focuses on removing all infested ash trees within a designated area, based on studies indicating limited dispersal distances of EAB larvae. However, eradication success depends on early detection and minimal spread. If complete eradication is not feasible, management efforts shift toward slowing the spread through selective felling, monitoring, and trap deployment.

Challenges and Recommendations. The establishment of EAB in Ukraine highlights weaknesses in quarantine measures and the complexity of pest managment amid hostilities and climate change. Long-term strategies, such as integration of resistant ash genotypes and promoting tree species diversification, are essential to restore ecological balance and mitigate future risks.

Conclusions

EAB is a severe pest now established in three regions of Ukraine. This review outlines key steps for early detection, containment, and impact mitigation. While eradication has proven challenging globally, adaptive strategies, including resistant genotypes and forest diversification, offer hope for managing EAB's ecological and economic impacts.

1 Fig., 24 Refs.

Effectiveness of fungicides for protection of Catalpa bignonioides against powdery mildew

2025-03-10T10:45:44+02:00

Introduction

The widespread use of introduced species of the genus Catalpa in landscaping necessitates a comprehensive investigation into phytopathogenic fungal species, disease etiology, and effective plant protection methods. Such research provides valuable insights into the success and future prospects of Catalpa introduction for landscaping and its potential application in other areas of environmental management.

Among the fungal pathogens affecting the assimilation apparatus of seedlings and saplings, powdery mildew pathogens (Erysiphales, Ascomycota) warrant particular attention due to their significant impact.

The aim of the study was to evaluate the effectiveness of modern fungicides against powdery mildew (Erysiphe catalpae) in catalpa seedlings cultivated in ornamental nursery conditions.

Materials and Methods

The research, conducted in 2023, assessed the extent of powdery mildew damage in catalpa plantations and evaluated the efficacy of fungicides against Erysiphe catalpae Simonian.

Following manufacturer recommendations, seedlings were treated twice – on June 10, and July 20 – using the fungicides Artis Plus, Thalius, and Verben at standard application rates.

Results

The results demonstrated a significant improvement in plant protection outcomes. Across all experimental variants, an almost complete absence of the powdery mildew pathogen was observed.

Disease prevalence decreased from an initial 30–33% to a range of 0.3–1.1% after two treatments. . The overall disease incidence was reduced to 5.5–1.7% in treated seedlings.

Based on monitoring data, we confidently confirm the efficacy of the tested fungicides in protecting catalpa seedlings from E. catalpae.

Additionally, assessing changes in the biometric parameters of treated seedlings provided insights into their viability, adaptation to pathogens, and potential effects of chemical treatments on plant health.

The average height of treated seedlings increased by 64–75% compared to the control, suggesting that the fungicides suppressed pathogen activity and promoted growth by reducing disease pressure. Moreover, no adverse effects on plant diameter parameters were observed, further supporting the conclusion that the selected fungicides are both effective and safe for Catalpacultivation.

Conclusions

The study demonstrated the effectiveness of the selected fungicides in protecting Catalpa bignonii seedlings from powdery mildew. Among the tested fungicides, Artis Plus provided the highest level of protection. The double treatment effectively reduced disease prevalence and severity, positively influencing the biometric parameters of the plants. These findings highlight the potential of the tested fungicides as reliable tools for managing powdery mildew in Catalpa cultivation.

1 Fig., 4 Tables, 16 Refs.

Mycorrhizal associations of pine: Species, their characteristics, and role in forest ecosystems

2025-03-10T11:00:12+02:00

Introduction

Addressing the preservation and adaptation of key tree species to climate change is an urgent task. The ability of trees to survive under extreme conditions largely depends on their adaptability, particularly the development of robust root systems. Mycorrhizal symbiosis is crucial in enhancing plant growth, improving nutrient uptake, and protecting against toxic compounds and pathogens. Additionally, mycorrhizal fungi contribute to nutrient cycling and carbon sequestration in the soil, thereby supporting tree productivity, especially in nutrient-poor environments.

Impact of climate change on mycorrhizal fungi. Climate change significantly affects mycorrhizal associations, which are essential for maintaining plant health and ecosystem stability. Rising temperatures, shifts in precipitation patterns, and increased atmospheric CO₂ levels pose new challenges for mycorrhizal fungi, influencing their symbiotic relationships with trees. For example, changes in soil moisture and temperature can promote the spread of pathogenic fungi, weakening the protective functions of mycorrhizae.

The role of mycorrhiza in forest ecosystems. Ectomycorrhizae (EM) play a vital role in forest ecosystems, particularly in nutrient-poor soils, by enhancing the uptake of nitrogen, phosphorus, and other essential minerals. This, in turn, improves tree growth and resilience to environmental stressors such as drought and extreme temperatures. Additionally, mycorrhizal fungi help protect trees against pathogens and toxic substances. In Ukraine, research on forest mycobiomes remains limited, primarily focusing on taxonomic descriptions. There is an urgent need for systematic studies to explore the functional roles of mycorrhizal fungi in nutrient cycling and forest stability. Furthermore, understanding the potential of mycorrhizal species for seedling inoculation could enhance reforestation efforts and improve forest resilience in the face of climate change.

Mycorrhizal companions of Scots pine. Pinus species rely on characteristic ectomycorrhizal (EM) associations with various soil fungi. Mycorrhizal networks in the soil and on tree roots enhance nutrient accessibility and create favourable conditions for tree growth and development. Research in Ukraine has demonstrated the positive effects of Suillus luteus and Amanita muscaria mycorrhizae on the survival of pine seedlings, especially after forest fires. Scots pine species depend on specific ectomycorrhizae formed by soil fungi, which enhance nutrient uptake and create favorable growth conditions. Mycorrhized seedlings with Thelephora terrestris, Suillus bovinus, and Scleroderma citrinum showed higher nitrogen assimilation rates and shoot-to-root ratios than non-mycorrhized seedlings but exhibited lower shoot growth rates. The mycelium of S. citrinum retains 32% of the nitrogen supplied to the plants, which resulted in reduced host plant growth rates. Another significant mycorrhizal partner of Scots pine is Imleria badia, which thrives in diverse environments, including areas contaminated with heavy metals. The symbiotic relationship between pines and ectomycorrhizal fungi, particularly species of the Suilloid genus, can support pine adaptation in various habitats.

Mycorrhiza and Disease Resistance in Pine. Mycorrhizal fungi play a vital role in the growth and survival of trees in nutrient-poor soils by protecting them from toxic substances and phytopathogens. By forming a biotrophic association with their host trees, these fungi receive carbohydrates while enhancing the trees’ resistance to environmental stress and pathogenic threats. Mycorrhizal symbiosis improves tree vitality by mitigating the effects of toxic compounds and harmful microorganisms, thereby contributing to overall forest health and stability.

Conclusion

Given the critical role of mycorrhizal fungi in the restoration and conservation of temperate and boreal forests, further research and conservation measures are essential, particularly in the context of climate change. Preserving native and stress-tolerant mycorrhizal fungi strains offers a promising, eco-friendly strategy for enhancing forest ecosystem stability and mitigating the impacts of climate change.

76 Refs.

Prevalence and severity of Tilia cordata Mill. foliage damage in urban and forest plantings of Kharkiv region

2025-03-10T14:27:41+02:00

Introduction

Tilia cordata Mill., 1768 is widespread in European forests, as well as in shelterbelts and urban plantings. In urban ecosystems, changes in light and temperature, restricted root development, and air pollution influence both the spread of pests and the trees’ response to damage. These effects are often reflected in leaf appearance. For instance, technogenic air pollution manifests as leaf burns, fungal infections appear as spots of various shapes and colors, and insect damage includes gnaws, mines, punctures, galls, etc. Some species of fungi, mites, and insects increase reproduction only up to a certain level of pollution, while others generally avoid colonizing leaves under such conditions.

Studies conducted in various regions show a greater diversity of arthropod species in natural habitats compared to street plantings and a decrease in the proportion of species with an open lifestyle as technogenic load increases. However, the composition of insect, mite, and fungal species depends on factors such as geographic location, annual weather conditions, and the phase in the cyclical population dynamics, highlighting the need for further research.

This study aimed to identify the causes of foliar damage in T. cordata and to assess the prevalence and severity of their effects in relation to the type of planting, thus making it possible to use trees as bioindicators of anthropogenic stress.

Materials and Methods

Our research was carried out in 2018–2021 in forests, forest parks, parks, courtyards, and street plantings in the Kharkiv region and the city of Kharkiv. In July-August, leaves were randomly collected from the upper, middle, and lower canopy layers. During the cameral analysis, leaves were grouped according to the following damage types: “gnaws” (caused by insects with gnawing mouthparts and an open lifestyle), “mines” (galleries inside leaf tissues), “punctures” (caused by sucking insects), “galls” (tissue growths caused by insects or mites), “spots” (caused by phytopathogenic fungi), and “burns” (resulting from anthropogenic air pollution). The prevalence of each type of leaf damage was calculated as the percentage of leaves exhibiting specific symptoms within different planting types. The severity of leaf damage was calculated as the proportion of damaged leaf area (%), estimated with an accuracy of 5%. The average rate of leaf surface removal (leaf loss) was determined as the product of the first two indices and the average proportion of leaf damage in stands of a given type.

Results and Conclusions

On the leaves of Tilia cordata (Mill) “gnaws”, “mines”, “punctures”, and “galls” caused by arthropods, as well as “spots” of fungal lesions and “burns” from air pollutants were identified. Arthropods were represented by two species of the class Arachnida and 10 species of the class Insecta. These species belong to 9 genera, 7 families, 4 orders, with 5 species classified as monophages. On average 21.5±1.84 % of leaves exhibited damage, with “gnaws”: (9.8±1.33 %) and “galls” (5.8±1.05 %) being the most prevalent. The prevalence and intensity of “gnaws” decreased in the following order: Forest – Forest Park – Parks – Courtyards and Streets. “Galls” were most prevalent in parks, while “mines” were found only in the first three types of plantings. “Punctures” were most frequent in courtyard and street plantings, while “spots” were prevalent in forests, the Forest Park, and parks. “Burns” were found only in street plantings. The greatest loss of leaves in forest stands was caused by gnawing insects (8.9 %) and leaf miners (3.45 %). The greatest loss of leaves by insects causing “punctures” was found in courtyards and parks (0.45 % and 0.41 %, respectively). Gall-forming insects caused the most significant leaf loss in parks (3.1 %), while fungal “spots” contributed to 0.47 % leaf loss in parks. The highest leaf loss due to air pollution-induced “burns” was recorded in street plantings (0.6 %).

10 Figs., 1 Table, 27 Refs.

Forecasting the development of pathogens and pests based on climate changes

2025-03-10T14:44:13+02:00

Introduction

Climate change in recent decades has led to a significant reduction in forest areas and has triggered various interrelated environmental challenges. One of the most serious consequences is the increasing spread of pathogenic organisms, affecting individual trees and disrupting entire forest ecosystems. Rising global temperatures and decreasing air humidity are key drivers of changes in the geographical distribution of pathogens and their vectors, exacerbating the risk of biological invasions. This study examines the main trends in the spread of pathogenic organisms to new geographic areas and identifies patterns that enable predictions regarding changes in pathogen species and their carriers.

Materials and methods

The research used existing data on rising global temperatures, decreasing air humidity, and their impact on forest ecosystems. Key methods included analysing the geographical distribution of pathogenic organisms, identifying patterns of their spread, and predicting changes in pathogen compositions. Additionally, an in-depth analysis was conducted on the types of pathogenic composition of microorganisms and their hosts under changing climatic conditions in Europe and Ukraine. Preventive measures aimed at mitigating the spread of forest diseases and infections were also evaluated.

Results

The increasing global temperatures and declining air humidity significantly alter the geographic distribution of pathogenic organisms and their vectors. A notable rise in fungal diseases, along with complex bacterial and viral infections, has been observed in many regions. These changes are closely linked to shifts in temperature regimes, which create favourable conditions for pathogens. The analysis showed that fungal diseases of trees remain dominant, while the incidence of complex bacterial and viral infections is also rising. Climate change facilitates the establishment and persistence of these pathogens in forest areas.

Conclusions

Increasing global temperatures and decreasing air humidity are key factors contributing to the spread of pathogenic organisms and their vectors. A change in the geographic distribution of pathogens and their carriers is the cause of invasions that negatively affect forest ecosystems. Understanding the dynamics of forest health across different regions is essential for developing targeted management strategies to mitigate the spread of forest infections. The international scientific community is actively addressing these challenges through collaborative programs that aim to coordinate global and regional efforts. Such initiatives focus on disease monitoring, preventive measures, and implementation of integrated strategies to safeguard forest biodiversity and ecological balance.

48 Refs.

Intensity of 137Cs and 40K accumulation by lily-of-the-valley (Convallaria majalis L.) in Zhytomyr Polissia

2025-03-09T12:40:51+02:00

Introduction

After the Chernobyl disaster, most research has focused on ¹³⁷Cs, while the natural radioisotope ⁴⁰К, which is considered as an analogue of ¹³⁷Cs, has been studied only fragmentary. In ecosystems, potassium is known to compete with ¹³⁷Сs, acting as its antagonist. This study aimed to quantify the accumulation intensity of ¹³⁷Cs and ⁴⁰K in the phytomass of lily-of-the-valley (Convallaria majalis L.) from contaminated soil.

Materials and Methods

The study was conducted in 2023 at four experimental plots (EP) in Branch «Luhyny Forestry» of the State Specialized Forest Enterprise «Forests of Ukraine». Floristic association Serratulo-Pinetum (sylvestris) (Matuszkiewich 1981) J. Matuszkiewich 1988 was presented on all experimental plots. Six subplots (1m² each) were laid down per experimental plot, where aboveground phytomass of C. majalis was collected, and soil samples were taken to a depth of 10 cm. As an indicator of the intensity of ¹³⁷Cs and ⁴⁰К accumulation by phytomass, transfer factor (TF) was calculated as the ratio of radionuclide activity concentration in the phytomass (Am, Bq·kg^-1) to the soil contamination density of the respective radionuclide (As, kBq·m^-2).

Results

It was revealed that ¹³⁷Cs activity concentration in soil ranged from 4109 ± 612,3 Bq·kg^-1 (EP-1) tо 576 ± 50,5 Bq·kg^-1 (EP-5), and ⁴⁰K activity concentration in the soil varied from 69 ± 6,1 Bq·kg^-1 (EP-1) tо 118 ± 7,5 Bq·kg^-1 (EP-6).

In C. majalis phytomass, ¹³⁷Cs content ranged from 112 ± 20,2 Bq·kg^-1 (EP-6, As = 61,5 ± 5,30 kBq·m^-2) tо 4212 ± 31,5 Bq·kg^-1 (EP-1, As = 345,1 ± 45,35 kBq·m^-2). The range of ⁴⁰K activity concentration in phytomass was narrower, from 667 ± 45,9 Bq·kg^-1 (EP-1, As = 6,0 ± 0,74 kBq·m^-2) tо 932 ± 44,8 Bq·kg^-1 (EP-6, As = 9,5 ± 0,84 kBq·m^-2). On almost all plots, the average ⁴⁰K activity concentration in C. majalis phytomass significantly exceeded that of ¹³⁷Cs.

The mean TF value for ¹³⁷Cs was 1,9 ± 0,41 m²·kg^-1·10^-3, whereas for ⁴⁰K it was 106,3 ± 4,43 m²·kg^-1·10^-3. The statistical distribution of TF values for both radionuclides in the soil–phytomass system followed a lognormal pattern, skewed toward lower values. A statistically significant negative linear correlation (r = -0.56, p = 0.004) was observed between the soil activity concentration ratio of ¹³⁷Cs/⁴⁰К and the TF values of ¹³⁷Cs.

Conclusions

⁴⁰K activity concentration in soil was significantly lower than that of ¹³⁷Cs across all experimental plots.
In Convallaria majalis phytomass, the trend was reversed, with ⁴⁰K activity concentrations significantly exceeding those of ¹³⁷Cs.
The mean TF value for ¹³⁷Cs in the soil–phytomass chain was essentially lower than that of ⁴⁰K (1,9 ± 0,41 m²·kg^-1·10^-3 vs. 106,3 ± 4,43 m²·kg^-1·10^-3, respectively.
The statistical distribution of TF values for ¹³⁷Cs and ⁴⁰K in the soil–phytomass chain followed a lognormal pattern, with a skew toward low values.
A significant negative correlation (r = -0.56, p = 0.004) was found between soil ¹³⁷Cs/⁴⁰К activity concentration ratios and ¹³⁷Cs TF values, indicating that increased potassium levels in soil reduce ¹³⁷Cs accumulation in phytomass.

5 Figs., 3 Tables, 28 Refs.

Assessment of potential changes in the fire danger in the Ukrainian forests under the climate change

2025-03-09T13:06:05+02:00

Introduction

The primary factors contributing to increased fire risk and wildfires occurrence include regional climatic conditions, socio-economic and anthropogenic influences – such as warfare – and the specific characteristics of vegetation in a given area. Abnormal weather conditions conducive to catastrophic wildfires, as observed in 2015 and 2020, are expected to become more frequent, while the war initiated by Russian Federation is likely to further exacerbate this trend. Ongoing climate change is projected to elevate fire risk in Ukraine's forests and increase wildfire density. This study aims to assess future projections of key fire-prone weather indicators under different climate change scenarios and their potential impact on forest flammability.

Materials and Methods

A nationwide database of forest fires in Ukraine, covering the period from 2007 to 2021 at the regional level, was analysed. Using statistical data of forest fires, we calculated temporal and spatial trends in fire occurrence, forest flammability, and fire density in different regions of Ukraine. The initial analysis of the influence of specific climatic factors was conducted by examining the baseline period at the regional level (including both climatic indicators and indicators of fire density and forest flammability) for 1981–2010. The analysis included the following indicators: the duration of rainless periods, the number of days with maximum temperatures exceeding 35°C, average air temperature (°C), wind speed (m/s), precipitation per rainfall event (mm), and the Fire Weather Index (FWI). As the climatic basis, data from the EURO-CORDEX initiative, the European branch of the international CORDEX climate modeling project, were used.

Results

The relationship between climatic variables and forest fire trends – expressed through fire density and forest flammability – was analysed using correlation analysis, with highly correlated variables filtered out. Regression models were developed across administrative regions to quantify the impact of specific climatic indicators on fire occurrence (fire density) and fire extent (forest flammability). Our findings indicate that an increase in the number of days classified as a high fire danger (FWI > 30) relative to the baseline period (1980–2010) is observed only under the RCP8.5 scenario. This scenario projects a global mean annual temperature increase of 2°C by the mid-21st century compared to the late 20th century. The highest increase in fire danger is expected in the southeastern Ukraine and along the southern border of the Left-Bank Forest-Steppe, as well as in the Ukrainian Carpathians and the Crimean Mountains. A slight decrease in fire danger, attributed to increased precipitation, is expected in the Volyn region and the western part of the Right-Bank Forest-Steppe.

Conclusions

Our analysis identifies the most fire-prone and vulnerable regions under specific climate change scenarios, providing a foundation for developing thematic layers based on factors directly or indirectly influencing wildfire occurrence. According to our findings, the highest wildfire risks will persist in the Kherson, Luhansk, Dnipropetrovsk, and Zaporizhzhia regions. Significant fire density was also identified in the Kyiv region, likely influenced by its high population density.

4 Figs., 4 Tables, 24 Refs.

Characteristics of Scots pine (Pinus sylvestris L.) seeds from seed orchards of different ages in the State Enterprise “Klavdiievo Forest Research Station”

2025-03-07T18:27:49+02:00

Introduction

The most effective method for establishing seed orchards is by planting grafted, containerised seedlings. Seed orchards focused on cultivating plus trees of Scots pine in the Staropetrivske and Pershotravneve Forestries in the Klavdiievo Forest Research Station were first established in 1976 using this approach.

The initial “flowering” of clone plantations was observed in the same year as grafting. By the third year after grafting, 15–25% of trees had already begun producing generative organs. By the age of 10, all clones were “flowering” and yielding seeds, with an average seed production of 2–5 kg per ha.

The operational lifespan of forest seed orchards is relatively short – 25 to 30 years – provided they receive annual maintenance. In our study, 25-year-old orchard trees reached an average height of 11.3 m, making it impossible to harvest cones from the ground. Even with ladders and hooks, only 17.7% of cones could be collected.

This research aimed to assess the relationship between Scots pine cone and seed characteristics and plantation age, as well as the feasibility of using seeds from older plantations for reforestation.

Materials and Methods

The study was conducted across 11 seed orchards of Scots pine (clonal, family, and family-clonal), ranging from 12 to 47 years old, within the Staropetrivske and Pershotravneve Forestries under the State Enterprise “Klavdiievo Forest Research Station”. The planting patterns of seed trees varied, including 5 x 5 m, 5 x 10 m, 10 x10 m, and 7 x 7 m configurations. For each orchard, data were collected on 20 trees, including total height, height to the first live branch, crown length, and crown projection.

During the winter of 2022–2023, research station specialists collected up to 60 cones from each of 11 seed orchards to assess the quality of genetically improved Scots pine seeds. As a control, cones of the bulk collection from a 73-year-old Scots pine plantation in compartment 109 of Staropetrivske Forestry were used. Cone morphological characteristics were analysed according to L.F. Pravdin’s method, while seed characteristics were determined using V.A. Cherepnin’s scale. Seed mass and sowing properties (germination and vitality) were assessed according to the Ukrainian State Standard DSTU 8558:2015.

Results

Quality indicators showed that cones from all seed orchards exceed those from the bulk collection. Cone size correlated with mass, with the heaviest cones (15.7 g) observed in the family-clonal plantation (KNP-2010). Cones from four plantations contained over 30 seeds each, compared to 12.8 seeds in the control sample. The yield of filled seeds ranged between 0.46–1.97%.

The seeds from all plantations, including those from the control plot, were classified as medium-sized (6.0–8.6 g). Germination tests under laboratory conditions showed that seed germination energy on the seventh day was 86–100%, with final germination rates of 96–100%.

Conclusions

Cones and seeds from all studied seed orchards outperformed the control (bulk collection) in terms of quality. All seeds had a high quality, and their germination rates remained consistently high (96–100%), indicating that seeds from seed orchards, regardless of plantation age, should be prioritized for producing planting material for reforestation efforts.

5 Tables, 25 Refs.

Dynamic of indicators of forest fund of the Branch “Zmiivske Forestry”

2025-03-07T15:15:04+02:00

Introduction

The optimal age distribution of forest stands, their alignment with forest types, and appropriate maturity ages are crucial for sustainable forest management. Analysing the dynamics of forest fund indicators and forest evaluation metrics over different periods is essential for understanding the current state and long-term trends in forest development. This study examines the temporal changes in these indicators for the Branch “Zmiivske Forestry” from 1970 to 2021.

The research aimed to characterise the structural and dynamic changes in forests within the State Specialized Forest Enterprise “Forests of Ukraine”, the Branch “Zmiivske Forestry”, located in Kharkiv region, Ukraine.

Materials and Methods

To assess forest stand characteristics, we utilized the “Forest Fund” database for the Branch “Zmiivske Forestry” as of 01.01.2022, along with forest fund accounting data from 1970, 1980, 1990, 2000, and 2010. The optimal distribution of forested areas by age groups was determined based on established maturity age, considering forest categories and the need for balanced stand distribution across age classes. Additionally, the potential average growing stock per hectare was evaluated to assess the degree of utilisation of forest vegetation capacity. Data from forest typological profiles and sample plots were also incorporated into the analysis.

Results

As of January 1, 2022, the total land area of the forest fund in the Branch was 35.7 thousand hectares, with 96.4% classified as forested land. The forests exhibit significant typological diversity, driven by geomorphological and edaphic variations in forest habitats. Over 65% of the forests are located in rich forest site conditions. Stands of the two main forest-forming species – Scots pine (Pinus sylvestris) and English oak (Quercus robur) – dominate, which are well suited for forestry purposes.

Forests of site class II (53.4%) and site classes I and above site classes (30.7%) are predominant, with an average site class of II.1.

Since 2000, a decline in forested land and an increase in non-forested areas have been observed. The area covered by Scots pine and English oak stands has decreased since 1990, while the presence of common ash (Fraxinus excelsior) and black locust (Robinia pseudoacacia) has expanded. Additionally, a continuous decline in the overall average relative density of stocking has been recorded across all assessment periods, decreasing from 0.74 to 0.66. The distribution of stands by age deviates significantly from the optimal structure. The proportion of forests under protection, where final felling is restricted, has increased, leading to stand aging and an imbalance in the age distribution. Consequently, the proportion of mature and overmature stands has gradually increased from 1.6% in 1990 to 15.9% in 2021.

The health condition of living trees in most sample plots was generally good, although in some plots it was weak. In aspen and black alder stands, a significant proportion of trees were dead or damaged, primarily due to rot.

Conclusions

Our analysis revealed distinct trends in forest fund dynamics, with both positive and negative ecological and economic implications. Notably, non-forested areas are expanding, tree species composition is shifting, and stand aging is leading to reduced productivity and a decline in forest vegetation capacity utilisation. Scots pine and aspen (Populus tremula) stands exhibit the lowest levels of vegetation capacity utilisation, at 52.5% and 52.7%, respectively. Furthermore, due to the ongoing aggression of the Russian Federation, the condition of forests has deteriorated, with some areas sustaining damage from shelling and wildfires.

7 Tables, 16 Refs.

Features of pine stand reforestation in clear-cuts of Male Polissia

2025-03-07T18:12:38+02:00

Introduction

Under modern conditions, the regeneration of pine forests is primarily achieved through the establishment of forest plantations. A review of scientific literature indicates that, in certain forest site conditions, greater emphasis should be placed on natural regeneration to enhance biocenotic diversity, improve the biological stability of pine forests, and support their adaptation to global climate change. The aim of the research was to evaluate the effectiveness of artificial, natural, and combined forest regeneration in clear-cuts following strip felling with width of 51–100 m.

Materials and Methods

Features of natural and artificial regeneration of Scots pine (Pinus sylvestris L.) in clear-cuts after 51–100 m width strip felling of the main use were studied in 2005–2021. The study was carried out in fresh and moist forest site conditions (B₂, B₃ and C₃) in five sample plots within the Male Polissia region (Branch “Brody Forestry” of the State Specialized Forest Enterprise “Forests of Ukraine”). The condition of natural regeneration was assessed using the methodology of the Ukrainian Research Institute of Forestry and Forest Melioration (URIFFM), the Instruction on Design (2016,) and the Sanitary Forests Regulations in Ukraine (2016). The research data were analysed using methods of variational statistics.

Results

The density of one-year-old natural regeneration in clear-cuts after 51–100 m width strip felling was 43,500 stems? ha^-1. For 3–5-year-old regeneration, the density was 23,800 stems·ha^-1, and for 10–11-year-old regeneration, it ranged from 13,100 to 23,750 stems?ha^-1. Such density of natural regeneration is sufficient for the growing of highly productive pine forests in the study region. The plant density of self-seeding and advanced growth was higher in sample plots where natural regeneration was actively promoted. Specifically, 71% of 3-year-old self-seeding and 57% of 4-5-year-old advance growth were concentrated in furrow bottoms, where grass cover was absent. At 10–11 years of age, the average height and height increment of plantations and natural regeneration were similar. In fresh relatively infertile site conditions, denser stands (over 40,000 stems?ha^-1) exhibited a lower productivity class (by one unit) compared to sparser stands (about 20,000 stems?ha^-1) in moist relatively infertile pine site conditions. Across all research sites, the amount of advanced growth was sufficient for growing the highly productive pine forests in the region.

Conclusions

In Male Polissia, in fresh and moist oak-pine forest and moist hornbeam-oak forest, the most favourable conditions for pine seed germination and subsequent seedling growth on clear-cuts after 51–100 m width strip felling were achieved through the prior promotion of natural regeneration. In the first three years, 3–6 times more self-seeding appeared on such plots compared to plots where no support measures were implemented. When clear-cuts undergo both natural regeneration and simultaneous establishment of pine plantations using bare-root planting material, the planted seedlings initially grow faster during the individual growth phase (1–5 years) and up to the closure phase (6–8 years). However, beyond this stage, natural regeneration exhibits a higher height increment, and by the age of 10–11 years, the height of naturally regenerated and planted trees equalizes.

6 Figs., 5 Tables, 29 Refs.

Loss of wood resources and biodiversity in Ukrainian forests

2025-03-10T15:06:08+02:00

Introduction

Ukraine’s forests perform ecological and social functions and are also a source of various renewable natural resources and wood. The use of forest resource potential should ensure the effective management of forested areas for wood production. In recent decades, combating deforestation and assessing forest biodiversity have gained significant importance, particularly in the context of climate change and increasing socio-economic pressures. The ongoing war in Ukraine, which began in 2022, has further exacerbated these challenges, posing severe threats to forest ecosystems and conservation efforts. The war’s negative impact on Ukraine’s forestry sector is evident in the declining share of forest-related revenue in the national GDP, workforce reductions, and a shortage of skilled personnel. However, tax revenues and payments paid to budgets of all levels by the forestry sector in 2023 indicate its significant contribution to the country’s economy. A partial stabilization of industrial activity was observed in 2023, particularly in the sectors related to wood processing, following the initial disruptions caused by the Russian invasion.

Materials and Methods

The study used quantitative statistical methods, including data grouping, comparative analysis, tabular and graphical modeling, and economic synthesis. The input information for the analysis was open-source information from the Food and Agriculture Organization of the United Nations (FAO), the State Statistics Service of Ukraine, SE “Forests of Ukraine”, the State Agency of Forest Resources of Ukraine (SAFRU), as well as legislative documents and scientific publications. A comprehensive assessment of the decline in wood harvesting in 2022 as a result of military actions was conducted by estimating losses in forest resource potential (due to the areas of temporarily occupied forest-covered territories).

Results

The study examined annual net forest area change rates from 2000 to 2020. By 2022, direct economic losses in the forestry sector of Ukraine from the reduced harvesting volumes due to the loss of forest resource potential under the influence of military actions were estimated at 1576.8 thousand m³ of wood, amounting to almost UAH 2.56 billion in prices of an impersonal cubic meter of harvested wood of SAFRU enterprises. Forest fires affected 15.8 thousand hectares in 2022 and 51.0 thousand hectares in 2023 in government-controlled areas, causing economic losses of UAH 302.4 million and UAH 2.05 billion, respectively. The total damage to Ukraine’s Nature Reserve Fund is estimated at UAH 628.25 billion, with 80.6% of losses attributed to the destruction and degradation of trees and vegetation. The interrelationship of ecological, social and economic risks from the loss of forest biodiversity has been studied.

The Russian invasion had a catastrophic impact on Ukraine’s socio-economic stability, significantly altering development trends. Its negative effects on forestry and related industries have disrupted the stability of Ukraine’s wood market. Over two years of military operations, total damage to the forest sector is estimated at UAH 20 billion (USD 540 million), with UAH 420 million (USD 11.5 million) in destroyed equipment and UAH 1.2 billion (USD 32.5 million) in damaged real estate. Given the intensity of hostilities and the challenges in controlling forest fires near front-line areas, further deterioration in forest conditions and increased economic losses in the forestry sector are anticipated due to declining resource availability.

Conclusions

The above trends in Ukraine’s forest sector will be observed over the next few years, given that military operations in the country are still ongoing. A certain period will be required to restore and develop the forest resource and production potential of the forestry and woodworking industries, as well as the state economy, after the end of military operations in the country.

The preservation of Ukraine’s forest resource potential and biodiversity remains a pressing issue, further complicated by ongoing large-scale military operations. The success of restoring and developing the forest resource potential and plant biodiversity of Ukraine, which was lost or damaged due to military operations in 2022-2024, will largely depend on improvements in national environmental legislation, as well as securing investments from state resources, private enterprises, international donors, and potential reparations from the aggressor country. Successful restoration and conservation will require a multi-faceted approach, integrating ecological, economic, and legal measures to mitigate long-term damage.

3 Figs., 3 Tables, 17 Refs.