Young Scientist, Conference / Jaunasis mokslininkas, konferencija
eISSN 1822–9913, ISSN 2335–7940 First Published: 2007– Frequency: Yearly Languages: English, Lithuanian Subjects: Develop the Ability to Publicize Scientific Research Results, Present their Scientific Research Achievements and Discuss Topical Issues of Bioeconomy, Green Course, Climate Change, Ecosystem Sustainability, Rational Use, and Protection of Natural Resources Fees: No Publication Fees
The 23nd annual conference of young scientists “YOUNG SCIENTIST 2026” organized by the Vytautas Magnus University Agriculture Academy (VMU AA) will be held on April 16 2025 remotely. The conference is intended for the first, second and third degree students. The purpose of the conference is to involve students in scientific activities, develop the ability to publicize scientific research results, present their scientific research achievements and discuss topical issues of bioeconomy, green course, climate change, ecosystem sustainability, rational use and protection of natural resources.
ASSESSMENT OF FLOWERING IN NORWAY SPRUCE (PICEA ABIES) GENOTYPES
This article, based on a literature review and research conducted in spring 2025, examines the flowering intensity and formation of generative organs in 9-year-old vegetatively propagated clones of Norway spruce (Picea abies (L.) H. Karst.). The aim of the study was to evaluate variation in the number of male and female flowers among different clones and to determine the number of cones formed in a young breeding archive. The study was carried out in grafted clones established in 2016 at the State Enterprise State Forest Enterprise – Forest tree‘s Breeding Centre (Kaunas district, Lithuania). At the beginning of the 2025 growing season, clear differences in flowering intensity among clones were observed. The number of male flowers ranged from a few to several dozen per ramet, and some clones showed a mixed flowering type with both male and female flowers. Clones with more intensive male flowering produced higher amounts of pollen. The number of female flowers was lower and more variable among clones, but the first cones were recorded in some clones, indicating an early onset of the generative phase. The results confirm that 9-year-old grafted Norway spruce clones have reached generative maturity, although flowering intensity and sexual structure depend strongly on genotype.
PHENOLOGICAL CHARACTERISTICS OF EUROPEAN LARCH POPULATIONS ORIGINATING FROM POLAND IN EXPERIMENTAL PLANTATIONS AT THE DUBRAVA REGIONAL BRANCH OF THE VMU
This article presents the results of observations of autumn phenology (yellowing and falling of needles) and establishment and survival of European larch stands originating from 6 different regions of Poland (Radom, Katowice, Krakow, Krosno, Lublin, IBL) conducted at the Dubrava branch of the State Forest Enterprise. The study was carried out in two stages: on 2024-11-15, the establishment of larch trees was visually assessed, taking into account their vitality (living trees had needles, dead ones were dry) and the activity of yellowing and falling of needles, assessed according to the 5-point scale of autumn phenology, where 1 point means all needles are green, and 5 points mean all needles are brown and their loss is no more than 50%. A year later, on 2025-11-20, the survival of larch trees was assessed based on visual and structural changes (the tree had disappeared from its location, was dry or had not grown during the year) and a repeated assessment of autumn phenology was carried out. The results of the study revealed that the overall establishment rate of European larch families was 70.16 percent, and the survival rate was 57.24 percent. In 2024, the average phenology of needle yellowing and falling was 2.8 ± 0.5 points (phenological stages ranged from 1.8 to 4.0 points), while in 2025 it was 3.3 ± 0.5 points (phenological stages ranged from 2.3 to 4.6 points). Summing up the results of the study, it can be stated that populations from Southern Poland, which naturally grow in milder conditions and in lower areas, are characterized by a later autumn phenology and better establishment and survival rates than families of central origin, which indicates that these families of European larch are better suited for survival in the climatic conditions of Lithuania.
ANALYSIS OF THE INFLUENCE OF LOGGING TIMING ON THE REGENERATION OF BLACK ALDER IN DZUKIJA FORESTS
The study was carried out in clear-cut sites established during 2020–2024 in the Krosna, Leipalingis, Latežeris, and Musteika forest districts of the Druskininkai Regional Unit of the State Forest Enterprise. These clear-cut sites were left for natural forest regeneration, and black alder had been the dominant tree species there prior to felling. A total of 20 clear-cut sites were selected for the study, in which 10 m² sample plots were established according to site area: 5 plots in clear-cut sites up to 1 ha and 8 plots in sites ranging from 1 to 3 ha. In each sample plot, the height, density, and condition of black alder regeneration were assessed, and the collected data were analysed according to felling year and quarter in order to determine the effect of felling time on black alder stand regeneration. The results showed that the average height of regeneration was greater in sites felled in earlier years, and in most cases the highest values were recorded in sites felled during the fourth quarter of the year. Regeneration density varied more by felling year than by quarter, and in all cases the number of promising regeneration individuals exceeded that of non-promising ones.
EFFECTS OF NORWAY SPRUCE STAND CHARACTERISTICS ON THE INTENSITY OF IPS TYPOGRAPHUS (L.) INFESTATION IN 2021–2025
The aim of the study is to assess how the taxonomic parameters of spruce forests are related to the intensity of damage caused by the European spruce bark beetle (Ips typographus L.) in 2021–2025. The data on Norway spruce (Picea abies (L.) H. Karst.) stands in the Žalioji giria forest complex of the Paežerys Forest District of the Panevėžys Regional Division of the State Forest Enterprise were analyzed. Damage was assessed based on recorded pest outbreaks, their extent, and the proportion of damaged trees compared to the overall structure of the spruce forest. It was found that damage is concentrated in medium-density and dense (0.7–0.8 thinning) spruce forests, as well as in older stands: 5–8 age classes. The structure of the damaged stands revealed an excessive representation of normal moisture fertility (Nc) sites compared to their share in the entire stand. In addition, it was found that, according to the proportion of spruce in the species composition of the forest stand, the largest proportion of damage caused by the European spruce bark beetle (Ips typographus L.) occurred in pure spruce forests. Thus, the results confirm that when planning sustainable forestry measures, it is necessary to differentiate monitoring and prevention according to the density, age, species composition, trophic-hydrological regime, and site quality of the forest stand.
CARBON CREDIT GENERATION POTENTIAL OF AFFORESTATION ON AGRICULTURAL LAND IN LITHUANIA
Afforestation and forest restoration have become central components of climate and biodiversity policy with voluntary carbon trading emerging as a potential tool. The aim of this study is to assess the carbon credit generation potential of afforestation on agricultural land in Lithuania. Eleven agricultural land plots located in the Utena, Vilnius, and Siauliai regions were analysed using data from the Arbonics assessment platform. Of these, eight plots were found suitable for afforestation, with a total eligible area of approximately 72 ha (59.6% of the total area). Plots were classified by forest site type: Ld (temporarily waterlogged fertile sites – birch), Nc (normal moisture fertile sites – Norway spruce), and Sd (wet fertile sites – birch). Over a 50-year period, the eight plots are projected to generate approximately 11,633 carbon credits with a total economic value of EUR 814,310 (at EUR 70 per credit). Birch (Ld) and Norway spruce (Nc) scenarios showed similar revenue efficiency (~EUR 11,250/ha), while wet fertile (Sd) habitat plots demonstrated the highest potential at EUR 19,122/ha. Revenue begins to accumulate significantly from years 6–9 and increases throughout the project period. This study thus shows that afforestation of agricultural land for carbon credits has the potential to be a valid business model. However, this is dependent on the economic markets of carbon trading.
ESTIMATION OF TREE VOLUME USING UAV LIDAR DATA
Remote sensing is rapidly establishing itself in forestry as a means of determining forest resources more efficiently and in greater detail, so it is necessary to assess the extent to which this technology can replace or supplement traditional field measurements. This study evaluated the suitability of UAV LiDAR data for determining the volume of Scots pine (Pinus sylvestris) trees. Field measurements were taken in six pine stands with different characteristics, and high-density LiDAR point clouds were used to create a canopy height model (CHM). After comparing several canopy height metrics, the 90th percentile of canopy height (P90) most accurately matched the field measurements and was therefore used to select the most suitable buffer zone. Subsequently, a broader set of metrics derived from the CHM was applied to model tree volume. Based on the CHM metrics, several regression volume models were tested, and their accuracy was evaluated by cross-validation using plots, applying a training scheme where one plot was left out of the training sample during each cycle (leave-one-plot-out). The most accurate results were obtained using a Neural network, with an average volume error (RMSE) of about 0.30 m³. The most significant systematic underestimation was found in the youngest stand with the smallest volume. Meanwhile, in more mature stands, the model errors were smaller and did not have such a clear directionality. The analysis also identified isolated outliers that had a greater impact on the overall distribution of errors, but their removal reduced the overall volume deviation. After combining the data at the stand level, the errors decreased and the overall volume deviation remained small. The results show that UAV LiDAR data can accurately reproduce tree height and provide reliable area-level volume estimates, but it is recommended to perform a local accuracy check before applying the method in new conditions.
VARIABILITY OF RADIAL GROWTH OF SCOTS PINE (PINUS SYLVESTRIS L.) POPULATIONS AND ITS RELATIONSHIP WITH CLIMATIC FACTORS IN PROGENY TRIAL
Scots pine (Pinus sylvestris L.) is one of the most widely distributed and economically important forest tree species in Europe and is characterized by high genetic and ecological variability. Due to its wide distribution range, populations originating from different geographical regions may exhibit different growth responses to climatic conditions. The aim of this study was to evaluate the variability of radial growth of Scots pine populations in experimental plantations and to determine its relationship with climatic factors. The study was carried out using radial growth data of ten Scots pine populations originating from different geographical regions and growing in experimental plantations in Lithuania. Radial growth was assessed using dendrochronological methods based on measurements of annual tree-ring widths. One-way analysis of variance (ANOVA) was applied to evaluate differences in radial growth among populations, while Pearson correlation analysis was used to assess relationships between ANOVA F values and monthly air temperature and precipitation data. The results showed that radial growth differed significantly among populations depending on their geographical origin. Populations originating from southern and mid-latitude regions generally exhibited higher radial growth compared with northern populations. The strength of the population effect on radial growth varied between years and was associated with interannual variability of climatic conditions. The results indicate that climatic factors play an important role in shaping differences in radial growth among Scots pine populations in experimental plantations.
QUALITATIVE STRUCTURE OF DEADWOOD BY DECAY STAGES AND ITS ASSOCIATIONS WITH CLIMATE INDICATORS IN THE AUKŠTAITIJA AND ŽEMAITIJA INTEGRATED MONITORING STATIONS
Deadwood is a key structural component of forest ecosystems, influencing carbon cycling and habitat availability, while its decomposition is driven by wood traits and climatic conditions. This study assessed the current qualitative structure of deadwood by decay stages (1–5) in the Aukštaitija and Žemaitija Integrated Monitoring Stations (KMS) and tested associations between decay stage and climate indicators. Annual meteorological data (temperature and precipitation; 1993–2025) were combined with deadwood inventory records collected during the 2025 field campaign (tree group, diameter, decay stage, and time since death). Deadwood structure was summarized across age classes, and climate links were evaluated using correlation and regression approaches. In both KMS, the clearest climate-change signal was a significant increase in mean annual air temperature, whereas annual precipitation showed high interannual variability without a consistent trend. Decay stage increased with time since death, but the distribution of stages differed among regions and tree groups. Climate variables were sometimes significantly related to decay stage; however, time since death remained the dominant explanatory factor in regression models. These results provide a regional baseline for interpreting deadwood decomposition in long-term monitoring sites and highlight contrasting temperature- versus precipitation-linked patterns between KMS.
PRODUCTIVITY AND ECOLOGICAL FEATUES OF PURE PINE STANDS AND MIXED PINE STANDS WITH BLACK ALDER
This study assesses the productivity and structural characteristics of pure Scots pine (Pinus sylvestris L.) stands and mixed Scots pine–black alder (Alnus glutinosa (L.)) stands growing in nutrient-poor forest sites in southern Lithuania. The mixed stands were established 40–60 years ago following the afforestation concept proposed by A. Olšauskas, aimed at improving soil fertility and forest productivity. The research was conducted in forest stands located in the Kapčiamiestis forestry of the Druskininkai regional unit of the State Forestry Enterprise. Field measurements in sample plots included diameter at breast height, tree height, stand density and stand volume. Comparative analysis revealed differences between pure pine stands and mixed pine–black alder stands. The results indicate that the presence of black alder improves nutrient cycling and creates more favorable conditions for Scots pine growth. Mixed stands also show greater structural diversity and higher ecological stability. The findings support species mixing as a sustainable forest management approach in nutrient-poor pine forest sites.
EFFECT OF FOREST OPENING SIZE ON RED DEER (CERVUS ELAPHUS) BEHAVIOUR IN PUNIA FOREST
Understanding the spatial behavior of red deer (Cervus elaphus) is crucial for sustainable wildlife and forest management, especially with growing population densities. The study aimed to evaluate the impact of forest gap size on red deer activity and behavior. Research was conducted in the Punia Forest using camera traps, yielding 350 independent events. Relative Abundance Indices (events per 100 camera days) were analyzed across four habitat classes: closed forests (A), small (B), medium (C) and large (D) gaps. The results revealed a relationship between habitat openness and deer activity. The highest relative activity occurred in small and medium forest gaps, while dense forests and large clear-cuts were utilized significantly less. Additionally, a distinct crepuscular activity pattern was observed across all habitats, with peaks at dawn and dusk. These findings suggest that red deer habitat selection is primarily driven by a trade-off between foraging opportunities and safety. Intermediate-sized gaps offer an optimal balance of abundant food resources and immediate protective cover. The study concludes that maintaining a mosaic of moderately sized forest openings is vital for mitigation disturbance risks and ensuring the stable, sustainable management of red deer populations.
ASSOCIATIONS BETWEEN EVOLUTIONARY LINEAGES AND ACORN MORPHOMETRIC TRAITS OF PEDUNCULATE OAK (QUERCUS ROBUR L.)
To preserve and restore pedunculate oak (Quercus robur L.) stands in Lithuania and their autochthonous gene pool, comprehensive studies are needed on the association of haplotype (maternal) origins with morphometric traits. The aim of this research is to study differences in the morphometric traits of acorns from pedunculate oak natural heritage objects trees based on cpDNA markers. For the study, acorns were collected from 39 different oak clones in the Josvainiai oak natural heritage objects clone collection (n = 1560). 3 cpDNA microsatellite loci were used for haplotype analysis. The results showed that the morphometric traits of oak acorns differ significantly depending on the cpDNA haplotype (maternal) origin. Acorns of Italian haplotype origin (H6_H1_IT) are significantly different in length and size. It was also found that the morphometric characteristics of acorns differ significantly depending on the natural forest region of Lithuania. The northeastern highlands region of Lithuania is significantly different in terms of acorn length and width. Acorns from this region are the longest and narrowest. This indicates that morphometric traits can preserve the genetic origin of the maternal line and its characteristic traits, and that these traits are influenced by the growing environment, while the acorns retain the adaptive traits typical to the region.
FEASIBILITY OF USING LITHUANIAN FOREST DATA FOR SUPPORTING EU FOREST HABITAT ASSESSMENT IN THE CONTEXT OF CLOSER-TO-NATURE FOREST MANAGEMENT
The decline of biodiversity and the degradation of forest habitats remain among the most significant environmental challenges in Europe. The European Union Habitats Directive and the Natura 2000 network require the identification and monitoring of habitats of Community importance. However, traditional field-based habitat inventory methods are often time-consuming and resource-intensive. This study evaluates the feasibility of using Lithuanian national forest stand data for the identification of EU forest habitats and the differentiation of their conservation status within the context of closer-to-nature forest management. The research was conducted using forest stand inventory data from the Šimoniai Forest area. Habitat distribution, ecological condition classes, and structural forest indicators were analysed. The results revealed that habitat type 9010 (Western taiga) is dominant, accounting for nearly 40% of the analysed habitats. The analysis also showed that larger habitat patches tend to be associated with better ecological condition and that stand age correlates with habitat conservation status. The findings indicate that national forest inventory data can serve as an additional tool for habitat identification and conservation status assessment. The study contributes to the development of methodological approaches for more effective use of existing forest data in biodiversity conservation and the implementation of closer-to-nature forest management practices.
DEPENDENCE OF SILVER BIRCH (Betula pendula Roth.) STEM VOLUME ON DIAMETER AT BREAST HEIGHT AND TREE HEIGHT
The study assessed silver birch (Betula pendula Roth.) stem volume using sectional stem measurements. Data from 130 model trees were analysed, comprising 1,595 measurement records. Diameter at the root collar and diameter at 1.3 m height were measured before felling, whereas sectional stem measurements were taken after the trees had been felled. Stem volume was calculated using the frustum formula, and the Huber method was additionally applied for comparison. Four stem volume models were analysed: a single-variable diameter model, a single-variable height model, a multiple linear model, and a logarithmic model. The mean stem volume calculated by the frustum formula was 0.440 m³, while the mean volume calculated by the Huber method was 0.438 m³. The diameter model explained 95.2% of stem volume variation, the height model explained 74.2%, the multiple linear model explained 96.3%, and the logarithmic model showed the highest accuracy with a coefficient of determination of 0.9876. Comparison of stem volumes calculated by the frustum formula and the Huber method showed that the results were practically identical.
ASSESSMENT OF THE MOST PRODUCTIVE MATURING SCOTS PINE (PINUS SYLVESTRIS L.) STANDS IN THE KRETINGA REGIONAL DIVISION
This study evaluates the most productive maturing Scots pine (Pinus sylvestris L.) stands in the Kretinga Regional Division of state forests. The aim of the research was to assess the main dendrometric parameters, tree quality indicators and sanitary condition of the stands, as well as to compare the characteristics of stands of cultural and natural origin. The study also seeks to identify the main factors determining the high productivity of these stands. Field measurements were carried out in ten pure Scots pine stands aged 90–100 years. Tree diameters and heights were measured in sample plots. Based on the collected data, main dendrometric parameters were calculated. The data were analysed using descriptive and comparative statistical methods. The results showed that the investigated stands are characterized by relatively high productivity and favorable growth conditions. High productivity was mainly associated with favorable site conditions, optimal stand density and well-developed stand structure. Cultural-origin stands were more uniform, while natural-origin stands showed greater structural diversity. Most trees belonged to the first three Kraft classes and had good stem quality. The sanitary condition was good, with only a small proportion of damaged trees. Overall, the results indicate that both cultural and natural Scots pine stands can reach high productivity under favorable site conditions.
ANALYSIS OF UNDERGROWTH ABUNDANCE IN PRIENAI RP LARCH STANDS
This study analyzed undergrowth abundance in 40 larch stands within the Prienai regional subdivision (aged 30–60 years, with a density of 0.5–1.0, located in Lc, Nb, Nc, and Nd site types). The research evaluated undergrowth abundance and its correlation with various stand parameters: stand degsite, tree count, secondary layer density, understory (shrub layer) density, and site type. Data processing was performed using MS Excel and Statistica software. The study revealed that site type, stand age, and stand composition (mixture) had a statistically significant impact on undergrowth abundance in the investigated larch stands. The highest undergrowth abundance was recorded in fertile sites with normal moisture (Ndp), reaching up to 2,000 units/ha. Regarding stand age, the peak abundance was observed in 45-year-old stands (approximately 1.45 thousand units/ha), while a declining trend was noted in older stands. Furthermore, it was determined that undergrowth abundance in pure larch stands is approximately 2.3 times higher than in mixed stands. Stand density, total tree count, and secondary layer density did not have a statistically significant influence on undergrowth abundance.
THE HUNTING LAW SYSTEM IN LITHUANIA AND GERMANY: STRUCTURE, SUBJECTS AND GOVERNANCE PRINCIPLES
This article analyses the hunting law regulatory systems of Lithuania and Germany, with the aim of identifying their structural and functional similarities and differences. The study examines the structure of the legal hierarchy, the status of hunting law subjects, the hunting licence system, as well as the regulation of game species, hunting seasons and harvest limits. The research is based on a combination of document analysis, comparative analysis, logical analysis and synthesis methods. The document analysis method is applied to examine national and European Union legal acts, allowing for the identification of the content and structure of legal regulation. Using the comparative analysis method and applying a functional approach, Lithuanian and German legal solutions are compared with regard to analogous hunting governance issues. The findings indicate that Lithuania’s centralised regulatory model is characterised by normative clarity, whereas Germany’s federal system provides greater regional flexibility, enabling a more responsive adaptation to ecological and administrative conditions.
EFFECT OF BODY MORPHOMETRIC PARAMETERS ON ANTLER QUALITY IN ROE DEER (CAPREOLUS CAPREOLUS)
The external phenotypic characteristics of roe deer may reflect the physical condition of individuals and the quality of their habitat. Stronger and healthier males tend to develop larger and better-formed antlers, and antler quality is commonly associated with their size-related parameters. Although studies worldwide have examined the relationship between antler traits and body morphometric measurements, in Lithuania the association between antler characteristics and both body morphometric and skull craniometric parameters has not been extensively investigated. Therefore, the aim of this study was to evaluate the influence of morphometric and craniometric parameters on antler quality in roe deer (Capreolus capreolus). Morphometric measurements have been collected since 2016 in the Vytautas Magnus University Agriculture Academy research and hunting areas and were continued during this study. After skull preparation, the age of individuals was determined and antler as well as skull craniometric parameters were measured. The obtained data were analysed statistically. The results showed that age had a statistically significant effect on some morphometric, craniometric and antler parameters, whereas no statistically significant differences were found between hunting units I and II.
PATTERNS OF SCAVENGER DETECTION AND CARCASS USE IN LARGE MAMMALS
Carrion is an important source of energy and nutrients for various organisms and plays a significant role in nutrient cycling within ecosystems. Although this topic has been widely studied worldwide, there have been no studies conducted in Lithuania on carrion and its consumption. The aim of this study was to investigate the use of large mammal carcasses in the diet of scavengers. The research was carried out in 2023–2024 in the Karšuva Forest and the Varnaitinė Forest located in the Jurbarkas district. Roe deer carcasses and roe deer or red deer viscera were placed at the study sites, and animal visits to carrion were recorded using camera traps. During the entire study period, 1,523 animal visits to carrion were recorded in the Karšuva Forest and 2,881 in the Varnaitinė Forest. A total of 13 animal species were identified in the Varnaitinė Forest and 9 species in the Karšuva Forest. The study analyzed species composition, time spent at carrion, and the influence of seasonality, study site, and carrion type. The results showed that the time animals spent at carrion differed significantly between species, seasons, study sites, and carrion types. Animals spent the longest time at carrion during winter and when an intact roe deer carcass was present. The obtained results contribute to a better understanding of the role of scavengers in forest ecosystems and patterns of carrion utilization.
ANALYSIS OF THE CAUSES OF HUNTING-RELATED INJURIES IN GAME ANIMALS: RESULTS OF A HUNTER SURVEY
The aim of this study was to evaluate the frequency of wounded game animals during hunting, to determine in which types of hunting animals are most often wounded, and to analyse the main factors influencing inaccurate shots during hunting. A questionnaire survey of hunters was used for the study. The results of the study showed that most respondents (about 48%) have extensive hunting experience and have been hunting for more than 20 years. 63.6% of respondents indicated that during the past year there had been cases when an animal was wounded during hunting and escaped. The most frequently mentioned species were deer (30.2%), while foxes, roe deer and wild boars were mentioned less frequently (about 10%), and moose were mentioned the least (3.1%). According to the respondents, the highest number of wounded animals occurs during driven hunts (about 73%), as such hunts are more intensive and animals are usually moving and may be turned at an angle that covers vital organs, leaving the hunter less time to prepare and aim accurately. The study also showed that the main factors influencing inaccurate shots are stress (28.7%), poor rifle sighting (22.5%), and lack of practice (20.2%). Other factors may include poor visibility, the condition of hunting equipment, and an unsuitable shooting angle. In conclusion, cases of wounded animals during hunting are associated with various factors. Therefore, to reduce such cases, it is important to pay more attention to hunters’ practical training, proper firearm sighting, and evaluation of hunting conditions.
BODY PARAMETERS AND HEALTH STATUS OF HUNTED WOLVES IN THE TERRITORY OF LITHUANIA
During the study, the parameters of morphophysiological bioindicators of wolves hunted in the territory of Lithuania during the 2018–2019 to 2023–2024 hunting seasons were determined and analyzed. The skulls of the hunted wolves were measured using calipers, and their bodies were weighed. Body injuries and infestation with mange mites were recorded. The data analysis revealed that the skull parameters of the hunted wolves differed significantly depending on sex. In many cases, skull length and width parameters within the same age group showed only slight overlap—or no overlap at all—between males and females. Most wolves had standard body weights according to sex and age group. Adult males weighed on average 45 kg, while females weighed 34 kg. Most juvenile males and females weighed between 26 and 30 kg. Various body injuries were found in 4.2% of all hunted wolves. The most common injuries affected the forelimbs and hind limbs. Among the hunted wolves, 16.4% showed signs of infestation with mange mites; however, this infestation was not evenly distributed across the country. Wolves infected with mange mites were most frequently hunted in the Vilnius district (42.5%), Zarasai district (40.0%), Kaunas district (37.5%), and Ignalina district municipality (35.1%). Throughout the entire study period (2018–2019 to 2023–2024), not a single case of rabies virus infection in wolves was recorded.
COMPARISON OF THE LEGAL REGULATION OF HUNTING IN LITHUANIA, POLAND, GERMANY, SWEDEN AND FINLAND
The legal regulation of hunting plays an important role in the context of environmental protection and the sustainable use of natural resources. This field encompasses the interests of hunters, landowners, farmers, environmental organizations, and society as a whole, which are often conflicting and constitute a primary source of multifaceted disputes. In this context, the legal regulation of hunting becomes an important governance instrument aimed at ensuring ecological balance and the rational use of wildlife resources. The aim of the study is to compare hunting legal systems and to identify the main models of hunting regulation. The research employs linguistic, systematic, and comparative methods. The results of the study indicate that different models of hunting legal regulation are applied in the selected European countries. In Lithuania, hunting rights are based on a state-centered model, where hunting rights are granted by the state. In Poland, a mixed regulatory model is applied, combining elements of state-based and decentralized (community-based) regulation. In Germany, hunting rights are linked to land ownership, while in Sweden and Finland, a property-based model prevails, combining elements of both state regulation and private ownership. A comparison of hunting legal regulation models in different European countries shows that the Lithuanian legal framework is the most distant from the property-based model; therefore, the role of landowners in the context of hunting is the most limited.
MOOSE (ALCES ALCES L.) ANTLER BEAM AND PEDICLE MORPHOMETRIC PARAMETERS IN RELATION TO AGE
This study examines the relationship between age and the morphometric parameters of moose (Alces alces L.) antlers, specifically the circumference of the antler beam and pedicle, and evaluates their applicability for age determination. Data from male moose aged 1.5–12.5 years were analyzed. Descriptive statistics and analysis of variance (ANOVA) were applied. The results showed that differences in antler beam circumference between older age groups were often not statistically significant. In contrast, pedicle circumference exhibited statistically significant differences between most age groups (p < 0.05), particularly between younger and middle-aged individuals. These findings indicate that pedicle circumference is a more reliable morphometric parameter for moose age determination than antler beam circumference.
THE ABUNDANCE AND HABITAT SELECTION OF THE RED-BREASTED FLYCATCHER (FICEDULA PARVA) IN WESTERN LITHUANIA
Based on scientific research it is believed that the population of red-breasted flycatcher in Lithuania is declining. Important Bird Areas (SPAs) should be established for this bird species, but there is still a lack of data on the populations and habitats of the red-breasted flycatcher in different regions of Lithuania. Therefore, the aim of this study was to investigate the ecological factors that determine the choice of nesting sites for the red-breasted flycatcher in the Šilutė and Tauragė districts. A total of 38 areas were selected in these districts for counting. Fieldwork was carried out in the spring, during the bird breeding season. The counts were performed using a single visit method, walking through the study area every 150–200 m. The red-breasted flycatcher was identified by its song and information about its location was recorded in a special table, where the habitat was assessed according to various indicators. A total of 40 red-breasted flycatchers were recorded, 6 of which were found outside the research locations. Analysis of the collected data showed that the average abundance of red-breasted flycatcher in Šilutė District is 0,88 pairs per plot, while in Tauragė District it is 0,93 pairs per plot. A trend was also observed that the habitats of red-breasted flycatchers were dominated by maturing and mature, taller and larger diameter stands, dominated by Norway spruce, silver birch, and aspen. Despite the observed trends, no statistically significant influence of habitat parameters on species abundance was found.
PHYSICAL PROPERTIES OF MICROENCAPSULATED STRAWBERRY JUICE
Microencapsulated strawberry juice powders were obtained by freeze-drying using maltodextrin and inulin as encapsulating materials at different concentrations (10–25%). The aim of the study was to evaluate the physical properties of microencapsulated strawberry juice powders (bulk density, yield, rehydration ratio, and color characteristics) and to determine the effect of the type and concentration of encapsulating materials on these parameters. The data were analyzed using analysis of variance (ANOVA), and statistically significant differences were determined at p ≤ 0.05. The results showed that no statistically significant differences in bulk density were observed between different concentrations of maltodextrin and inulin, while the bulk density of strawberry juice powder without encapsulating materials could not be determined due to pronounced hygroscopicity and stickiness after freeze-drying. Powder yield increased with increasing concentrations of encapsulating materials, with the highest values (approximately 24–25%) obtained in samples containing 25% maltodextrin or inulin. In contrast, the rehydration ratio decreased as the concentration of encapsulating materials increased, which may be associated with higher total solids content and reduced powder solubility. Color analysis using the CIE Lab* system showed that increasing the concentration of encapsulating materials resulted in a statistically significant increase in lightness (L*) values, while redness (a*) and yellowness (b*) values decreased. The highest L* values were observed in samples containing 25% encapsulating materials, particularly when inulin was used, producing lighter powders compared to maltodextrin. The results indicate that both the type and concentration of encapsulating materials significantly influence the physical properties and technological applicability of microencapsulated strawberry juice powders.
DYNAMICS OF PHOTOSYNTHETIC PIGMENTS IN SWEET POTATO (IPOMOEA BATATAS L.) LEAVES
The aim of this study was to evaluate the effect of harvest time and cultivar on the content of photosynthetic pigments in the leaves of sweet potato (Ipomoea batatas L.). Leaves of three sweet potato cultivars, 'Morado', 'Tainung 65', and 'O'Henry' were analyzed. The leaves were harvested in July, August, and September. The contents of chlorophyll a, chlorophyll b, total chlorophyll (a+b), and total carotenoids in the leaves were determined using a spectrophotometric method. The results showed that both harvest time and cultivar had a significant effect on the content of the analyzed pigments (p < 0.05). The highest amounts of chlorophyll (a, b, and a+b) were found in the leaves of the 'Morado' cultivar harvested in July. The lowest amounts of these pigments throughout the entire study period were found in the leaves of 'Tainung 65' compared with the leaves of the other studied cultivars. A decrease in chlorophyll (a, b, and a+b) content was observed in the leaves of all cultivars harvested in September, indicating changes in the photosynthetic system and the processes of leaf senescence. The significantly highest total carotenoid content was found in the 'Tainung 65' leaves harvested in July, while the significantly lowest amount was detected in the 'Morado' leaves harvested in the same month. Throughout the entire study period, the highest content of these pigments was found in the leaves of the 'Tainung 65' cultivar. Based on the obtained results, it can be stated that harvest time and cultivar are important factors influencing pigment accumulation in sweet potato leaves. The obtained data contribute to a better understanding of the photosynthetic system of sweet potato leaves and will be useful in evaluating the biochemical value of this raw material.
CHANGES IN BIOLOGICALLY ACTIVE SUBSTANCES IN YOGURT DURING STORAGE
During the research, it was determined how biologically active substances in yogurt change during storage, three storage periods were selected - 24 hours, 1, 2 and 3 weeks. The object of the research - yogurt enriched with honeysuckle and blueberry berry purees. Yogurt research was conducted in 2025 at the Plant Raw Materials Quality Laboratory of the Open Access Center for Food Raw Materials Quality Research and Land and Forest Joint Research, Department of Plant Biology and Food Sciences, Faculty of Agronomy, Vytautas Magnus University Academy of Agriculture, where total phenolic compounds, total anthocyanin content, DDPH and color changes were determined for yogurt samples. The results of the research showed that significantly the highest content of total phenolic compounds was determined in yogurt with honeysuckle berry puree after 1 week of storage, and significantly the highest total anthocyanin content was determined in yogurt with honeysuckle berries after 2 weeks of storage. The research showed that the highest DPPH antioxidant activity was found in yogurt with honeysuckle berry purée after 24 hours. The studies performed showed that the significantly highest intensity of red color was in yogurt with honeysuckle puree, and significant changes in blue color (b*) intensity were also obtained in yogurt with honeysuckle puree. The significantly highest intensity of yellow color in yogurt with blueberries and the blue color intensity in yogurt with honeysuckle were obtained 24 hours after production.
THE INFLUENCE OF CULTIVAR AND DRYING TEMPERATURE ON THE CHEMICAL COMPOSITION OF BEETROOT CHIPS
The study compared the chemical composition of dried chips of three different beetroot cultivars - white 'Avalance', yellow 'Boldor' and red 'Cylindra'. Considering that dried beetroot chips can be considered a healthier alternative to traditional snacks, research into their chemical composition is scientifically sound and relevant. In dried beetroot chips, the following chemical composition indicators were determined using standard methods: dry matter, protein and fiber content. After evaluating the chemical composition indicators of dried beetroot chips, it was found that the dry matter content was significantly higher in chips of the 'Avalance' cultivar, dried at a temperature of 50 °C. The same cultivar was also characterized by the highest fiber content. Meanwhile, the protein content was significantly higher in chips of the 'Cylindra' and 'Boldor' cultivars, also dried at a temperature of 50 °C.
WHEAT SOURDOUGH BREAD WITH PROTEIN ADDITIVE PHYSICAL PROPERTIES
Plant proteins are increasingly used to increase the nutritional value of baked goods. The study evaluated the physical properties of wheat sourdough bread with 20, 30, and 40% chickpea and green lentil flour additives: the color and texture of the bread crumb and crust and the porosity of the bread. The results of the study showed that as the amount of legume flour in the bread increased, its color changed, its porosity decreased, and the density of the crumb increased compared to the control bread. Chickpea and green lentil flour had an uneven effect on the formation of the bread structure, and the differences found are related to their composition and the interaction of proteins during fermentation, which affects the formation of the gluten network. The greatest changes in physical properties were observed with a 40% addition of legume flour, when the structure of the sourdough bread became denser and less porous. The optimal physical properties were observed in wheat sourdough bread with a 20% addition of legume flour. The results of the study show that legume flour can be used in the production of wheat sourdough bread, but it is necessary to select the optimal amount in order to maintain a balance between nutritional value, technological stability, and product quality.
EFFECT OF LEMON (CITRUS LIMON L.) PEEL EXTRACT ON THE CHEMICAL COMPOSITION AND ANTIOXIDANT ACTIVITY OF TEA WINE
A study was conducted on the effect of different amounts of lemon (Citrus limon L.) peel extract on green and black tea wines, which is relevant for assessing the effect of natural plant-based additives on fermented beverages, increasing the amount of biologically active compounds and antioxidant properties, and promoting sustainable use of raw materials in production. Tea wine was produced by fermentation using green tea "Green Snail" (Bi Luo Chun) and black tea "Golden Snail" (Jin Luo) as the main raw materials. Lemon peel extract was added at different concentrations to assess its effect on the composition of bioactive compounds in the beverage. During the study, the total content of phenolic compounds and flavonoids was determined by spectrophotometric method, and antioxidant activity was assessed by DPPH free radical scavenging method. The results showed that black tea wine samples to which lemon peel extract was added, especially 50 ml, had increased phenolic compounds content (79.7 mg 100 g1 SM), flavonoid content (27.93 mg 100g1 SM) and antioxidant activity compared to the control. Meanwhile, in green tea wine samples, phenolic compounds content and antioxidant activity slightly decreased after the addition of lemon peel extract, although flavonoid content slightly increased. The black tea wine sample with 50 ml of lemon peel extract was significantly different from the other samples. The results indicate that lemon peel extract can increase the content of biologically active compounds and antioxidant activity in fermented beverages, but the effect depends on the type of tea: the effect is positive in black tea wines and slightly negative in green tea wines.