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Recurrent wildfires in Ukraine exert severe impacts on the environment, human health and security as well as damage to private and public assets. From 2007 to 2020, the frequency of large wildfires has increased and reached a level that has not occurred previously. The period during April-October 2020 was the worst in modern Ukrainian history for the occurrence of catastrophic fires, e.g. in the Chernobyl Exclusion Zone (67 000 ha), Zhytomyr oblast (43 000 ha), Lugansk oblast (35 000 ha) and Kharkiv oblast (8 000 ha). In Ukraine there is the additional problem of open burning, mainly burning agriculture residues, which covers two million hectares (ha) annually. State forestry enterprises who are responsible for the management of 71% of the Ukrainian forests (7.6 million ha)and agricultural holdings are also responsible for the management of 41.3 million ha of croplands. The remaining forest users manage forest areas of 3.1 million ha within reserves and national nature parks. This article presents a brief overview of the problem of forest fires as well as of fires in other landscapes in Ukraine, and includes a critical reviews of the current wildfire management system and a description of the main features of the national wildfire management strategy. It also highlights the results of a survey of numerous stakeholders conducted on landscape fires in Ukraine. Based on the review of global and regional experiences, as well as existing fire risks in Ukraine, recommendations were developed for implementing an integrated landscape level national fire management approach.

The russian military aggression and the related socio-economic and environmental consequences have significantly affected the climate and production of ecosystem services through damage to forests, ecosystems, landscape fires and emissions of gases into the atmosphere. The study aims to estimate carbon dioxide emissions due to landscape fires in Ukraine during the year 2022. The OroraTech wildfire monitoring technology was used to detect fires, while perimeters of burned areas were delineated with Sentinel 2 time series. The Copernicus Dynamic Land Cover map was used to extract burned land covers. Emissions were calculated based on the intensity of fires (dNBR) with the share of burned biomass in different types of land cover. Biomass models were selected considering the dominant tree species within a specific region and the species structure of the sown areas of croplands. The volume of biomass losses was estimated as a result of fires of different severities. It was estimated that during in 2022, landscape fires burned 749.5 thousand hectares thereof: croplands - 419.1 thousand hectares; other natural vegetation - 273.8 thousand hectares; conifer forests - 31.1 thousand hectares; other forests - 25.5 thousand hectares. The impact of the war on landscape fires is confirmed by the large proportion of fires in the 60-kilometre buffer zone along the frontline - 68.9% of the total area of fire. Among all fires, 42.5% of fires occurred in the occupied territory. Total CO2 emissions from all types of landscape fires reached 5.20 million tons and other greenhouse gases - 0.28 million tons. It is the first detailed mapping of landscape fires with an analysis of each polygon for the whole territory of Ukraine. The results provide important information for assessing the loss of ecosystem services and estimating carbon dioxide emissions as well as for confirming the impact of hostilities on landscape fires. [ABSTRACT FROM AUTHOR]

The phenolic compounds in the leaves of 12 species of birch trees of the subgenera Neurobetula, Betulenta, and Betula were biochemically profiled using HPTLC. The duration of the vegetation period was found to be significantly related to the content of total phenols (r = 0.74) and flavonoids in leaves (r = 0.65). The correlations for Neurobetula plants were 0.86 and 0.91, respectively. The relationship between the duration of the growing season and the concentration of phenolic compounds in Betula plants was inverse (r = −0.84). A cluster analysis of phytochemical profiles revealed that the studied birch species form groups that coincide with the subgenera proposed by De Jong due to an affinity with the qualitative composition of phenolic compounds. A multiple correlation analysis confirmed the relationship between the qualitative composition of phenolic compounds and the morphological characteristics of the leaves. The results of phytochemical profiling revealed that the qualitative composition of polyphenols in the leaves of 12 birch species is quite specific, allowing the use of individual compounds as additional differential biochemical characters in identifying species and hybrids and studying their potential role in plant adaptation to habitat conditions. [ABSTRACT FROM AUTHOR]

Net primary production (NPP) is considered by the world scientific community as an important indicator that reflects the features of the condition and peculiarities of the functioning of forest ecosystems. It also allows quantifying the potential of forests in performing their ecosystem functions. The information basis of the research consists of data from the industrial database of the Ukrainian State Forest Management Planning Association -- IA "Ukrderzhlisproekt". The dataset contains the biometric description of stands in the study region. Also, a system of mathematical models, algorithmic support, and software for quantitative assessment of net primary production are utilized within this research. As a result, the research determines the quantitative values of the total volume and specific intensity of formation of net primary production in the forests of Kyiv region. The total volume of NPP in the forests of the region exceeds 6.5 million tons of dry matter, of which 56% is accounted for by forests dominated by Scots pine. The highest mean values of primary production per unit area are observed in stands composed of tree species belonging to the hardwood broadleaved species group (black locust, hornbeam, European ash, and common oak, 1550--1910 g·m-2. The highest intensity of organic matter production is observed in the stands of V to VIII age classes. Highly productive stands generate a major part of forest NPP in the study region. Among forest types, the highest intensity of the bioproduction process is observed in fresh hornbeam-oak and fresh hornbeamoak site types -- 1872 g·m-2 and 1646 g·m-2, respectively. The forests subordinated to the State Agency of Forest Resources of Ukraine concentrate the largest volumes of annually formed organic matter. The lowest productivity is typical for forest plant communities under the control of the Ministry of Defense of Ukraine. The research results will serve as an informational basis applicable to the formation of a strategy for sustainable use of ecosystem functions of the forests in the study region. [ABSTRACT FROM AUTHOR]

The issue of using nitrogen to eliminate fires in granaries is related to ventilating the grain mass with nitrogen while it is necessary to take into consideration the change in gas concentration. Therefore, the object of this research was the value of the minimum concentration of nitrogen to eliminate the combustion of sunflower grain. It has been proven that in the process of thermal destruction of sunflower grain, the composition of gaseous products of thermal destruction of sunflower grain contains more than 70 % of combustible gases. Namely: carbon monoxide, over 51 %; hydrogen, about 5.7 %; and hydrocarbons with a total concentration of 13.72 %, which provide fire hazardous properties of organic material. Therefore, it should be noted that the release of the amount of combustible gases during pyrolysis requires a reduction in the amount of oxygen in the gasair environment to eliminate fire sites. Obviously, such a mechanism for the decomposition of sunflower grain during pyrolysis is a factor in regulating the extinguishing process, due to which the amount of nitrogen to eliminate combustion increases. Comparison of experimental studies on the composition of gaseous products of thermal destruction of sunflower grain and studies to determine the minimum fire extinguishing concentration of nitrogen, at which combustion was stopped, made it possible to justify the use of nitrogen. Based on the study’s results on the elimination with nitrogen of fire sites of sunflower grain, the values of the minimum fire extinguishing concentration were revealed at extinguishing, about 33.7 % by volume. At the same time, terminating the combustion of sunflower grain occurs with a decrease in the concentration of oxygen in the gas-air environment of about 14 %. The practical significance is the fact that the results obtained for determining the minimum fire extinguishing concentration of nitrogen make it possible to establish operating conditions for granaries when eliminating fire sites. [ABSTRACT FROM AUTHOR]

This paper reports the analysis of compositions for fire protection of wood that established that there are not enough data to explain and describe the process of fire protection and, accordingly, the fire-hazardous properties of wood, in order to protect people. The development and research of a set of properties of fire-resistant materials leads to the design of new types of such materials. The object of this study was a fire-protective two-component intumescent varnish for wood. The essence of the research is to determine the indicators of fire danger of wood, fire-protected by coatings, and the impact exerted on them by the formed heat-insulating layer of coke, making it possible to justify the effectiveness of the fire-retardant coating under the influence of temperature. The volume of fire-retardant and hydrophobic coating has been optimized, which ensures the lowest value of loss of mass by fire-protected wood during thermal action. Its lowest value was determined when using flame retardant in the volume of 589 g/m² and a hydrophobic agent in the volume of 54 g/m². When determining the combustibility of fire-resistant wood, it was established that the temperature of flue gases during tests was no more than 103°C, the length of damage to the sample did not exceed 143 mm. At the same time, the weight loss did not exceed 19 g, and the independent burning of wood did not exceed 23 s. In addition, the wood withstood the surface effect of a heat flow of 35 kW/m2, while surface combustion did not occur, and the value of the coefficient of smoke formation was 432 m²/kg during the smoldering of the fire-proof sample. Unlike wood protection with fire-retardant swelling paint, the fireproof wood with two-component varnish, does not change color and refers to low combustibility materials; it is hard to ignite, dose not spread the flame by surface, with moderate smoke-forming ability. The practical significance is the fact that a certificate of conformity was issued based on the reported results. Thus, there are grounds to assert the possibility of directed adjustment of wood fire protection processes by using coatings that can form a protective layer on the surface of the material [ABSTRACT FROM AUTHOR]

Energy independence of the country can be solved in several ways. One of them is the creation of energy plantations of woody plants. The area increase of such plantations is limited by the insufficient amount of high-quality planting material. Hybrid plants of the genus Populus are of considerable interest when creating plantations. Given that not all hybrids are successfully propagated by conventional vegetative methods, the use of biotechnological methods, namely microclonal propagation, solves the mentioned problem. This method allows obtaining a large amount of highquality, uniform planting material. The purpose of this study was to develop the technology of microclonal propagation of black poplar hybrids ‘San Giorgio’ and ‘Ghoy’. The study used generally accepted biotechnological methods in the author’s modification at all stages of obtaining planting material of regenerating plants of poplar hybrids. Studies have established a positive effect when obtaining an aseptic culture of sterilising substances 0.1% AgNO3, 2.5 and 1.25% NaClO, 0.05% sodium merthiolate and 0.1% HgCl2. The largest number of aseptic viable explants was obtained by cultures using a 0.05% solution of sodium merthiolate after exposure for 5 and 10 minutes. When rooting microshoots on a hormone-free nutrient medium ½ MS and with the addition of 0.1-1.0 mg/l IBA, it was established that the best parameters for rooting microshoots are on a hormone-free nutrient medium ½ MS. Adaptation was carried out for 4 weeks in a greenhouse on a substrate that included components of peat:sand:perlite in a ratio of 1:1:1. The viability of regenerating plants of black poplar hybrids ‘San Giorgio’ and ‘Ghoy’ was more than 91%. The conducted research and the obtained results will be useful for producers of planting material and the scientific environment, which develop renewable energy sources through the creation of energy plantations of fast-growing woody plants. [ABSTRACT FROM AUTHOR]

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The analysis of fire-protective materials for wooden building structures was carried out and the need to develop reliable methods for studying the process of washing out fire retardants from the surface of the building structure, which is necessary for the creation of new types of fire-protective materials, was established. That is why there arises a need to determine the conditions for the formation of a barrier for washing out and to establish a mechanism for inhibition of moisture transmission to the material. In this regard, a mathematical model was built of washing out fire retardants using a polymeric shell made of organic material as a coating, which makes it possible to estimate the effectiveness of a polymer shell by the amount of the washed-out fire retardant. According to the experimental data and theoretical dependences, the dynamics of the release of fire retardants from the fire-protective layer of the coating was calculated; it did not exceed 1.0 %, and therefore, ensures fire protection of timber. The results of determining the weight loss of the sample under the influence of water indicate the ambiguous impact of the nature of protection on the washout. In particular, this implies the availability of data sufficient for performing a high-quality process of moisture diffusion inhibition and, based on it, detection of the moment, from which a decrease in efficiency of a coating begins. The experimental studies proved that a sample of fire-protected timber after exposure to water for 30 days withstood the influence of a heat flow. In particular, the loss of timber weight after the temperature exposure was less than 6 %, and the temperature of flue gases did not exceed 185 °C. Thus, there is a reason to assert the possibility of directed control of the processes of fire protection of timber through the use of polymer coatings capable of forming a protective layer on the surface of fire-protected material, which inhibits the rate of washing out the fire retardants. [ABSTRACT FROM AUTHOR]

[Display omitted] • First use of imputation technique to support forest monitoring in Ukraine. • Landscape-level (21.65 km2) aggregated prediction accuracy was high. • Forest area increased (2%-4%), though local losses were common. • Greatest growing stock volume increases before 2000. • This study promotes the use of limited historical plot data in forest management. While many countries regularly produce timely and accurate estimates for a range of forest attributes through national forest inventory programs, many have access to no such inventory or their inventory is discontinuous in space and time, such as a sample-based approach in Ukraine limited to two regional (Ivano-Frankivsk and Sumy) inventories conducted in 2008–2015 at a total area of 37,700 ha. This study addresses the extent to which limited historical forest inventory data may facilitate forest mapping efforts using dense Landsat time series (LTS) and mapping techniques (i.e., classification and imputation) to predict multiyear forest dynamics. We used the Continuous Change Detection and Classification (CCDC) segmentation approach to extract inter- and intra-annual trends in LTS and utilized these fitted trends as covariates in further modeling. We developed random forest (RF) classification models for forest mapping based on field data collection and LTS, and then generated yearly forest maps for 1990–2020. The RF model accuracies were high for both producer's and user's accuracy (>0.93 ± 0.04). Based on yearly forest dynamics, we detected an increasing trend in forest loss during 2000–2010 and 2010–2020 in our regions. We used the gradient nearest neighbor (GNN) method to generate species presence (basal area (BA) ≥ 1.0 m2 ha−1) and growing stock volume (GSV) maps at the 30-m pixel level. Our nearest neighbor imputation models achieved better accuracies (Cohen's kappa > 0.4) for species that are prevalent within regions, occupy distinct geographical areas, and have higher plot BA abundance. To obtain estimates of species abundance with higher R2, we used the GNN model with k = 3 nearest neighbors. Aggregating species based on similar environmental niche resulted in greater R2 values of BA that varied within two regions from low (0.129 and 0.416) for a group of hardwood deciduous species to high (0.531 and 0.712) for coniferous species. The accuracy was systematically better at 5-km hexagonal level, thus we recommend using the maps at coarser aggregations. The study showed that forests accumulated more GSV in 1990–2000, albeit higher rates of GSV loss were observed during the two last decades. We attribute the spatial and temporal character of forest change to forestry activities in the past, the current age structure of forests, and afforestation of abandoned farmlands. We are aware that forecasting performance of the nearest neighbor imputation approach merits more detailed consideration as new forest inventory data are available. [ABSTRACT FROM AUTHOR]

Climate change continues to threaten forests and their ecosystem services while substantially altering natural disturbance regimes. Land cover changes and consequent management entail discrepancies in carbon sequestration provided by forest ecosystems and its accounting. Currently there is a lack of sufficient and harmonized data for Ukraine that can be used for the robust and spatially explicit assessment of forest provisioning and regulation of ecosystem services. In the frame of this research, we established an experimental polygon (area 45 km2) in Northern Ukraine aiming at estimating main forest carbon stocks and fluxes and determining the impact caused by natural disturbances and harvest for the study period of 2010–2015. Coupled field inventory and remote sensing data (RapidEye image for 2010 and SPOT 6 image for 2015) were used. Land cover classification and estimation of biomass and carbon pools were carried out using Random Forest and k-Nearest Neighbors (k-NN) method, respectively. Remote sensing data indicates a ca. 16% increase of carbon stock, while ground-based computations have shown only a ca. 1% increase. Net carbon fluxes for the study period are relatively even: 5.4 Gg C·year−1 and 5.6 Gg C C·year−1 for field and remote sensing data, respectively. Stand-replacing wildfires, as well as insect outbreaks and wind damage followed by salvage logging, and timber harvest have caused 21% of carbon emissions among all C sources within the experimental polygon during the study period. Hence, remote sensing data and non-parametric methods coupled with field data can serve as reliable tools for the precise estimation of forest carbon cycles on a regional spatial scale. However, featured land cover changes lead to unexpected biases in consistent assessment of forest biophysical parameters, while current management practices neglect natural forest dynamics and amplify negative impact of disturbances on ecosystem services. [ABSTRACT FROM AUTHOR]

Hitherto unknown benzotriazocines (III) are synthesized on a preparative scale via regioselective cyclocondensation of easily accessible azadienes (I) with 2-aminomethylaniline. [ABSTRACT FROM AUTHOR]

The most comprehensive dataset of in situ destructive sampling measurements of forest biomass in Eurasia have been compiled from a combination of experiments undertaken by the authors and from scientific publications. Biomass is reported as four components: live trees (stem, bark, branches, foliage, roots); understory (above- and below ground); green forest floor (above- and below ground); and coarse woody debris (snags, logs, dead branches of living trees and dead roots), consisting of 10,351 unique records of sample plots and 9,613 sample trees from ca 1,200 experiments for the period 1930-2014 where there is overlap between these two datasets. The dataset also contains other forest stand parameters such as tree species composition, average age, tree height, growing stock volume, etc., when available. Such a dataset can be used for the development of models of biomass structure, biomass extension factors, change detection in biomass structure, investigations into biodiversity and species distribution and the biodiversity-productivity relationship, as well as the assessment of the carbon pool and its dynamics, among many others.