One of the main objectives for the Baltic Sea regions is the harmonisation of the economic development and environmental sustainability. The identification of knowledge-intensive bioeconomy as one of the primary fields of the strategy for smart specialization (RIS3) in Latvia indicates the transition to sustainable and climate neutral approach for the development of Latvia. The strategy aims to promote a more sustainable and efficient use of natural resources, to create high added value, to promote coordination of export and economic interests with environmental protection. This is a multi-faceted and complex process. A scientifically sound approach is needed to develop the most appropriate solutions. The article examines algae biomass as a potential for renewable resources in the agriculture of Latvia in the context of sustainability. The research is aimed at exploring the potential of the Baltic Sea algae as a sustainable agricultural resource in Latvia, focusing on its impact on cultivated plants during the study. The potential is being assessed by conducting a practical study in two stages. The results of the study confirm the potential use of Baltic Sea algae as an agricultural resource in Latvia, which requires further evaluation of the effect of the liquid digestate fraction on crop green mass to determine its potential applicability in agriculture using algal biomass.

In the world, hydrological models are often used in the modelling of ecological components. In the context of the Paris Agreement and the European Green Deal, it is necessary to develop GHG emission modelling capabilities. The development and refinement of the conceptual model METQ is necessary not only for the quantitative analysis of flow, but in addition to its refinement, it is possible to conduct interdisciplinary research in the subfield of ecohydrology, which studies the interaction of water and ecosystems, and in environmental engineering, which addresses the issues of reducing diffuse pollution and reducing greenhouse gas emissions, technology implementation issues, where water content in the soil and groundwater fluctuations play one of the main roles, for example, in the processes of the formation of nitrous oxide emissions. This paper examines potential GHG emission calculation algorithms used to successfully model GHG emissions from soils, with a particular focus on agricultural soils, which contribute one of the largest amounts of GHG emissions in national emission reports for the agricultural sector. Available algorithms for nitrous oxide nitrification calculations are reviewed and possible algorithms that can be used for modelling emissions from soils and integrated into the conceptual hydrological model METQ are discussed. The developed conceptual solutions for modelling GHG emissions from soils will develop a modelling tool that will be used to estimate the volumes of GHG emissions and evaluate the effectiveness of various GHG emission reduction measures, as well as to perform a complex assessment of the soil GHG balance.

The sector of agriculture is one of the most crucial in the context of ensuring food security as well as in the care for sustainable development. The food security can be improved through several aspects, one of them being the agriculture system transition, implementing more and more regenerative measures. From the agriculture transition, due to the efforts needed to achieve the expected level of green transition, farmers themselves are expected to benefit less than the future society and nature in a whole. Yet both financial institutions and agriculture companies have not reached a common understanding, what requirements should be in place to establish mutually beneficial financial products to achieve the expected level of transition in a timely manner. The aim of this study is to evaluate funding options for agriculture transition in Baltic countries – Latvia, Lithuania, and Estonia. In total, for screening purposes, 29 different Banks operating in the Baltics were identified. The analysis of the financial product purposes provides a high-level perception, that loans, even if not indicating signs of support for green transition, may still support the improvements of overall country and society sustainability. The expert judgement was used to find potential links with the United Nations Sustainable Development Goals (UN SDGs) identifying the potential SDGs that could be tackled when providing the financing to the specific purpose. Only two banks are observed to provide financial products that can be assessed as focused on green transition, and this research shows that financial products for agriculture companies willing to transition to sustainability are not broadly available.

Two approaches to incorporating black alder (BA) bark extractives-derived polyol into a polyurethane (PU) network were studied. In the first case, fractionation of bark extractives with tetrahydrofuran (THF), focusing on isolating the biomass fraction available for obtaining PU elastomers by casting methods using cyclic ethers as a solvent, was employed. Another approach aimed to obtain liquid bio-polyols that could be suitable for producing rigid PU foams. For this purpose, oven-dried crude BA bark water extracts were liquefied with polyethylene glycol (PEG 400) at temperatures of 130–170 °C. The effect of adding sulfuric acid as a catalyst on biomass processing was studied. Wet chemistry, GC, FTIR spectroscopy, analytical pyrolysis (PyGC/MS/FID) and rheological methods were employed to characterize the obtained polyols and insoluble fractions, enabling an assessment of biomass transformation during processing. The resulting THF-soluble fraction comprised 62% of the BA bark extract, mainly consisting of the xyloside form of the diarylheptanoid compound oregonin, along with oligomeric flavonoids and carbohydrates. The THF-insoluble fraction was most enriched with carbohydrate compounds. Moreover, it was observed that the PEG 400-insoluble fractions were predominantly composed of carbohydrate components. The results indicated that the use of sulfuric acid as a catalyst (1–1.5% of solvent) promotes the complete liquefaction of extractives, enabling biomass content in polyols of up to 15–25%. Surpassing the extract content in the starting suspension up to 30% resulted in incomplete liquefaction of biomass. These findings offer valuable insights into tailoring BA bark extractives as building blocks suitable for obtaining PU materials.

Urban trees, integral to urban environments, demonstrate intricate responses to atmospheric pollutants like particulate matter (PM), tropospheric ozone (O₃), and carbon dioxide (CO₂). Notably, O₃ induces oxidative stress in leaf tissues, while PM, consisting of fine airborne particles, interacts with urban trees through foliar deposition. This interaction is particularly interesting as tree canopies are highly effective filters, capturing and accumulating PM on their surfaces. The present study focused on silver birch, small-leaved lime, and Norway maple seedlings responses to elevated O₃ and CO₂). With and without PM. Maple seedlings exhibited the highest stem height increment, followed by lime and birch. Elevated O₃ and CO₂ without PM led to substantial height increments for lime and maple. Elevated O₃ and CO₂ without PM increased the total polyphenols in lime and maple leaves but decreased the content of total flavonoids in birch and lime leaves. Our findings underscore the adaptability of lime and maple seedlings to elevated O₃ and CO₂, positioning them as promising species for urban environments in the face of changing climates. Birch, while exhibiting biochemical changes, demonstrated less pronounced growth responses. This studyʼs insights into the intricate interactions between urban trees and multiple pollutants, particularly the species-specific responses, are of significant value for urban planning and environmental management.

This paper traces the growing interest in the development of Criteria and Indicators for sustainable forest since the declaration of the 'Forest Principles' at the Rio Conference 1992. Several processes are underway in the different regions of the world to define sets of criteria and indicators that can be used to assess the social, economic, and ecological sustainability of forest management. Some have focused more at national level, while others have emphasised information needs at the forest management unit level. In an attempt to produce a generic 'master set', the Center for Internetional Forestry research (CIFOR) has carried out several tests to compare the different sets of criteria and indicators currently existence. At the forest level, ecological criteria have been found much easier to apply than social ones as the latter often require an in-depth understanding of areas beyond the intermediate boundaries of the forest management unit. In an attempt to help people in different areas adapt the generic hierarchy of criteria and indicators to their own conditions, CIFOR is developing a computer programme, CIMAT, which allows for the addition of local knowledge and an iterative development of locally-specific criteria and indicators. In spite of the work still needed, the importance of defining a comprehensive but practical set of criteria and indicators lies in the fact that such a measurable and comparable methodology would build public confidence in the issue of forest sustainability.