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The impact of frequent water deficits on dominant tree species in boreal forests has received increased attention, particularly towards addressing the global climate change scenarios. However, the impacts of coupled light intensity and water deficit in the regeneration and growth of Larix gmelinii seedlings, a dominant species in China's boreal forests, are still unclear. We conducted a dual-factor controlled experiment with four light intensities (natural sunlight, 50% shading, 75% shading, and 90% shading) and three soil water conditions (80%, 60%, and 40% soil saturated water content). The results showed that the coupling of light and water has a significant effect on the growth and development of Larix gmelinii seedlings. In 40% of the saturated soil moisture content, net photosynthetic rate, transpiration rate, chlorophyll a, and total phenol—leaf were significantly lower than the same light conditions under 80% soil saturated water content. Under the coupling treatment of 60% soil saturated water content and 50% shading treatment, the plant height increment, net photosynthetic rate, stomatal conductance, transpiration rate, chlorophyll a, and phenolic compound content were significantly higher than those of other coupling treatments; however, more than 75% shading inhibited photosynthetic parameters, chlorophyll a, total flavonoid—leaf, and total flavonoid—branch. Our results have important implications for forest management practices; they provide a scientific reference for the early growth of Larix gmelinii seedlings under the coupling of light and water and promote the survival and growth of seedlings. [ABSTRACT FROM AUTHOR]

The material flow analysis (MFA) method is widely used in the fields of resource management, environmental governance, and sustainable development evaluation, but the progress of its international research and the paths to support carbon neutrality are still unclear. Therefore, following the logic of ' sorting-integration - expansion,' this study first analyzed 2 148 documents included in the core database of Web of Science from 2000 to 2022 by using CiteSpace bibliometric tools, captured the key knowledge base and topic evolution of the international MFA research, and conducted a detailed review and comprehensive analysis of the MFA frontier application research. Second, by integrating the current status of international MFA research and the paths to carbon neutrality, this study constructed an integrated MFA research framework towards carbon neutrality. Finally, this paper summarized the support paths of MFA application research for the four important carbon reduction sectors and proposed current research deficiencies and future development directions. The main findings include: (J) The key studies in the fields of ' resource management,' ' environmental accounting,' and ' indicators ' could serve as a methodological and theoretical basis for MFA to perform its management, accounting, and evaluation functions. © With the support of the basic research topics of 'industrial ecology,' 'material flow analysis,' and 'material flow management, ' the application research topics of MFA had gradually evolved from the outdated topics of ' nitrogen,' ' Tarragona province,' ' heavy metals,' and ' alloying elements' to the frontier topics of ' municipal solid wastes,' ' iron,' ' circular economy,' ' exposure,' and ' renewable energy,' and the integrated application of MFA with the methodologies of scenario analysis, life-cycle assessment, and input-output modeling had become a mainstream trend. © The integrated MFA research framework towards carbon neutrality consisted of three modules, i.e., theoretical and methodological basis, application research paradigm, and supporting pathway for carbon neutrality, of which the structure of the application research paradigm reflected the core functions of the MFA, i.e., accounting material stocks and flows, assessing material demand and recycling potential, and developing the material management system. The elements of the application research paradigm covered the metabolic object, spatial scale, application triggers, main content, and application purpose of MFA research. ® The studies of MFA application supported the four important carbon reduction sectors in heterogeneous ways, and their relevance to the goal of achieving carbon neutrality needed to be further improved. In future research, MFA can be applied to account for the resource demand and waste generation of specific zero-carbon technologies in the energy production sector, to assess the resource and environmental impacts of end-use electrification, efficiency, and cleaner technologies in the energy consumption sector, to measure the environmental exposures and economic feasibility of the technologies for decarbonization and solid-waste utilization in the industrial and commercial sectors, and to evaluate the metabolic efficiency of nutrients and the performance of biological carbon fixation in the agriculture and forestry sectors. [ABSTRACT FROM AUTHOR]

Aims: Microbial residue deposition is considered an important part of soil carbon sequestration. However, there is still a lack of understanding of the link between tree species composition and diversity and microbial carbon deposition, which hampers the rational selection and allocation of tree species for artificial carbon sequestration afforestation in northern China. Methods: In this study, plots from temperate planting forests (>60 years) were examined for the importance values of tree species, mycorrhizal types, tree diversity, and soil properties. Soil amino sugar was used as the biomarker to indicate the accumulation of fungi- and bacteria-derived carbon. Results: We found that tree species diversity and the importance values of tree species and mycorrhizal types were significantly positively correlated with soil microbial residual carbon. Hierarchical partitioning modeling showed that three groups of variables significantly affected soil microbial residual carbon, accounting for a total of 26.75% of the variation. Among them, tree species diversity accounted for the largest proportion (11.5%), and tree species diversity and importance values had a high joint impact (9.74%). The importance values of all AM-associated species constituted one of the most significant individual factors and could independently account for 10.9% of the variation in microbial residues. The findings of piecewise structural equation modeling showed that the importance of tree species had a large direct impact on GluN, GalN, and the GluN/MurN ratio. By influencing soil properties, the importance values of tree species also had indirect effects on soil microbial residual carbon. Conclusions: We suggest that an increase in the importance values of AM-associated tree species, such as Acer negundo L., will be accompanied by an increase in the total importance value of AM-associated tree species, which can significantly increase soil microbial residual carbon. [ABSTRACT FROM AUTHOR]