<p>Recently, most cities have opted for urban greening as a way to mitigate climate change. However, the urban characteristics, such as the fragmented land cover and harsh environment hard to maintain vegetation healthy, reduce the efficiency of greenery. Therefore, a continuous and scientific management tool is required to mitigate climate change through urban greenery. In this study, we developed the decision-making tool, CMRI (Carbon Management Requiring Index), which can identify the area with low carbon sequestering performance and propose the priority for the carbon management requirement. The index was determined by integrating five parameters; 1) terrestrial carbon storage, 2) terrestrial carbon uptake, 3) soil texture, which implies the capacity for soil carbon sequestration, 4) green area ratio, which means that the chance of carbon management, and 5) landscape context, which represents the edge effect by the adjacent urban landscape. The three parameters of terrestrial carbon storage, green area ratio, and landscape context were estimated based on the 0.25 m land cover map using satellite data through machine learning. The terrestrial carbon uptake was determined by the data-driven model through satellite measurement data. Lastly, we acquired the soil texture data from ISRIC – World Soil Information dataset. We normalized each parameter with the z score method. We applied the index in our test site (Suwon, Republic of Korea), and we mapped CMRI with its spatial resolution of 30 m x 30 m considering the resolution of each parameter. The CMRI values had a gradient which showed the high management demand in the city center and the relatively low in the forest interior. The range of CMRI values was from 0.2 to 0.8. To suggest the priority of carbon management requirements, we divided the CMRI grids into four quarters, low, medium, high, and extremely high. To verify that CMRI represents the carbon management requirement level properly, we plan to validate it by field observation. Three grids in each priority level will be selected to measure the vegetation condition, including DBH and chlorophyll-a content, and soil characteristics, including soil texture, soil carbon stock, and soil respiration. Through principal component analysis (PCA) using field measurement results of the grids, we can weigh each parameter and make the index more accurate.</p>

Background Green areas are thought to reduce particulate matter (PM) concentrations in urban environments. Plants are the key to PM reduction via various mechanisms, although most mechanisms do not lead to the complete removal of PM. Ultimately, PM falls into the soil via wind and rainfall. However, the fallen PM can re-entrain the atmosphere, which can affect plants capacity to reduce PM. In this study, we simulated an urban green floor and measured the resuspension of PM from the surface using a new experimental system, a wind tunnel-mounted closed chamber. Methods The developed system is capable of quantifying the resuspension rate at the millimeter scale, which is measured by using the 1 mm node chain. This is adequate for simulating in situ green floors, including fallen branches and leaves. This addressed limitations from previous studies which focused on micrometer-scale surfaces. In this study, the surfaces consisted of three types: bare sand soil, broadleaves, and coniferous leaves. The resuspended PM was measured using a light-scattering dust detector. Results The resuspension rate was highest of 14.45×10−4 s−1 on broad-leaved surfaces and lowest on coniferous surfaces of 5.35×10−4 s−1 (p < 0.05) and was not proportional to the millimeter-scale surface roughness measured by the roller chain method. This might be due to the lower roughness density of the broad-leaved surface, which can cause more turbulence for PM resuspension. Moreover, the size distribution of the resuspended PM indicated that the particles tended to agglomerate at 2.5 µm after resuspension. Conclusion Our findings suggest that the management of fallen leaves on the urban green floor is important in controlling PM concentrations and that the coniferous floor is more effective than the broadleaved floor in reducing PM resuspension. Future studies using the new system can be expanded to derive PM management strategies by diversifying the PM types, surfaces, and atmospheric conditions.

&lt;p&gt;Urban soil is the foundation of ecosystem functioning in urban green spaces, which plays an important role in sustainable urbanization. To maintain the ecosystem services provided by urban green space, it is important to manage and monitor the urban soil using appropriate evaluation parameters. Given that the urban soil is under direct and indirect influence of anthropogenic factors, the characteristics of urban ecosystem should be considered when assessing the soil quality. My research group already suggested a new soil quality parameter set for urban roadside soils, which is composed of soil penetration resistance (PR), pH, the C/H ratio of particulate organic matter (POM-C/H), POM-N, and soil microbial respiration (RES). This parameter set indicated that the urban soil has very unique quality of soil organic matter (SOM) and it should be considered as well as SOM quantity when assessing the urban soil status. In this study, we aimed at assessing the SOM quality in various types of urban green space using the C/H ratio and N of POM and analyzing the relationship between SOM quality and soil RES. Soil RES was regarded as a representative parameter for overall soil health and used as a dependent variable. The study was conducted in three different types of urban green spaces, which are roadside, urban park, and riverside green in Seoul, Korea. In each type of green space, three sites were selected varing in the degree of human disturbance. Soil samples were collected from the 0-15 cm depth, passed through 2mm sieve and dried before analysis. The POM was separated after wet sieving using 53 um screen and the C, N, and H contents of POM were measured using combustion analysis using the Carlo Erba NS Analyzer Carlo Erba, Milan, Italy). We calculated the POM-C/H as a proxy for aromaticity, which increases with high non-degradable OM. To trace the source of SOM, we measured the N stable isotope ratio of POM (POM-&amp;#948;&lt;sup&gt;15&lt;/sup&gt;N). On the same day of soil sampling, soil RES was measured on-site using the EGM CO&lt;sub&gt;2&lt;/sub&gt; Gas Analyzer PP Systems, MA, USA). We performed multiple regression to analyze the relationship between SOM quality and soil RES. The POM C/H was higher in roadside soil than urban park, which means the urban roadside soil has a significantly higher amount of non-biodegradable compounds such as PAH. This further implies that OM quality is significantly different among types of urban green spaces. Using the POM delta N value, we found that OM in the roadside soils was originated from sewage sludge, animal urine/feces as well as atmospheric deposition. Analysis of OM source tracing in the urban park and riverside soil will be conducted. There was a negative correlation between POM C/H ratio and soil RES, which indicates the poor soil health condition partly due to low OM quality. In conclusion, this study clarifies the importance of OM quality for assessing the soil in urban green spaces affected by anthropogenic factors and indicates that the SOM quality management needs to be established.&lt;/p&gt;