The visual morphology of trees significantly impacts urban green micro-landscape aesthetics. Proximity to tall buildings affects tree form due to competition for space and light. The study investigates the impact of tall buildings on six visually morphological traits of eight common ornamental species in urban micro-landscapes in Beijing, with the distance and direction between trees and buildings as variables. It found that as trees grow closer to buildings, most angiosperms show increased crown asymmetry degree and crown loss, and reduced crown round degree and crown stretch degree (i.e., Sophora japonica L. and Acer truncatum Bunge saw a 52.26% and 47.62% increase in crown asymmetry degree, and a 20.35% and 21.59% decrease in crown round degree, respectively). However, the pattern of crown morphological changes in gymnosperms is poor (the closer the distance, the lower the height-to-diameter ratio of Pinus tabuliformis Carr., while the height-to-diameter ratio of Juniperus chinensis Roxb. significantly increases). In terms of orientation, gymnosperms on the west side of buildings have a greater crown asymmetry degree. It suggests that planting positions relative to buildings affect tree morphology. Recommendations include planting J. chinensis closer to buildings but keeping angiosperms like Fraxinus velutina Torr., S. japonica, and A. truncatum more than 3 m away to ensure healthy crown development.

Increasing soil carbon storage is an important strategy for achieving sustainable development. Enhancing soil carbon sequestration capacity can effectively reduce the concentration of atmospheric carbon dioxide, which not only contributes to the carbon neutrality goal but also helps maintain ecosystem stability. Based on 146 soil samples collected at plot locations selected across Beijing, we examined relationships between soil organic carbon (SOC) and key characteristics of urban forests, including their spatial structure and species complexity. The results showed that SOC in the topsoil with a depth of 20 cm was highest over forested plots (6.384 g/kg–20.349 g/kg) and lowest in soils without any vegetation cover (5.586 g/kg–6.783 g/kg). The plots with herbaceous/shrub vegetation but no tree cover had SOC values in between (5.586 g/kg–15.162 g/kg). The plot data revealed that SOC was better correlated with the physical structure than the species diversity of Beijing’s urban trees. The correlation coefficients (r) between SOC and five physical structure indicators, including average diameter at breast height (DBH), average tree height, basal area density, and the diversity of DBH and tree height, ranged from 0.32 to 0.52, whereas the r values for four species diversity indicators ranged from 0.10 to 0.25, two of which were not statistically different from 0. Stepwise linear regression analyses revealed that the species diversity indicators were not very sensitive to SOC variations among a large portion of the plots and were about half as effective as the physical structure indicators for explaining the total variance of SOC. These results suggest that urban planning and greenspace management policies could be tailored to maximize the carbon co-benefits of urban land. Specifically, trees should be planted in urban areas wherever possible, preferably as densely as what can be allowed given other urban planning considerations. Protection of large, old trees should be encouraged, as these trees will continue to sequester and store large quantities of carbon in above- and belowground biomass as well as in soil. Such policies will enhance the contribution of urban land, especially urban forests and other greenspaces, to nature-based solutions (NBS) to climate change.

(1) Woody plant species selection for urban forests is one of the key factors in reducing traffic noise in urban areas, and the ability of sound wave attenuation by leaves is one of the foundations for species selection. However, less references regarding the relationships between leaf morphological traits and noise reduction have been reported, especially the relationships between leaf texture (LT), leaf surface roughness (LSR), and noise reduction. (2) Eighteen arbors and shrubs were selected based on leaf texture and surface roughness characteristics, and noise reduction was measured using white noise sources in a self-designed device in a quiet laboratory at night. Then, the changes in noise reduction with LT and LSR were analyzed. (3) The noise reduction was significantly affected by LT, LSR, and their interaction (p < 0.05). The coriaceous leaf was usually more efficient in noise reduction than the chartaceous leaf, and LSR had an auxiliary effect on noise reduction. The effects of noise reduction were mainly influenced by leaf texture through physical blocking and by leaf surface roughness through interference. (4) The findings demonstrate that leaf texture and leaf surface roughness are the suitable predictors for selecting highly efficient woody plants for establishing and improving noise-reduction-oriented forests.

In recent years, research into the optimization of teaching reform for computer-aided mapping has continuously advanced in China. It plays a vital role in the development of urban forestry-related curricula and the cultivation of urban forestry professionals in higher education institutions. However, current research into the teaching reform of computer-aided mapping within the urban forestry domain remains insufficient. To address this, the study employs CiteSpace to conduct a visualization analysis of existing literature samples from journals, systematically integrating research trends and cutting-edge knowledge. The results indicate that relevant research perspectives primarily focus on teaching methods and theories, teaching reform and improvement, and teaching application and practice of computer-aided mapping. Furthermore, the study proposes future prospects for existing computer-aided mapping courses within urban forestry disciplines in China. In future higher education teaching, the urban forestry discipline can draw upon existing computer-aided mapping teaching methods, theories, innovative reforms, and practical applications. Emphasis should be placed on conducting more research in areas such as building multi-party academic collaboration, comprehensively utilizing diverse teaching methods, and expanding theories from multiple perspectives. This will facilitate the systematic and scientific development of computer-aided mapping curricula within the urban forestry discipline.