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The spatial pattern of color patches plays a crucial role in affecting the visual quality of peri-urban forests dominated by Cotinus coggygria var. cinerea Engl. in autumn. The impact mechanism has been studied to facilitate algorithm-based automatic visual quality estimation. The color patterns of 120 photographs were calculated after color quantization and automatic color substitution. The scenic beauty of the forest was estimated by 698 respondents. Multiple correlations between visual quality and color pattern metrics were explored with stepwise regression. Principal component analysis (PCA) was also employed to investigate the impact mechanism of color patterns on visual quality. Number of patches (NP), largest patch index (LPI), mean patch area (AREA_MN), patch size standard deviation (AREA_SD), and Shannon's evenness index (SHEI) were the main factors affecting the visual quality of the Cotinus coggygria forest. AREA_MN correlated positively with visual quality, while NP, LPI, AREA_SD, and SHEI correlated negatively. Moreover, AREA_SD had the most significant impact on the visual quality of the landscape, while SHEI, LPI, and AREA_MN had the second-highest impact. The evenness and the size of color patches significantly affected the visual quality of the forest landscapes. Balancing the diversity and evenness of color patches plays a decisive role in creating a forest landscape with high visual quality. [ABSTRACT FROM AUTHOR]

At present, the focus on greenway construction in China is shifting from production protection and environment beautification to ecological protection and leisure and recreation. The ways in which to explore a comprehensive and efficient ecological health functional greenway plant landscape model are of particular importance for greenway construction and community belt park management. In the present study, nine landscape configuration patterns of three green space structure types (trees-shrubs-grass, trees-grass, and shrubs-grass) in typical community demonstrative belt park greenways in Changchun Fitness Park in Beijing were selected as the study objects on which to perform quantitative study and evaluation of the single and comprehensive effects of six core ecological health factors, namely green space landscape beauty degree, negative air ions, human comfort, PM2.5, and bacteria and noise reduction. The results show that the ecological health care effects of the greenways differ due to various community structures. The score range of the plant landscape beauty of spatial composition groups is − 1.333 to 0.932, the highest value of air negative ions released in summer reaches 1176 cm−3, and the reduction rate of PM2.5 concentration is 1.94–12.21%. The greenways have a strong effect on improving human comfort in spring, summer and autumn. The temperature difference inside and outside the green spaces is as high as 3 ℃, the humidification is about 20%, the net noise attenuation rate is 0.10–11.36%, and the bacteria reduction rate reaches up to 50–60%. The comprehensive index method was used to evaluate the six-core health factor system, the range of the comprehensive index of ecological health function of the three types of green space structures was 2.3187–10.3334, and the overall order was trees-shrubs-grass > trees-grass > shrubs-grass. The three landscape configuration patterns that were screened with better ecological health care effects can be used for the construction of the urban community belt park greenways. [ABSTRACT FROM AUTHOR]

Urban vegetation plays an important role in filtering atmospheric pollution. Understanding the functional traits of the plants that have strong capacity to retain fine particulate matter (PM 2.5) is important to design configuration schemes for urban green spaces. In this study, phenological observations, direct sampling, and electron microscope analysis of leaf surfaces were conducted to analyze and compare the 65 plant species commonly grown in green spaces in Beijing in terms of their ability to retain particulates from the air. Analyses of the size distribution of particles revealed that >94% of the particles retained on leaf surfaces were smaller than 10 μm (PM 10), and the majority of these (>87%) were smaller than 2.5 μm (PM 2.5). Coarse particles accounted for <6% of all retained particles. The average volume percentage of PM 10 was 93.8%, that of PM 2.5 was 35.8%, and that of coarse particulates (D p > 10 μm) was 17.8%. The PM 2.5 retention amount per unit leaf area differed greatly among tree and shrub species. This number was 38.8 times higher for Acer truncatum (0.659 g·m−2) than for Salix matsudana (0.017 g·m−2), and 33.4 times higher for Buxus sinica (1.168 g·m−2) than for Sabina vulgaris (0.035 g·m−2). The trees with the strongest capacity to retain PM 2.5 on a whole-plant basis were ranked as A. truncatum (115.639 g·week−1) , Robinia pseudoacacia (48.876 g·week−1), Platanus acerifolia (43.413 g·week−1), Celtis bungeana (37.383 g·week−1), Sophora japonica (31.998 g·week−1), Diospyros kaki (29.945 g·week−1), and Ginkgo biloba (27.613 g·week−1), while the tree species with the strongest PM 2.5 retention capability per year were A. truncatum (3245.170 g·year−1), R. pseudoacacia (1744.198 g·year−1), C. bungeana (1199.707 g·year−1), S. japonica (1108.382 g·year−1), Sabina chinensis (895.712 g·year−1) and G. biloba (865.733 g·year−1). The shrubs with the strongest ability to retain PM 2.5 on a whole-plant basis were ranked as Prunus cistena (3.921 g·week−1), Syringa oblata Lindl. var. alba Rehder (3.767 g·week−1), Lespedeza bicolor (2.642 g·week−1), Hibiscus syriacus (2.255 g·week−1), Paeonia suffruticosa (1.969 g·week−1), and Amygdalus triloba (1.831 g·week−1), while the shrub species with the strongest ability PM 2.5 retention capability per year were P. cistena (113.933 g·year−1) , S. oblata Lindl. var. alba Rehder (98.736 g·year−1), L. bicolor (70.457 g·year−1), and H. syriacus (60.645 g·year−1). The results of this study will be useful for designing planting schemes for green spaces in urban areas to optimize the retention of particulates from the air. [Display omitted] • An approach was developed to study the ability of 65 plants to retain air particles. • A comparison on the PM 2.5 annual retention ability per plant for 65 urban plant species were conducted. • Functional traits of plants and environmental factors jointly affected the air particles retained by the plants. • Scheme on plant community planning towards improving air quality was suggested. [ABSTRACT FROM AUTHOR]