A study on the effects of urban tree parameters and planting forms on the wind environment in Kunming

The impact of tree variables such as tree height(TH), crown width(CW), under branch height(UBH), and leaf area index(LAI) on the wind environment was scrutinized through numerical modeling utilizing Phoenics 2019 to elucidate the attributes of the wind environment under different planting configurations. The findings demonstrated that: The magnitude of influence of trees on the wind environment fluctuated. The influence of trees on the wind environment ranges from subtle at 1.5 m to most pronounced at 5 m, and the alteration in wind speed tends to be substantial with the augmentation of vertical distance. LAI is the primary driving factor for the modification of wind speed, which is positively correlated to the degree of influence of trees on the wind environment, and the influence domain of wind speed is situated within the range of 8-18 m from the origin of the coordinates, and the wind speed initially escalates and subsequently tends to stabilize with the expansion of horizontal distance. The influence of trees on the wind environment in the vicinity of 1.5 m height is minimal at 1.5 m height, and most evident at 5 m height. tends to be stable; In the vertical direction, the influence of CW on wind speed exhibits a gradual escalation from the center to both sides, and the influence of TH on wind speed aligns with the distribution range of the tree canopy; with the augmentation of UBH, the location of the high interference wind speed interval progressively ascends; The maximum and minimum wind speeds under different planting configurations manifest in the angular flow zone and wind shadow zone, respectively, and exhibit diverse lengths of the wind shadow zone, area of the low-wind speed zone and dispersion of the wind speeds. The trajectory of air age in windward, angular flow, eddy flow, and wind shadow zones was "Increase first and then decrease", and the coefficients of variation of air age under different planting configurations were considerably disparate. The outcomes of this study can furnish a scientific rationale for the selection and management of urban trees, which is a crucial reference value for the mitigation of urban issues such as pollution diffusion, disease transmission, and heat island effect, and is of paramount significance for the amelioration of the urban wind environment and the comfort of outdoor space.