This study presents a computational fluid dynamics (CFD)-based approach for extracting and validating flow resistance values for six major street tree species commonly found in urban environments. To simplify the modeling process while retaining aerodynamic accuracy, complex tree geometries were replaced with porous media regions in numerical wind tunnel simulations. Pressure drop data across a range of inlet velocities (1–20 m/s) were used to derive species-specific resistance coefficients through second-order polynomial fitting.
The extracted coefficients were validated by comparing the pressure drop profiles of the porous models with those of full-scale tree models, showing strong agreement (coefficient of determination R² ≈ 0.9999) and less than 5% error at higher velocities. The results also revealed that aerodynamic resistance is more closely related to canopy morphology—such as leaf area, shape, and volume fraction—than to leaf density alone.
This method provides a practical and scalable solution for incorporating vegetation effects into urban airflow simulations, significantly reducing computational costs. The findings offer a useful framework for integrating species-specific tree characteristics into urban environmental planning and design, including applications in urban ventilation analysis, pollution dispersion modeling, and green infrastructure planning.