Ecosystem Services Synergies and Trade-Offs from Tree Structural Perspectives: Implications for Effective Urban Green Space Management and Strategic Land Use Planning

Urban green spaces (UGSs) are critical in providing essential ecosystem services (ESs) that enhance the quality of life of urban communities. This study investigated the synergies and trade-offs between structural characteristics of urban trees and their ecosystem services and their implications for urban park management within Yurim Park, Daejeon, South Korea, using the i-Tree Eco tool. The study specifically focused on regulating and supporting services, assessing diversity, air pollution removal, carbon sequestration, and avoiding runoff. A systematic review of urban park management practices complemented the empirical analysis to provide comprehensive management recommendations. The findings of a total of 305 trees from 23 species were assessed, revealing moderate species diversity and significant variations in structural attributes, such as diameter at breast height (DBH), leaf area index (LAI), and crown width (CW). These attributes were found to be strongly correlated with ES outcomes, indicating that healthier and larger trees with extensive canopies are more effective in providing benefits such as pollution removal, runoff reduction, and carbon sequestration. However, the study also identified trade-offs, particularly regarding volatile organic compound (VOC) emissions, which can contribute to ground-level ozone formation despite the trees' pollution removal capabilities, sensitivity to water stress, requirements for shade and cooling effects, and impacts on water yield. The results highlight the importance of strategic management practices to balance these trade-offs, such as selecting low-emitting species and employing incremental pruning to enhance pollutant removal while minimizing VOC emissions. Additionally, the findings underscore the significance of tree placement and landscape patterns in optimizing year-round benefits, particularly in reducing urban heat island effects and enhancing energy efficiency in adjacent buildings. The study concludes that while urban parks like Yurim Park offer substantial ecological and environmental benefits, continuous monitoring and adaptive management are essential to maximize synergies and mitigate trade-offs. The insights provided on species selection, tree placement, and landscape design offer valuable guidance for urban planners and landscape architects aiming at enhancing the effectiveness of urban parks as nature-based solutions for sustainable urban development.