From two to three dimensions: Advanced techniques for evaluating ecosystem services in urban green spaces

Urban green spaces, as a crucial nature-based solution to mitigate "urban diseases", have received significant attention due to their pivotal role in providing ecosystem services. Available studies on the assessment of ecosystem services in urban green spaces predominantly rely on two-dimensional spatial characteristics, with insufficient exploration of three-dimensional structural attributes and their associated ecosystem service effects, which makes it difficult to comprehensively and accurately reveal the actual contribution of green space to enhance residents' well-being. We systematically reviewed current methods in assessing ecosystem services in urban green spaces, critically analyzed the limitations of two-dimensional spatial assessment approaches, and highlighted the application of emerging technologies (e.g., LiDAR, street view imagery, and artificial intelligence algorithms) in three-dimensional spatial evaluation. Then, we proposed an innovative framework integrating advanced technologies with three-dimensional assessment of urban green space ecosystem services, and discussed future research directions to address the challenges of current technologies, particularly in terms of data processing efficiency and multi-scale applications, aiming to provide theoretical support and practical guidance for the refined management and sustai-nable development of urban green spaces.