A Framework for Multifunctional Green Infrastructure Planning Based on Ecosystem Service Synergy/Trade-Off Analysis: Application in the Qinling–Daba Mountain Area

The multifunctionality of green infrastructure (GI) can be enhanced through intentional planning that promotes synergies among various functions while minimizing trade-offs. Despite its significance, methodologies for implementing this approach remain underexplored. This paper presents an application-oriented framework for GI planning that emphasizes the relationship between GI functional performance and the provision of ecosystem services. By reframing the issues of multifunctional synergies and trade-offs as quantifiable and spatially explicit problems associated with ecosystem services, the framework offers both a conceptual foundation and technical protocols for practical application. This framework was implemented in the Qinling–Daba Mountain Area (QDMB) in China to evaluate its practicality and identify potential challenges. The planned GI system aims to fulfill multiple functions, including biodiversity maintenance, water and soil conservation, eco-farming, and ecotourism development. Additionally, 73 wildlife corridors were established to connect GI elements, thereby enhancing habitat services for biodiversity. Furthermore, the analysis identified 245 townships and 273 sites as strategic areas and points requiring targeted intervention to mitigate potential multifunctional trade-offs. These locations are characterized by their location within protected areas, protected buffer zones, or wildlife corridors, or at the intersection of wildlife corridors with existing transportation infrastructure. The findings validate the framework’s practicality and highlight the necessity for additional research into the capacity of GI to support diverse human activities and the approaches to enhance GI elements’ connectivity for multifunctionality.