Reclassification of Green Infrastructure Types and Functions: Focused on Matsudo City, Chiba Prefecture, Japan

Abstract

Background and objective: Globally, the sustainability of urban areas is being compromised due to indiscriminate urban development, making the creation and management of green spaces increasingly critical. Green spaces play a pivotal role in connecting degraded natural ecosystems, and the concept of Green Infrastructure is gaining prominence as a strategy for managing green networks. A Green Infrastructure (GI) is a network of interconnected green spaces that provide benefits to humans through their utilization and management, fulfilling environmental, social, and economic functions. However, in most urban areas, green spaces lack connectivity between each other and are not managed in an integrated manner. Additionally, the types and functions of green spaces defined by policies and regulations vary, making it challenging to implement GI. Therefore, this study aims to examine and reclassify precursor indicators in order to effectively apply GI to urban strategies. It seeks to discuss management approaches based on GI, with the aim of facilitating its implementation.Methods: The city of Liverpool in the UK has presented a multifunctionality strategy for GI, which has been utilized as a global exemplary case. This study adopts the multifunctionality GI strategy proposed by the city of Liverpool, and reclassifies the types and functions of GI. It selects indicators through Focus Group Interviews(FGI) with GI experts and field surveys. The selected indicators of GI were utilized in a survey for evaluation of multifunctionality. The quantitative data collected through the survey were mapped using overlay techniques, in which led to the deriving a multifunctionality map of GI. In the process of mapping, weights derived from Analytic Hierarchy Process (AHP) analysis were applied to enhance the reliability of the quantitative data from the survey.Results: In this study, suitable indicators for GI in the study area were selected, and the functionality of each land cover (LC) type was evaluated. As a result, the study area was found to provide multifunctionality within a single land parcel. The highest-scoring LC type is Woodland, and the predominant functional category is Human-Wildlife Coexistence. The lowest-scoring LC type is Cemetery, with the least represented functional category being Timber Production.Conclusion: GI fulfills multiple functions that provide a range of benefits to humans (multifunctionality). To maximize such multifunctionality, it is crucial to manage scores for each functional category according to LC type. GI is not solely focused on specific functions, but also requires strategies to enhance functionalities lacking in LC types with low multifunctionality scores. The GI indicators proposed in this study and the GI multifunctionality assessment can serve as essential data for review when local authorities are formulating spatial plans related to urban areas, green spaces, forests, and other relevant areas.