Urban green space availability and change patterns (a case study of Tbilisi, Georgia)

Abstract

Aim: This research aimed to determine the distribution of different types of Urban green spaces (UGS) in Tbilisi districts, the distribution of access zones, the number of people who have access to UGSs, how current active housing construction affects UGSs and where reduction hotspots are located. Methodology: A 500-m buffer was set around UGSs. UGS changes were detected based on the NDVI from the 2017 and 2023 (June-August) PlanetScope imagery. The NDVI classification thresholds were -1 to 0.19 (nonvegetation), 0.19 to 0.5 (shrubs), and 0.5 or greater (trees). Thereafter, UGS patterns and reduction hotspots were determined in the district. Results: The percentage of access zones was lowest for Didube (5.4%) and highest for Nadzaladevi (14.7%). Chughureti (8.3%), Mtatsminda (8.8%), Isani (9.3%), and Gldani (9.9%) had similar numbers. The worst situation was observed in Samgori (8.9%) whereas the best situation was in Didube (69.8%). UGS degradation was high in Saburtalo (35.3%), and only a 0.6% decrease was found in Chughureti. Interpretation: UGSs are better distributed spatially and available to more people in "old" districts (Mtatsminda, Chughureti) and territories that were developed in the 1970s. The urban green spaces were neglected by contemporary urban sprawl. Though legislation has helped to preserve urban green spaces with status, but locations without status are victims of active development. Key words: Hotspots, Image analysis, Land use and land cover, Normalized difference vegetation index, Tbilisi, Urban green spaces