Street vegetation response to road proximity and functional street hierarchy: a GIS and remote sensing assessment in Kharkiv, Ukraine

Urban street corridors represent ecologically sensitive environments where vegetation is exposed to elevated thermal loads, soil compaction, pollution, and restricted rooting space. This study provides a spatially explicit assessment of how vegetation condition and land surface temperature vary with road proximity and functional street hierarchy in Kharkiv, Ukraine. Using an integrated GIS workflow and multi-source remote sensing data processed in Google Earth Engine, we combined Sentinel-2 vegetation indices (NDVI, NDRE, NDMI) with Landsat-derived land surface temperature and distance-to-road rasters. A stratified sampling and non-parametric statistical analysis were applied to evaluate vegetation and thermal responses within two near-road buffers (0–30 m and 30–60 m) across primary, secondary, and residential streets. The results show no detectable variation in vegetation condition or surface temperature within the 60-m road-adjacent zone, likely due to the medium spatial resolution of satellite imagery and the relatively uniform distribution of street greenery in Kharkiv. In contrast, pronounced and statistically robust differences were found between street types: residential streets exhibited the healthiest vegetation and coolest surfaces, secondary streets showed intermediate values, and primary streets demonstrated the lowest vegetation indices and highest temperatures. The findings highlight the dominant influence of street hierarchy and adjacent land use over micro-scale road proximity and emphasize the need to prioritize greening interventions and resilient tree species selection along primary urban roads.