Analysis of Vegetation Changes Based on Vegetation Indices (Case Study: Rasht County)

This study investigates changes in vegetation cover and land surface temperature in Rasht County during the years 2010, 2015, 2020, and 2024. To achieve this, Landsat satellite imagery and various vegetation and water indices, including NDVI, MNLI, MSR, SAVI, OSAVI, VARI, MNDWI, IPVI, and EVI, were utilized. The data were processed through the Google Earth Engine (GEE) platform and analyzed with high precision. The vegetation data analysis revealed a significant reduction in vegetation health and density in areas undergoing urban and industrial development. In particular, the NDVI and SAVI indices highlighted severe degradation of vegetation in the northern and eastern parts of Rasht, where agricultural and forest lands have been converted into residential and industrial areas. These changes have also led to a decline in environmental quality. Regarding land surface temperature (LST), results showed a considerable increase in urban areas due to reduced vegetation cover and the expansion of hard infrastructure such as asphalt and concrete. The phenomenon of urban heat islands was clearly observed. Average temperatures ranged from 17.6°C to 65.3°C across the study years. Areas with dense vegetation experienced lower temperatures due to higher evapotranspiration, whereas areas with little to no vegetation and substantial hard surfaces exhibited higher temperatures. This research underscores the importance of using vegetation and water indices for environmental monitoring. The findings can serve as a foundation for improving management strategies to protect natural resources, mitigate the adverse impacts of urban and industrial development, and enhance the quality of life for local residents. Furthermore, the results highlight the need for continuous monitoring of vegetation and land surface temperature to identify critical areas and develop appropriate solutions.