Spatio-Temporal Assessment of Forest Health Dynamics of Sikkim Using MODIS Satellite Data by AHP Method and Geospatial Techniques

Forest is the most imperative piece of the environment to maintain ecological balance in any region and it also support the economy of the neighbouring populace. India is a country where forest resource is very much limited; still, some of its states holding the baton to improve the situation and the state Sikkim is one of it. Sikkim is the north-eastern state of India situated in the Himalayan region, which has accounted the forest cover of about 82.31% of its geographical vicinity. In the current effort, the spatio-temporal dynamics of forest health of Sikkim were analyzed using the Moderate Resolution Imaging Spectroradiometer (MODIS) [16-day products (MOD13Q1) of 250 m spatial resolution] satellite data. The Normalized difference vegetation index (NDVI), Enhanced vegetation index (EVI), Leaf area index (LAI), Optimized soil adjusted vegetation index (OSAVI), Infrared percentage vegetation index (IPVI) and Renormalized difference vegetation index (RDVI) have been employed to generate diverse vegetation indices to estimate the temporal variations of forest health from 2000 to 2020. Apart from the appliance of geospatial techniques, the Analytical Hierarchy Process (AHP) method is employed on a GIS platform to recognize the dynamics of forest health pattern to cover the research gap of the earlier studies. It reveals form the outcome of the study that, the forest health of the South and West districts of Sikkim is most affected during the study period. It also found that the very high category of vegetation cover gradually decreased; while the low vegetation cover are comparatively increased. The present investigation provides forest health database, which will definitely help in forest planning and management and the outcomes obtained from this study will aid forest recovery and mitigate the negative effects of forest health deterioration on biodiversity and ecosystem services in the region.