Assessment of Vegetation Impact Using Vegetative Indices Due to Forest Fires in Uttarakhand

Abstract

Forest fires impact the forest ecosystems in the form of decline in forest cover, loss in biodiversity, and alterations in land use/land cover, which further modify the hydrological cycle, accelerating the runoff and soil erosion. All these problems require effective management strategies. This study estimates the impact of forest fires on soil moisture and vegetation in Uttarakhand, using Landsat 8 imagery and four vegetation indices: NDVI, NDMI, NBR, and MSAVI based on different forest types. Data from 42 forest fire sites within five forest types were analysed to evaluate the changes in vegetation loss, moisture depletion, and burn severity. The results show a significant decline in NDVI in the Himalayan Moist Temperate Forest at sites S36, S37, and S1. NBR effectively shows burn severity, which was found to be highest in Subtropical Pine Forest at sites S19, S12, S16 and Tree Outside Forest types at S33.  NDMI index shows considerable decreases in soil moisture in Subtropical Pine forests at sites S19 and S39, while MSAVI detected considerable vegetation cover loss, especially in Subtropical Pine forests at sites S35 and S16. Statistical analysis highlighted the NDMI index’s sensitivity to moisture changes and shows the highest M-statistics with 1.55, followed by NBRs, which is reliable in assessing burn severity. The study highlights the effectiveness of different indices in assessing the impacts of forest fires, which may be of immense utility to establish strategies for post-fire forest management, monitoring, and rehabilitation.