Ecological recovery after the 2020 August Complex Megafire: remote sensing, community risk, and social implications

Wildfires are among the most destructive natural disturbances, with far-reaching impacts on ecosystems, carbon balance, and substantial socio-economic consequences including health risks, property losses, and community displacement. The 2020 August Complex wildfire in northern California burned over 1 million acres, releasing 27.7 million metric tons of CO, and causing significant ecological and structural damage. This study assesses post-fire vegetation recovery using Landsat 8 NDVI data from 2020 to 2025. After radiometric and geometric correction, NDVI was derived from red and near-infrared bands to quantify vegetation cover changes. Pre-fire imagery showed high vegetation density, which sharply declined in 2021. Gradual recovery was observed from 2022 onward, nearing pre-fire levels by 2024, though some areas lagged due to poor soil and erosion. Analytic Hierarchy Process (AHP) scores dropped from 6.59 (2020) to 2.66 (2021), then recovered to 6.22 by 2024. Entropy values similarly declined from 6.384 to 3.126 post-fire, rising to 6.238 by 2024, confirming ecosystem recovery supported by rainfall, yet highlighting spatially heterogeneous regrowth. This study provides new insights into the dynamics of post-fire recovery and delivers critical evidence to guide policy, planning, and restoration practices in regions increasingly threatened by megafires. These ecological patterns also shaped the pace of community recovery, influencing local risk exposure, watershed stability, and long-term resilience planning. By integrating ecological metrics with social implications, this study underscores the importance of science-based decision-making in protecting communities increasingly threatened by megafires.