Comparative Analysis of Post Fire Vegetation Change Across Three California Wildfire Sites Using NAIP Derived NDVI (2016-2022)

In California, wildfires have grown significantly more severe and frequent in recent years, with the 2020 fire season alone burning over 4 million acres across the state (2020 Fire Season | Welcome to CAL FIRE, 2020). This study explores the post-fire vegetation change in three of the major California wildfires from 2020: the August Complex, the Creek Fire, and the SQF Complex. Normalized Difference Vegetation Index (NDVI) data gathered from 2016 and 2022 National Agriculture Imagery Program (NAIP) aerial imagery was used to measure the vegetation health and density both before and after the fire. The change in NDVI was then calculated at each site to find the magnitude of vegetation loss and recovery. Pearson’s correlation revealed significant negative relationships between the pre-fire NDVI and NDVI change in all three of the sites. Welch’s T-tests confirmed that statistically significant differences in mean NDVI change between all three sites exist, establishing a ranking of August Complex being most severe, followed by the Creek Fire, and lastly the SQF Complex. The SQF Complex ended up with a slightly positive mean change in NDVI despite the damage to its giant sequoia population. This suggests that some ecosystems, like the giant sequoia forests, have a higher potential to recover fast due to their fire-resistant properties. This indicates that fire impact on vegetation is shaped by certain ecological factors beyond just the vegetation density. This also implies the advantages of more site-specific fire management that is modified to fit unique ecosystems and their needs.