2021 Dixie Fire NDVI Vegetation Health Analysis

The Dixie Fire was a wildfire event which occurred in the Sierra Nevada mountain range in California in 2021. This fire burned 963,309 acres, or 1,505 square miles, which made it the largest single fire event in California history. The fire was also of particular note due to the fact that the blaze crossed from west to east over Sierra Crest, a milestone previously thought impossible for wildfires in California. This "impossible" feat was achieved again by the Caldor Fire later during the same fire season.

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Data Overview

We are going to use data acquired from the MODIS sensor on the Aqua satellite platform. Aqua is an earth observing platform launched by Nasa in 2002. It carries a number of earth observation sensors including MODIS (Moderate Resolution Imaging Spectroradiometer) which collects data over 36 spectral bands.

MODIS data can be used to visualize landcover using NDVI processing, which is a remote sensing method used to analyze reflectivity on Near Infrared and Red bands. NDVI is useful in analyzing vegetation health.

Citation:

AppEEARS Team. (2023). Application for Extracting and Exploring Analysis Ready Samples (AppEEARS). Ver. 3.38. NASA EOSDIS Land Processes Distributed Active Archive Center (LP DAAC), USGS/Earth Resources Observation and Science (EROS) Center, Sioux Falls, South Dakota, USA. Accessed October 9, 2023. https://appeears.earthdatacloud.nasa.gov

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Significant Imapacts to Vegetation Health

Analysis of NDVI data within the Dixie Fire boundary shows a significant reduction to vegetation health as a result of the fire.

Vegetation Recovery Trend

NDVI analysis reveals that vegetation heatlh began to recover in 2022. It is likely that this trend of recovery will continue as more data is collected through 2023 and into 2024. Although there were likely high levels of tree mortality due to the fire, it is possible that some evergreen conifer and hardwood communities that did not experience complete kill were able to regenerate over this time period. Otherwise, it is likely that most of the vegetation regeneration indicated by NDVI were shrub and grassland communities.