Normalized Burn Ratio (NBR) and Normalized Difference Vegetation Index (NDVI) Study of Vegetation Health and Regrowth Rate Post 2018 Mendocino Complex Fire in Northern California Coastal Mountains

Abstract

The Mendocino Complex fire burned for two months from July 27th 2018 to September 18th 2018. The Mendocino Complex fire comprised of two fires: the River and the Ranch fire. Both wildfires burned 459,136 acres of the Mendocino National Forest in the Northern Coast Range of northwestern California. This study tries to measure the impacts and understand the forest structure and recovery through the use of Landsat 8 imagery to analyze Normalized Burn Ratio (NBR), Normalized Difference Vegetation Index (NDVI). NDVI is calculated to understand the impacts to the vegetation health and was studied to understand which index would provide the best results for the study area. The NBR was calculated to understand the overall burn severity in the study area. To understand the impact to the specific types of vegetation, 50 evenly distributed control points were established across the five dominant vegetation types that make up 95% of the study area. There is a positive correlation between the dNBR and dNDVI with an R² of 0.8635. The dNBR indicated that the vast majority of the burn area was a low to moderate severity burn. Post fire NBR and NDVI showed that over the five vegetation types shrubland observed the highest post fire loss in terms of reflectance values, -122.75% and -78.67% respectively. May 28, 2020 NDVI showed the largest increase of NDVI values across all control points with an average of 0.228 up from 0.117 for a 95% increase from one month post fire in 2018, thus proving that the forest is in its early stages of recovery.