Post-Fire Forest Vegetation State Monitoring through Satellite Remote Sensing and In Situ Data

Abstract

Wildfires have significant environmental and socio-economic impacts, affecting ecosystems and people worldwide. Over the coming decades, it is expected that the intensity and impact of wildfires will grow depending on the variability of climate parameters. Although Bulgaria is not situated within the geographical borders of the Mediterranean region, which is one of the most vulnerable regions to the impacts of temperature extremes, the climate is strongly influenced by it. Forests are amongst the most vulnerable ecosystems affected by wildfires. They are insufficiently adapted to fire, and the monitoring of fire impacts and post-fire recovery processes is of utmost importance for suggesting actions to mitigate the risk and impact of that catastrophic event. This paper investigated the forest vegetation recovery process after a wildfire in the Ardino region, southeast Bulgaria from the period between 2016 and 2021. The study aimed to present a monitoring approach for the estimation of the post-fire vegetation state with an emphasis on fire-affected territory mapping, evaluation of vegetation damage, fire and burn severity estimation, and assessment of their influence on vegetation recovery. The study used satellite remotely sensed imagery and respective indices of greenness, moisture, and fire severity from Sentinel-2. It utilized the potential of the landscape approach in monitoring processes occurring in fire-affected forest ecosystems. Ancillary data about pre-fire vegetation state and slope inclinations were used to supplement our analysis for a better understanding of the fire regime and post-fire vegetation damages. Slope aspects were used to estimate and compare their impact on the ecosystems’ post-fire recovery capacity. Soil data were involved in the interpretation of the results.

A synchronized remote sensing monitoring approach in the Livingstone island region of Antarctica

“…In present study, we introduced the Disturbance Index (DI) for monitoring objects with SRC in the environment of Livingston Island. The index is primarily applied for assessment vegetation disturbances and it has shown to be more accurate, compared to the standard spectral indices 29 . The DI is based on the linear orthogonal transformation of multispectral satellite images -Tasseled Cap Transformation (TCT) 48,49 and uses unique transformation matrices for each sensor.…”

“…Most of the indices are developed to monitor vegetation but they could also be informative for detecting changes in other types of objects, especially in their transition stages. These conditions can be observed and evaluated remotely utilizing the Disturbance Index (DI) 28,29 , Modified Chlorophyll Absorption Ratio Index (MCARI2), Modified Soil-Adjusted Vegetation Index (MSAVI2), Normalized Difference Vegetation Index (NDVI), Normalized Differential Greenness Index (NDGI), Normalized Difference Water Index (NDWI), and Moisture Stress Index (MSI).…”

Postfire forest disturbances and initial regrowth using direction angle

“…Due to the financial resources required for field work, as well as the engagement of experienced specialists, remote aerospace methods and data are widely used for ecological research monitoring [1][2][3][4][5][6] . Aiming to assess post-fire disturbances, many studies have based their methodologies on vegetation indices as the most commonly used are NDVI (Normalized Difference Vegetation Index) and NBR (Normalized Burn ratio) [7][8][9][10] .…”

Modeling post-fire forest regrowth using tasseled cap-derived indicators

“…The application of Tasseled cap transformation (TCT) is considered more accurate technique, compared to the standard monitoring methods, using VIs assessing the post-fire forest regrowth 9,10 . The high accuracy of the methodology is due to the linear orthogonal transformation of multispectral satellite images [11][12][13] , which increases the degree of identification of the three main components changing during firesoil, vegetation and water/moisture 14 .…”