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

Abstract

Wildfires are natural processes in the ecosystem, some of them causing significant environmental disturbances. The remote aerospace methods and data can provide an efficient, easy and cost-effective tool for monitoring the recovery of burnt forests which is an essential task in the ecological research. The aim of this study is to monitor post-fire forest regrowth introducing an approach using the tasseled cap derived Disturbance Index (DI), Vector of Instantaneous Condition (VIC) and Direction Angle (DA). The high accuracy of the methodology is based on the linear orthogonal transformation of multispectral satellite images (Tasseled cap transformation (TCT)), which increases the degree of identification of the three main components changing during fire – soil, vegetation and moisture. The proposed method was tested on the territory of three test fires with different forest environments, located next to Bistritsa, Ardino, and Perperek, Bulgaria. For the purpose of post-fire regrowth monitoring Landsat and Sentinel-2 satellite imageries have been used for the study period – 2012-2022. For the purpose of validation very high resolution (VHR) satellite data have been used that include World View (2/3) and GeoEye (1) sensors as well as aerial images. Results obtained by the implementation of the proposed approach represent the post-fire regrowth dynamics. The DA follows the change trends of the VIC, however, more clearly represents the changes of the Greenness TC component for the studied period.

Postfire forest disturbances and initial regrowth using direction angle

“…Monitoring of the disturbances and the initial regrowth after the wildfire was carried out on the base of a methodology using the DA. DA is an index, derived on the basis of TCT, introduced by the authors and validated in previous research [11][12][13] . DA is calculated using the following formula:…”

“…The purpose of the present research is to assess the disturbances and the initial regrowth after the forest fire near the village of Hvoyna (Bulgaria) using a methodology different from the standard approaches using vegetation indices. The proposed methodology is based on the Direction Angle (DA) [11][12][13][14][15] index obtained by applying tasseled cap transformation (TCT) 16 . The methodology using DA is based on linear orthogonal transformation of multispectral satellite images and is characterized with higher accuracy compared to standard methodologies using vegetation indices 8,11,13 .…”

“…The proposed methodology is based on the Direction Angle (DA) [11][12][13][14][15] index obtained by applying tasseled cap transformation (TCT) 16 . The methodology using DA is based on linear orthogonal transformation of multispectral satellite images and is characterized with higher accuracy compared to standard methodologies using vegetation indices 8,11,13 . The changes detected in DA values depict the trend of the green component for the different moments of the investigation period that allows estimation of the disturbances and monitoring regrowth processes 11,12 .…”