Fire severity assessment on peatland vegetation diversity

Abstract

Forest fires have a significant impact on peatland ecosystem, including its vegetation diversity. Several approaches applied for forest fire severity assessment are available in the literature. This study aimed to implement field-based and spatial-aware fire severity assessments and to compare both approaches. Peat swamp forests of Ogan Komering Ilir, South Sumatera Province, for field assessment and Siak, Riau Province, for spatial assessment were selected in this research. Field-based fire severity assessment used indicators of vegetation analyses (individual tree damages, burned vegetation severity, and diversity index), which were measured and analyzed from sample plots in both burned and unburned areas. Spatial analyses of fires severity assessment employed Sentinel-2 satellite imagery with Normalized Burn Ratio (NBR) approach. The research revealed a significant change in tree species diversity, indicating a lower diversity in burned areas than the ones in pristine fields. Magnitude of changes in diversity was influenced by fire severity levels in burned areas and pre-fire condition of burned areas. Spatial analyses indicated low to high fire severity with burned area estimation for each fire severity class. Both approaches have their own benefits and challenges. Field-based severity assessment is beneficial for a detailed assessment of fire damages and losses, whereas spatial analyses would be considered for a broader estimation of fire severity. Both assessments are mutually implemented. Field-based assessment can serve as a verification tool for spatial assessment.