Multispectral imagery is a widely used source of information to address post-fire ecosystem management. The
aim of this study is to evaluate the ability of remotely sensed indices derived from Landsat 8 OLI/TIRS to assess
initial burn severity (overall, on vegetation and on soil) in fire-prone pine forests along the Mediterranean-Transition-
Oceanic climatic gradient in the Mediterranean Basin. We selected four large wildfires which affected pine
forests in a climatic gradient within the Iberian Peninsula. In each wildfire we established CBI plots to obtain field
values of three burn severity metrics: site, vegetation and soil burn severity. The ability of 13 spectral indices to
match these three field burn severity metrics was compared and their transferability along the climatic gradient
assessed using linear regression models. Specifically, we analysed the performance of 12 indices previously used
for burn severity assessments (8 reflective, 2 thermal, 2 mixed) and a new reflective index (dNBR-EVI). The results
showed that Landsat spectral indices have a greater ability to determine site and vegetation burn severity
than soil burn severity. We found large differences in indices performances among the three different climatic
regions, since most indices performed better in the Mediterranean and Transition regions than in the Oceanic
one. In general, the dNBR-EVI showed the best fit to site, vegetation and soil burn severity in the three regions,
demonstrating broad transferability along the entire climatic gradient.
