7th Workshop on Forest Fire Management - EARSeL, European ...

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II - VALIDATION OF RS PRODUCTS FOR FIRE MANAGEMENT
where CR (λi) is the differential absorption in each wavelength (λi), R (λi) is
the reflectance, Rc λ(i) is the reflectance of the continuous tendency.
4 - Results
The three sets of spectral data, reflectance (R), FDS and BD, were analyzed
using a stepwise multiple linear regression routine. The number of points
of the data set (n=305) allowed choosing until six independent variables.
Results are summarized in the Table 1.
Statistically significant relationships are observed between the vegetation
remains product and the three spectral datasets (adjusted r 2 > 0.8). The
results of the charcoal product show more differences between spectral
datasets although the values are quite good in all of them: adjusted r 2 near
0.6 in the R and BD datasets and higher than 0.7 in the FDS. Differences
between datasets are also observed in the ash product although with this
product the analysis with the BD dataset does not achieve good results
(adjusted r 2 = 0.46), relationships with R and FDS shown values of 0.67 and
0.74, respectively.
Table 1 - Summary of the regression results.
5 - Conclusions
This research has shown the validity of the combined used of high spatial
resolution photography and field spectrometry to better the understanding
of fire severity variable. According to the results we can state some conclusions
related to the usefulness of the different spectral dataset. The calculation
of transformed hyperspectral data is justified only for ash products
and especially for the charcoal because vegetation showed the same adjust-