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

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IV - BURNED LAND MAPPING, FIRE SEVERITY DETERMINATION, AND VEGETATION RECOVERY ASSESSMENT
2 - Materials and methods
In the framework of the project we used mainly images acquired by the
NASA-Terra Advanced Spaceborne Thermal Emission (ASTER) sensor that
provides measurements of the surface reflectance in the visible (VIS), near
infrared (NIR) and shortwave infrared (SWIR) regions of the spectrum. Since
the ASTER coverage was not deemed sufficient for the project’s requirements
over the Aspromonte, Cilento, Gargano and Pollino National Parks in
2005, we acquired SPOT 2, 4 and 5 images in the framework of the OASIS
(Optimising Access to Spot Infrastructure for Science) Programme. The
database is therefore composed by about 500 ASTER scenes and 20 SPOT
images. Only satellite images that contained burned surfaces were
processed to derive burned area maps with one of the following methods:
photo-interpretation, maximum likelihood supervised classification and
multi-index multi-threshold approach (Brivio et al., 2009). The multi-index
multi-threshold approach was applied approximately to half of the satellite
images selected for classification; for this reason we focused the validation
exercise only on burned area maps derived with this technique from ASTER
images, that constitute the core of our satellite database. Accuracy measures
(Congalton, 1991) were derived by comparison with a reference database
built by photo-interpretation of about 20 ASTER scenes.
3 - Results and discussion
The major result is a geo database of burned area maps that fills the gaps
of the 2001-2005 historical archive of fire information for protected areas
in Italy.
Year n. images n. burned polygons Area [ha]
2001 65 140 1179
2002 92 49 228
2003 140 177 1172
2004 90 157 1441
2005 74 129 1018
Total [ha] 461 652 5038
Table 1 - Number of satellite images (ASTER and SPOT) used for mapping burned perimeters,
number of detected burned polygons and total burned area between 2001 and 2005.
We estimated that more than 5000 ha were affected by fires in the study
period and the distribution of burned polygons and burned surface among
the years is given in the table. About 75% of the total burned area was
within the boundaries of parks located in Southern Italy (i.e. Cilento,
Pollino, Aspromonte and Gargano). It is likely that the much higher tem-