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

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I - PRE-FIRE PLANNING AND MANAGEMENT
The distance bands so found were introduced in Getis and Ord’s G, in order
to find where clusters were localized. Getis and Ord’s index value was classified
according to date of occurrence of the event as reported in figure 1
and in table 2, which shows the example of the 2000 year.
Figure 1 shows fire location and “seasonal” occurrence for the years 1999,
2002, 2003, 2005 which exhibited the higher time and spatial clusterization.
The spatial distribution of fires depends on different types of land use
and also on different interannual climate variability, which lead to different
fire susceptibility. It is quite interesting the fact that: (i) for the 1999
year fires mainly occurred in the summer, as usual for the Mediterranean
ecosystems (ii) for 2002 fire occurred, as usual, in summer but also during
winter, and finally (iii) for both 2003 and 2005 years fires happened during
the spring, summer and winter season. This behavior shows a significant
variability in the fire “seasonality” for the Basilicata Region.
Season Day of the year when the event occurred Getis and Ord’s G
winter 1 79 -4,02502 -2,01534
356 365 1,89023 2,83819
springer 80 171 -2,01534 -0,00567
summer 172 294 -0,00567 0,94228
autumn 295 355 0,94228 1,89023
Table 2 - Classification of Getis and Ord’s G for dataset of 2000 year.
4 - Final remarks
The aim of this study was to characterize the interannual fire activity in the
Basilicata Region. Areas of homogeneous fire dynamics were identified with
cluster analysis. The cluster obtained are physically meaningful and this
allows us to better characterize and understand fire activity variability. This
provides useful information to investigate the relative importance of different
factors influencing short-term variability in fire occurrence at different
scales and to better understand the contribution of human activities
and climate variability to the fire incidence. Our results show that rainfall
variability significantly influences the fire occurrence and areas with different
types of land use react in a different way to interannual climate variability,
leading to different fire susceptibility depending on the land use
type.