## 2 Materials and Methods
### Data
#### 2.1.2 Wildfire Records  
The wildfire database comprises 15 years (2000-2014) and was established by the Forest Authority of Murcia in 2000. The database includes day and hour of the wildfire, location, burned area, causes (real and presumed), type of vegetation, previous wildfires in the area, and relationships with soil conditions. In the 2000-2014 period, 2694 forest fires were recorded in the region with a total burned area of 39.41 km\({}^{2}\). Table 1 shows the main characteristics of the wildfires in the region in the studied period (2000-2014). More than 75% of the burned surface is located only in forest areas, as can be seen in Figure 1. Although the surface of all zones is between 2500 and 3500 km\({}^{2}\), the number of wildfires and burned area varies widely depending on the zone itself and its geographical, climatic, and ecological characteristics more than its extension. Zone 4 has the lowest number of fires of the region (20.49%) but, on the contrary, its burned area in the studied period is the highest (45.18%), since the mean ratio of m\({}^{2}\) per fire is 32,261 m\({}^{2}\)/fire versus the 6327 m\({}^{2}\)/fire of Zone 1, which has the highest amount of fires (43.28%). Furthermore, despite Zones 2 and 3 having similar surfaces (2378.50 and 2439.53 km\({}^{2}\), respectively) and similar numbers of wildfires (614 and 661, respectively), the burned area in Zone 2 is nearly triple that of Zone 3 (26.64% and 9.46%, respectively). All zones show similar values for 50 th, 75 th and 95 th percentiles (around 1000, 5000, and 20,000 m\({}^{2}\), respectively) except Zone 4 where the burned area in the studied period is significantly higher than the rest of the region.  
Concerning the size of the fires, although more than 94% of fires in all zones were below 30,000 m\({}^{2}\) of burned area (histogram in Figure 1), the remaining 6% of fires accounted for almost 80% of the total burned area in the region in the studied period. This fact clearly points to the importance of big fires in the forest ecosystems and their subsistence and whose impacts transcend the damage and degradation of ecosystems and material properties, especially in semiarid regions [58].  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & & **Zone 1** & **Zone 2** & **Zone 3** & **Zone 4** \\ \hline \multicolumn{2}{c}{Area (km\({}^{2}\))} & 2928.80 & 2378.50 & 2439.53 & 3564.96 \\ \hline \multirow{4}{*}{Burned Surface Statistics (m\({}^{2}\))} & Mean & 6328 & 17,099 & 5634 & 32,300 \\  & Max & 828,621 & 5,798,460 & 152,000 & 4,181,500 \\  & 50 th percentile & 697 & 1000 & 1000 & 2160 \\  & 75 th percentile & 3000 & 4000 & 5000 & 10,000 \\  & 95 th percentile & 20,000 & 20,479 & 25,772 & 89,200 \\ \hline \multirow{4}{*}{Number of fires} & \(<\)1000 m\({}^{2}\) & 676 & 315 & 334 & 210 \\ \cline{2-6}  & 1000 m\({}^{2}\) \(<\) A \(<\) 30,000 m\({}^{2}\) & 443 & 275 & 302 & 275 \\  & \(>\)30,000 m\({}^{2}\) & 47 & 24 & 25 & 67 \\  & Total & 1166 & 614 & 661 & 552 \\ \hline \multirow{4}{*}{Burned area (m\({}^{2}\))} & \(<\)1000 m\({}^{2}\) & 203,078 & 99,926 & 88,076 & 67,090 \\  & 1000 m\({}^{2}\) \(<\) A \(<\) 30,000 m\({}^{2}\) & 2,407,935 & 1,586,832 & 1,937,735 & 1,991,938 \\ \cline{1-1}  & \(>\)30,000 m\({}^{2}\) & 4,767,182 & 8,811,748 & 1,703,265 & 15,749,205 \\ \cline{1-1}  & Total & 7,378,195 & 10,498,506 & 3,729,076 & 17,808,233 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Summary of burned area and number of wildfires according the subdivision of zones in the study area (2000–2014).