## 2 Materials and Methods  
### Forest Fire Susceptibility Index  
It is well known that the high probability of the forest fire occurrence is predetermined with a specific state of climatic elements in a certain area, but it is also important to determine where fire would most likely emerge under certain conditions. Therefore, it is  
Figure 1: Location of Nature Park Golija and UNESCO Man and Biosphere (MaB) Reserve Golija-Studenica in Serbia Zones of protection regimes in the Nature Park Golija. necessary to analyze other natural conditions that determine whether a certain territory is more or less susceptible to forest fires, especially the type of vegetation and terrain topography. Additionally, it is important to determine the scope and character of human activities, since man is the main cause of this disaster [31]. Forest fire susceptibility is calculated on the basis of the following formula [11]:  
\[\text{RC}=7\;\text{Vt}+5\;(\text{S}+\text{A})+3\;(\text{Ds}+\text{Dr}) \tag{1}\]  
where RC is the Forest Fire Susceptibility Index, Vt is vegetation type index, S is slope index, A is aspect index, Ds is distance from settlements index, and Dr is distance from roads index. Each factor is analyzed separately and classified with the assigned values from 1 to 5, where 5 indicates the highest and value 1 indicates the lowest susceptibility to the occurrence of forest fires. Vegetation type is the most important factor for determining forest fire susceptibility. Coniferous vegetation, which contains resins and oils, is most susceptible to fire occurrence. Dry shrubs are also suitable for the occurrence of this disaster, while in broad-leaved forests, the probability is significantly reduced. Topography is an important physiographic factor that affects the fire proneness of the area [11]. Fire spreads faster at higher slopes by preheating, drying, and increasing the combustion of the available fuels in the canopy [32; 33]. Fire travels most rapidly up steeper slopes and the least rapidly down slopes; therefore, terrain slope must be given significant importance in the determination of forest fire susceptibility. One aspect is another feature of topography that must be taken into account. It determines the amount of solar radiation that a particular area receives and affects the humidity of the vegetation. Forests that are located next to roads, or have roads that pass through them, are more fire prone. Therefore, it is important to obtain data consisting of all roads in the research area. Here, not only paved or dirt backfilled roads used for vehicle movement are taken into account. The database should contain all the paths by which people can move through the forest, since human presence increases the probability of forest fire occurrence. Forests located near settlements are more vulnerable to fire, because people living there can cause an accidental fire [11]. All manmade structures, especially residential buildings, should be taken into account. Since in Serbia, many forest fires each year occur near the agricultural areas, due to the widespread but very irresponsible custom of preparing agricultural areas for the new agricultural season by burning them, distance from such areas must be taken into account in order to perform adequate forest fire susceptibility zonation. Therefore, the existing Forest Fire Susceptibility Index formula must be modified, so that it contains the distance from agricultural areas index (Df). The lower-weighted value of the Df index stems from the fact that this is a protected natural area with a lower intensity of agricultural production. The new formula is:  
\[\text{RC}=7\;\text{Vt}+5\;(\text{S}+\text{A})+3\;(\text{Ds}+\text{Dr})+2\;\text {Df} \tag{2}\]  
Table 1 shows the distribution of values on different classes of used parameters.