In forestry of Russia, for assessing forest areas according to the degree of fire occurrence the natural fire danger classes are used. The class of natural fire hazard (KPPO) of a forest fund is determined by the type of ground vegetation cover, forest specie composition and age, land categories and a number of other characteristics of forests. Natural fire hazard is divided into five classes depending on fired type of land category (natural forests, forest logging, other categories of forested and non-forest lands), as well as the conditions of occurrence and spread of fire. The first class corresponds to the highest probability of fire occurrence and propagation; the fifth class corresponds to the lowest fire probability or it absence…