Pyrogenic changes in iron-illuvial podzols in the middle taiga of the Komi Republic

The changes in the morphological, physicochemical, and chemical properties of iron-illuvial podzols under middle-taiga dwarf shrub-green moss pine forests in the first months after fires are examined. It is shown that forest fires are accompanied by changes in the morphology of the litter horizons, their compaction, and by changes in the chemical properties of the soils. The data on the polycyclic aromatic hydrocarbons (PAHs) indicate a significant increase in the contents of chrysene, fluorene, naphthalene, pyrene, and anthracene in the Opyr(L) horizon in comparison with the litters in the background pine forest. The total PAH content in the O(F)pyr horizon increases mainly at the expense of di- and tri-nuclear PAHs (naphthalene and fluorene). The mineral soil horizons in the burnt area become enriched in the most mobile amphiphilic fractions of the organic matter, which is seen from the increase in the absolute and relative contents of the hydrophilic fractions, which might be represented by the products of combustion of fresh plant remains and litter.