| Abstrakt: |
This paper examines fire-induced transformations of the main ecosystem components in steppificated pine forests that grow in the mid-mountain part of the Selenga River basin (Western Transbaikalia). It has been established that medium-intensity ground fires that occur most frequently in the region transform the living ground cover and alter the composition and properties of forest litter, as well as the morphological, physicochemical, and hydrothermic properties of soils. The changes in the species diversity, projective cover, and phytomass of the herbaceous vegetation observed in the course of the postfire dynamics are minor. In contrast, the parameters of the moss–lichen cover, forest litter, and soils undergo significant transformations. In recently burned areas, mosses and lichens are completely destroyed; while the forest litter is thin, consists primarily of recently fallen needles and branches, and its reserves are low. Immediately after a fire, the moisture content in the upper pyrogenic soil horizons decreases, while the soil temperature increases. The following pyrogenic signs are observed in the humus-accumulative horizons of the soil profile: very dark coloration of organic matter combustion products, alkalization, and increased concentrations of calcium and carbon cations; concurrently, an increase in content of oxalate-soluble iron is observed in the illuvial horizons. At 5 or more years after a ground fire, a number of positive changes are observed, including an increase in forest litter thickness, formation of the moss–lichen cover, gradual changes in the chemical properties, a decrease in soil temperature, and some stabilization of field moisture parameters in the upper part of the soil profile. It has been established that the pyrogenic transformations of the forest litter, moss–lichen cover, and soils adversely affect the postfire restoration of the forest vegetation and regeneration of pine stands in areas affected by medium-intensity ground fires. [ABSTRACT FROM AUTHOR] |
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