Impact of Fires in Boreal Forests on Carbon Dioxide Emissions from Soil Surfaces (Review)

Forest fires have a significant effect on the structural and functional organization of ecosystems, affecting all its components. The purpose of the work was to analyze and systematize data on the impact of fires in boreal forests on CO2 emissions from the soil surface and the combustion of forest fuels (CFF). It has been shown that pyrogenesis is one of the leading soil-forming factors affecting the physicochemical properties and reserves of organic matter in the forest litter and upper soil horizons, as well as their temperature regime, especially in light coniferous forests formed by pine and larch. In forest litter, after the forest fire, there has been a decrease in acidity and carbon reserves, and a narrowing of the C : N ratio. The fractional composition of organic matter changes due to the accumulation of combustion products. In the organic horizon, an increase in soil density, base saturation, and the hydrophobicity of soils is noted. This, combined with the death of plant root systems, leads to a decrease in the rate of CO2 emissions from the soil surface. The intensity of fires greatly affects the release of carbon dioxide and the time required to return this indicator to its original state. The effect of fire on the temperature coefficient Q10 can be multidirectional: negative (especially in the case of intensive fire), or positive, or with no effect. It has been found that the inhibition of CO2 emissions and the Q10 value is primarily due to reduction of autotrophic respiration.