Unconsidered sporadic sources of carbon dioxide emission from soils in taiga forests

Long-term monitoring in the Russian taiga zone has shown that all known extreme destructive effects resulting in the weakening and death of tree stands (windfalls, pest attacks, drought events, etc.) can be sporadic, but significant sources of CO₂ soil emission. Among them are (i) a recently found effect of the multiyear CO₂ emission from soil at the bottom of deadwood of spruce trees that died due to climate warming and subsequent pest outbreaks, (ii) increased soil CO₂ emissions due to to the fall of tree trunks during massive windfalls, and (iii) pulse CO₂ emission as a result of the so-called Birch effect after drought events in the taiga zone. According to the modeling, while depending on the spatial and temporal scales of their manifestation, the impact of these sporadic effects on the regional and global soil respiration fluxes could be significant and should be taken into consideration. This is due to continuing Climate Change, and further increase of local, regional and Global human impacts on the atmospheric greenhouse gases balance, and land use, as well.