The effect of forest disturbances and regeneration scenario on soil organic carbon pools and fluxes: a review

Forest ecosystems are one of the largest terrestrial carbon (C) reservoirs on Earth and an important sink of anthropogenic CO₂ emissions. Abiotic and biotic disturbances such as windfalls, fires, outbreaks of insects or pests may negatively affect C storage in forest ecosystems decreasing their role as CO₂ sink. The objective of this review was to summarize the current knowledge on the impact of large-scale forest ecosystem disturbances caused by windthrow and insect outbreaks on soil C stocks and cycles, and to gather information on the impact of restoration treatments performed in disturbed stands in the context of carbon accumulation in forest soils. Discussed were effects of windstorms and insect outbreaks as well as impacts of various approaches of forest regeneration after disturbance on C stocks and fluxes. Disturbances decrease C stocks in forest ecosystems and turn them from C sink into C source for a certain time. Regeneration of the disturbed forest restores its role as a CO₂ sink. In montane forests artificial afforestation seems to shorten the time of achieving C parity. However, no data exists for lowland forests. Hence, there is an urgent need for studies that assess effect of windfalls and insect outbreaks on carbon storage in forests of lowland Europe.