Forest soil CO₂ efflux (FCO₂) is a crucial process in global carbon cycling; however, how FCO₂ responds to disturbance regimes in different forest biomes is poorly understood. We quantified the effects of disturbance regimes on FCO₂ across boreal, temperate, tropical, and Mediterranean forests based on 1240 observations from 380 studies. Globally, climatic perturbations such as elevated CO₂ concentration, warming, and increased precipitation increase FCO₂ by 13 to 25%. FCO₂ is increased by forest conversion to grassland and elevated carbon input by forest management practices but reduced by decreased carbon input, fire, and acid rain. Disturbance also changes soil temperature and water content, which in turn affect the direction and magnitude of disturbance influences on FCO₂. FCO₂ is disturbance- and biome-type dependent, and such effects should be incorporated into earth system models to improve the projection of the feedback between the terrestrial C cycle and climate change.

Peer-reviewed journal articles from 1970 to 2021 were searched using the ISI Web of Science database.  This study narrowed the search to disturbance effects on FCO₂ in boreal, temperate, tropical, and Mediterranean forests, and excluded non-forest ecosystems. Searches were limited to disturbance effects on FCO₂ under field conditions. Studies that lasted less than one growing season were also excluded. Each observation had at least one pair of total (FCO₂), autotrophic (AFCO₂) or heterotrophic (HFCO₂) components measured simultaneously in both the control and treatment groups. If studies reported more than one disturbance level, each level was recorded and listed as a separate observation.

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