Meta-analysis shows forest soil CO 2 effluxes are dependent on the disturbance regime and biome type.

Forest soil CO 2 efflux (FCO 2 ) is a crucial process in global carbon cycling; however, how FCO 2 responds to disturbance regimes in different forest biomes is poorly understood. We quantified the effects of disturbance regimes on FCO 2 across boreal, temperate, tropical and Mediterranean forests based on 1240 observations from 380 studies. Globally, climatic perturbations such as elevated CO 2 concentration, warming and increased precipitation increase FCO 2 by 13% to 25%. FCO 2 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 FCO 2 . FCO 2 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.