This database contains the data set described in Andrieux B. et al. (in preparation) about soil organic carbon bioreactivity in Quebec's spruce feathermoss forests. The soil carbon bioreactivity has been evaluated with long-term lab incubations. Carbon density in different soil functional reservoirs is available at the plot scale (n = 72): total C stock in the O layer (FH horizon), total C stock in the mineral soil (0 to 35 cm), total bioreactive C stock, total acid-insoluble C stock. Ancillary biophysical data includes climate variables, species occurrences in the moss mat, time since fire, and some soil properties.