Data from: Different effects of continuous-cover and rotation forest management on soil organic carbon stabilization in a boreal Norway spruce forest

Clear-cut-based rotation forest management (RFM) is the dominant
silvicultural system in boreal forests. Continuous-cover forestry (CCF),
an emerging alternative, operates without clear-cutting. How these
silvicultural regimes affect long-term SOC storage and quality remains
unclear. This dataset contains measurements from a field study that
examined the effects of CCF and RFM on SOC quantity and stabilization in
spruce-dominated forests in central Finland. We sampled (1) recently
clear-cut plots, (2) even-aged mature plots (both representing RFM
stages), (3) uneven-aged CCF plots, and (4) uncut controls. We analysed
SOC stocks, root biomass, condensed tannins (root metabolites) and soil
fungal necromass (indicated by glucosamine). SOC recalcitrance and
accessibility for decomposition were assessed through chemical and
physical fractionation and laboratory incubation. 13C and 15N abundances
indicated the decomposition stage of soil organic matter (SOM) and the
contribution of mycorrhizal residues. Uncut forests had marginally higher
root biomass than clear-cut and even-aged forests, while uneven-aged
forests fell in between. Tannin concentrations were decreased in clear-cut
plots. Fungal necromass correlated strongly with SOC but was unaffected by
forest management. Contrastingly, greater 15N enrichment in CCF plots
suggested higher impact of mycorrhizae in SOM formation. Although soil
respiration rate in uncut plots was higher than in managed plots, chemical
and physical fractionation analyses showed no treatment effects. While we
did not find differences in total SOC stocks between treatments, our
results revealed long-term management impacts on SOC quality and
stabilization processes, as mycorrhizal fungi appeared to be more involved
in SOM formation in uneven-aged plots. This may indicate a greater
potential for long-term accumulation of stable SOM.