Shelterwood-managed forest stands show similar soil microbial activity patterns as beech-dominated old-growth forests

Close-to-nature silvicultural systems are increasingly applied as an alternative to intensive forest management, but their effects on soil microbial communities remain insufficiently understood. We investigated whether shelterwood management affects soil microbial properties in comparison with old-growth beech forests in three national nature reserves in eastern Slovakia: Havešová, Kyjov and Stužica. In each reserve, data on soil properties and microbial activity were collected from a network of sampling points covering both the core of the reserve and the managed stands (146 plots in total). CLPP was used to assess the responses of soil microbiota to environmental conditions and stand management. While microclimate and vegetation were similar in all three reserves, significant variation was observed among the reserves in soil chemistry and the diversity and activity of soil microbiota. In contrast, differences between old-growth forests and managed stands were few and not consistently statistically significant across the three sites. Substrate availability was the most important determinant of microbial activity in the organo-mineral A-horizon, while soil moisture was the sole factor influencing soil microbiota in the litter O-horizon. Our results suggest that when management mimics natural ecosystem processes, as in the shelterwood system applied in the studied forests, the effect on soil microbial processes need not to be negative.