This thesis had two objectives: the first objective was to evaluate the response of forest ground vegetation to selected forestry operations, i.e. cutting of different intensities and scarification; the second objective was to compare the use of survey data in vegetation research with that of more traditional research using field trials - i.e. can survey data be used and produce results that comply with those emerging from field trials? Here, the results from an analysis of survey data has been compared with results emerging from a field trial.

Survey data was analysed from the National Forest Inventory (NFI), using 789 sample plots in central and northern Sweden visited twice at an interval of 10-11 years, 294 of which had been subjected to logging between inventories. This was compared with a field trial in central Sweden: a complete block design with four replicates - three treatments and conventional harvesting as the control.

The cutting intensity was found to have an impact on the ground-layer flora, the change being mostly differences in abundance rather than change in species richness. Those increasing were early successional species, i.e. crustose lichens, Deschampsia flexuosa. In contrast, Vaccinium myrtillus was decreasing substantially in response to increased cutting intensity. A number of species appeared to be indifferent to cutting, i.e. Vaccinium vitisidaea, Trientalis europaea.

Scarification had a different impact on the flora than cutting: only Polytrichum spp. increased substantially, while many decreased.

For those effects that were possible to compare in both studies, the results from survey data comply with those from the field trial, indicating that survey data is possible to use in forest vegetation research.