In 1990, the catastrophic storm Vivian created extensive windthrows, particularly in some mountain forests of the Swiss Alps. We have since been observing the vegetation succession and the tree regeneration in uncleared and cleared windthrown stands on four study sites in mountain forests at altitudes of 900 to 1600 m a.s.l. On the study sites, microsites were mapped and, subsequently, 236 permanent quadrats were installed. At two-year intervals, data were collected on plant and moss species between 1992 and 2000. Vegetation dynamics were analysed with respect to the succession of microsites, disturbance types, treatments and years of tree seed germination. Vegetation cover increased in all quadrats observed independent of microsites and types of disturbance. On most of the microsites, Rubus idaeus increased in frequency and in cover during the first 10 years after the windthrow. Grasses such as Calamagrostis villosa, Agrostis capillaris and Avenella flexuosa also increased. The most abundant regenerating tree species were Picea abies, Acer pseudoplatanus and Sorbus aucuparia. Seedlings and saplings were small or absent in tall herb communities. Advance regeneration was of predominant importance on all study sites. Post-windthrow regeneration was greatest on disturbed microsites. The regeneration density of the whole study area (projected from the permanent quadrats) ranged between 2000 and 45 000 seedlings and saplings per ha. This indicates considerable differences in recruitment conditions in mountain forests after windthrow. Disturbance to tall herb-dominated gaps in mountain forests favours seedling recruitment during the early succession after the windthrow. Disturbance effects caused by timber harvest after a windthrow resulted in a large density of post-windthrow regeneration that may compensate, at least partly after only 10 years, for the advance regeneration destroyed.