Sapling density and height were monitored for ten years after the 1990 storm Vivian on four windthrow study sites in four different regions of the Swiss Alps. Each study site was divided into three different treatments: (1) uncleared, (2) cleared, and (3) planted after clearing. In each treatment the number, height and condition of natural and planted saplings higher than 20 cm were assessed in 25 sample plots of 50 m². In 2000, ten years after the storm, a mean of 1700 saplings ha^-1 was counted. 14 species were found, of which Acer pseudoplatanus, Picea abies, Sorbus aucuparia, and Salix spp. were the most frequent. In two out of three study sites sapling density was significantly lower in the uncleared treatment than in both cleared treatments. Hardly any regeneration stock stemmed from the previous stand and survived the storm, so that almost all regeneration established by germination. The natural increase in the density of saplings was rather slow. In treatment "cleared and planted" 2000-2600 saplings per ha were planted, with a mortality rate of up to 30% within 10 years. After ten years, the natural regeneration had not yet reached the density of the planted trees, and natural saplings were on average much smaller than planted saplings. Planting is, therefore, helpful in speeding up reforestation, which is particularly important on mountainous sites where protection against natural hazards is an important forest function.