Since prehistoric times, natural and man made fires were important for forest ecosystem dynamics. This study shows that species richness on the southern slopes of the Swiss Alps was significantly higher on sites with repeated fires than on those, which did not burn. Fast spreading surface fires of low to medium intensity are likely to be crucial for initiating succession and adaptation processes in plants and animals, thus enhancing biodiversity and promoting species conservation. On the other hand, fires pose significant threats to people and goods - through direct damage, erosion or emissions. Therefore, in order to reduce biodiversity loss, it is suggested to introduce silvicultural methods, which mimic sporadic fires through providing a mosaic forest with open gaps of different successional stages.