In the project of a survey of the main forest communities of Switzerland, vegetation units of the publication «Waldgesellschaften und Waldstandorte der Schweiz» by Ellenberg and Klötzli (1972) are not only completed, but also revised by the application of new numerical methods. The new classification of the beech forests with Luzula nivea of the Southern Alps in Switzerland is presented as better with regard to productivity. The decisive site factors are discussed also with regard to changes of productivity.