In two beech forest areas of Zurich and Zofingen, AG (situated in the central plains), a partly new method to quantify their degree of naturalness has been investigated with the help of 41 plots. The assessment is based on the modified vegetational survey according to Braun-Blanquet and on the comparison between the actual and potential natural vegetation. The method can be employed with a reasonable use of time and money. In addition, plant diversity was recorded. 51% of the plots are more or less in their natural state, while 10% of the plots show a strong anthropogenic influence. Very few differences in the beech forests were recorded between the two test areas of Zurich and Zofingen. While foresters are mainly responsible for the maintenance and improvement of the state of forests, much can also be contributed by members of the public.