Article

A numerical analysis of data more than 50 years old shows that two zones of particularly high fuzziness appear in the as yet valid classification of forest vegetation in Switzerland. This raises the question of the causes of the phenomenon, but also that of a possible correction. The results show that the crispness of the classification is significantly improved by bypassing some dominant tree species. This is true for Fagus sylvatica in lower altitudes of the country, but especially for the beech forests in general. Picea excelsa, probably the most frequently tree species planted in the past, predominantly blurs the subalpine forest classification. For some less frequent tree species (Castanea sativa, Larix decidua) it can be shown that rare plantings were often made in locations unsuitable for the species. Many analyses are only possible with the help of a more recent, systematically collected data set, which also includes numerous environmental variables. This is now already 25 years old, which means that the species composition known today is not up do date. The general species poverty of all forests of Central Europe is likely to make them particularly vulnerable to drought events, storms and insect infestation