This question was discussed during a workshop in February 2002 at the Federal Research Centre for Forestry and Forests Products (Hamburg). The background of the question is the conservation and sustainable utilisation of biological diversity in the sense of the Convention on Biological Diversity (CBD) adopted at the United Nations Conference on Environment and Development (UNCED) in Rio de Janeiro.The species list of typical vascular plants in the North German lowland can serve as criterion for the assessment of the quantity of species diversity in these forests. The list contains 634 taxons which are divided in six different subgroups. The validity of the list is restricted to the North German lowlands and enclosed by a forest definition. The extension of the list to the German low mountains, the foothills of the Alps and the Alps is planned