Definition: Forests and other uninhabitable areas
The recommendation is to include forests and other uninhabitable regions in the surface area. However, the German case with areas outside any commune can be solved by creating pseudo-communes, having surface area but most often no inhabitants.
Wetlands and mires are proposed to be included in the surface area, except such wetlands which are due to tidewater. Wetlands in tidewater areas are classified according to the recommendations for the coastline.
Eurostat, "Empfehlungen zur Festlegung eines einheitlichen Verfahrens für die Berechnung der Fläche von Gebietseinheiten - Ausgabe 1999; Recommendations for a harmonised definition of calculation of surface area of territorial units, 1999 edition; Recommandations pour une définition harmonisée du calcul de la superficie des unités territoriales - Édition 1999", Office for Official Publications of the European Communities, Luxembourg, 1999, p.17