The article describes the Ålandian vegetation of most typical habitats with greatest detail. The primary goal of the paper is to find out which deciduous species are native in the Åland Islands and hence can be seen as indicator plants for the living conditions. In addition to determining the native species of the Åland Islands, the study seeks to determine the human influence to the vegetation systems: which species are original, which have been introduced by agricultural activities, and how has the human activity influenced the abundance of the species.
The number of species varies from 44.1% to 79% of the total number of deciduous species. There is a close relation between the size of the area available for species and the number of species found. Because of that, there is a need to consider the abundance of the species alongside their diversity when studying the formation of vegetation systems or their habitats.