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Research article - Peer-reviewed, 2012

Diversity and distribution of the urban tree population in ten major Nordic cities

Sjöman, Henrik; Östberg, Johan; Bühler, Oliver


In order to have a healthy and sustainable urban tree population, a high diversity of species and genera is needed. This study examined (1) the diversity and distribution of genera and species of urban trees in the Nordic region; (2) the diversity in different sites of the city, distinguishing between street and park environments; and (3) the presence of native versus non-native tree species in urban environments in the Nordic region. The analysis of tree diversity was based on urban tree databases comprising a total of 190682 trees in 10 Nordic cities - Aarhus and Copenhagen in Denmark; Espoo, Helsinki, Tampere and Turku in Finland; Gothenburg, Malmo and Stockholm in Sweden; and Oslo in Norway. The tree databases for Copenhagen, Espoo, Helsinki, Stockholm and Tampere only record street trees, while the remaining databases also include park trees. Tilia was the most dominant genus in Arhus, Copenhagen, Espoo, Gothenburg, Helsinki, Oslo and Stockholm, while Sorbus was the most dominant in Malmo and Betula in Tampere and Turku. Tilia x europaea was the most common species, comprising 16.0% of the total number of tree species. There was a higher proportion of species in parks than in street environments. The number of non-native species was higher than the number of native species in both street and park environments. However, the number of individuals belonging to native species was higher than the number of non-native individuals in all cities and environments except park environments in Arhus. The concluding recommendation from this study regarding greater diversity of genera and species is to exploit local experiences of rare species from local urban tree databases. After appropriate evaluation, urban tree planners can evaluate these rare species in larger numbers for e.g. street environments, where the need is greatest. (C) 2011 Elsevier GmbH. All rights reserved.


Invasive species; Native species; Non-native species; Park trees; Species diversity; Street trees

Published in

Urban Forestry and Urban Greening
2012, volume: 11, number: 1, pages: 31-39

Authors' information

Bühler, Oliver

UKÄ Subject classification

Environmental Sciences related to Agriculture and Land-use
Landscape Architecture

Publication Identifiers


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