i-Tree Sweden Strategiskt arbete med stadsträd
Johanna Deak Sjöman
In collaboration with 25 organizations throughout Sweden the project aim to evaluate the urban forests in Sweden using the i-Tree Eco tool.
i-Tree Sweden is a nationwide project funded by Movium Partnerskap, 25 municipalities and organizations such as housing companies, arboricultural contractors, and cemetery management organizations. A mutual interest in joining the project is to retrieve tangible results relating to ecosystem services and to find means to support future policy making. Based on inventories conducted in nine municipalities, from the very far northern city of Luleå to Malmö in the south, i-Tree ECO v6 is used to value the ecosystem services provided by Swedish urban forests throughout the country. This includes urban trees from a temperate continental climate in the south to a subarctic climate in the north. Field measurements have resulted in an inventory of 16,223 trees that represent an estimated total urban tree population of 12,530,555 in the i-Tree Sweden project.
In most Swedish municipalities, Scots pine, Norway spruce, silver birch, and rowan dominate the tree population. It is only in the two most southern cities, Malmö and Helsingborg, that these are not included in the top five most occurring species. Similar to other i-Tree Eco projects, it is not only the number of species within a population that determine which species contribute the most to ecosystem services. The percentage of leaf area also plays a pivotal role, thus, a tree species with a limited number of individuals may still provide considerable ecosystem services due to the expansive crowns associated with large individual trees. The ecosystem services that are highlighted in this project includes avoided runoff, carbon storage, carbon sequestration, and air pollution removal.
In municipalities with a high amount of woodland cover, the provision of ecosystem services is generally high. In contrast, cities with limited amount of woodland may contribute with a higher degree of species diversity and thus be more resilient to certain outbreaks of pests and pathogens.