Eeva-Maria TUHKANENa, Miia MÄNTTÄRIa, b, Inkeri SALOb, Anu RIIKONENb, Ariele CINTIc, Leena LINDENb, Aki MÄNNISTÖc, Minna TERHOd, Juha RAISIOd, Mari SAINIOf, Heli VUORILAMPIg and Timo KOSKIg

Institution: aNatural Resources Institute Finland (Luke); bUniversity of Helsinki – Finland; cUniversità Politechnica delle Marche – Italy; dCity of Turku – Finland; eCity of Helsinkiv – Finland; fCity of Pori – Finland; gCity of Tampere – Finland

Contact: eeva-maria.tuhkanen@luke.fi, miia.manttari@helsinki.fi

Keywords: Tree Inventory, Carbon Storage, Carbon Sequestration, Stormwater, Air Pollution, Tree Cover, Tree Species Diversity

Urban trees provide several ecosystem services that improve the health and well-being of inhabitants, support the biodiversity of other species groups and increase the resilience of urban environment.

In Finland, ecosystem services of urban trees are being studied in Helsinki, Turku, Tampere and Pori. We focus on carbon sequestration and storage, air pollution removal and avoided stormwater runoff and model their amount and value by using i-Tree software and inventory data of city trees.  We will also describe the structure of urban tree population, like tree cover, species composition and their relative importance.

Our goals are to communicate the environmental benefits of urban trees to decision-makers, planners and inhabitants and to increase the general understanding of the effects of trees on the health and well-being in a built environment. Specifically, the effects of tree species diversity on the resistance and resilience of city tree population to abiotic and biotic disturbances will be studied, and related to the long-term ability of urban trees to provide ecosystem services. The structure and amount of urban tree population will be studied as well and considered which kind of indicators would be applicable to set targets for the amount of trees in a city, e.g. tree cover percentage.

In the four Finnish cities, existing city tree databases will be used as data sets for modelling. In addition to that, additional tree inventories will be done. In Helsinki, a plot inventory according to the i-Tree method was performed in 2018, with 200 research plots. In Turku, a large and old park in the Finnish scale was selected as a case study and tree inventory was done in 2018. In Pori and Tampere, additional inventories will be performed in 2019.

In the cities, the special need is to communicate the benefits of urban trees growing on public land in densely built areas, as those trees need the highest input for maintenance, are most threatened when the space gets limited and on the other hand, are essential for well-being of the habitants living in city centers. These needs have to be considered when sampling for i-Tree modelling, as the sampling method affects the applicability of results for communicating.

Presentation: link