Urban street tree characteristics and benefits in city centre, Reykjavik, Iceland

Urban street trees are often overlooked as essential contributors to the total urban canopy. The city centre of Reykjavik, Iceland was surveyed using random plots throughout the central portion of Reykjavik to determine species composition, structure, potential conflicts with infrastructure, and environmental benefits. In this portion of Reykjavik, 11 tree species were observed, dominated by Populus trichocarpa. For all species, the density was approximately 67 trees/km, which when compared with other Nordic cities was quite high. However, in terms of number of species, diversity was much lower compared to other Nordic cities. Street trees in this portion of the city sequester approximately 793 Mg of carbon. Value to the city summed to 15,764,000 ISK (134,000 USD), which partitioned to 187,000 ISK per kilometer or 128 ISK per capita. There were also conflicts identified with buildings and with sidewalks buckling, particularly with P. trichocarpa. Given the density and value of the trees in this portion of Reykjavik, it is imperative for additional work to be undertaken to manage the urban canopy and mitigate any costs associated with conflicts between trees and infrastructure throughout the city.