More than 16,000 trees have been inventoried in total - an inventory which in turn represents almost 12,550,000 trees.
- We have looked at the benefits that the trees can take care of, says Johanna Deak Sjöman, researcher from the project i-Tree Sweden at SLU in Alnarp.
The results show, among other things, how the birches in Luleå's city center store the amount of carbon that corresponds to an annual carbon dioxide emission from approximately 1,600 cars and that the spruces in Umeå and the forest oaks in Hässleholm handle up to 100,000 cubic meters of rainwater per year.
In Stockholm, the city's trees annually catch air associations that can be equated with SEK 99 million in socio-economic value.
"Measures stem and crown"
For three years, the project i-Tree Sweden, at SLU, has made calculations of what city trees contribute to so-called ecosystem services.
26 organizations, housing companies, municipalities and more have participated.
The i-Tree software is used around the world to calculate the capacity of trees for various societal benefits.
- You measure the trunk and the crown.
Much of the capacity for ecosystem services is in the foliage, even in conifers, so these have been important measures, says Johanna Deak Sjöman.
Private gardens important
It is important that you have a diversity of species so that a buffer is created for possible diseases and attacks and that trees can grow into prosperous individuals, she says.
According to the report, Malmö is the city in Sweden that has the greatest diversity in the number of different tree species.
Of all the tree species in Malmö, it is the black poplars and park lindens that have the greatest capacity to store carbon, despite the fact that these species only make up one to three percent of the total tree population, says Johanna Deak Sjöman.
She also wants to emphasize the value of the trees in the private gardens and courtyards.
- Up to 50 percent of society's green capital is on private land and plays an important role in nurturing and caring for, she says.