Trees cool cities and act as carbon sinks – but only if there is sufficient canopy cover in residential areas. The researchers’ maps show the huge differences in the amount of trees in the Helsinki Metropolitan Area.
Urbanization, climate change and the progression of nature loss are global challenges that urgently need solutions. For example, greening and protecting trees are multi-beneficial ways to increase carbon sequestration, mitigate urban flooding and heat waves, and support the well-being of both humans and other species. Although the benefits of trees are already widely known, their position in our cities is threatened: the number of trees is decreasing, they are being felled and damaged, and not always enough space is reserved for new trees.
Aalto researchers Professor Ranja Hautamäki and Postdoctoral Researcher Antti Kinnunen want to express their concerns about the future of urban trees and highlight the amount and distribution of trees in the Helsinki Metropolitan Area. At the same time, they also highlight the benefits of trees and ways to nurture this important tree asset.
As part of the Co-Carbon project, researchers have published Canopy Cover Atlas and Urban Tree Manifesto that highlight urban trees as critical infrastructure. The atlas allows residents to find out how much tree cover there is in their city district and residential block.
The atlas reveals that in some city districts, tree canopy cover reaches 70 percent, while in others it is only 4 percent. The international recommendation that city districts should have tree canopy cover of at least 30 percent can be used as a point of comparison, and this is justified specifically from the perspective of mitigating heat waves and also from the perspective of health and well-being benefits.
More info:
Professor of Landscape Architecture Ranja Hautamäki, ranja.hautamaki@aalto.fi
Postdoctoral researcher Antti Kinnunen, antti.e.kinnunen@aalto.fi
Photo: Ranja Hautamäki