The thesis studies the ‘green infrastructure’ of the Helsinki Metropolitan Area. Green infrastructure refers to the strategically planned network of green and blue structure. The aim of the thesis is to present principles for a common Green Infrastructure Plan of Helsinki Metropolitan Area that would be more precise than the Regional Land Use Plan for Helsinki-Uusimaa but more general than the individual masterplans of the cities.
In this thesis, the existing green infrastructure of Helsinki Metropolitan Area and its quality is assessed by following criteria: 1) ecosystem services supply, i.e. benefits of nature to people, 2) biodiversity and 3) green structure connectivity, i.e. how well larger green areas are connected to each other. In addition, the future green infrastructure quality is affected by ecosystem services demand i.e. where the people are located compared to ecosystem services supply, and by future challenges like climate change and planned land use changes.
Existing location-based data was used as a key assessment material, and it was reclassified according to the need based on the criteria defined in the thesis. In the thesis, the core of the Helsinki Metropolitan Area green infrastructure consists of both green areas that belong to the best 20% based on ecosystem services supply and / or biodiversity and green connections connecting the areas to each other. By comparing the defined top 20% green infrastructure to the Helsinki Metropolitan Area planned land use, it was discovered that while the masterplans of the cities mainly recognise the top 20% Helsinki Metropolitan Area green infrastructure, some conflicts also emerge.
In this thesis, the main discovered challenges of the Helsinki Metropolitan Area green infrastructure are the presently poor green quality within built-up areas, connectivity together with future planned large land-use changes, densification along green fingers / areas, increasing ES demand i.e. pressure on the green, increasing rainfall and the rise of sea level caused by climate change. As a conclusion, the thesis proposes a common green infrastructure plan for the Helsinki Metropolitan Area. Possible elaborating strategies are also discussed.
Green infrastructure is in the key position both in cities’ adaptation to climate change and in securing resilience, i.e. ability to act under changing conditions. Mainstreaming the concepts of green infrastructure, ecosystem services and biodiversity might help in fitting land use development interests together with GI challenges in a sustainable way. The green infrastructure of the Helsinki Metropolitan Area should be understood as a whole, and it should be planned in cooperation with the cities, developers and citizens, regardless of the administrative boundaries.