Developing a Green Factor Tool for the City of Helsinki

Urban green space plays a vital role in the adaptation to climate change e.g. by reducing stormwater impacts, air pollution,and urban heat islands. The goal of the green factor approach is to mitigate the effects of construction by maintaining a sufficient level of green infrastructure while enhancing the quality of the remaining vegetation. The development of the Helsinki Green Factor, carried out in 2013, is part of the project Climate-Proof City (ILKKA) – Tools for Planning.

Figure 1. The calculation of the green factor.

The green factor is calculated as the ratio of the scored green area to lot area. Various green factor approaches with the same basic concept have been developed previously e.g. in Berlin, Malmö, Stockholm, Seattle, and Toronto.

In developing the Helsinki Green Factor, the aim was to critically assess the previous green factor approaches and then compile the best practices and applicable green factor elements from those. In addition, surveys were conducted with various groups of experts. Based on the results, new elements found important for the City of Helsinki were added to the green factor and a thorough re-evaluation of element scoring was conducted to reflect the suitability of each element for local conditions and values. The excel-based tool was found straight-forward and easy to use in a testing workshop arranged for city land-use planners and environmental experts in Fall 2013.

As with previous green factors, the Helsinki Green Factor is now finding its place in the city’s land-use planning process. Experiences from ongoing and future pilot projects will determine whether the Helsinki Green Factor is accepted as a means to promoting ecosystem services in the urban green infrastructure. Discussions with city officials, land-use planners, and landscape architects made it clear that the Green Factor Tool could benefit several groups of specialists at different stages of the planning process.
Read more:
Summary of Developing a Green Factor Tool for City of Helsinki (in English)
The Excel-based Green Factor Tool ( in Finnish)