Geobotanically Helsinki is situated in an oak zone between the Central European deciduous forest and the northern coniferous forest zones. Helsinki nature displays features of both forest zones. Biodiversity in Helsinki relies on versatile rock and soil formations as well as the city’s situation on the coast.
Helsinki forests and shorelines still feature diverse types of nature in its natural state. In addition, human activity has promoted the diversity of species in parks, yards and gardens.
Green areas in Helsinki total about 8,500 hectares. This is about 40 percent of the Helsinki land area. The Public Works Department maintains over 7,000 hectares of various green areas including forests, fields, parks, meadows, street green zones and nature reserves. In addition, there are allotment gardens, garden plots and summer cottage areas, supplemented by private yards and gardens.
The City Council has set the objective to retain Helsinki’s diverse nature and its special features as part of a sound urban structure (City of Helsinki environmental policy 26 September 2012). To achieve this objective, the action plan 2008-2017 includes measures to secure biodiversity.
Securing biodiversity is important for nature itself and for resident wellbeing.
A typical problem in cities is unbroken connections between green areas. As a result, the opportunities of various species to move and spread are weakened. As a result of human activity, the number of original species diminishes, and original species are replaced by escape and introduced species.
The City Biodiversity Index measures the biodiversity of urban nature.