Green densification model

The Eco-District at the Banks of the Bohrie Ostwald is structured around water with the Bohren pond, the river Ostwaldergraben and the seasonal and permanent wetlands (Ref. 2). The project covers 50 hectares and was initiated by Strasbourg Eurométropole with 2 developers: CM CIC SAREST and Nexity-Foncier Conseil (Ref. 1, 7). The district will integrate its structures into the surrounding water land and vegetation to provide for agricultural water management and flood preventing procedures (Ref. 2). It will also have green roofs, public green spaces, (Ref. 4) vegetable gardens, (Ref. 7) and composting, while on-site vegetation will participate in the deployment of green infrastructure (Ref. 5). "An eco-district of 48 hectares (17 urbanized hectares) is being created" (Ref. 11).

The 100-hectare site that is situates in the socially disadvantaged neighbourhood and river island called Wilhelmsburg was designed for the IGS 2013 (International Garden Show) and was opened to the citizens of Hamburg in 2014. On the 9-hectare large area that was a former brownfield site, mostly free or inexpensive outdoor leisure facilities were planned. The new park, named “Island Park” aims to attract people of all ages to do sport, including recreational and professional sports outdoor. Among others, the park is equipped with a high-rope course, a climbing wall, a canoeing canal a running track, a boules pitch and a garden for meditating (Reference 1, 2). The park also offers additional services, such as workshops and hands-on activities for people who want to experience a sport under expert guidance. (Reference 3)

Hamburg decided to increase the number of trees in the city, however, the budget was not enough to completely fulfil this goal. Therefore, the city not only tripled the municipal budget dedicated to tree planting and but began encouraging the citizens to contribute to greening the city through the donation campaign "My tree - My city”. The project was launched in 2011 as part of the European Green Capital programme of Hamburg. Citizens can donate and by using an interactive map, can choose a site and a tree species to be planted, and follow-up the implementation of their tree. (Reference 1, 3) The City of Hamburg gave for each tree that reached donations of 500 Euro the same amount on top to cover the average costs of 1.000 Euro per tree, which includes the preparation of the planting pit, the planting itself and maintenance. (Reference 4) The campaign was so successful that it continued even after Hamburg’s year as the European Green Capital and is still going on in 2020. (Reference 2, 7)

Opened in June 2006, the Jean-Baptiste Lebas Park, which occupies a space once used for illegal parking and marred by 11 lanes of traffic, is surrounded by the boulevard of the same name. This park plays an important role in creating an urban green space into a derelict grey area. The park helped to increase the biodiversity of the area. It has an area of 3-hectare (7-acre) and it contains a large lawn with flowerbeds, play areas for children and places for playing "boules" (Ref 1).

While Hamburg has already had an impressive green infrastructure, it is now (since 2013) implementing an interconnected green network that will cover the 40 % of its area and support commuting by bicycle, recreation and climate change resilience. The project is planned to be completed by 2034. (Reference 9) The project aims to connect the two green belts, parks, recreational areas, cemeteries and animal habitats to each other with green paths and with the already existing “green axes” leading from the agglomeration to the urban core. The green network could not only absorb more CO2 but also prevent flooding by soaking up an increased amount of rain- and seawater caused by storms. (Reference 1, 2). An extensive network of cycle paths is also being built as part of the project. (Reference 2)

A 21-kilometer regional cycle and footpath between the cities of Essen, Mülheim am der Ruhr and Duisburg was developed from the former unused railway route of the Rheinische Bahn. The path was landscaped to ensure the comfort of pedestrians and cyclists. Part of the route passes through Emscher Park and become a full-fledged part of the green infrastructure of Essen (Ref. 1).

The Newton and Arkwright roof, buildings of the Nottingham Trent University campus, holds one of the region’s largest sedum roofs, which spans its way 2,500m² across the building, creating a home for 13 varieties of sedum, insects, songbirds and a new colony of honey bees, creating a trio of hives over all campuses (ref. 1). A 150m2 bank surrounding the building is unmown in order to promote biodiversity and attract pollinating insects in the summer months. Green-walled gates was also part of the implementation activities of this project. (ref. 5).

It started with the “Let’s Plant for the Earth, Let’s Plant for Murcia” project, as Murcia’s committed to the United Nations Billion Trees Campaign. The city of Murcia committed itself in 2008 to plant 12 000 trees around the urban fabric through a series of action projects. The target was exceeded in 2010 with a total of 23 576 trees pledged and planted toward the campaign (Ref. 1).
In 2020, after having surpassed their 12,000 planted trees goal, Murcia has the new goal of planting 100,000 trees by 2030. It is a long-term project that the municipality committed itself to make (Ref. 5, 2020a).

The “Cities Dare Wilderness” project is part of the overall Hanoverian program of “More Nature in the City”, a new future-oriented approach to green spaces in urban areas. The aim of the project is to bring wilderness back to the city by increasing urban biodiversity, strengthening nature in the city and making it habitable for its inhabitants. For fulfilling these goals, eleven sites were chosen (some parts of the city park Eilenriede, some currently intensively cultivated areas or some derelict small gardens), in which different methods have been tried out, like planting local woody plants, grazing, and the implementation of interpretive trails. The development of the flora and fauna in the new wilderness is now being observed and investigated. The first step in the wilderness was made on a meadow along the course of the Fße in the Badenstedt which was fenced. It was made available for cattle to graze and influence the new growth of shrubs through feeding preferences (Reference 1, 2). The flowering meadows have attracted a variety of species. The rich habitat resulting from the project has attracted songbirds, hedgehogs, butterflies and some of the 67 bee varieties endemic to the state of Saxony (Reference 10).
Campaigns for environmental education are regularly offered in order to involve the population in the process of wilderness development. The series of “Wilderness Concerts” were organized, a “wilderness woodlice” was installed in one of the project areas (Mittlefield), and handicraft activities have been regularly offered, in addition to excursions and guided tours (Reference 8). Citizen science is also part of the project through the iNaturalist app that allows the community to record observations of the flora and fauna in the area (Reference 9).
The project is financed by the Federal Ministry for the Environment, Natura Conservation and Nuclear Society. Two other cities, Frankfurt am Main and Dessau-Roßlau is also involved as model cities. (Reference 1,2)

When the national German railway company shut down parts of the former East station of Leipzig and its tracks in 2012, citizens developed an idea for its secondary use and came up with the concept of the "Parkbogen Ost" which represents a 5-kilometre long circle of bicycle lanes, footpaths and outdoor space surrounding the East of Leipzig. The city of Leipzig recognized its potential to connect the Eastern Leipzig with the city centre and developed the strategy further by issuing a "Masterplan Parkbogen Ost" as the base for a step-wise implementation of the project in 2013 (Ref. 5).