Greening Stevenson Square's Story
With funding support from the council, businesses and a successful crowdfunding campaign, the green infrastructure project was initiated in 2013 and ongoing maintenance work has continued over the last 7 years. Eleven Gingko biloba trees were planted in Stevenson Square, accompanied by 12 cherry blossom trees in a street nearby. These trees help to not only store carbon but also to provide adaptation and resilience against climate impacts such as higher temperatures in urban areas (i.e. shading and cooling effects) and heavy rainfall (i.e. water absorption). To further improve water absorption, pavements were extended and upgraded with a permeable surface made from recycled tyres.
In addition, a green roof with plants, flowers and shrubs was set up on top of a disused toilet block. Creating green roofs, also known as living roofs, is a historical practice of adding substantial vegetation coverage on the top of built structures. Green roofing normally involves planting and growing flora species on layers of soil or substrate over waterproofing systems. This is done in different ways (e.g. partial or complete coverage) and with different aims, including aesthetic, climate action, biodiversity, and/or for cultivation purposes.
Green roofs provide a variety of benefits, including additional building insulation to reduce energy consumption, reduction of rainfall-runoff through water retention, cooling surroundings during heatwaves, and carbon storage and sequestration (estimated at 0.4kg of carbon storage per m2 and 1.3kg of carbon absorption per m2 annually). Moreover, green roofs can attract, and become a habitat for, wildlife, increasing biodiversity in urban spaces. Overall, these were the benefits sought by City of Trees and its partners when creating the green roof and planting the trees (in particular eyeing flood risk reduction), together with providing a more amenable recreational space for residents.
Useful Learnings from Greening Stevenson Square
Unused buildings in urban centres can be repurposed as green infrastructure with climate, biodiversity and social benefits.
Maintenance is important to sustain newly greened spaces, and their benefits, for years.
Crowdfunding can be a good alternative/addition to funding low-carbon and climate resilience projects, provided that the benefits for the public are well-laid out. It can also inspire institutions & entities with financial resources to provide match funding.