The importance of a green urban habitat

Peter Irwin, Senior Executive Consultant & Past President, Rowan Williams Davies & Irwin Inc., Council on Tall Buildings and Urban habitat, Board of Trustees

The unprecedented wave of exceptionally tall buildings being designed and constructed around the world is only one of the most eye-catching manifestations of the rapid urbanization of mankind. Architects, designers and urban planners are increasingly aware of the need to build more sustainable buildings and infrastructure. But there is a need to give equal knowledge-based attention to creating and preserving an ecologically sustainable natural environment within our urban areas.

Most architects and planners are aware that green spaces, parks and woodlands are essential elements of the urban habitat and that they contribute greatly to the livability of cities and to the health and well-being of citizens. Trees provide shade, help retain water and control run-off; flowering plants and shrubs beautify and attract wildlife such as birds and butterflies, and can provide shelter from winds. However, designers and landscapers often take a narrow view of what this means in practical terms.

The High Line in New York. Image: James Corner Field Operations and DS+R

Planting hardy and drought-resistant plants to minimize maintenance and reduce water usage is simply part of creating sustainable natural environments in urban areas. We need to green our cities in a way that fosters an ecologically diverse natural environment; one that supports the lifecycles of the insects, birds and other small mammals that are part of a healthy and sustainable eco-system. These creatures need food and water as well as nesting, roosting and overwintering sites – a habitat that for thousands of years has been provided by the plants growing naturally in the local area. Landscaping that emphasizes turf grass and a narrow range of non-native shrubs and flowering plants will not support viable eco-systems and will hasten the decline in the number of birds, butterflies and other beneficial insects, found in urban areas.

The urban habitat can actually help restore diversity if we plan it right, by including parks and landscaping features that are deliberately planted with species that cater to pollinators and other native insects. There are now many interesting examples of ways to create ecologically diverse and sustainable green infrastructure in urban areas: the High Line project in Manhattan, Ken Yeang’s bioclimatic skyscrapers and the proliferation of green roofs in a number of cities are just a few examples. The Royal York Hotel in Toronto uses its 13th floor roof terrace as a garden to grow fresh herbs, tomatoes and edible flowers for its kitchens and also has beehives to ensure pollination. In my hometown of Guelph, Ontario, Canada, a local charity, Pollination Guelph, is raising awareness of the need for pollinator-friendly gardening and landscaping by planting demonstration gardens in parks and domestic and commercial properties. They also plan to re-naturalize and create a pollinator meadow on a 45-hectare decommissioned landfill site. I suspect we are only at the beginning of exploiting the urban habitat’s capacity to provide both green and liveable spaces while supporting ecological diversity.

Note: This post is excerpted from an earlier column in the CTBUH Newsletter. The CTBUH will be hosting its 9th World Congress in Shanghai, 19-21 September (

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