The International Sustainable City

Functionalism and Environments

The landscape designer’s role within an urban context is evolving into ever more complex forms. This includes the traditional pursuits of creating functional, aesthetic, and sensory landscapes and, more recently, the creation of sustainable and productive landscapes. Environmental efficiency is now considered the vital way forward; politics and economics are beginning to push this agenda ahead. Our urban landscapes have become part of the solution to much larger issues that respond to the urban condition and human needs in a world that is far more environmentally aware.

JA+U The International Sustainable City by Kathryn Gustafson and Henry Steed

The Urban Landscape and Urban Problems

Most of the major cities in Asia are extremely dense built environments. Roads and cities are overheated, congested, and polluted. The green spaces are small and many of the waterways are disfigured and polluted, which reduces their ability for real environmental impact. Our cities, where most people live, are concrete jungles. Future public policies will need to have increased emphasis on environmental issues in order to control the quality and quantity of buildings, and the expansion of roads and infrastructure. The city’s inhabitants are dependent on food, supplies, and energy from outside. They produce little themselves to sustain their daily lives. Resources are exhausted at an increasingly rapid rate with little to no concern for how any of this can be sustained in the future. In Asia, public spending on environmental quality has only just begun, and progress is slow and erratic. At present, large cities are deteriorating and there is no sign of real improvement.

How the Green City Evolves

As we know today, there are a number of tools. They are led by the creation of public and private policies, which include the ‘Green City’. This policy allows the impermeable parts of the city – buildings, roads, and infrastructure – to become balanced by permeable green open spaces in both land take and volume. There is a general need for discussion about how we define and qualify open space and how we measure this parity. In the ‘Green City’, private and public lands are both part of the open space. The value to the community is economical, natural, and physical. An example of this type of policy is the latest move to replace lost natural ground in Singapore. The Urban Redevelopment Authority’s initiative requires new buildings to replace 100% of lost ground with ‘Skyrise Greenery’. Inevitably, we lose ground to buildings in an intensive city. In this case, the new landscapes will rise above the ground at multiple connected levels to become vertical greenery, green roofs and roof gardens, roof farms, roof ponds, and water catchments.

JA+U Gardens by the Bay

Gardens by the Bay, Singapore

In planning for the future city, three main ground plane areas need to be considered...
Transportation: For the planning of the spatial dimensions of roads and rail, it is essential to set aside sufficient free ground space for efficient storm water management with planting in central dividers and side tables. This space for street greening will create even more cool and shady spaces, reducing the temperature of the city.
Connections: Pedestrian pathways and cycle tracks should be segregated and have ample space between them to allow planting. Linear green spaces along storm water canals and watercourses should allow significant tree and mitigation planting. Open landscaped parks and open public spaces need to be generous and abundant; and ideally they should be linked to each other to allow ecological connections.
Roofs: They need to be universally green for water catchment, to enable the reuse of water within buildings, to reduce storm water run-off, and to create additional accessible open space.

JA+U Jalan Elok House by Chang Architects

Jalan Elok House © Chang Architects 

The Spaces and Tools of Implementation

There is a plethora of new techniques that are continually evolving. City builders, urban planners, landscape architects, developers, architects, and engineers have to use all their creativity – not only to invent new design solutions, but also to make this a political and environmental priority in their designs. New regulations in cities like Singapore are already achieving measurable and remarkable changes in the way we build today.

Planting on Vertical and Horizontal Urban Structures

Replacing real ground on structures is expensive. Nothing can genuinely replace ‘true ground’, particularly large trees and ‘real’ landscapes. It is impossible to grow large trees without sufficient soil. For large trees, planters must be ample and have a very good drainage system. The economic and technical challenges need to be planned for and embraced by developers/owners, project engineers, and designers. The greening of buildings, however, is inevitable and necessary, and so we strive to develop effective techniques for establishing new environments in the most hostile and often unsuitable conditions. To do this we use a number of techniques, which have been tried and are being continually tested.

Green Roofs and Extensive Roof Gardens

A ‘green roof’ technique is used for non-accessible roofs with the objective of providing a green surface for insulation and environmental reasons. The intent is to create a green carpet of plant species which have been rigorously tested to find the strongest plants with a good growing habit, drought resistance, and the ability to withstand full sun, and which have a very shallow rooting system.

Green Walls

Accurately, these walls cannot be included in the balance of the 100% replacement, but they contribute to the environment in their role of providing insulation, and ecological connectivity and diversity. Large bare, blank walls that are covered with vertical greenery are always examples of the existing technology, which combines a support frame, a vertically supported soil-less growing medium, a suitable irrigation system, and a selection of tested high-performance plant species. Many plants can climb vertically up walls without complex, expensive mechanical devices, but they take time to provide cover, so they tend to get overlooked. However, they should be used more widely.

JA+U The International Sustainable City by Kathryn Gustafson and Henry Steed

Roof Gardens

Within accessible spaces on higher levels, ‘roof gardens’ perform as both aesthetic and social environments. These spaces may be sizeable and can contain entertainment, services, and recreation, which will turn them into small open spaces. The structural design will be very different from the green roof, providing larger planting infrastructure where trees can be grown and water features and various structures incorporated. All of these vertical greening methods can be applied from the second level to the very highest. As the microclimate of buildings changes, so design and plant selection will change. Wind will be a key issue at the higher levels.

The Seamless Urban Landscape

In addition to the planting of urban structures, there is enhancement of the traditional ground plane. The ultimate green city has no boundaries. Visible junctions between buildings will not exist, as landscape and paving blend seamlessly into each other at different levels. Singapore is a leader in implementing this concept, and many urban areas are already boundary free. It is a concept of total environmental integration, where a single, unified environment of exceptional quality is being created and woven throughout the entire urban fabric. The urban forest is part of this network. Planting large numbers of trees along roads and in parks requires long term planning and a vision to use and replace this viable timber. Also part of this network is the urban farm. In future, large parts of our infrastructure and nonprogrammed open space will be managed like farms, producing vegetables, herbs, fruit, and livestock. Our roofs, particularly the large roofs of factories, schools, and public buildings will be used as market gardens, seedling nurseries, and fish and vegetable farms.


Much in our lives is inextricably bound to the world of plants, with the effect that we take them for granted. Plants are our most easily available contact with nature. We eat them, we sleep on them, our clothes are made from them, and a great proportion of our medicines come from them. In a new generation of urban landscapes we will cherish and nurture plants in new ways, bringing them into good use, and acknowledging the bounty of plants throughout our urban environments. In doing this, we will improve our health and enrich our lives. People of all ages will learn about plants and nature and become educated in natural husbandry, once again passing skills and knowledge from one generation to the next to create a better future.