Stephen Cushing of Halifax-based Urban Perspectives
on the 5 most common misconceptions about landscape architecture.
1. Landscape design is not for decoration- landscapes are essential infrastructure.
Landscapes are just as integral to the urban environment as buildings and other forms of infrastructure. This is often referred to as green infrastructure. Landscapes have the power to direct people, encourage gathering, influence user comfort, and provide space for recreation. Environmentally, we know that green spaces have the power to reduce stormwater flow, cool environments, shade us on hot days, and remove CO2 from the atmosphere, among other values. Trees, in particular, are one of the few forms of infrastructure that appreciate in value as they age. In fact, trees have the potential outlive many forms of modern construction. Still, landscape budgets often are trimmed back. This is because the values described above are not often understood or easily translated into tangible deliverables. Some people are getting it, I’ve heard this called the Highline effect – it wasn’t until high profile projects like the Highline in New York City that people realized that landscapes of quality construction and plant material will provide a wide array of social, environmental, and economic values.
2. Urban densification doesn’t have to mean a loss of greening.
Urban densification is often cited as a sustainable way to grow our cities because municipal boundaries are not forced to expand while increasing population, also, because services are shared between many residents. Research also shows that urban green spaces are essential to urban sustainability. However, our (collective) track record at maintaining ‘green’ as cities expand is poor. Trees, a dominant form of vegetation in cities, are often the first structures removed to make way for buildings. Trees and other plant material need to be considered early in the planning process to ensure adequate soil volume and site permeability. Sometimes, the simple process of tree protection during construction can save unnecessary tree removal. That being said, trees aren’t always the best solution in difficult urban situations, green roofs, green walls, vines, and planters may be better suited in some applications. What is needed is more creative and adaptable design solutions rather that are able to adapt to unique urban situations.
3. Soil will determine the success of a planting.
This sounds like a funny statement, but rarely do people realize how much soil most large plants require. A plant will only grow as large as the soil volume in which it occupies. Think of a bean sprouting in a thimble, this sounds ridiculous because there is no way that bean will have room to grow into a plant. Similarly, the amount of space we give to trees in the city is ridiculous. The repetitive nature of installing a tree in a sidewalk pit only to have it die in 3-5 years is exhausting and expensive. American landscape architect James Urban has extensively researched urban trees and minimum soil volumes. Urban maintains that an average urban tree should receive 28m2 (1000ft3) of soil if there is any hope of it reaching a substantial size (~30cm). In an urban setting, 28m2 is not easy to come by without being creative. There are many technologies like structural soil, soil cells, and cantilevered sidewalks that allow trees to mature in difficult urban settings. Let’s not forget that soil volume alone isn’t a limiting factor, but also the water in which the soil holds.
4. Greening those places where we live and work is more influential than only having nature as a destination.
Where I live, in Halifax, Nova Scotia. The city is locally known as the City of Trees. Much of the urban tree cover is privately owned, but it is the old street and park trees that have contributed to city identity. Although regional and other destination parks have significant value (e.g. naturalness, biodiversity of species, recreation, wildlife habitat), it is those places that are traveled or visited on a daily basis that influence how a city looks and feels (e.g. along streets and sidewalks, in parkettes and plazas, rooftops). People shouldn’t have to wait for a weekly or monthly trip to experience nature, it should be available every day while walking to work, while having lunch, or while shopping downtown.
5. We don’t have to quantify the utility of a landscape for it to be valued.
We have an incessant desire to put a dollar value on everything. In the landscape this is also true, from economic impacts of vegetation or the cost to replace a tree. This has some utility when a developer needs to budget for landscape design and installation. However, the presence of ‘green’ in the urban context has an unspoken qualitative value that is essential to city character and livability. It is often those things that are difficult to quantify that are said to be the most important, including the calming influence that ‘greening’ has, the mental escape when surrounded by plants, and the aesthetic qualities plants exhibit. These qualitative values can often be collected by simply asking, “What do you value about trees (or other plants) in the landscape”? Perhaps if we incorporate these values in the landscape it will make these spaces more meaningful to the people who use them?