SUSTAINABLE LANDSCAPING
Arch. PhD Francesco De Luca

Sustainable landscape design is an approach to designing and constructing the natural landscapes that surround our buildings. If possible these landscapes should maintain themselves and survive by being part of the natural cycles of the local environment. This means finding out what the original local environment was like, although the landscape in our cities and even in rural areas, has undergone significant transformations almost everywhere.

A substantial contribution to creating a sustainable landscape can be made by restoring as much as possible of the original ecosystem and increasing the ecological value of urban sites, particularly where all the indigenous vegetation has been removed for development. In fact one of the most important aspects of sustainable landscaping is about designing landscapes to fit the new ecology created when buildings are constructed and putting back much of what was in place before development. This means introducing things that were not there before, especially new vegetation with the aim of helping to take up carbon dioxide, restoring and maintaining biodiversity, providing privacy from surrounding buildings and helping create pleasant areas for recreation. To obtain the above listed results it is important to make a careful plant selection by choosing the most efficient plants and vegetation that perform well in the local area, once established on existing soils and with existing rainfall patterns,  avoiding where possible non-native or exotic plants. Suitable plants may include native and indigenous plants which have adapted to local climate conditions and will require less work without the need for excessive watering, soil modification and intensive maintenance regimes.

Vegetation can be used to filter air from outside whilst indoor air quality is improved by selection of appropriate plants - some are able to take toxins like formaldehyde out of the air. At the same time, since vegetation can cool and filter air as part of a passive cooling strategy, it can be used as an integral part of passive design plan.

Sustainable landscaping is one of the key factors of ECO-Architecture design and developing real estate. For example, taking into account the characteristics of windbreaks vegetation, can reduce wind chill or the impact of hot winds, not to mention that plants used as windbreaks can save up to 30% on heating costs in winter. The use of such natural resources has been considered as a priority  in the planning of the mixed-used project for the J2 eco-village, in central Estonia. This has influenced all the various step of the development process, from the choice of the site, to the design of the general development layout, from the orientation of the houses in relation to local existing vegetation to the connections of interior spaces with green elements and exterior gardens.

The definition of a sustainable landscape has evolved to include landscape elements that are literally part of a building and among many solutions the most popular are green roofs and green walls.  Many extensive green roofs are constructed specifically to support native and indigenous vegetation with the prospect of enhancing or replacing the natural biodiversity of a place or region. Moreover roofs can be used to capture rainwater that can then be used to irrigate new vegetation, perhaps even on a roof garden or balcony. Capturing water this way also reduces the release of storm water to the street. Depending on their context, function, vegetation types and watering regimes, green walls can be seen as legitimate contributions to the creation of a sustainable landscape and may even be integrated into wastewater treatment systems

The extent and type of vegetation is obviously important but sustainable landscape design can do many things including providing practical solutions to reducing water use through water sensitive design and as part of a wastewater treatment system. The use of water bodies like ponds and water features can be integrated into a sustainable landscape solution as part of an overall water management system and as part of the passive climate response strategy for your home.
 
Finally, but as essential as the previous aspects,  the value of landscape materials, which account for much of the embedded energy in a landscape project, has to be considered. Since the basic idea is to consider the landscape as an integral part of your home’s sustainable design, it is important to think of reusing existing site materials such as pavers and excavated rocks; to employ recycled materials wherever possible such as crushed brick/ concrete, recycled timber and products like recycled glass. Where recycled timber is unavailable use sustainably managed plantation timber or timber composite products in preference to imported rainforest timbers.

Hadley Barrett www.oxfordsustainable.com