Site Analysis
Understanding all the features of a site, using and protecting the best, and minimising the impact of the worst.
Plants, Trees and Landscape Features
Plants and trees can influence how comfortable and energy efficient a home is, by providing shade or access to sun when needed. Plants and trees also help with erosion control and stormwater control, and can make a site more attractive and enjoyable for residents. It may pay to consult a landscape architect early in the process.
Landscape features such as ponds and wetlands can provide an effective way to control surface water runoff as well as providing a habitat for native or other wildlife.
What to consider
When you’re assessing a site, consider its existing topography and vegetation with respect to:
- access to sun in winter
- the amount of summer shading provided and required
- shelter from cold or strong winds
- enhancement of cooling breezes
- privacy
- existing biodiversity
- species planted – do they support native wildlife
- the age of the existing planting – young trees will get taller.
Some trees are protected under local authority district plans. A district plan might protect specific trees, or it might protect trees of a certain size or type. Even where trees on a site are not legally protected, consider what community value they add and whether they should be preserved. For example, trees, streams and wetlands can provide important food or shelter to local wildlife. Streambanks and long areas of planting provide “corridors” allowing some creatures to move between areas of bush. New planting can also assist in passive design, and using native species can improve biodiversity.
It’s easier to preserve existing trees and plants than to restore the area later – moving a mature tree may be a better solution than removing it. Planting that remains during the construction process should be protected from damage.
Removing trees and other vegetation can alter drainage patterns and increase risks of erosion and land slippage. It may mean greater exposure to air pollution and particulates from adjacent major roads. If you’re planning tree removals you’ll need to consider the effects removal, if permitted, will have on the site and its human or animal inhabitants.
Plants as a passive design tool
Plants and trees can assist the passive design of buildings by:
- providing shade when needed
- having species that let in winter sun during cooler weather
- funneling breezes where cooling is required
- moderating intrusive winds
- reducing glare by filtering harsh summer sun
- deflecting undesirable wind.
- Deflect wind rather than dam it
- Funnelling cooling breezes
Finding out information
Consider plants and trees as part of a site visit. The land information memorandum (LIM) or property information memorandum may also have information about trees and plants on the site. Check the district plan for information about protected trees and plants.
Aerial photographs and geographical information from sources such as Terralink and Google Earth may also be useful.
For information about native plants, see the Landcare Research and the Department of Conservation websites.
For your clients
To help clients who want information about sustainable planting and landscaping, refer them to www.smarterhomes.org.nz/siting-landscaping/planting-landscaping and www.smarterhomes.org.nz/siting-landscaping/native-plants-and-wildlife.