Urban greenery and biodiversity
Biodiversity is an important facet of sustainable building, bringing social, economic and environmental benefits to any development. The positioning of vegetation in relation to buildings and green corridors needs to be closely considered, as does the type of vegetation and future maintenance requirements. Urban vegetation, combined with light and reflective surfaces, can reduce surface temperatures by 10–20°C. Evergreen vegetation can reduce wind speeds in winter. There is a clear correlation between the location of a dense, mostly evergreen, ‘shelterbelt’ and the reduction of space heating demand. Sufficient solar shading must be provided regardless of vegetation maturity. Vegetation helps to screen noise but it is not a sufficient noise barrier on its own. Planting and protecting urban trees is crucial for CO2 absorption: the older the tree, the more carbon sequestered over its lifetime. Urban trees need to live for at least 5–10 years before their initial planting and ‘maintenance’ embodied carbon is paid back.