Effect of Vegetation on Noise Propagation in Streets and Squares

Vegetation as an essential positive sustainable element of urban spaces has recently gathered increased attention from landscape architects and urban planners. Vegetation growing in urban settings can bring environmental benefits that enhance the health and well-being of citizens through, for example, improved air quality, increased thermal insulation for buildings, reduction of the urban heat-island effect, and alleviation of storm water runoff. There are plentiful opportunities for the application of vegetation to urban streets, squares, roofs and roadside courtyards. In the context of urban streets, belts of trees, bushes and seasonal flowers represent the common vegetation usually grown on the edges of roads. In urban squares these can be extended to patches of grass, green spaces or small parks. Green walls are implemented in modern urban design. These include green facades which are made up of climbing plants growing either directly on a wall or, more recently, on specially designed supporting structures. Another type of green wall is the ‘living wall’ consisting of modular steel containers, geotextiles, irrigation systems, a growing medium and vegetation. Roadside courtyards may accommodate trees and bushes and their facades may be treated with green walls too. The application of modern green roofs, i.e. a system of layers including vegetation covering the top of a building, has also become popular in recent decades.