by CF Fang, DL Ling
Landscape and Urban Planning 63:187–1952003
Despite several decades of proposals to use vegetation as a means of noise reduction, there exist few specific guidelines on how to plant the trees to maximize noise reduction. The current study explored the effect of evergreen-tree belts on noise reduction; and examined how factors such as height and density of the tree belts affected noise reduction. A point source was placed in front of the tree belts at discrete points and then a noise meter was used to capture noise levels. Results indicated that noise reduction was primarily associated with the visibility, width, height and length of the tree belts. Comparing the assortment of 35 vegetation belts studied, shrubs were found to provide the best noise reduction due to scattering from their dense foliage and branches. Since most shrubs were low and the trees had little foliage with scarce branches, researchers recommend shrubs be planted under trees. This planting strategy allows both the benefits of shrubs and trees to be utilized, enabling tree belts to more effectively reduce noise levels.