Control of noise by trees arranged like sonic crystals

In this paper, we demonstrate that it is possible to improve the sound attenuation obtained from a mass of trees by arranging them in a periodic lattice. The outdoor experimental results have shown that the largest sound attenuation, within a certain range of frequencies, was obtained for a range of frequencies related to the array periodicity. This behaviour induces us to believe that these arrays of trees work like sonic crystals. The sound attenuation values obtained in outdoor experiments for some periodic tree configurations, especially at low frequencies (f<500Hz), were far higher than those obtained from a typical green belt or forest. Therefore, these periodic arrays could be used as green acoustic screens.