Investigation of tree characteristics for traffic noise abatement

Abstract

There is a connection between noise reduction and roadside tree plantation. Understanding how prop-erties of trees (density, height, leaf type, crown spread, etc.) impact noise attenuation is crucial. The current study measured and compared the roadside traffic noise at various locations (with/without trees/plantations) in selected Multan areas. Eight locations (Bahawalpur Road, Expressway, Vehari Road, Bosan Road, Eidgah Road, Masoom Shah Road, Piran-Gaib Road, and Khanewal Road) throughout Multan City. A digital sound level meter (MS-6701) was used to measure the noise levels during months of winter and summer seasons. During field visits, the tree type, leaf type, average height, density, canopy crown spread, and presence of any vegetation in each designated area were noted. The sound pressure data was compared with the noise level standards as recommended by Punjab Environment Quality Standards. A clear reduction in sound levels can be observed with trees. The tree plantings reduced the noise only on the Express-way (65 dbA) and Piran Gaib Road (64 dbA) in May 2022. In June 2022, the trees were only beneficial in reducing noise near Piran Gaib Road (64 dbA). Due to tree plantation, the maximum reduction of 11 dbA was reported in June 2022 at Eig Gah Road, followed by a 10.1 dbA reduction in December 2021 at Khanewal Road. Maximum noise reduction was observed at the Expressway and Piran Gaib Roads, where Pongamia pinata and Melia azedarach are planted along with some grass. The comparison clearly showed a reduction in noise due to roadside plantations. Tree plantation helps improve the area’s overall look and enhances aesthetic sense and scenic beauty.