Urban Hedges as Noise Barriers: Does Plant Species Choice Affect Insertion Loss?

Webb, J.; Cox, T.; Blanusa, T.; Griffiths, A.; Umnova, O.

Abstract

Noise in urban environments is responsible for annoyance and adverse health effects. Noise barriers are used to mitigate noise and are effective when properly designed and installed, but provide little visual or biodiversity benefit. Hedges are frequently used as boundaries in urban spaces around parks and playgrounds, schools and gardens, and have been demonstrated to provide valuable ecosystem services (e.g. biodiversity support, flood mitigation, air quality improvement). This study aims to determine what sound attenuation is provided by hedges, and how that varies with plant species. The normal incidence insertion loss of vegetative parts of two hedge species commonly used in the UK, and with different canopy characteristics (crown density, leaf thickness and size) was measured. Tests were done on ëinstant hedges’ planted in grow-bags, in their winter state. Measurements were carried out in a hemi-anechoic chamber to provide controlled conditions. Insertion loss results are presented showing that evergreen Prunus laurocerasus provides a greater insertion loss than deciduous Fagus sylvatica. Losses are seen at mid to high frequencies only. The marcescent leaves of F. sylvatica are shown to provide some acoustic benefit compared with the same plant without leaves.

• Presentation Conference Type: Conference Paper (published)
• Conference Name: 10th Convention of the European Acoustics Association Forum Acusticum 2023
• Acceptance Date: Aug 7, 2023
• Online Publication Date: Jan 17, 2024
• Deposit Date: Feb 21, 2024
• Publicly Available Date: Feb 21, 2024
• Journal: Proceedings of the 10th Convention of the European Acoustics Association Forum Acusticum 2023
• Peer Reviewed: Peer Reviewed
• DOI: https://doi.org/10.61782/fa.2023.1152