Valuing the urban trees in Bridgend county borough

Abstract

Urban forests provide a range of services, often termed ecosystem services, that help alleviate problems associated with urbanisation. Trees improve local air quality, capture carbon, reduce flooding and cool urban environments. They provide habitat for animals,and can improve social cohesion in communities. Ecosystem service provision is directly influenced by management actions that affect the overall structure of an urban forest.The first step to improve the management of an urban forest is to better understand its current structure, composition and distribution in order to obtain a baseline from which to set goals and to monitor progress. By measuring the structure of the urban forest (the tree species present, their size and condition), the benefits of the urban forest can be determined and the value of these benefits calculated and expressed in monetary terms.Valuing services provided by the urban trees in Bridgend County Borough (Bridgend CB) could allow Bridgend County Borough Council (Bridgend CBC) and Natural Resources Wales (NRW) to increase the profile of the urban forest thereby helping to ensure its value is maintained and improved upon. The Bridgend CB, as described in this study, is spread across 5 separate urban districts with a total area of 4,400 ha. In order to gain a better understanding of the urban trees in Bridgend CB and to value the services they provide, an i-Tree Eco survey was undertaken in the summer of 2014. i-Tree Eco is a model developed by the US Forest Service to measure a range of ecosystem services provided by urban trees. This study was funded by NRW and Bridgend CBC and the survey was carried out by Barton Trees. This report presents a baseline quantitative assessment of the air pollution removal, carbon storage and sequestration, rainfall interception and visual amenity of the urban forest of Bridgend CB, and is accompanied with detailed information on the forest’s structure and composition. Residents in Bridgend CB benefit significantly from the urban trees present, including the provision of ecosystem services worth £950,000 per year. This value, however, excludes many of the ecosystem services of trees that are mnot currently assessed by i-Tree Eco, including cooling local air temperatures and reducing noise pollution. Therefore, this value is a conservative estimate of the ecosystem services provided. This study captures a snapshot-in-time ‘picture’ of the urban forest. It does not consider how the urban forest has changed over time or the reasons for this. Decisions on how the structure and composition of Bridgend CB’s urban forest should change in the future or how to ensure that it is resilient to the effects of a changing climate are beyond the scope of this report, though this study goes a long way to providing the necessary baseline data required to inform such decision making

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