Valuing the urban trees in Bridgend county borough

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

Valuing urban trees in Glasgow

Urban trees provide a range of services, often termed ecosystem services, that help alleviate problems associated with the high population densities found in urban areas. Urban trees improve local air quality, capture carbon, reduce flooding and cool urban environments. They provide food and habitat for animals, such as birds and bees, and can improve social cohesion in communities. Urban forests are, therefore, a valuable source of ecosystem services in towns and cities.Planning developments often overlook the value of urban trees, quantifiable or otherwise. Valuing the quantifiable services provided by trees in Glasgow could improve this and allow Glasgow City Council and Forestry Commission Scotland to increase the profile of the urban forest and ensure its value is maintained and improved upon. Valuing ecosystem services also aids town planners, landscape architects and tree officers to plan where trees can be planted for maximum benefit.An i-Tree Eco survey was undertaken in summer 2013 to value a number of ecosystem services provided by Glasgow City Council‟s trees. i-Tree Eco is a model developed by the US Forest Service to measure a range of ecosystem services provided by urban trees, from carbon sequestration to pollutant removal. The study was funded by Glasgow City Council and Forestry Commission Scotland and was carried out by Forest Research.Residents in Glasgow benefit significantly from the urban trees present, with quality of life improved by trees helping alleviate flash flooding and sewer blockages, providing cleaner air and supporting wildlife. Glasgow‟s urban forest also contributes significantly to the local economy, saving an estimated £4.5 million in services per year. This would be enough money to plant 2 900 medium sized oak trees in Glasgow and is comparable to the £4 million spent on the Glasgow 2014 Cultural Programme Open Fund, which provided cultural experiences during the Glasgow 2014 XX Commonwealth Games. However, this value only includes those ecosystem services currently assessed within i-Tree and omits a large range of other ecosystem services such as cooling the urban heat island and reducing noise pollution. This value is, therefore, likely to underestimate the true value of ecosystem service provision by Glasgow‟s trees.Glasgow has a high density of trees compared to other cities in England and Scotland. Canopy cover in Glasgow is also high compared to the average in England, but lower than in neighbouring Edinburgh. Glasgow had a higher proportion of large trees (60cm+) than all previous i-Tree studies conducted by Forest Research. However, a lack of medium sized trees puts this at risk in the future.Vacant land supports a significant number of trees in Glasgow, second only to parks. This could be a major consideration in development plans, particularly as vacant land is most likely to be developed. Development of this land would remove a significant portion of ecosystem services provision by trees and the mitigation of this should be considered.There may be up to 32% of Glasgow‟s urban space available to plant trees or shrubs. Planting a diverse range of tree species will improve the resilience of Glasgow‟s urban forest to pests and diseases and further improve the quality of life for Glasgow‟s residents by providing more ecosystem services