Valuing urban trees in Glasgow

Rumble, Heather; Rogers, Kenton; Doick, Kieron; Albertini, Angiolina; Hutchings, Tony

Abstract

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.

• Report Type: Technical Report
• Online Publication Date: Jun 1, 2015
• Publication Date: Jun 1, 2015
• Deposit Date: Apr 19, 2023
• Pages: 1-57
• Public URL: https://uwe-repository.worktribe.com/output/10634016
• Publisher URL: https://www.forestresearch.gov.uk/research/i-tree-eco/i-tree-eco-projects/i-tree-eco-glasgow/