iTree Bristol Background
iTree Eco 6 Context
iTree Eco has been widely and successfully used in the USA and is a robust valuation model for the range of environmental services provided by trees. In Britain, it was first used in Torbay in 2011, with its application quickly widening and informing tree care budgets and investment decisions in 16 cities including Edinburgh, Glasgow, London and Manchester. The latest version (iTree Eco 6) generates an even wider range of data on the environmental services provided by an area’s trees.
iTree Bristol Context
iTree Bristol was delivered by the Forest of Avon Trust, who helped fund it along with partners Bristol City Council, the Woodland Trust, and the Forestry Commission. An important part of the brief for the work was that the survey should be undertaken by volunteers and along with Talking Trees: Bristol (run through summer 2018), it should help raise awareness of trees across the city, building interest in Bristol's trees and underpinning the forthcoming Action Plan for Bristol’s Urban Forest (Tree Strategy).
iTree Bristol Survey
Using the latest iTree Eco 6 model, the survey ran between May and September 2018. 29 volunteers took part, recruited by the Forest of Avon Trust and through the Talking Trees: Bristol campaign. A total of 201 randomly generated 0.04ha plots were surveyed across the administrative area of the city in this period, the majority being undertaken by volunteers, supplemented by Anna Brunton (Forest of Avon Trust).
iTree Bristol Report
The documents which can downloaded above summarise the main findings of iTree Bristol report, adapted to make use of the latest UK data.
The full report can be provided on request.
Please note that whilst iTree Eco 6 has been adopted by at least 16 cities in the UK and makes extensive use of UK data, it is a U.S. model and as such our promoted findings differ in the following ways from the full report. We:
- Use the latest (2018) UK values adopted by HM Government for avoided run-off, carbon dioxide storage & capture, and pollution capture, which have been by calculated by consultants Treeconomics, using iTree Bristol base data. This is line with best practice for other recent UK iTree studies.
- Use the most recent (2018) average annual UK car emissions and mileage to calculate comparator values for carbon dioxide storage and capture by Bristol’s trees. The age profile of vehicles in Bristol is not known and emissions may be higher.
- Use the avoided run-off figures for trees only, so the figure is lower than in the report. This is to maintain comparability with other findings. Precipitation data comes from the UK climate station closest to Bristol (within iTree Eco 6); the model has also been run with alternative UK precipitation data to check the validity of findings. We aim to run iTree Bristol with a new dataset for Bristol in 2019, although avoided run-off is unlikely to be significantly different.
To request a pdf of the full iTree Bristol report and/ or to ask any questions about the study, please email: Jon Clark