This page provides guidance on the UK benefits prices for the reporting phase of an i-Eco Tree survey. Full guidance on project set up, fieldwork and reporting is available in the i-Tree Eco manual, available as free download from www.itreetools.org/resources/manuals.php. Details of UK training for i-Tree Eco are available from https://www.trees.org.uk/.
Reporting your i-Tree Eco survey should include the following stages:
- Ensure all data is entered into the i-Tree Eco programme. If this was done manually, having used paper field-survey sheets, perform a Quality Control exercise by re-opening 10% of the plots within the i-Tree Eco programme and checking that the information has been entered correctly.
- Follow the i-Tree Eco manual instructions to generate your ‘urban forest structure’ results.
- Follow the i-Tree Eco manual instructions to generate your ‘ecosystem service provision’ results. Ecosystem services are reported as both quantities of provision (for example, tonnes of carbon stored, tonnes of particulate air pollution removed, volume of stormwater intercepted) and as an economic value (in US $ or GB £). Default values for UK Benefit prices are built into i-Tree Eco V6, where possible. Where these are not reported or where you intend to use a more up to date or locally specific value, a Benefit price can be entered and the report re-run. Guidelines on Benefit prices are given below.
- Collate outputs as an interim report with headline figures for discussion with project partners.
- Produce final report.
UK Benefit prices and data sources
- Pollution removal value: Calculated based on the UK social damage costs (UKSDC) (available from www.gov.uk/guidance/air-quality-economic-analysis). These figures were last updated in September 2015 and are periodically revised. UK pollution values are source and location specific, for example, the UKSDC of pollution in Central London is greater than that for a town in the north east of England. Depending on the location of your project you may want to select the appropriate damage costs. The default values for the UK within i-Tree Eco V6 are as follows:
- £955 per metric ton NOx (oxides of nitrogen - UKSDC)*
- £1,663 per metric ton SO2 (sulphur dioxide - UKSDC)*
- £(n/a) (domestic sources) £73,261 (industrial sources)* per metric ton PM10 (Particulate matter less than 10 microns and greater than 2.5 microns – UKSDC; Government guidance also includes values for other sources (click here to view the source).
- The 2015 values for the UK are as follows:
- £14,646 per metric ton NOx (oxides of nitrogen - UKSDC)
- £1,956 per metric ton SO₂ (sulphur dioxide - UKSDC)*
- £33,713 (domestic sources)* £30,225 (industrial sources)* per metric ton PM10 (Particulate matter less than 10 microns and greater than 2.5 microns – UKSDC; Government guidance also includes values for other sources).
- UKSDCs are not currently available for carbon monoxide (CO), ozone (O₃) or PM2.5 (particulate matter less than 2.5 microns). Therefore, US externality cost prices (USEC) for pollutants are reported in i-Tree Eco.
- Carbon storage and carbon sequestration values: Calculated from a baseline year of 2014 and the respective 2014 DECC (Department of Energy and Climate Change) per metric ton value (the social cost of carbon). The default value in i-Tree Eco v6 value is £57*, it is updated by DECC every year. The 2016 value is £60* (click here to view the source). In the UK carbon is report using CO2 equivalence; this is achieved by mulitplying i-Tree's carbon value by 44/12.
- Stormwater alleviation value: Calculated based upon the amount of water held in the tree canopy and re-evaporated after the rainfall event (avoided runoff) and not entering the water treatment system.
The cost of treating surface water runoff avoided is not reported directly by water treatment companies in the UK. Typically, FR led projects have inferred a value as the standard volumetric rate per cubic metre charge (i.e. the cost of removing, treating and disposing of used water including a charge for surface water and highway drainage) minus the standard volumetric rate–surface water rebated per cubic metre charge (i.e. the cost of removing, treating and disposing of used water).
For example, using Welsh Water’s 2015/16 prices, this calculates as £1.6763 - £1.3238 = £0.35 per m3 (i.e. the cost of managing surface water, or the surface water rebate charge).
However, this cost is a conservative estimate of the total ‘avoided charges’ across the full survey area as it does not account for infrastructural, operational and treatment charges linked to surface water management by local authorities, internal drainage boards and government. Therefore, the Bridgend County Borough Council and Tawe Catchment i-Tree Eco studies used the ‘Standard volumetric rate – Surface water rebated per cubic metre value’ of £1.3238 as a representative value of the avoided cost of treating surface water runoff across the whole survey area. These are charges common to water utility companies, published annually.
Use values from the water utility company operating within your study area for reporting your i-Tree Eco project.
Other projects, for example the London Victoria BID and Sidmouth, have used the Energy and CO2 emissions savings from reduced volume of stormwater entering combined sewers and water company information on site area charges for surface water drainage. These figures are not available from a single source nationally. They need to be calculated depending on the water utility company operating within the area of the project.
- Building energy saving value: Domestic and Commercial average and regional UK costs are published by DECC and are update annually. The default values in i-Tree Eco v6 are set at £152.0 per MWH and £14.24 per MBTU. The values for 2016 are £147.6 per MWH and £13.57 per MBTU (click here to view the Source).
- Replacement Cost: This is termed ‘structural value’ in the US and within i-Tree Eco, however the term has a different meaning to economists in the UK and so ‘replacement cost’ is used.
This is the cost of the trees based on the physical resource itself (e.g. the cost of having to replace a tree with a similar tree), the value is determined within i-Tree Eco according to the CTLA (Council of Tree and Landscape Appraisers) method and the value is reported in UK £.
Funders and partners
This work was funded by the Forestry Commission. Our partners were the Arboricultural Association, Treeconomics and the US i-Tree Co-operative.
Forestry Commission policy
Climate change represents a significant threat to urban infrastructure, environmental quality and the health of city dwellers. Green infrastructure is itself at risk through greater extremes in temperature fluctuation, consequent flourishing of tree pests and diseases, drought and perceived increased risk of subsidence leading to tree removal.
There is no clear system for determining the biophysical interactions, benefits, or managing potential trade-offs within a risk-benefit context, so as to optimally support the protection and sustainable regeneration of UK towns and cities. The Urban Trees and Greenspace in a Changing Climate Programme intends to develop such a system through consolidating and building upon existing work to provide the evidence base for urban trees, definition and communication of best practice guidance, and robust assessment, evaluation and dissemination tools. This will enable society, policy makers and planners to more fully assess the risks and benefits of urban trees.
The Programme also maintains the Centre of Excellence which Forest Research has developed over several decades on land regeneration practices to establish and maintain urban greenspaces on former brownfield and contaminated sites.
This project is ongoing.