Valuing Non-Woodland Trees

Economics Socio economic research

Forest Research and Defra have made the first estimate of the monetary value of non-woodland trees in the UK.

This work helps us to understand the overall value of our treescape, in which non-woodland trees play a critical role.

Non-woodland trees are:

single trees in urban and rural places,
groups of trees covering less than 0.1 hectares, and
small woods covering less than 0.5 hectares.

There are an estimated 0.74 million hectares of non-woodland tree canopy cover in Great Britain, and a further 31 thousand hectares in Northern Ireland.

This work is part of the Future Proofing Plant Health Defra Network partnership. The final report is available to download at the bottom of this page.

Research objectives

This project aimed to provide the first estimate of the economic value of non-woodland trees (also called trees outside woodlands) in the UK.

The valuation will be useful to policymakers in considering where to allocate resources, in making decisions, and in the preparation of future policies.

Findings and Recommendations

We estimate the total annual value of the UK’s non-woodland trees to be between £1.39 billion per year and £3.83 billion per year, in 2020 prices.

Using the 100-year Net Present Value method we have calculated the Natural Capital Value of non-woodland trees to be between £68.5 billion and £151.5 billion, in 2020 prices.

The valuations can be updated as new data about the extent of non-woodland trees becomes available.

This study considered some ecosystem services that are not currently included in the UK natural capital accounts (NCA). For example, avoided runoff provided by trees in urban areas could be included in future NCA evaluations.

Trees provide a host of social and cultural values. Many of these have not been monetised, and those that have relate mainly to woodlands. Social and cultural benefits were therefore not included in this study. Future work building on this research could add in these benefits when their monetary value is better understood.

Approach

Eight tools were reviewed for their suitability for this project. From these we selected:

i-Tree Canopy,
Capital Asset Valuation for Amenity Trees (CAVAT) and
woodland Natural Capital Accounting (NCA) benefit transfer methodologies

These three tools enabled us to calculate the provision of these ecosystem services:

carbon storage
carbon sequestration
air pollution removal
temperature regulation
noise reduction
avoided runoff
flood mitigation
amenity

The benefits from these services include:

climate change mitigation
increased productivity
amenity
reduced damage to human health
reduced damage to buildings
reduced damage, injury and disruption from floods
reduced waste water treatment
reduced energy consumption for air conditioning
reduced sleep disturbance and annoyance

We used the Forestry Commission’s 2017 Tree Cover Outside Woodland dataset as our source of non-woodland tree coverage.

For each method we designed a logic chain. Each logic chain includes:

the extent of non-woodland tree coverage,
the provision of ecosystem services per hectare of tree cover,
the value of the benefits from the ecosystem services, and
assumptions and uncertainties.

We followed HM Treasury Green Book guidance for benefit valuation, and we considered stocks (static values), annual flows, and 100-year Net Present Values.

Limitations

This work considers a limited set of ecosystem services provided by non-woodland trees. We did not consider social and cultural values because very few of these have been monetised.

There is very little data about the extent and type of non-woodland trees in the UK. Trees in different places provide different benefits, and therefore have different values. Where possible we have used regional tree canopy cover and ecosystem service provision. We have reported values per hectare of non-woodland tree cover, and per theoretical tree. It is important to note that this work does not replace an in-depth study of a local tree population and the benefits it provides.

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