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Woodlands provide a wide range of environmental and societal benefits, including several related to water. Prominent among these are the improvement of water quality, reduction in flood flows, and ‘water cooling’.

Forest Research has led a range of projects to increase knowledge about the water-related benefits of woodlands and to evaluate the costs and benefits of associated investments, including the Payments for Ecosystem Services (Forests for Water) COST Action, commonly referred to as PESFOR-W. This was an international research network that reviewed evidence on the ability of woodland creation to improve the freshwater environment, and on the governance and cost-effectiveness of woodlands for water payments for ecosystem services schemes.

The development of a Woodland Water Code (WWC) as a crediting mechanism to encourage private investment in trees for the improvement of the freshwater environment is a key action under the England Trees Action Plan (ETAP). This project, funded by the UK Government through Defra’s Nature for Climate Fund programme, aims to develop a novel WWC that is applicable across the UK.

The work is currently focused on the water quality elements of the Code, to help tackle the intractable issue of diffuse pollution (specifically nitrate-nitrogen, phosphorus, sediment, pesticides, and faecal indicator organisms). Attention will then turn to developing units for flood alleviation and water-cooling benefits provided by woodland creation.

This project is working closely with the well-established Woodland Carbon Code (WCC). A concept note for integrating the WWC with the WCC was approved by the WCC Executive Board in January 2023.

It is intended to be a voluntary code, with the potential to combine water, carbon and other co-benefits from woodland creation. The areas that may benefit from woodlands for water will be identified through a series of target maps.

Research objectives

The objective of the project is to research, develop, and undertake desk-based pilot testing of a UK-wide WWC for one or more water services by March 2025.

This is primarily a development project, drawing on a sound understanding of woodland water benefits. However, work will also address related research questions to inform the approach, including:

  • What are the strengths, weaknesses, opportunities and threats of alternative approaches to assessing the different water benefits?
  • How to account for woodland buffer design and management factors?
  • How do existing nutrient trading schemes treat woodland and what is the preferred option for designing credits for other water quality benefits?
  • Is there any evidence of significant ‘leakage’ of water-related benefits of tree planting and how should we best account for this?
  • How can the WWC and any associated new finance mechanisms be developed in a way that maximises additional private sector investment in woodland creation?

Latest updates

The methodology for quantifying the benefits of woodland creation for water quality is currently being finalised.

This will be followed by a number of desk-based pilots to test the water quality methodology alongside the development of flood alleviation and water cooling methodologies. Discussions are ongoing with our Steering and Technical Groups to ensure that the WWC is accessible and aligned with the most up-to-date information from across the UK.

A key challenge for the development of the WWC is understanding the voluntary market demand for water services. An initial market research phase is underway, focused on identifying the key concerns of potential investors in the WWC. Further engagement activities are planned for 2024 to assess the potential market demand, collect feedback on the draft Code and align with the emerging BSI standards framework for UK nature markets.

If you would like to learn more about the WWC, please contact

Frequently asked questions (FAQs)

Why is only woodland creation included, and not other habitat types?

Alongside a UK-wide target of 30,000 ha per year of woodland creation by the end of the current Parliament,[1] each devolved nation has set its own woodland creation targets. The aim of the Woodland Water Code (WWC) is to facilitate the quantification of the water benefits provided by woodland creation projects to increase private investment and further incentivise land use change. It is estimated that the gap in finance to meet the UK’s woodland creation goals between 2022 – 2032 is at least £1,800 million.[2]

There is an abundance of research that has evidenced the benefits of woodland to water, examples of which can be found in the Woodland for Water (2011) report, the payments for Ecosystem Services (Forests for Water) PESFOR-W (2016-2021) and IUFRO: Forests and Water on a Changing Planet. In addition to water, woodlands provide benefits such as carbon sequestration, biodiversity and improvements to health and wellbeing.

While our focus is on woodland, it is recognised that other habitat types, such as wetlands, also deliver water benefits. These are outside the project scope, however, the WWC team are interested in collaborations to explore whether the WWC could fit within a wider code, such as an overarching water code or land use change code. The team is working closely with the Woodland Carbon Code (WCC), which is currently considered the best option for integrating the WWC in the next two-three years. A wider code, whilst valuable, is expected to take much longer to develop.

The inclusion of agroforestry and other tree/ vegetation planting also remains outside the scope of the WWC, as this would complicate the quantification of water benefits (e.g. developing or modifying existing hydrological models) and the rules for key issues such as leakage and permanence. This aspect will be kept under review and considered for future refinements of the WWC.

Will the WWC be UK-wide?

The aim is to develop a UK-wide WWC. Representatives from all four devolved nations are on the project Steering Group, and discussions are ongoing to ensure the WWC is applicable across the UK.

How are water resources considered?

It is recognised that woodland creation presents a potential disbenefit for water resources, depending on a wide range of factors. Consequently, water resources are not part of the WWC, but instead considered under the regulatory process for woodland creation projects. Vulnerable areas have been identified and will be excluded if woodland creation is assessed as likely to further exacerbate the issue.

The World Resource Institute (WRI) has developed a Volumetric Water Benefit Accounting method for implementing and valuing water stewardship activities. Whilst this method does include reforestation, it does not provide a standardised methodology for quantifying the impact of woodlands on water resources, or a private finance mechanism tailored to woodland creation in the UK – which is the focus of the WWC project.

Will the WWC be applicable for both voluntary and regulatory/compliance markets?

The WWC is expected to be a voluntary Code at the outset, aligning with the WCC. However, the methodologies underpinning the WWC could be utilised in other markets. For example, the WWC team are working with Natural England to ensure the approach is consistent with Nutrient Trading in England.

The project team are also liaising with contacts in the Welsh Government and Natural Resources Wales to ensure consistency with developments in Wales on nutrient neutrality. It is recognised that some water companies are already working with farmers to undertake nature-based solutions to tackle water quality issues – some involving tree planting (e.g. see case studies).

In these instances, the WWC may not be required as a vehicle for financing woodland creation schemes but could provide a consistent methodology for assessing the water benefits for reporting purposes. For organisations outside the water sector with an interest in investing in woodlands for water, the WWC will provide both a methodology and investment opportunity.

Woodland creation can involve pesticide usage, including herbicides. How is this included in the water quality metric?

The Farmscoper model (version 5, 2021) developed by ADAS is used to calculate pollutant loads from the field/farm to the watercourse on an annual basis. Farmscoper estimates pesticide losses in dose units, which incorporates herbicides, fungicides, insecticides, molluscicides and growth regulators.

The number of sprayer applications used to apply some of these chemicals is also included. Pesticide values for arable land in Farmscoper’s calculations are obtained from the Pesticide Usage Survey Report of Great Britian 2005-2006 and averaged across a farm rotation. For woodland, pesticide values are not included. Unlike arable land, the use of pesticides in woodland is relatively uncommon and where needed, is usually limited to a few years after planting to achieve tree establishment, such as by controlling weeds or pests. Woodland is considered to have a rotation of 100 years, which is much longer than that of arable land (3-5 years). The combination of the very infrequent use of pesticides over this period and the spot treatment nature of applications means that losses to water are very small/negligible, especially when averaged annually. This is evidenced by targeted studies often  failing to detect the presence of pesticides in waters draining woodland.

As for all woodland creation projects, United Kingdom Forestry Standard (UKFS) requirements and guidelines will apply and should be checked as part of associated grant awards or for UK Woodland Assurance Standard (UKWAS) accreditation. [3],[4],[5]

What is a Woodland Water Unit?

Woodland Water Units will represent a new type of credit. They will be used to represent the quantified benefits provided by the created woodland for the three water elements included in the WWC (water quality, flood alleviation and water cooling). Woodland Water Units will be complex compared to carbon credits which use a common metric (greenhouse gas equivalent). Work to determine the appropriate metrics, timing, scale and format of the water credits is ongoing.

How will good woodland management practices be enforced?

Woodland management practices will follow the United Kingdom Forestry Standard (UKFS) regarding all aspects such as woodland design, establishment and water protection. The Woodland Creation Sensitivity Map, ground truthing, Environment Impact Assessments (EIA) and other requirements will be followed before woodland is approved and Woodland Water Units are generated to ensure existing priority habitats and species are not affected.

Who are the buyers of Woodland Water Units?

Market research is currently underway to identify potential buyers of Woodland Water Units through the WWC. Buyers include any company or organisation looking to invest in woodland creation with an interest in delivering water benefits. Initial market research has indicated a particular interest from companies/ organisations:

  • with a direct reliance on a supply of clean water (e.g. food and drinks industry and water companies);
  • impacted by flooding (e.g. insurance and reinsurance companies, local authorities and local communities); and/ or
  • involved in river restoration (e.g. Wildlife/ Rivers Trusts and Fishery Groups).


[1] Department for Environment, Food & Rural Affairs, England Tree Strategy Consultation, June 2020, p.6

[2] Green Finance Institute, The Finance Gap for UK Nature, October 2021, p.53

[3] G. Sellers, Forest Research (2014), Weed Control BPG Note 11: Best Practice Guidance for Land Generation, 2014.

[4] Forestry Commission (2019), Managing forest operations to protect the water environment, Forestry Commission Practice Guide.

[5] Forestry Commission (2004), Reducing Pesticide Use in Forestry, Forestry Commission Practice Guide.

Funding & partners
  • Defra - Nature for Climate Fund Programme
Table of Contents
Rosie Brook

Senior project manager

Forestry Staff Tom Nisbet Cropped 2.391c9c68.fill 600x600 1
Tom Nisbet

Science Group Leader

Forestry Staff Gregory Valatin.d744f2ef.fill 600x600 1
Gregory Valatin

Principal Economist

Romany Vassell

Environmental Scientist