What is the Woodland Carbon Code?

Quick Answer: The Woodland Carbon Code is the UK government-backed quality assurance standard for woodland creation projects that generate independently verified carbon credits. Delivered by Scottish Forestry on behalf of the UK, Scottish, Welsh and Northern Irish governments, it sets out the requirements projects must meet to produce carbon units that companies can use to report against their emissions. As of August 2025, validated projects have created 38,705 hectares of woodland and are predicted to sequester over 13 million tonnes of CO2 equivalent over their lifetimes.

What is the Woodland Carbon Code?

The Woodland Carbon Code is the UK's quality assurance standard for voluntary woodland creation projects that remove carbon dioxide from the atmosphere. Launched in 2011 by the Forestry Commission and now delivered by Scottish Forestry, it sets out the principles, methodology, and requirements that a project must meet to generate high-integrity carbon credits.

The code is backed by government and endorsed by the International Carbon Reduction and Offset Alliance (ICROA). It also aligns with the UK Forestry Standard, BSI's Nature Investment Standards, and the Integrity Council for the Voluntary Carbon Market's Core Carbon Principles, giving it credibility across both domestic and international carbon markets.

Organisations accredited to ISO 17029 by the UK Accreditation Service independently validate and verify projects registered under the code. This independent oversight is what separates Woodland Carbon Code credits from unverified carbon offset claims.

What are Woodland Carbon Units?

The code produces two types of carbon units, each serving a different purpose.

Woodland Carbon Units (WCUs) represent one tonne of CO2 equivalent that has already been removed from the atmosphere by a registered project. They are independently verified and guaranteed. Companies can use WCUs to report against UK-based emissions or to support net zero claims.

Pending Issuance Units (PIUs) are forward-looking. They represent a promise to deliver a Woodland Carbon Unit in the future, based on an independent validation of predicted carbon sequestration. PIUs allow companies to plan ahead and commit to compensating future emissions before the carbon has actually been removed.

Both unit types are recorded on the UK Land Carbon Registry, managed by S&P Global, which stores data on all Woodland Carbon Code and Peatland Code projects, including the ownership and transfer of carbon units.

How does carbon measurement work under the code?

Before a project can generate carbon units, it must establish a baseline scenario: a projection of how carbon stocks on the site would change over the project duration if no woodland creation took place. This baseline accounts for four carbon pools: tree biomass (above and below ground), litter and deadwood, non-tree biomass, and soil carbon.

The project then calculates net carbon sequestration by measuring the difference between what the woodland will sequester and what the baseline scenario would have produced. This approach means the code credits only genuinely additional carbon removal.

Projects carry out carbon calculations using a standard spreadsheet tool provided by the code. Projects predict changes in carbon stocks over the full project duration, which can run up to 100 years. Verification begins at year five and repeats every ten years, confirming that the woodland is performing as predicted.

The code is deliberately conservative. It includes buffers to account for unexpected events such as disease or storm damage, and it does not credit carbon stored in harvested timber or the substitution benefits of using wood products in place of higher-carbon materials.

What does a Woodland Carbon Code project require?

To register a project under the code, a project developer must meet several requirements.

• Register the project on the UK Land Carbon Registry, including location, mapping, and carbon calculations
• Meet national forestry standards to confirm the woodland is sustainably managed
• Produce a long-term management plan covering the full project duration
• Use the standard methodology for estimating carbon sequestration
• Demonstrate additionality: that the carbon benefits would not have occurred without the project

Additionality is a central requirement. The code does not generate credits for activities that would have happened anyway, for example where woodland creation is already the most commercially attractive land use, or where restoration is required by law.

Once validated, a project can sell Pending Issuance Units. Once verified (from year five onwards), it can sell Woodland Carbon Units that support net zero and carbon neutrality claims.

Why does the Woodland Carbon Code matter for businesses reporting on emissions?

For companies working to measure and reduce their carbon footprint, the Woodland Carbon Code is the benchmark for assessing the quality of UK woodland carbon credits. Buying units from a registered project gives a company confidence that the carbon removal is real, additional, independently verified, and recorded on a public registry.

This matters because not all carbon credits are equal. Credits from projects without independent verification or a public registry entry carry significant reputational and reporting risk, particularly as scrutiny of corporate net zero claims increases.

The code is compatible with several grant funding schemes, which means projects can combine public funding with carbon credit revenue. A native woodland can sequester 300-400 tonnes of CO2 equivalent per hectare by year 50, and 400-500 tCO2e per hectare by year 100, making well-managed woodland creation one of the more substantial nature-based carbon removal options available in the UK.

For sustainability managers and operations leads building out their company's carbon reporting, understanding which offset standards carry genuine credibility is part of getting the numbers right. Seedling's approach to carbon accounting is built on the same principle: that data quality and methodological rigour matter more than a quick headline figure. When evaluating woodland carbon credits as part of a broader net zero strategy, the Woodland Carbon Code is the standard to look for.

The code also sits alongside the Peatland Code, which applies the same quality assurance principles to peatland restoration projects. Together, they form the foundation of the UK's voluntary land carbon market, and the UK Land Carbon Registry now consolidates both.