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3.3 Project carbon sequestration


  • Emissions resulting from the preparation of a site prior to planting, shall be calculated and subtracted from the project carbon sequestration at year 1.  This includes losses of carbon through removal of vegetation (trees or other biomass) or disturbance of the soil.
  • Project developers shall use the relevant template WCC Carbon Calculation Spreadsheet (Standard or Small Project) to predicte the project carbon sequestration.
  • Carbon sequestration in woodland biomass shall be restricted to the long-term average carbon stock that is projected to accumulate on the site.

The prediction of project carbon sequestration is checked at validation.  It may be re-assessed at verification if there are changes to the management or growth rate/health of trees.

What is 'project carbon sequestration'?

Project carbon sequestration is the changes in carbon stocks due to woodland creation over the project duration as a direct result of the project.

This page outlines how to predict changes to carbon stocks that will occur over the duration of the project.  The Monitoring section explains how to assess actual carbon stocks later on in the project once the trees are growing and carbon has been sequestered.

Project developers should bear in mind when agreeing to sell PIUs that the tools here provide a prediction of the carbon that is likely to be sequestered, and not a guarantee that a particular woodland will sequester a certain amount.


Accounting for project carbon sequestration

Projects should account for project carbon sequestration using the WCC Carbon Calculation Spreadsheet following the associated Guidance.  The calculator includes the following:

  • Emissions from establishment activites, ongoing management and clearfell. 
  • Emissions from soil disturbance
  • Sequestration in tree biomass, litter and deadwood (and in a limited number of scenarios, soil)

SMALL PROJECTS (5 hectares net planting or less): Should use the 'Small Project Carbon Calculator' which is simpler to complete, and conservative.  Projects using this prediction tool can use the less intensive 'Small Project Monitoring Protocol' from year 15 onwards.

STANDARD PROJECTS: Should use the 'Standard Project Carbon Calculator'.

Vegetation removed at start of project 

If any vegetation is removed prior to the start of the project, this should be accounted for (both tree and non-tree biomass).  Projects can contact us for further information on estimates of the carbon stocks of non-tree biomass; they can also refer to the IPCC 2003 Good Practice Guide for Land Use, Land-Use change and Forestry and the IPCC 2006 Guidelines for national GHG inventories for guidance on estimating the carbon stock of existing vegetation. 


Carbon in the soil

Soil Carbon and the Woodland Carbon Code sets out the methodology for Organomineral and Mineral soils.  The WCC Carbon Calculator includes assumptions about the likely soil carbon disturbance.  Alternatively, projects can make a soil carbon assessment prior to tree planting with repeat assessments as the project progresses.

Soil carbon accumulation can currently only be claimed for projects on a mineral soil where the previous landuse was arable or rotational grass and the woodland will be managed as minimum intervention.  This is included within the WCC Carbon Calculator.


Future developments

  • Non-tree biomass:  We will publish estimates of the carbon stock of other types of non-tree vegetation.
  • Tree biomassWe will develop our Carbon Calculator to include a wider selection of spacings, and to account for the carbon stored in roots and stumps when clearfelling.
  • Soil.  There will be a number of developments:
    • We will update the soil carbon methodology using results of ongoing research.  This will allow us to say with more certainty both the amount of soil carbon lost on woodland establishment as well as the rate of accumulation of soil carbon as the woodland grows and matures.
    • We will establish a soil carbon assessment protocol to enable projects to consistently assess the soil carbon content of their soil. 
    • Ongoing research will help us better understand the changes to soil carbon due to woodland creation and management


Last updated: 8th March 2018