Woodland Carbon Code calculator clarification: EIR release

Information requested

I work as a senior scientist at the James Hutton Institute. Part of my research is on forest and carbon sequestration.

With regard to this reply about carbon neutrality of forests,

https://www.gov.scot/publications/foi-202300383722/

could you please disclose the assumptions in the WCC calculator under which the figures reported were obtained? In particular , what soil carbon stocks and Sitka Yield Class were assumed? Although they might be correct in some places, there is growing scientific evidence that that estimate is optimistic in many other locations.

Response

As the information you have requested is ‘environmental information’ for the purposes of the Environmental Information (Scotland) Regulations 2004 (EIRs), we are required to deal with your request under those Regulations. We are applying the exemption at section 39(2) of the Freedom of Information (Scotland) Act 2002 (FOISA), so that we do not also have to deal with your request under FOISA.

This exemption is subject to the ‘public interest test’. Therefore, taking account of all the circumstances of this case, we have considered if the public interest in disclosing the information outweighs the public interest in applying the exemption. We have found that, on balance, the public interest lies in favour of upholding the exemption, because there is no public interest in dealing with the same request under two different regimes. This is essentially a technical point and has no material effect on the outcome of your request.

The following provides information on the assumptions you have asked about. Using the following example calculations in the woodland carbon code calculator, if you take the Sitka spruce clearfell at year 40 tab, the project is assuming Sitka spruce grows at yield class 20, and ground has been prepared by a ‘low disturbance’ method including hinge mounding or patch scarification, then the woodland creation is net positive by year 15 on organomineral soil and net positive by year 5 on a mineral soil.

To find out more about the assumptions for soil carbon and ground disturbance, see this paper which was written in collaboration with several soil scientists, including input from the James Hutton Institute.

For further background information and to download and conduct your own analysis with the Woodland Carbon Code calculator see this page.

If you have any feedback or comment on the way we account for soil carbon loss or gain in the Woodland Carbon Code, please contact vicky.west@forestry.gov.scot. We appreciate your input.

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