Sitka plantations and soil carbon: EIR release

Information requested

1. Has Scottish Government carried out an assessment of the amount of carbon sequestered by a Sitka spruce plantation versus the carbon released from Sitka plantation soils as a result of soil degradation?

2. If so, how long does it take for a Sitka plantation to become carbon neutral?

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.

1. Scottish Forestry has carried out assessments of the level of carbon sequestration - net of any soil emissions - for a wide range of woodland types including those that include Sitka spruce (under the UKFS, a new woodland can contain no more than 65% of a single species). These assessments are based on carbon models developed by Forest Research which are used for reporting net CO2 removals from woodlands in the UK’s GHG Inventory.

2. The time taken for a woodland to deliver positive net CO2 removals depends on a number of factors including the soil type, the techniques used for planting the trees, and the rate at which different species grow subsequently. The carbon calculator used for the Woodland Carbon Code shows that Sitka spruce planted on an organo-mineral will deliver net CO2 removals after 10-15 years, even with high levels of initial ground disturbance. Where trees are planted on mineral soils, net CO2 removals can be reported within 5 years.

3. It is important to examine which types of woodland can generate CO2 removals over different timescales. Recent analysis by Forest Research shows that faster-growing conifers can achieve the greatest rates of CO2 uptake in the period to 2050. Broadleaf woodlands begin to catch up later, and accumulate a large and permanent on-site store of carbon.

About FOI

The Scottish Government is committed to publishing all information released in response to Freedom of Information requests. View all FOI responses at http://www.gov.scot/foi-responses.