With human activity threatening to take global warming to levels that could create ever more severe weather events, the ability of forests to remove large amounts of carbon dioxide from the atmosphere is coming sharply into focus. Of course, trees have been sequestering carbon since the first trees appeared on planet Earth around 400 million years ago. However, growing anxieties over climate change are now highlighting the positive role that forests and investment in our woodlands can play. 

Back in 2011, the Scottish Government introduced the Woodland Carbon Code (WCC), a scheme administered by Scottish Forestry, but available UK wide. The scheme provides the owners of new woodland planting projects with a way of calculating the total carbon sequestration capacity of their woodland over its full lifecycle. 

Emma Kerr, Carbon Manager at Scottish Woodlands, one of Scotland’s largest forest management businesses, explains how the scheme works and why it is of great interest to investors and landowners. “There has been a huge acceleration of interest in carbon sequestration over the last few years and this interest, along with the WCC, has really created a new niche in the forestry business,” Kerr comments. 

There is quite a bit of consultancy work required when a landowner or an investor wants to register a new woodland planting with the WCC. As Kerr explains, working out the carbon calculation over the prospective lifetime of a new forest has a number of moving parts to it. “We need to factor in the type of ground preparation as well as any fencing and road construction work that may be involved in the project. Then we record the species of trees that will be planted along with the initial tree spacing, or ‘stocking density’ of the forest. We also take into account the anticipated yield class of the tree crop and what the management plans are for the forest. All these elements are recorded in the WCC calculator which has been developed by Forest Research (FR).”

This is the research agency of the Forestry Commission and is the UK’s principal organisation for forestry and tree-related research. It is an internationally renowned institution, providing scientific research and evidence-based data and services in support of sustainable forestry. 

The WCC is also independently endorsed by ICROA, the International Carbon Reduction and Offset Alliance. The carbon fixing capacity of the new woodland can be traded; thus the carbon value can create an additional source of revenue for the forest owner, over and above the value of the timber itself.

This valuable incentive is helping to encourage landowners to plant more woodlands, which must happen if the UK is to meet its ambitious carbon reduction targets. “Generally, if we are looking at a new woodland that is going to be predominantly planted with commercial conifers, say Sitka spruce, we’d be anticipating a carbon project life of around 35 years. Once the trees are harvested, a clear fell cap is applied representing the maximum carbon sequestration value,” she explains. Native broadleaf trees are considerably slower-growing, so the amount of carbon being fixed by a broadleaf plantation will plateau at around 65 years.  As an indication, a typical carbon yield, measured as a tonne of carbon dioxide equivalent, for a hectare of conifers would be between 120 and 150 tonnes of CO2 equivalent, over the 35-year lifespan of the tree crop. 

A native broadleaf woodland will sequester about 350 tonnes of CO2 equivalent per hectare over an average 65-year project. “Each site is specific and has different ingredients in terms of ground preparation, fencing and road access, as well as a unique management regime. The planting plan will also be unique to the site, but these are the kinds of typical carbon yields we can expect,” Kerr says. Of course, if we look at the overall contribution a woodland makes to the environment, there are a number of other ecosystem services which forestry provides.  

Flood attenuation, bio-diversity improvements, recreation and employment all make a positive contribution to the wider environment. Kerr points out that once a woodland is validated on the WCC, a case study can be written that highlights these wider benefits which in turn can increase the profile of the project and enhance the value of the carbon.

“When you register a project with the WCC it generates two types of carbon units, both of which are of interest in the general carbon market. The first units are pending issuance units (PIUs), which are the predicted number of carbon units a project is expected to sequester over the lifetime of the project. 

These units can be traded to offset future UK based emissions at whatever date in the future the units mature. But they cannot be used to offset a company’s current emissions or indeed, any of its emissions before the maturation of the units. The other type of unit issued is verified woodland carbon units (WCUs). The project must be independently verified at year five and every 10 years thereafter. 

At each verification a certain number of those PIUs are converted to WCUs and they can be immediately used to offset UK based emissions. The sale of carbon units creates a legal burden on the forest property over the full lifespan of the forest. This requires careful consideration by any landowner considering this additional income stream. 

The WCC is a complicated scheme and each project must prove it is not economically viable without the additional money brought in via the sale of carbon units.  However, the WCC provides the platform to recognise the  carbon sequestration value of forestry, which then supports new woodland creation that contributes to UK Net Zero goals. 

For more information visit www.scottishwoodlands.co.uk