The Allerton Project is a living, breathing research project in the shape of a 320ha mixed arable and livestock farm near Loddington on the border of Leicestershire and Rutland. Part of the Game & Wildlife Conservation Trust (GWCT), the Allerton Project researches a huge range of sustainable farming techniques, monitoring their effects on wildlife and the wider environment.

One of their latest projects is developing a Hedgerow Carbon Code (HCC).

Currently, carbon markets allow people to buy carbon credits which can be used for carbon offsetting or traded for money. The amount you pay for a carbon credit reflects the amount of carbon dioxide which is taken out of the atmosphere through habitat work, and the investment in these credits funds the habitat creation.

A carbon code is like a regulator for carbon markets, which helps provide reassurance for investors. A Hedgerow Carbon Code could raise the profile of the importance of hedgerows and their carbon sequestration potential for investors and help incentivise the creation of new hedgerows. As a critical habitat for butterflies and moths, a Hedgerow Carbon Code could provide a lifeline for many of our declining species.

Joe Stanley, Head of Sustainable Farming & Knowledge Exchange at the Allerton Project, shares his update from the project.

Through 2022-2023 the GWCT Allerton Project, a research and demonstration farm on the Leicestershire/Rutland border, undertook the development of a Hedgerow Carbon Code with funding from a Natural Environment Investment Readiness Fund (NEIRF) grant from Defra and the Environment Agency. The aim was to establish a credible means of quantifying and subsequently monetising the carbon sequestered within the approximately 800,000km (120,000ha) of hedgerows to be found across the UK, as well as in the many thousands of kilometres of newly established hedgerows to be established in the coming years by farmers and land managers.

It's thought that at present existing hedgerows store some 9m tonnes of carbon worth around £65m at today’s values, with a large hedge able to store approximately 60-80t of carbon per hectare in both aboveground and belowground biomass. The aim of the Hedgerow Carbon Code (HCC) is to encourage the better management of hedgerows and to bring an additional, novel income stream on-farm. By managing hedgerows for both nature (under agri-environment schemes) and for carbon (through the HCC) these invaluable features on the landscape might finally bring a reasonable level of income to farm businesses.

Additionality is key to any carbon scheme – that is, to qualify as a genuine carbon offset, the carbon taken out of the atmosphere through the project needs to be ‘additional’ to what would have happened without the project. Ironically, our own hedgerows at the Allerton Project, long managed to increase their size and density, have little to no scope to build additional carbon. It is farms which have maintained ‘tidier’, smaller hedgerows which stand therefore to benefit most from the HCC, alongside those who wish to plant new hedgerows – with pre-registration with the HCC being a requirement.

Hedges sequester carbon at twice the rate of woodland, and a doubling of the average dimensions of a hedge can quadruple the volume of carbon stored. By entering the dimensions and species mix of a hedge into the calculator developed by the NEIRF grant, users can generate a current and predicted future carbon value for their hedgerows. As with the existing Woodland and Peatland codes, the HCC is backed by government and maintained to strict national standards.

Better management of our hedge stocks is a highly desirable outcome of estate management in the coming decades; around 145,000km of the UK’s hedge stock is thought to be in a poor condition, with a further 26,000km of ‘relict’ status. Laying, coppicing and gapping up will be vital management measures to return more of this important habitat to good condition.

The HCC is now ready for launch, having been trialled by the Allerton Project on a number of farms which are part of the Kelloggs Origins project. To find out more, contact Natural Capital Advisory.

Joe Stanley
Head of Sustainable Farming & Knowledge Exchange, The Allerton Project

Find out more about hedgerows and how important they are for butterflies and moths here.