Shortlisted for the Georgina Mace Prize 2024
Nancy Burrell gives an insight into her team’s study investigating how carbon storage is measured and valued in rewilded landscapes.
About the Research
Overview
Our research dives into a critical blind spot in carbon accounting—how we measure and value carbon storage in rewilded landscapes. While tree planting is often championed as the go-to climate solution, natural regeneration and scrubland ecosystems remain undervalued in carbon markets. Using the Knepp Estate as a case study, we tested whether widely used models, like i-Tree Eco, accurately capture the true carbon storage potential of rewilded ecosystems. We found that they fall short—especially when it comes to below-ground biomass. Our work aims to reshape how rewilding is recognised in climate policy and carbon offset schemes.
Surprises and challenges
One of the biggest surprises in our research was discovering that current carbon accounting methods vastly underestimate below-ground carbon storage—by up to four times! We found that rewilded scrubland stores as much, if not more, carbon in its roots than in its above-ground biomass. This revelation challenges conventional thinking about carbon storage and has major implications for how we value rewilding in climate strategies, particularly regarding root and soil carbon sequestration.
Excavating and measuring the root systems was a formidable task, not only due to Sussex’s infamous clay and wet English weather but also because of the sheer number of trees we sampled—270 in total! To avoid damaging the delicate roots, we used compressed air to blast the soil away, which was both highly effective and an intense process.
Next steps and broader implications
The next step is to build on this foundation by developing species-specific allometric equations tailored to rewilded landscapes. Current models rely on data from traditional forestry, which doesn’t account for the unique growth patterns of rewilded scrub. By creating a more accurate way to estimate both above- and below-ground carbon, we can ensure that rewilding is fully recognised in natural capital frameworks. This will help integrate rewilding into carbon markets, policy strategies, and conservation finance—ensuring its immense climate and biodiversity benefits are properly valued and incentivised.
This has implications for policy, as our findings challenge the very foundation of existing carbon accounting frameworks. By revealing that rewilded landscapes may store significantly more carbon than previously recognised, our work strengthens the case for rewilding as a cornerstone of climate mitigation. Without accurate assessment methods, vast reservoirs of below-ground carbon in rewilded ecosystems risk being ignored in policy and financial mechanisms. Our research lays the groundwork for integrating rewilding into natural capital markets and carbon offset schemes, ensuring that its full ecological and economic value is recognised, incentivised, and scaled up as a critical climate solution.
About the Author
Getting involved in ecology
I was all set to study history at university. Then I took a gap year and, because I love diving, I volunteered on a coral reef conservation project in Cambodia. What I saw completely changed my path. On the surface, everything looked pristine—glassy blue seas, thriving mangroves—but just below lay biological dead zones. That stark contrast was a wake-up call, making me realise how much environmental destruction goes unnoticed. Determined to understand these hidden processes, I returned to the UK, went back to school to study maths and science A-levels, and enrolled on the MSci marine biology course at the University of Southampton. I’ve never looked back!
Current position
Having recently completed my DPhil, I now have more time to focus on my startup. I co-founded the Argosaronic Environment Foundation (AEF) in 2021 and currently serve as Chair. AEF supports local environmental initiatives to protect and restore the Argolic and Saronic Gulf regions in the Aegean Sea, Greece. Having spent summers in this area, I have witnessed first-hand the impact of overfishing and pollution. AEF funds projects to enhance marine conservation and climate resilience, including a study I supervise at the University of Oxford, where a master’s student is investigating seagrass meadows and the effects of fish farms on these vital ecosystems.
In addition, I recently joined a research project in the Department of Biology at the University of Oxford, studying the influence of local vegetation on mosquito feeding behaviour. Funded by the Innovative Vector Control Consortium (IVCC), the project explores whether vegetation in study sites in Benin and Kenya affects the efficacy of Attractive Targeted Sugar Baits (ATSBs)—a novel mosquito control method designed to reduce malaria transmission by targeting Anopheles species. While my background is in marine biology and rewilding, this role allows me to apply ecological principles to global health challenges, particularly in mosquito-borne disease control. This shift underscores the interconnectedness of ecosystems, climate, and public health, making it an exciting and impactful endeavour.
Current research focus
My DPhil thesis expanded on the discoveries from this paper, asking: What is the carbon storage potential of scrubland created by rewilding? Over four years, we set out to tackle one of the biggest knowledge gaps by conducting the largest destructive sampling project of scrubland on record. We excavated 270 trees—roots and all—across five different scrub taxa. This dataset provides the foundation for scrub-specific allometric equations, allowing us to build accurate carbon lookup tables and properly account for the carbon storage potential of rewilded landscapes.
Advice for fellow ecologists
Step back, watch, and trust in nature’s ability to heal itself. We’ve been conditioned to think conservation means control—planting trees in neat rows, managing landscapes to fit our expectations—but real recovery happens when we let go. Given time and space, nature will reassemble itself in ways more complex, resilient, and abundant than we could ever design. Scrub, brambles, and thorny thickets may look untidy, but they are the scaffolding of regeneration, the raw ingredients of future forests. Rewilding is about patience, humility, and learning to see beauty in the wild, unpredictable dance of natural processes.
Read the full article ‘The inadequacy of current carbon storage assessment methods for rewilding: A Knepp Estate case study’ in Ecological Solutions and Evidence.
Find the other early career researchers and their articles that have been shortlisted for the Georgina Mace Prize 2024 here!
