Paying farmers to create woodland and wetland is the most cost-effective way to hit UK environment targets, study suggests
Study of farmer preferences shows that turning whole areas of farmland into habitats comes with half the price tag of integrating nature into productive farmland , whilst delivering the same, biodiversity and carbon targets
Peer-Reviewed PublicationIncentivising farmers to restore some land as habitats for nature could deliver UK climate and biodiversity targets at half the taxpayer cost of integrating nature into land managed for food production, according to a new study published today in the British Ecological Society journal People and Nature.
This research is also being presented today at the British Ecological Society’s annual meeting in Edinburgh by Professor Nicholas Hanley, an environmental ecologist based at the University of Glasgow.
The research, led by the universities of Cambridge, Leeds and Glasgow, provides the first evidence for the taxpayer savings offered by focusing food production in certain areas to allow the creation of new woods, wetland and scrub habitats on some of the land currently used for farming.
The study suggests that this “land sparing” approach would cost just 48% of the funds required to achieve the same outcomes for biodiversity and the climate through an approach known as “land sharing”, where conservation measures get mixed into farming by adding hedgerows to fields, reducing pesticides, and so on – all of which lowers food yield.
Additionally, the researchers say that trying to share land with nature through making farming more wildlife-friendly would see the UK lose 30% more of its food production capacity than if farmers are encouraged to spare portions of land entirely for creating semi-natural habitats.
The UK government has legally binding commitments to reverse nature declines by 2030 and reach net zero carbon by 2050. Sparing land for habitats could hit these targets at half the cost of trying to farm on land shared with nature, say researchers.
“Currently, only a fraction of the £3.2 billion of public money annually paid to farmers goes on biodiversity and climate mitigation, some £600m a year,” said Lydia Collas, who led the study as part of her PhD at Cambridge’s Department of Zoology.
“Almost all this fraction of funding supports land-sharing approaches that may do little to benefit species or sequester carbon, but do typically reduce food yields. Until now there has been no research on whether this is the most cost-effective solution to delivering environmental targets.”
Cambridge’s Prof Andrew Balmford, senior author of the study, said: “Greater incentives for farmers to create woodlands and wetlands will deliver for wild species and climate mitigation at half the cost to the taxpayer of the land-sharing approach that currently receives ten times more public funding.”
The researchers say their findings – presented at the British Ecological Society’s annual meeting by study co-author Prof Nick Hanley, an environmental economist from the University of Glasgow – should inform the current Brexit-prompted rethink of England’s new Environmental Land Management Scheme (ELMs).
The researchers conducted a choice experiment study with 118 farmers responsible for 1.7% of all England’s arable land, asking them to estimate the payments they would require to implement land-sharing practices or habitat-creating “sparing” approaches on their land.
Farmers chose from a variety of agricultural approaches, nature interventions and, crucially, payment rates. The study also considered the government's costs of administering and monitoring these schemes.
The team used three bird species – yellowhammers, bullfinches and lapwings – as a proxy for effects on biodiversity, as well a range of ways farmers could help slow climate change, such as woodland and hedgerow creation.
On average, farmers in the experiment accepted lower payments per hectare for land sharing practices. However, habitat creation schemes deliver far greater environmental outcomes per hectare, so creating woodlands, wetlands and scrublands would deliver the same overall biodiversity and climate mitigation benefits at half the cost to the taxpayer.
“We found that enough farmers are willing to substantially change their business to benefit from payments for public goods in the form of habitats, provided the government rewards them properly for doing so,” said Balmford.
Collas, now a now a Policy Analyst at Green Alliance, added: “Existing evidence already shows that semi-natural habitats deliver far more biodiversity and climate mitigation per unit area, and creating them has far less impact on food production than meeting targets through land sharing.
“This evidence is dismissed when thinking about agricultural policy in the UK because of an untested assumption that farmers are unwilling to create natural habitat. We now have evidence showing this assumption is wrong.”
JOURNAL
People and Nature
METHOD OF RESEARCH
Survey
SUBJECT OF RESEARCH
People
ARTICLE TITLE
Paying farmers to create woodland and wetland is the most cost-effective way to hit UK environment targets, study suggests
ARTICLE PUBLICATION DATE
20-Dec-2022
UK woodlands could store almost twice as much carbon as previously estimated
Peer-Reviewed PublicationUK forests could store almost double the amount of carbon than previous calculations suggest, with consequences for our understanding of carbon stocks and humanity’s response to climate change, according to a new study involving UCL researchers.
For the study, published today in the journal Ecological Solutions and Evidence, the international team of scientists used a novel 3D scanning technique and analysis to assess the amount of aboveground biomass (AGB) - used to derive carbon storage - of 815 trees in a UK woodland. The team found that their results were 77% higher than previous estimates (410 t ha-1 of biomass vs 232 t ha-1).
The authors say that their study could have implications for the role of forests in tackling climate change, with the potential underestimation of forest carbon stocks having both positive and negative consequences for climate policy.
Study co-author Professor Mat Disney (UCL Geography and the National Centre for Earth Observation) said: “Forests currently act as a carbon sink in the UK. However, whilst our finding that the carbon storage capacity of typical UK woodland could be nearly double what we previously thought might seem like a purely positive outcome, in practice this means that for every ha of woodland lost, we’re potentially losing almost twice the carbon sink capacity we thought.
“This has serious implications for our understanding of the benefits of protecting trees in terms of climate mitigation - and deforestation and afforestation targets more broadly.”
The study was a collaboration between researchers from UCL, UK’s National Centre for Earth Observation (NCEO), the Universities of Ghent, Oxford and Tampere, The National Physical Laboratory, and Sylvera. To establish their findings, the team undertook 3D terrestrial laser scanning (TLS) analysis in a 1.4 ha section of Wytham Woods in Oxfordshire. TLS is a remote sensing technique whereby millions of laser pulses are emitted to capture the environment and structures of trees in the woodland in 3D.
They then used statistical modelling to calculate the mass and volume of the trees, and subsequently the carbon storage capacity of the area, and compared this to the findings of previous models.
The authors say that their study brings into question the certainty of estimates of forest carbon storage across the UK, particularly for the largest and most carbon-heavy trees, which are currently based on widely used models that estimate tree mass from the trunk diameter. It is likely that previous studies have been greatly underestimating forest biomass across the UK.
Study lead author Professor Kim Calders (Ghent University) said: “Currently, most estimates of forest carbon stocks are based on simple allometric models that assume that a tree’s size and mass increase at a steady rate. Our findings show that relying on these models is problematic, as they are not representative of UK forests. While the models work well for trees smaller than around 50 cm in diameter, which are fairly uniform in terms of their size and volume, this isn’t what we see for larger, heavier trees. These are far more complex when it comes to structure - and they vary hugely across place and species.
“It’s vital that we’re able to reduce uncertainty in forest carbon estimates, given that land use, and forest protection and restoration in particular, constitute a quarter of countries’ current commitments to their Paris Agreement targets.”
Currently, the UK’s biomass stock reporting to the Food and Agriculture Organization of the UN is based on these allometric models, which the authors say have very likely resulted in significant under-reporting.
Study co-author Yadvinder Malhi (Oxford University) added: “Wytham Woods belongs to the University of Oxford and has witnessed over 70 years of detailed scientific research. This research shows how new approaches can yield surprises in even well-studied forests, with profound consequences for our understanding of forests and their role in tackling climate change that apply across the UK and beyond.”
Notes to Editors
For more information or to speak to the researchers involved, please contact
Evie Calder, UCL Media Relations. T: +44 (0)7858 152 143 / +44 20 7679 8557 E: e.calder@ucl.ac.uk
Prof. Disney’s mobile number is 07788 577401 (m.disney@ucl.ac.uk).
Calders, K., Verbeeck, H., Burt, A., Origo, N., Nightingale, J., Malhi, Y., Wilkes, P., Raumonen, P., Bunce, R. G. and Disney, M. I. (2022), ‘Laser scanning reveals potential underestimation of biomass carbon in temperate forest’ will be published in Ecological Solutions and Evidence on Tuesday 20 December 2022, 05:01 UK time / 00:01 US EST and is under a strict embargo until this time.
The DOI for this paper will be: 10.1002/2688-8319.12197
The URL is https://besjournals.onlinelibrary.wiley.com/doi/10.1002/2688-8319.12197.
This work was funded in part by European Metrology Programme for Innovation and Research (EMPIR) through the Metrology for Earth Observation and Climate (MetEOC) program led by NPL, as well as the UK Natural Environment Research Council and NERC National Centre for Earth Observation.
Additional material
Paper figures/images: https://www.dropbox.com/sh/d8kd7y9krlud8vp/AAAtV2jmmbO7ITNOIMBCftRFa?dl=0
A walk through a laser scanned Wytham Woods: https://vimeo.com/manage/videos/233204068
Dataset - Terrestrial laser scanning data Wytham Woods: individual trees and quantitative structure models (QSMs): https://doi.org/10.5281/zenodo.7307956
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JOURNAL
Ecological Solutions and Evidence
ARTICLE TITLE
Laser scanning reveals potential underestimation of biomass carbon in temperate forest
ARTICLE PUBLICATION DATE
20-Dec-2022
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