Farming with trees is key to net zero, new research shows

A new report from the Woodland Trust shows how a major increase in agroforestry – farming with trees - in England, is essential if the country is to meet nature and climate targets, whilst at the same time securing long term food production.  

The report draws on new analysis commissioned from Cranfield University and reveals arable farms which adopt silvoarable systems (integrating trees into arable farming which is one type of agroforestry) could lock up eight tonnes of CO2 per hectare per year over 30 years. Eight tonnes of CO2 is equivalent to the annual emissions of a UK citizen.  

It explains that agriculture is responsible for 10% of UK territorial greenhouse gas emissions with the net effect of “land use, land use change and forestry” responsible for another 1%. Establishing agroforestry on 10% of arable land and 30% of grassland could enable agriculture-related emissions to reach net zero by 2050 whilst maintaining high levels of food production. Integrating trees into farming systems will enable farms to become more resilient both economically and environmentally. 

The report also shows that agroforestry would help address the biodiversity crisis by increasing the abundance and richness of farmland species, and birds and invertebrates in particular. It is estimated that the total number of breeding birds in the UK fell by 44 million between 1967 and 2009, and many once-common farmland birds are continuing to decline (references below).

Agroforestry is not only good for supporting wildlife but enhances soil health by improving soil structure and microbial diversity. It may also lead to passive benefits in other ecosystem services such as pollination, pest control, nutrient cycling and decomposition, all of which are essential for long-term sustainable food production.  

The report, a culmination of ten months’ work, is timely given the Government is anticipated to outline its plans for the future of farming and land management policy on November 7. Speculation has arisen in recent weeks on the future of its post-EU policy, Environmental Land Management Scheme (ELMS), which is designed to pay farmers and landowners for public goods such as carbon mitigation and habitat restoration. This is essential as it provides the payments and support needed to implement agroforestry and support long term investment and wide scale implementation. 

Scientists, a former environment minister, and environmental charities have voiced alarm at any plans to abandon or dilute support for farmers helping nature. 

The report shows data which provides evidence for the necessity for the widescale uptake of agroforestry. 

Key findings include: 

• Over 30 years arable farms which adopt agroforestry could lock up, on average, eight tonnes of CO2 per hectare per year – equivalent to the average annual carbon footprint of a UK citizen. This contrasts with typical emissions from arable land, of nearly two tonnes of carbon dioxide equivalent per hectare per year. Establishing agroforestry on 10% of the UK arable area over 30 years (i.e. 484,000 ha; 16,000 ha per year), and assuming a halving of arable GHG emissions per hectare, would enable the arable sector to reach net zero by 2050.
• Meanwhile silvopastoral agroforestry can sequester the equivalent of sixteen tonnes of CO2 per hectare per year over 40 years compared to a mean emission for UK grassland with livestock of about four tonnes of carbon dioxide equivalent per hectare per year. Establishing agroforestry on 30% of UK grassland over 40 years (i.e. 3.35 million hectares; 84,000 ha per year), and assuming no other changes, would enable the livestock sector to reach net zero by 2050. 
• Allowing existing hedges to increase in height from two to three metres can store an additional seven tonnes of carbon per hectare. 

Abi Bunker, director of conservation and external affairs at the Woodland Trust said:  

“This new research shows just how much good that having many more trees within our farmed landscapes could bring, not just in terms of making important contribution to tackling climate change and helping reverse biodiversity declines, but also in supporting farm businesses to adapt to climate change and become more resilient to the types of financial, social and environmental shocks that are likely to be a part of the future.

“This is about making trees work for farm businesses and the local environment that they operate within and rely on. As a land use it will make farms more resilient both economically and environmentally - maintaining food production while providing public goods that are not supplied by many intensive farming systems. It is a sign of hope that there are solutions to grasp - if we take them. 

“We urge the Government to commit to ELM with schemes that reflect the long-term investment required to establish and manage trees and set a series of new targets. This report shows how upping agroforestry can help the country meet our climate targets, while maintaining effective farming production.” 

Paul Burgess, professor of sustainable agriculture and agroforestry at Cranfield University, who conducted the research said:

“Consumers and retailers increasingly want their food derived from farms with zero or negative greenhouse gas emissions and increased tree planting (agroforestry) is one of the few ways that farm businesses can maintain food production whilst achieving net zero targets over the next 30 years. Because the carbon sequestration of newly planted trees is initially slow, planting needs to occur now to achieve targets for 2050. 

“The analysis shows that the integration of new agroforestry on between 18 and 30% of the farmed area through incremental planting can allow UK agriculture to reach net zero by 2050, assuming no change in current per hectare GHG emissions from arable and livestock systems."

Farmer David Brass, CEO of The Lakes Free Range Egg Company, who has undertaken biodiversity surveys with the support of the Woodland Trust, said:  

“It’s been fascinating seeing the results of these surveys each year. We already know the trees that we and our suppliers have planted bring a range of benefits to our farms in terms of poultry welfare and production, and we’ve always had anecdotal evidence of them attracting wildlife. 

“Having clear evidence of just how many species we are attracting, and the role being played in terms of tackling climate change is fantastic. It is a pleasure and privilege to be able to plant trees, improving hen welfare and profitability whilst creating much needed habitat for wildlife.

“It is also pleasing to be part of Defra’s co-design of ELM and to see that they are open to applying what we have learnt into new silvopoultry schemes.” 

Off the back of the report, and with the prevalence of tree disease and pests increasing, the Trust says there needs to be investment in domestic tree supply to meet demand and reduce reliance on imported stock which carries increased biosecurity risk. 

The Woodland Trust urges the Government to set a target for converting 10% of land suitable for cropping to agroforestry systems as part of a 40-year rotation. This would require about 16,000 hectares to be converted each year.  And to establish silvopastoral agroforestry (livestock farming with trees) on 30% of UK’s grasslands requiring about 81,000 hectares to be converted annually.

It also says there should be a commitment to new hedge and shelterbelts to a minimum of 11% of arable land in England which would create the equivalent of 417,000 hectares of new nature-rich habitat and would add 65 million new trees - estimated to be equivalent to replacing all trees outside woods lost on arable land since 1850. 

Read the full report. 

Notes to editors 

For more information contact Andy Bond in the Woodland Trust press office on 07725 480434. 

*Erratum

Page 3, bullet point 2 should read:

"Establishing silvopastoral agroforestry on 30% of UK grassland (3.35 million hectares; 84,000 ha per year for 40 years starting in 2022) would result in net zero emissions from the grassland sector by 2050, and a net sequestration rate of 21 million tonnes of CO2 equivalent per year by 2062.

(it currently reads "Establishing silvopastoral agroforestry on 30% of grassland (3.35 million hectares) would result in a net storage of over 21 million tonnes of carbon over 40 years", which is incorrect. 

About the Woodland Trust    

The Woodland Trust is the largest woodland conservation charity in the UK. It has over 500,000 supporters. It wants to see a UK rich in native woods and trees for people and wildlife.    

The Trust has three key aims:      

• protect ancient woodland, which is rare, unique and irreplaceable  
• restoration of damaged ancient woodland, bringing precious pieces of our natural history back to life    
• plant native trees and woods with the aim of creating resilient landscapes for people and wildlife.    

Established in 1972, the Woodland Trust now has over 1,000 sites in its care covering approximately 29,000 hectares. Access to its woods is free so everyone can benefit from woods and trees. 

About Cranfield University

Cranfield is a specialist postgraduate university that is a global leader for education and transformational research in technology and management. The most recent Research Excellence Framework results demonstrate Cranfield University’s excellence with 88% of research rated as world-leading or internationally excellent.

References

Eaton et al. (2012). The state of the UK’s birds 2012. Available at: https://www.rspb.org.uk/globalassets/downloads/documents/conservation-science/state-of-the-uks-birds_2012.pdf

Burns et al. (2020). The State of the UK’s birds 2020. Available at: https://www.bto.org/sites/default/files/publications/state-of-uk-birds-2020-report.pdf