CR2025_34 Agroforestry solutions: harnessing trees for climate resilience and food security

Lead Supervisor: Amelia Hood, Department of Sustainable Land Management, University of Reading

Email: a.s.hood@reading.ac.uk

Co-supervisors: James Bull, Department of Biosciences, Swansea University; Kate Beauchamp, Forest Research; Becks Spake, Department of Ecology and Evolutionary Biology, University of Reading

Global food security is threatened by intensifying climate change, with UK food production already severely affected¹. Conventional farming practices (e.g. high-input monocultures) are driving climate change (1/3 global emissions) and accelerating biodiversity loss^2,3. We urgently need to design farming methods that reduce environmental impacts whilst maintaining resilience to climate change and food production.

Silvoarable farming is an innovative farming method that supports this goal. It is an agroforestry system where trees (e.g. apple) are planted through arable (e.g. cereal) fields in rows. Compared to arable farming, silvoarable farming has greater structural complexity (e.g. deeper roots), which can promote biodiversity, carbon sequestration, soil health, food production and profits^4–6. Silvoarable farming may also promote resilience to climate change via microclimatic buffering (e.g. tree shade), improved soil health, and functional redundancy from increased biodiversity, but this has not yet been quantified.

These environmental and production benefits have sparked global interest in silvoarable systems. The UK government has committed to increase silvoarable area from <1% to 10% of arable land by 2050⁷. This year, DEFRA released schemes to pay farmers to adopt silvoarable farming, with similar initiatives emerging internationally. However, due to its rarity there is a lack of robust evidence on the ecological impacts of silvoarable farming under climate change, and this hinders our ability to manage systems optimally in the long-term⁴.

This PhD will quantify silvoarable’s potential to provide climate resilience compared to arable farming under three climate scenarios. It will use novel spatial modelling methods to create evidence-based predictions about large-scale silvoarable adoption. Objectives:

• How does silvoarable’s long-term viability, in terms of production, profits, and climate resilience, compare to arable farming?
• Where can the greatest environmental and production gains be made from planting silvoarable agroforestry? How is this affected by different climate and tree planting scenarios, including DEFRA’s current planting targets? 

Methods

This research will be conducted on five mature silvoarable sites in the East of England, which is the largest arable producing region in the UK. Each farm has silvoarable fields and adjacent arable controls. This project sits within an existing transdisciplinary research programme across these sites, which includes baseline data on soil health.

Fieldwork: With the assistance of a wider research team, you will simulate climate change in silvoarable and arable fields over three years. You will increase winter wetting using existing farm irrigation infrastructure and summer drought with shelters following a well-established design⁸. Three treatments will be replicated 30 times across the five farms, based on 2100 emission scenarios (SSP1-2.6, SSP3-7)⁹ and one control (no shelters or irrigation).

You will collect data on arable crop health (e.g. water stress, uniformity, pest damage), yield, quality, and profits. The wider research team will quantify the microclimate and soil health, including structure, biodiversity, and carbon, with results published separately. 

Modelling: Using 3-5 key indicators from the climate experiments (e.g. yield, profit, carbon), you will create spatial models to identify opportunity areas where silvoarable is most suitable and likely to achieve the greatest benefit, focussing on the East of England. National maps (e.g. landcover), local farm maps (e.g. fertiliser use), and the experimental results will be combined to create data-driven geospatial models and predict the environmental and production impacts of different silvoarable planting scenarios under climate change¹⁰. We will work with DEFRA and stakeholders to shortlist 5-10 tree planting scenarios varying in density and location, including a control (no additional agroforestry planting), and feed results back via an interactive web application.

You will work closely with policy makers (project advisors DEFRA) and industry partners – including three months of placement at Forest Research – to gain industry experience and ensure the results translate to policy. Findings will be disseminated via publications, stakeholder and policy briefs, annual conferences, and the wider media.

Impact

By determining the environmental and production impacts of different agroforestry tree planting scenarios under three climate change trajectories, this project will promote climate resilience, food security, and an evidence-based tree planting strategy across the UK. It will strengthen the UK’s position as global leaders in agroforestry, as this topic gains recognition for its potential to address the climate and biodiversity crises^7,11.

Training opportunities:

You will receive subject-specific (e.g. ecology, agronomy, mathematical modelling) and general (e.g. science communication, inclusivity) training at Reading, Swansea, and externally. Swansea University will provide training on spatial modelling. Forest Research will provide training in agroforestry, climate change, spatial modelling, and tree policy via three one-month placements. DEFRA will act as advisors and provide training in agricultural policy. You will attend seminars and annual academic/industry conferences to develop your communication skills and networks. You will have access to several large multi-partner projects (UKRI, H2020) via the supervisory team and be invited to relevant events. 

Student profile: 

The student must have, or be nearing completion of, a relevant BSc (e.g. ecology, zoology), and a relevant MSc or equivalent is desirable. The student must demonstrate the ability to work well in a team, and skills or capacity in mathematical modelling and field ecology, or a related outdoor activity. An interest in and understanding of ecology and agricultural systems in the UK is required. Experience with spatial modelling or machine learning is desirable. Capacity to travel for field trips is needed (driving license not required). 

Co-Sponsorship details: 

The project will receive a CASE award from Forest Research.

References:

1. Lesk, C. et al. Compound heat and moisture extreme impacts on global crop yields under climate change. Nat Rev Earth Environ 3, 872–889 (2022).
2. Crippa, M. et al. Food systems are responsible for a third of global anthropogenic GHG emissions. Nat Food 2, 198–209 (2021).
3. Benton, T., Bieg, C., Harwatt, H., Pudassaini, R. & Wellesley, L. Food System Impacts on Biodiversity Loss. Energy, Environment and Resources Programme (2021).
4. Kletty, F., Rozan, A. & Habold, C. Biodiversity in temperate silvoarable systems: A systematic review. Agric Ecosyst Environ 351, 108480 (2023).
5. Staton, T., Breeze, T. D., Walters, R. J., Smith, J. & Girling, R. D. Productivity, biodiversity trade-offs, and farm income in an agroforestry versus an arable system. Ecological Economics 191, 107214 (2022).
6. Varah, A., Jones, H., Smith, J. & Potts, S. G. Temperate agroforestry systems provide greater pollination service than monoculture. Agric Ecosyst Environ 301, 107031 (2020).
7. Climate Change Committee. The Sixth Carbon Budget: The UK’s path to Net Zero. The Carbon Budget 34 (2020).
8. Hoover, D. L., Wilcox, K. R. & Young, K. E. Experimental droughts with rainout shelters: A methodological review. Ecosphere 9, (2018).
9. Ukkola, A. M., De Kauwe, M. G., Roderick, M. L., Abramowitz, G. & Pitman, A. J. Robust Future Changes in Meteorological Drought in CMIP6 Projections Despite Uncertainty in Precipitation. Geophys Res Lett 47, 1–9 (2020).
10. Ahmad, F., Uddin, M. M., Goparaju, L., Rizvi, J. & Biradar, C. Quantification of the Land Potential for Scaling Agroforestry in South Asia. KN J Cartogr Geogr Inf 70, 71–89 (2020).
11. Westaway, S., Grange, I., Smith, J. & Smith, L. G. Meeting tree planting targets on the UK’s path to net-zero: A review of lessons learnt from 100 years of land use policies. Land use policy 125, 106502 (2023).