Sustainable food

Written evidence submitted by the Woodland Trust



· We believe that sustainable food production is inextricably linked to a sustainable and resilient natural environment.

· In the medium to long term the greatest risks to food security are likely to result from issues around oil supply and climate change.

· Agricultural land use produces negative externalities but can also contribute towards developing ecosystem services

· Sustainable food production must include the wider sustainability issues which flow from land use.

· Understanding waste is critical to increasing the sustainability of food production.

· Better application of existing technologies, particularly the integration of trees into farming systems, could improve agricultural adaptation and lead to increased production

· New technologies should reduce the likely impact of food production on the environment.

General remarks

1. The Woodland Trust is the UK's leading woodland conservation charity. We have three aims: to enable the creation of more native woods and places rich in trees; to protect native woods, trees and their wildlife for the future; to inspire everyone to enjoy and value woods and trees. We own over 1,000 woods and have 300,000 members and supporters.

2. We agree with the assessment in the Foresight report on the Future for Food and Farming [1] that we face a convergence of demand side pressures for increased food production, with greater competition for land, water and energy. The uncertainty created by climate change is likely to amplify these problems, as is political instability in many parts of the world, particularly those where water shortages are anticipated.

3. Greater frequency of extreme weather events is likely to increase the uncertainty of food production and lead to years in which there is serious global undersupply.

4. We believe that agriculture and sustainable food production are inextricably linked to a sustainable and resilient natural environment. Although an increasing global human population puts pressure on agricultural land and water resources to produce the food needed, this must be achieved whilst maintaining or increasing natural capital.

5. Agricultural land use and other parts of the food production cycle produce negative externalities e.g. greenhouse gas emission, but can also contribute towards developing ecosystem services e.g. flood mitigation. Sustainable food production must include the wider sustainability issues which flow from land use. Whilst this will have implications for the way in which agricultural land is managed, we do not believe it should result in a drop in production

6. Our particular interest is in the way in which agriculture and food production impacts on biodiversity of the UK’s trees and woodland, and the contribution which tree and woodland cover can make towards sustainable land use, including supporting sustainable food production.

7. Nonetheless we recognise that sustainable production and food security require consideration of all parts of the food supply chain.

Climate change

8. Climate change is predicted to lengthen the growing season across the UK, with increased summer droughts particularly in the south and east, but milder winter temperatures and higher winter rainfall especially in the west of the country [1] . There is likely to be an increase in severe weather events including heat waves, higher intensity rainfall and storms. This will have consequences for both livestock and arable producers [2] .

9. A 2009 survey showed that half of all farmers already believe they are being affected by climate change, and over 60 per cent expect to be affected in the next 10 years [3] . All sectors see climate change presenting more risks than opportunities.

Dependence on oil

10. Modern agriculture is dependent on oil, not just as a fuel source but in the production of pesticides and fertilisers, and in processing, packaging and distribution of food. Sustainable food production and distribution in the UK is strongly associated with issues around energy security, illustrated dramatically when supermarket food stocks began to run out after just one week of the fuel tanker driver strikes in 2000. In our view in the medium to long term the greatest risks to food security are likely to result from issues around oil supply and climate change.


11. Waste in the food chain also has a major impact on sustainable food and Greenhouse gas (GHG) emissions. The UK wastes around 6.7 million tonnes of food every year, around a third of all food bought for home consumption [1] . Some is recycled but most goes to landfill where contributes to the creation of methane, a powerful GHG [2] .

12. Improved understanding of the impacts of waste through all parts of food production, processing, distribution and consumption, would increase the sustainability of the food produced and reduce GHG emissions.


13. Increasing wealth across the globe is leading to more meat consumption with concomitant greater demand for animal feed. This puts more pressure on land for crop production, and increases GHG emissions from livestock. We recognise that diet is a matter of personal choice and can be deeply culturally embedded. However, dietary changes, in particular lower meat consumption, could contribute towards increasing the sustainability of food production and reducing GHG emissions.

New technologies

14. Maintaining production will mean more research for new technologies which can protect crops and livestock and maintain or increase production. We support the need for further research provided it takes proper account of the risks of new technology to human health and the natural environment. Wherever possible new technologies should reduce the likely impact of food production on the environment. For instance, through reducing the need for crop spraying with pesticides, or reducing reliance of crops for irrigation. Reduced pesticide use could also contribute to making it easier for wildlife to move through the landscape.

15. Genetically Modified (GM) crops have been particularly contentious. Whilst we recognise the potential benefits which might come from GM crops, any future commercial release needs to be supported by clear evidence that GM crops will not hybridise with other species, and will not harm ecological food webs or spread in an uncontrolled way.

16. Should it be decided that GM crops are suitable for release we would argue for tight regulation and monitoring of the farming systems under which they are grown to ensure delivery of environmental benefits e.g. genuine reductions in use of agrochemicals.

Integration of trees into farming systems

17. In addition to the need for research on new technologies, we strongly believe that better understanding and application of existing technologies could improve agricultural adaptation to climate change and lead to increased production. At the same time it could also support wildlife and the delivery of ecosystem services.

18. Thoughtful integration of trees into farming systems could improve the sustainability of food production through lowering energy use and reducing or mitigating negative externalities of farming.

19. Simple–to-use technologies, such as tree planting have fewer barriers to adoption than some new technologies and could increase the sustainability of food production. Whilst this requires some trade of in terms of land for farming, we don’t believe this is significant in area, particularly when set against wider sustainability benefits.

Mitigating GHG emission

20. Agriculture is responsible for around 7 per cent of UK GHG emissions [1] . There are a range of measures which farmers can take to mitigate emissions, dependent on the farming system. These range from changes to agronomy, particularly tillage practice and fertiliser application, management of animal waste, slurry digesters to reduce methane emission, and on-farm renewable energy production.

21. The planting of trees on farms, for whatever purpose, will have some benefit in sequestering atmospheric carbon. In addition shelter for housing and buildings can reduce energy consumption and CO2 emissions. Windbreaks of trees can improve the heat budgets of houses and buildings by 10-40 per cent [2] , [3] , [4] .

22. The use of woodfuel as a renewable energy source both for farm use, and for sale will displace fossil fuel use and reduce the carbon footprint of agriculture [5] . The use of native tree species has the added benefit of supporting biodiversity, important in its own right, but also to create a diverse and resilient ecosystem to support agriculture, particularly pollinating insects.

Water quality

23. Agricultural land use has a major impact on water quality and quantity. Winter rainfall has increased throughout the UK over the last 40 years with greater frequency of very heavy rainfall [1] . This increases the risk of runoff from agricultural land which affects both the probability of flooding and the level of sedimentation and pollutants entering water courses. This has subsequent impacts on wildlife and fisheries, and downstream energy costs in purification.

24. Woodland can reduce floods from hill slopes and in headwater catchments. The use of buffer strips of trees alongside watercourses and contour planting of trees and hedges can help reduce sedimentation and runoff of manure and fertiliser following heavy rainfall [2] . Studies at Pont Bren in Wales found soil-infiltration rates were up to 60 times higher under young native woodland than heavily grazed pasture [3] .

25. Woodland buffers have been shown to reduce the concentration of nitrogen carried in overland flows of swine lagoon effluent over a distance of 30m [4] . Improvement in water quality reduces downstream costs for water purification.

26. Trees provide the added advantage of offering dappled shade to watercourses which reduces water temperature and is associated with improved oxygen levels in the watercourse to the benefit of fish and other wildlife [5] .

Air quality

27. Trees also capture both gaseous and particulate pollutants from the atmosphere [1] , [2] . Livestock units, particularly intensive poultry and pig unit, emit ammonia and methane, a powerful GHG. Trees located close to livestock units are able to intercept a part of these emissions through dry deposition on the leaf and bark surfaces [3] . The high leaf surface to ground area ratio of trees, and electrostatically charged leaf surfaces makes them particularly effective and scavenging air borne pollutants.

Shade and shelter

28. Tree planting and woodland creation to provide shade and shelter for livestock can improve feed efficiency through reduced heat stress in summer and less wind chill in winter [1] . Shelter from trees can have a positive impact on pasture growth and has been shown for instance to increase lambing percentage and yields of wool from sheep reared in sheltered pastures [2] .

29. The shade from trees is not necessarily in conflict with productivity of pasture, as the shelter effects can provide positive benefits by increasing water infiltration and reducing evapotranspiration loss from pasture [3] . In addition the trees can produce timber, fodder and bedding for housed livestock [4] . The latter can have cost advantages over straw bedding and has been shown to reduce the release of volatile nitrogen compounds into the air.

30. The Woodland Trust has been working for a number of years with Sainsbury’s and the Woodland Egg Producers to promote free range egg production in newly created woodland [5] . Through linking the product to increased animal welfare, new woodland has been created which will have wider benefits in carbon sequestration, capture of pollutants, biodiversity etc.

31. Windbreaks are already extensively used for shelter of top fruit and might be used more extensively for other crops. An increase in the frequency of storms creates greater need for crop shelter to reduce physical damage, water loss through evapotranspiration and to encourage crop pollination [6] , [7] . Wind related soil erosion can also be reduced on vulnerable soils (peaty and light soils in particular). Crop yields can be seen to increase as a result of use of windbreaks [8] .

32. In addition to the protection from physical damage to crops, windbreaks can increase the abundance of pollinating insects [9] , [10] , [11] . This is as a result of increased shelter, by acting as a food source and through the provision of breeding areas, particularly where windbreaks are integrated into hedgerows.

33. At least 39 crops grown for their fruit or seed are insect pollinated, and a further 32 need insects for propagative seed production [12] . The economic value to farmers of plant pollination by bees is estimated between £120 and £200 million per year [13] . Action to tackle declining numbers of pollinators needs to happen across the farming sector.

Wildlife Conservation

34. Ensuring the conservation of biodiversity is critical to maintaining the value and service functions of the natural environment.

35. Woodland, and especially ancient woodland, has been fragmented through clearance for agriculture over many centuries. Today woodland covers just 12 per cent of the UK with native woodland representing just 4 per cent of land cover, only half of which is ancient.

36. Creation of native woodland to buffer and extend existing habitat, particularly ancient woodland, can reduce external edge effects e.g. spray and fertiliser drift, and increase habitat resilience.

37. In order for species to move across the landscape in response to climate change the nature and quality of agricultural land is crucial. This includes both the way in which land is farmed - intensity and frequency of cultivation, periods of fallow, pesticide and fertiliser application and the types of crops- as well as other features integrated into agricultural systems. Targeted tree planting and woodland creation may also help the movement of species around the landscape as climate change alters their ranges [1] .


38. It is our strongly held view that a healthy and resilient natural environment underpins productive agriculture and sustainable food production. We believe that the integration of trees and woods into agriculture can support food production whilst also enhancing the delivery of ecosystems services. The land use trade-offs implied by this increase in tree cover are, we believe, insignificant when set against the benefits.

23 March 2011

[1] Foresight, The Future of Food and Farming (2011) Executive Summary. The Government Office for Science, London.

[1] UK Climate Impacts programme, available at:

[2] Commission for the European Communities (2009), Adapting to climate change: the challenge for European agriculture and rural areas , Commission Working Document, available at:

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[3] Theobald , M. R ., et al. ‘ Potential for ammonia recapture by farm woodlands: design and application of a new experimental facility, The Scientific World , available at;

[1] Slusher , J. P., and D. Wallace. (1997). Planning tree windbreaks in Missouri . MU Guide G5900. University Extension. University of Missouri-Columbia.

[2] Bird, P.R. (1988) Financial gains of trees on farms through shelter , the international forestry conference for the Australian Bicentenary 1988. Proceedings of papers contributed Volume II of V. Albury-Wodonga 25th April-1st May 1988

[3] Macaulay Land Use Research Institute, Agroforestry Forum, available at:

[4] Centre for Alternative Land Use (2005) Woodchip for animal bedding and compost, Technical Note, available at:


[6] Smith, B.D., and Lewis, T. (1972) ‘ The effects of windbreaks on the blossom-visiting fauna of apple orchards and on yield’, Annals of Applied Biology , 2 Volume 72 Issue 3 , pp 229 – 335. Published Online: Feb 26 2008 at:

[7] USDA National Agroforestry Centre, Conservation Buffers, Energy Conservation: site, available at:

[8] Sudmeyer , R., Hall, D. and Jones, H., The effect of tree windbreaks on grain yield in the medium and low rainfall areas in Western Australia , Department of Agriculture and Food, Western Australia, available at:

[9] Merckx , T. et al (2009) Effect of field margins on moths depends on species mobility: field-based evidence for landscape-scale conservation, Agriculture, Ecosystems and Environment, 129 (2009) pp 302-309

[10] Merckx , T. et al (2009) Optimising the gain from agri -environment schemes, Agriculture, Ecosystems and Environment, 130 (2009) pp 177-182


[12] The Bee farmers Association of the United Kingdom, The economic value of bees, available at:

[13] DEFRA, Farming Link April 2009, Honeybees in crisis , available at:

[1] Woodland Trust, Space for Nature, available at: