Academic Advisory Panel - integrating trees on farms: advisory note

The Academic Advisory Panel (AAP) prepared this advisory note in response to a request from Scottish Government officials to discuss the benefits and principles of tree planting on farms. This note summarises the discussion held during the AAP meeting on 12 May 2025.

Introduction

Integrating trees on farms can take various forms: farm woodland, agroforestry systems (i.e. integrating trees and agriculture on the same land), shelterbelts, hedgerows, shrubs, and small-scale tree planting and enabling natural regeneration. When implemented properly, tree planting can deliver multiple benefits aligned with strategic objectives such as climate mitigation, climate adaptation, biodiversity enhancement, and economic gain.

Government funding has traditionally focused on woodland creation rather than integrating trees within active farmland. Current schemes, such as the Forestry Grant Scheme (FGS) and the Agri-Environment Climate Scheme (AECS), often do not adequately support low-density or flexible planting approaches. Policy is now shifting to explore how more farmers and crofters can be supported to plant trees on farms, without necessarily creating woodlands and forests.

A deeper understanding of how the benefits of integrating trees on farms align with strategic objectives, and how these benefits can be maximized, would provide valuable evidence to inform further interventions. The Panel was invited to share their professional opinion on how to optimise the benefits of tree planting on farms for each strategic outcome and to help generate initial interest in such practices.

Key Summary

AAP recommends that:

To encourage low-density, flexible tree planting approaches, and ensure the best use of public funding and meeting environmental objectives, a clear definition of small scale planting is required. To better integrate trees into agricultural systems, policy must evolve to recognise and support on-farm trees currently excluded from farm payments, such as those deemed ineligible on the Single Application Form. Care should be taken when reviewing policy framework to ensure that credits are not awarded for existing infrastructure that does not deliver new benefits, or that mature trees are not removed to plant new trees. Grant schemes should reflect the real-world challenges of tree establishment, for example damage to trees from livestock and wildlife, by offering better support for protection measures such as fencing. Financial barriers, including fencing costs, must be addressed to ensure tree planting is economically feasible. Greater use of existing woodlands could diversify farm income, while reforms to tenancy agreements are needed to encourage long-term investment in trees.

Whole-farm carbon assessments, which account for tree-based sequestration, should be promoted to help meet net zero goals. Early, small-scale tree planting initiatives which align with the productive aims of the farm (e.g. shelterbelts for livestock) can foster positive attitudes and encourage broader adoption. Effective tree management should be incentivised through payments and backed by clear guidance.

Biosecurity practices must be strengthened through better sourcing and the use of nursery protocols to prevent pest introduction. The implications of tree planting on animal health in silvopasture systems (type of agroforestry that combines trees, livestock, and forage on the same land) require further research in order to fully understand the benefits and potential unintended consequences. Highlighting potential environmental benefits, such as reduced ammonia emissions by trees planted near livestock housing, can play an important role in encouraging integrating trees on farms Additionally, tree planting can help mitigate wildfire risks if carried out strategically. Addressing farmer concerns about predators and protecting open habitat species are also critical, as is avoiding planting in ecologically sensitive areas or on deep organic soils. Finally, improved data on non-woodland tree cover and livestock behaviour around trees would enhance land use planning and ecological understanding

Key discussion points

AAP recommends that to promote tree planting, and maximise benefits of each climate, adaptation, climate mitigation and biodiversity enhancement, policy officials should take the following recommendations into consideration:

1. Incorporate trees into Agricultural Policy Framework

To encourage small-scale, flexible tree planting approaches a clear definition of what constitutes “small-scale” is required. Additional guidance is needed on what type of trees to plant, putting focus on native species, and in what locations, to help maximise their ecological and agricultural benefits and make best use of public funding.

Many trees on farms are under-recorded and unrecognised in official policy because they are classified as ‘ineligible features’ on the Single Application Form (SAF), which is used to apply for agricultural payments. As a result, farmers and crofters receive no credit for these trees, discouraging maintenance or new planting. This also leads to the actual tree cover on farms being underrepresented. Revising the policy framework to include these trees is essential to foster long-term engagement with tree planting, and to accurately reflect tree coverage at landscape level. However, care should be taken that credits are not awarded for existing infrastructure that does not deliver additional benefits. Additionally, if only new trees are eligible for subsidies and credits, there is a risk of unintended consequences such as cutting of existing mature trees to plant new ones to qualify. Any new policy should include safeguards to ensure that new trees are not replacing mature trees that were removed shortly before implementation.

2. Design Grant Schemes with Realistic Success Criteria

Tree establishment is often more difficult than expected. In areas like the Upper River Spey, beavers damage young riparian planting. If grant conditions are not met because of such damage, farmers and crofters may suffer financial losses.

Some dairy farmers have reported difficulties in maintaining low-density tree planting, as livestock frequently damage young trees by breaking low branches. Fencing off specific areas may be necessary for successful tree establishment as tree guards are often ineffective against cattle and other animals such as rabbits, rodents, and roe deer, which can damage or remove guards entirely.

Overall, establishing broadleaf trees on farms is proving to be much more difficult than previously thought, highlighting the need for more realistic grant criteria and stronger support for protective measures.

3. Account for financial barriers

The cost of establishing trees can significantly impact farm profitability, particularly when measures such as fencing are being adopted. These costs must be factored into policy support to ensure feasibility and uptake.

4. Maximise the Value of Existing Woodland.

Using existing woodland more effectively could diversify farm income and improve timber and firewood market access. The Scottish Forestry Harvesting and Processing Grant helps cover the harvesting costs, including expenses for equipment and fencing, making forestry a more practical business for farmers.

5. Address Tenancy Related Barriers

Tree planting is a long-term investment and the benefits such as carbon sequestration, shelter, or timber may not be realised for many years. The duration of tenancy agreements is short in comparison to the time required to accrue benefits from tree planting. This mismatch discourages tenant farmers from investing in tree planting, especially where grant eligibility or long-term value is uncertain. Tenant farmers may be hesitant to invest in tree planting if they are uncertain about their future access to the land or if there are unclear arrangements about who retains the value of the trees or any associated grants. Landowners may also be reluctant, fearing land reclassification or potential impact on future flexibility of land use.

AAP recommends developing supportive policy frameworks, and clear guidance to enable tree planting under tenancy agreements and promote collaboration between landlords and tenants.

6. Integrate Farm-level Greenhouse Gas (GHG) Assessments

Carbon assessments can support farmers working towards net zero goals by including carbon sequestration from young trees as a part of the business strategy. There are two main ways of measuring a farm's carbon footprint:

• Product-based: Emissions per unit of product (e.g., per litre of milk), which usually only accounts for emissions and does not include carbon sequestration from trees.
• Whole–farm: Tools like Farm Carbon Toolkit or Agrecalc, account for sequestration from trees, hedgerows, and soils.

The choice depends on whether the market focuses more on overall farm-level net zero or emissions intensity. Supporting policies for whole-farm assessments could accelerate adoption.

7. Promote tree planting as an entry point

Research shows that initial experiences with practical tree planting, such as shelter belts, can shift attitudes, and increase openness to further planting. Supporting small scale or initial tree planting efforts builds farmers’ and crofters’ confidence and fosters positive attitudes, making long-term engagement more likely. These early interventions should be prioritised as strategic entry points.

8. Improve management of existing trees

Tree management practices for existing trees are often poor or entirely neglected. Introducing a universal action payment, similar to Sustainable Farming Scheme (SFS) in Wales, could incentivise proper care of broadleaf trees and woodlands. Currently, there is a lack of guidance and data on what constitutes effective woodland management and associated costs, which hinders quality improvement and Habitat value. Developing and disseminating best practice guidelines is a necessary step to improvement.

8. Strengthen Biosecurity and Tree Health Practices

Biosecurity risks must be addressed through thoughtful sourcing of trees for planting. Poor sourcing practices have previously led to unintended consequences, such as the introduction of pests into sensitive natural habitats which can have significant ecological impacts. Farmers and crofters should be encouraged to:

• source trees locally where possible
• use tree nurseries adhering to the Plant Healthy scheme
• ask about nursery biosecurity protocols
• conduct soil testing and acclimatising saplings before planting

10. Account for Animal Health in Silvopasture Systems

While trees can benefit livestock by providing shade, shelter, or improving pasture quality, they may also contribute to negative impacts on animal health. For example, disease may spread among animals more easily when they congregate in shaded or sheltered areas or come into contact with insects or other animals that carry disease. Small groups of trees can pose a higher risk of disease transmission due to the concentration of animals in small spaces. In contrast, larger woodlands may reduce this risk by allowing animals to spread out, but they could introduce other risks, such as predator exposure. Overall, both small- and large-scale tree planting have trade-offs in terms of animal health risks.

Currently, there are significant research gaps on potential unintended consequences of silvopasture systems in Scotland. Further research is needed to understand and mitigate risks, supporting wider adoption of trees in livestock systems. Additional information on the role of trees in silvopasture systems and research gaps are provided in Annex I.

11. Promote Environmental Benefits of Trees for Ammonia Mitigation

Tree planting on farms has a range of environmental benefits, including mitigation of ammonia emissions. Research shows that planting trees near pig and poultry housing can reduce ammonia emissions and improve air quality around livestock facilities.

Research by the Centre for Ecology & Hydrology and Forest Research led to development of a free online Tree Calculator for Ammonia Mitigation tool and guidance which helps design woodlands to capture airborne ammonia. 

Promoting environmental benefits of tree planting can play an important role in promoting tree planting on farms.

12. Explore Fire Management Benefits

Strategic tree planting could help manage wildfire risks by breaking up continuous tree cover.

13. Address Perceptions that Woodlands Attract Predators

Concerns exist about woodlands attracting predators (e.g. foxes, badgers, ravens) which may threaten livestock, particularly in upland areas. Peer-led engagement within the agricultural community is essential to shift perceptions and build trust, as farmers and crofters are more receptive to advice from fellow practitioners than from external authorities.

14. Protect Open Habitat Species

Tree planting in areas used by species reliant on open habitats, such as wading birds, can be harmful. These areas provide critical nesting and breeding grounds. Future policy should incorporate maps of areas identified as sensitive for wading birds and follow Forestry Commission Trees and Wader Guidance to avoid tree planting in ecologically inappropriate locations.   

15. Improve Data on Non-Woodland Tree Cover

There is limited data on tree cover outside designated woodlands. Better tracking of these trees (potentially using LIDAR data) would improve land use planning and ecological assessments. Additionally, research using GPS collars on livestock to monitor their use of shaded areas could provide valuable insights for integrating trees on farms more effectively.

Annex I additional information on the role of trees in silvopasture systems and research gaps

Summary of research and research gaps relating to animal health and welfare in silvopasture systems.

Improved livestock health and welfare in silvopasture systems have been considered in several publications, focusing on reduced heat stress encountered by animals grazing in shaded areas, for example (Amorim et al., 2023; Skonieski et al., 2021). There is a scarcity of peer-reviewed published research on the impacts of such systems on unintended negative animal health consequences through increased predation and transmission of infectious disease.

1. Predation

There is a concern amongst some livestock keepers that the introduction of trees into grazing land will result in an increase in local populations of predators including corvids, foxes and badgers occupying this niche. This represents a research gap for the study of impacts of predation on livestock production in systems where silvopasture has been introduced, particularly where woodlands have been created or where livestock have been allowed access to existing woodland for grazing.

2. Infectious disease

A general principle of infectious disease transmission is that proximity to a pathogen source increases the likelihood of infection from that source, hence the increase in infectious disease transmission when animals are brought into close proximity (a lack of “social distancing”). An extreme example of this is in housed vs. outdoor-raised sheep where maedi-visna virus has transmission rates ~1000 times faster in housed sheep than in outdoor-raised (Illius et al., 2020). Silvopasture systems may present the opportunity for animals to gather in larger numbers in smaller areas around trees than they would in open pasture, while seeking shade or shelter for example. This potentially represents an increased opportunity for transmission of infectious diseases caused by viruses, bacteria and fungi or parasites such as sheep scab mites (Psoroptes ovis). As well as increased risk of transmission from direct contact, sheep suffering from sheep scab rub themselves against stationary structures such as fence posts and trees to alleviate symptoms and this behaviour dislodges parasites which are then viable for up to 16 days to re-infest other hosts.

3. Vector-borne disease

In a study performed on 16 livestock farms in Denmark, the presence of deciduous trees within 500 m of the farms resulted in higher numbers of Culicoides obsoletus s.s., while the presence of wetlands increased the numbers of Culicoides punctatus and Culicoides pulicaris (Nielsen et al., 2014). Culicoides spp. midges, including C. obsoletus, are the principal vectors of some of the most devastating vector-borne diseases of livestock including bluetongue virus (Melhorn et al., 2007) and Schmallenberg virus (Wernike and Beer, 2024). Ticks also represent major vectors of diseases of both humans and livestock. A recent study from Italy demonstrated that cattle grazing in silvopasture systems were parasitized by higher numbers of ticks than those in open pasture and that the ticks were harbouring pathogenic Rickettsia spp belonging to the “spotted fever” group (Jimale et al., 2024). The increase in biodiversity associated with integrating trees into livestock grazing areas has the potential to increase exposure to arthropod vectors including midges, ticks, biting flies and mosquitoes which exploit the canopy as a resting place.

4. Gastrointestinal nematodes

The production-liming effects of infection with gastrointestinal nematodes (GIN) result in one of the largest economic impacts on both sheep and cattle systems in the UK. In addition, the inefficiencies and physiological impacts associated with GIN infection contribute to increased greenhouse gas emission from the sector (Rose Vineer et al., 2020). GIN with a direct lifecycle develop into their infective stages on pasture after hatching from eggs in livestock faeces. One of the key factors governing the survival of these infective larvae is exposure to ultraviolet (UV) radiation with higher levels of exposure resulting in substantial losses of infective larvae (van Dijk et al., 2009). The protection from direct UV exposure afforded by trees in a silvopasture system, combined with increased animal density around trees in a silvopasture system has the potential to result in increased parasitism. In relation to this, cattle faeces containing GIN larvae which were maintained for 15 days in non-shaded conditions contained significantly lower numbers of viable GIN larvae compared to those maintained in shaded areas for the same period (Bilotto et al., 2018). There is a general scarcity of data around this issue for sheep and cattle, but horses grazed in a silvopasture system in North-West Spain had significantly increased infection with GIN when compared to those managed in open pasture farms (Francisco et al., 2009).

Conclusion

Considerable research gaps exist in the literature surrounding the unintended consequences of the increased biodiversity associated with silvopasture systems in Scotland. Research into the potential risks, and their mitigation, represented by increased exposure of livestock to predators and pathogens as a result of adopting silvopasture in Scottish livestock farms would assist in increasing the levels of adoption of this practice in the sector. One of the key predictors for adoption has been identified as “Trust in the source of the information” (Zabala et al., 2025) and considerable weight should be given to this in the delivery of the research.

• How can the benefits of tree planting on farms be maximised for each of (1) climate adaptation, (2) climate mitigation, and (3) biodiversity enhancement?

Maximum benefits in silvopasture can be achieved by the introduction of stands of appropriate tree species to provide shade and shelter during periods of extreme weather which are predicted to increase. These adaptations may be beneficial for productivity but also for water conservation during prolonged dry and hot weather. For example, dairy cattle maintained in silvopasture conditions during hot dry summer weather in Brazil had reduced physiological heat stress, increased grazing time, decreased standing time and decreased water intake compared to cattle raised in conventional pastures (Skonieski et al., 2021). In a study in the USA, cattle raised in silvopasture conditions in pastures planted with a range of nut species and native deciduous and coniferous species had similar daily weight gain to those raised on conventional pasture (Amorim et al., 2023). The authors estimated that the conventional pasture system would require approximately four times more land to yield equivalent net productivity as a result of the increased yields of nuts etc. in the silvopasture system (Amorim et al., 2023). From a climate mitigation perspective, such efficiency/productivity increases are highly relevant. Closer to home, the shelter provided by stands of trees during and immediately after lambing could prevent neo-natal losses, for example, which represent a major loss to the Scottish livestock industry and contribute to inefficiencies relevant to carbon emissions. From an adaptation perspective, riparian planting has the potential to protect pastures from flooding and also to use undesirable grazing areas for woodland (for example, wet areas with high liver-fluke risk being planted with alder, willow or birch and fenced off to prevent livestock access). Biodiversity enhancement advantages are clear and obvious with the introduction of native tree species, less so with non-natives. Some unintended consequences of increased biodiversity should be considered (see Section 2, below).

• What are the key principles for determining what trees should be planted, where, and in what quantity to have an effect, for each of these three goals respectively?

“Right tree in the right place” principles are being used, for example, by the Integrated Tree Network and will partly depend on the farmer’s objectives (shelter, shade, riparian, commercial crop). Given the range of grazing pasture types in Scotland, this will need to be highly flexible, with upland grazing likely to be challenging in terms of limitations in the tree species appropriate for such terrain. The impacts on each of the concepts (adaptation, mitigation, and biodiversity) will only be fully maximized by farmer engagement via peer-to-peer learning and demonstration from respected peers. Interestingly, the farmers engaged in the Integrated Tree Network identified “biodiversity” as their key motivation for adopting silvopasture. Economic drivers through biodiversity audits and carbon audits/credits need to be co-designed to maximise impacts on adaptation, mitigation, and biodiversity

• What is the economic impact for farmers for each type of planting trees on farms?

This will be dependent on the farmers objectives for the adoption of tree planting. Economic incentives through payments for woodland assessments will mitigate early adoption costs but costs of upkeep of fencing, maintenance of the tree crop etc may be barriers to adoption in some systems. There may be increased costs to livestock farmers through losses of livestock to predation and disease and/or treatment costs of disease but these are largely unknown currently.