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The potential benefits and challenges in managing hedgerows for woodfuel
- 8. • Shelter • Food • Nesting and breeding sites • Sink /source populations • Wildlife corridors • Functional diversity BiodiversityBiodiversity Biodiversity
- 11. (Kotzageorgis, 1997) (Sparks et al., 1996)
- 13. Regulatory Services • Water runoff • Erosion • Water quality • Air quality • Carbon storage
- 14. (Oreszczyn and Lane, 2000)
- 24. References Kotzageorgis, G.C., Mason, C.F., 1997. Small mammal populations in relation to hedgerow structure in an arable landscape. Journal of Zoology 242, 425-434. Oreszczyn, S., Lane, A., 2000. The meaning of hedgerows in the English landscape: Different stakeholder perspectives and the implications for future hedge management. Journal of Environmental Management 60, 101-118. Sparks, T.H., Parish, T., Hinsley, S.A., 1996. Breeding birds in field boundaries in an agricultural landscape. Agriculture, Ecosystems and Environment 60, 1-8. Wolton, R., 2012. The yield and cost of harvesting wood fuel from hedges in the Tamar Valley and Blackdowns AONBs, South-West England . European Cordiale Project. Wolton, R., 2013. Wood fuel from West Country hedges. Devon Hedge Group. Photos sourced from Hedgelink: www.hedgelink.org.uk
Editor's Notes
- So - good morning and thank you for giving me the chance to present to you today. I’ve thoroughly enjoyed refreshing my memory on the topic of hedgerows and would like to talk to you about the potential benefits and challenges in managing them for woodfuel.
- So- why are we interested in managing hedges for woodfuel? In the past, hedgerows were used for fuel and were laid or coppiced every 15 years. However as coal and electricity became cheap and agriculture become intensified, hedges for fuel become unpopular and many were removed. More recently rising electricity and gas costs, and concerns about climate change, have made woodfuel from hedges more attractive
- Today many hedges are either over managed or neglected. This hedge has been over managed and repeatedly cut at the same height resulting in gaps
- Neglected hedges on the other hand may become tall lines of trees and lose their shrub layer.
- This hedge is likely to of been left for 10 years and provides an excellent habitat for wildlife. However if left, it will also degrade into a line of trees.
- In any case, these hedges will eventually need to be rejuvenated through coppicing or laying. This process is an important stage of a hedgerows life cycle and produces the biomass that can be used as a fuel. Reviving their economic value through using them as woodfuel therefore has the potential to encourage hedgerow planting, mangement and rejuvenation.
- So – what are the potential benefits and challenges Rather than just list the pros and cons I’ve decided to look at a few a examples through areas of tension in managing hedges for fuel. This way I hope to highlight some of the complexities and trade-offs that can occur.
- Hedges are important to a diverse range of flora and fauna. They provide multiple micro-habitats, food sources, shelter and ecological corridors.
- While managing degraded hedges for fuel is likely to restore their value to wildlife, coppicing hedge such as this one is likely to Reduce such functions until it has regrown
- For example, gaps from harvesting hedges may inhibit the movement of some small mammals, such as the dormouse and reduce the production of food sources such as berries. Dormouse (Bright, 1994; Bright, 1998) Berries (Croxton, 2002)
- Hedgerow management may also support one species but be detrimental to another. For example, hedgerows four years after being coppiced have been found to have higher butterfly abundance than those uncut. However, in some cases coppicing has led to the complete abandonment of hedges by the yellow-necked mouse.
- It is therefore important that hedgerows are managed at a landscape level. With small sections harvested on a rotation to allow for different stages of re-growth and landscape connectivity.
- Hedges provide ecosystem services such as regulating runoff, reducing soil erosion and maintaining water quality. These regulatory services are often complex processes with multiple variables making it hard to determine the effects of management. For example it’s uncertain whether coppicing would reduce the drying effect on crops through reduced root systems or increase it through increased wind speeds?
- An obstacle to managing hedges for woodfuel may be cultural resistance. Hedges contribute aesthetically to the characteristic of a region and are often valued for their role in improving views and providing privacy. A study done in 2000 found British farmers and the public to consider hedgerows a unique and important part of their national heritage.
- Although they shared this view they valued different types of hedges and management regimes. One the one hand - Farmers liked tidy hedgerows and on the other the public preferred less managed hedgerows It’s possible that managing hedgerows for fuel could therefore cause conflict and tension between different stakeholders
- Many people are unaware of the need for hedges to be managed in cycles and that coppicing and laying are an essential part of their life cycle Education may therefore be needed to raise awareness within communities
- Regular hedge trimming is widely accepted as the norm. In contrast hedge management for fuel involves coppicing and no top-cutting With a lack of advisory materials such as manuals Improved guidance is needed on management especially on suitable chippers, machinery and drying techniques.
- It is estimated by Wolton that energy can be produced by a Coppice + Chip system at about 2-3p/KWh, compared to oil at 6p/KWh hedges hence have potential to provide a sustainable and cost effective source of energy. However, numerous factors determine whether it is economical for a farm to manage hedges for woodfuel.
- First you have to have suitable hedges and enough of them. The cost of energy gained depends on maturity, species, size of cordwood and whether the hedge was layed or coppiced. In some cases degraded hedges might even respond poorly to coppicing and need replanting.
- Hedges with a high proportion of trees such as ash, beech and oak are likely to produce higher yields while hedges with a high % of hawthorn or blackthorn might be less suitable. It is also recommended that no more than 50% of a farms hedgerow should be managed for fuel. A farm must therefore have enough accessible and suitable hedges for it to be worthwhile
- Wolton also found a coppice and chip system to be faster and more cost-effective than the traditional laying and log system Although expensive specialist equipment is required to produce chip, the process is less labour intensive, the chip can be used within a few months and for every one unit of fossil fuel used an estimated 44 units of renewable energy are produced
- Although farmers have been encouraged to plant hedgerows through agri-environment payment schemes there is little incentive for the rejuvenation of degraded hedges. Future schemes should therefore support management for hedges for fuel or at least be modified to ensure those that do aren’t penalised. Government subsidies, such as the Renewable Heat Incentive, are also a powerful incentive for the installation of biomass boilers and should continue to be promoted
- So - In conclusion… Managing hedges for woodfuel has the potential to provide communities with low cost, renewable and sustainable energy It does however have its challenges and can present some very real tensions between different stakeholders and trade-offs between ecosystem services Such interactions are also often complex and will vary between sites Appropriate and sympathetic management is therefore needed to minimise negative impacts However with few working examples of hedges being used as woodfuel at a farm level There is a need for demonstration of the practicality of management methods and the potential benefits I’ll now leave it to you to ask some questions Thank you for you time and attention