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The Traditional Farm Hedgerow

Your undiscovered ally

By JIM JONES

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There may be places on your farm that you drive past every day and think nothing of, or perhaps you wonder if that unused strip of land could serve you better and you should be rid of it entirely. But wait, this woody, perhaps rock-strewn strip between your fields, known in North America as a fencerow, and in Europe as the hedgerow, is quietly working for you and with a little help it could do much more.

Defining a hedgerow

The terms fencerow and hedgerow are often confusing and loosely applied. The dictionary definition of a fencerow is ‘an uncultivated strip of land on each side of and below a fence’, but is commonly used to describe without a fence as ‘a narrow linear strip of trees that defines a laneway or boundary between fields or properties’ (this definition from Durham Municipal By-Law 31/2012). A hedgerow can describe a range of linear features, but in the United Kingdom it has the technical definition of ‘any boundary line of trees or shrubs over 20m (67ft) long and less than 5m (16ft) wide at the base’ (Hedgelink/DEFRA) (Picture 1). A major difference between fencerows and hedgerows is that the latter are usually managed and the former not, however the type and timing of management for both can vary enormously.

The origins of hedgerows

It’s thought that hedgerows or hedges were first used by early humans as ‘dead hedges,’ using thorny plants to corral livestock. Similar structures, such as the thorny acacia enkang used by the Masai peoples of East Africa to protect their villages, are still in use today. With the advent of agriculture, clearance of woodlands created fields with tree and shrub boundaries that were managed to create livestock-proof ‘living fences’. Hedgerows have been planted since the time of the Romans and reached their peak in Britain during the Enclosure Acts of the 1700s when an estimated 200,000 miles of mostly hawthorn (Crataegus species) hedgerows were planted.

Useful hedges

A hedgerow may take seven to 10 years to establish, depending on the species composition, and with good management is not only more robust than a fence but also brings additional benefits. Chief amongst these for the arable farmer is protection of their fields’ soil from wind and water erosion. Dense and structurally strong hedgerows composed of species such as oak, hawthorn and hazel have been shown to be the most effective barriers. In areas where winds are strong hedgerows can reduce erosion by as much as 50 per cent. Hedgerows can also intercept water-borne sediment and reduce surface flow rates, capturing soil from fields above and reducing flow over fields below them.

Hedgerows also make water more available to crops through the retention of moisture in leaf litter and by facilitating the infiltration of surface water into the soil. As well, they can reduce water loss through evaporation and transpiration as a result of increased shading and wind shelter. Studies from Britain have shown that hedges can greatly increase infiltration of water into the soil, by a factor of 60 to 70 times compared to compacted upland pasture. The role of hedgerows in controlling water flows has led to their use in natural flood management.

Hedgerows enhance populations of natural enemies (predators and parasites) of crop pests by providing a wide range of habitats across the shrub layer, trees, banks, base, margins, ditches and soil. The greater the structural and floristic diversity of hedges, the greater their insect diversity and, it’s assumed, insect predators. Strong evidence exists, based largely upon bees (especially bumblebees) and hoverflies, that hedgerows are also important in agricultural landscapes for the existence of healthy and diverse pollinator populations.

Agriculture contributes 10-15 per cent of global carbon dioxide emissions so in the future, farms will need to play an important role in mitigating climate change. Hedgerows store more carbon than cropped land and so planting more hedgerows may mitigate climate change impacts.

Of course, hedgerows are essential for wildlife in agricultural landscapes. One survey in Devon, UK, showed a single hedge was home to over 2,000 species of plants and animals. Hedgerows offer nesting sites and food, but can also provide linkages between farm woodlots, scrubland and ponds for animals finding mates and new territory.

Hedgerows, and their absence, are a feature of landscape character, or what can be described as the ‘feel’ or ‘sense’ of a place. The French term bocage is used to describe a terrain of mixed woodland and pasture connected by hedgerows. In a small study comparing attitudes to hedgerows in Canada and England, hedgerows evoked childhood memories and provided colour and diverse views to an otherwise featureless agricultural landscape.

Planting and management

Like fencerows, hedgerows can arise naturally along fences and other linear features and they can also be planted with intention. They can be single species but are more useful with a diversity of plants. Volunteers at Mount Wolfe Farm in Caledon, Ontario, planted a hedge in 2017, which contains American hazelnut, gray dogwood, chokeberry, nannyberry, arrowwood, serviceberry, black chokeberry and fragrant sumac. To provide a dense hedge with opportunities for nesting and many stems for laying in the future, the planting was done in a double line, spaced 40cm (16in) apart, with plants in a staggered pattern at 30cm (12in) centres, giving five plants per metre. 

Hedgerows are composed of living shrubs which will grow and will need to be managed so there is a balance to be found between allowing shrubs to grow and keeping the hedge from becoming a line of trees, developing gaps and eventually disappearing. Hedgerows can be cut to slow their growth but annual cutting can limit flower production and the development of fruits, berries and seeds. Annual cutting also stresses and eventually kills the plants. Evidence has shown cutting every two to three years and increasing the cut height by a few inches each time can maintain the health of the hedge. As a hedgerow grows, the shrubs will thicken and become gappy at the base, so at some point it will be necessary to rejuvenate the hedge. The hedge could be coppiced (felled), however, with the shrubs removed it cannot function as a fence. 

The practice of hedgelaying has evolved to rejuvenate a hedge while still maintaining a stock-proof structure. Hedgelaying is a catch-all term used to describe the rejuvenation of a hedge from the base by cutting and ‘laying-over’ of the shrub. There are many different styles of hedgelaying throughout the world, with at least 16 styles in the UK alone. In some styles wooden stakes are positioned at intervals along the hedge and long ‘binders’ are woven in across the top to give the hedge strength.

Hedgelaying in Ontario’s landscape and beyond

In 2016 the University of Waterloo and partners in southern Ontario, funded by the Social Sciences and Humanities Research Council, began working together to examine landscape planning and management practices within the Greater Golden Horseshoe, using hedgerows and hedgelaying to connect to broader themes including place-making, collective stewardship, agro-ecology and social-ecological resilience. Two pilot plantings at Mount Wolfe Farm, Albion Hills Community Farm, were undertaken with a third at a private property in Inglewood.

In 2018 this author worked with the project, offering advice and delivering workshops on hedgerows, hedgelaying and other traditional rural skills such as scything, basket making and green-woodworking through the Ontario Rural Skills Network. It’s thought that hedgerows were once more widespread across Canada and so it is more than likely that traditional hedgerow management is being carried out somewhere still. I would love to hear from you if you can help find layed hedges or Canadian hedgelayers or if you would like to get involved in our pilot project in Ontario. Please contact jim.jones@uwaterloo.ca.

References

Wolton, R. et al (2014) Regulatory services delivered by hedges: The evidence base, LM0106 Technical Report for Defra and Natural England

For more information

Hedgelink: bóng đá trực tuyến www.hedgelink.org.uk A good source of information on hedgerows in England and beyond

National Hedgelaying Society:
www.hedgelaying.org.uk

Ontario Rural Skills Network:
www.ontarioruralskillsnetwork.com