Roselle Chapman - Community Ecologist
Wildlife such as small mammals, farmland birds, perennial wildflowers and many invertebrates benefit from healthy, dense mixed species hedges, with few gaps. They provide a home, forage, hunting ground, shelter and routes of travel within our increasingly fragmented and intensively managed landscape. They also sequester carbon above and below ground, both in woody growth and in soils. Estimates of the carbon stock of UK hedgerows range between about 15 tonnes of carbon per hectare for short hedges (1.5m height) and 30-40 tC/ha for tall hedges (2.7m), with a similar amount of carbon in below-ground biomass. We also know that well managed hedges provide shelter for livestock, intercept pollutants improving air and water quality and can help with flood alleviation. Hedges running across slopes capture eroding soil and can increase soil organic carbon up to 60m uphill of them.
Hedges also form an important element in Oxfordshire’s landscape, such as the rectangular grid of the Parliamentary Enclosure hedges, especially well seen from the Ridgeway, and the chequerboard pattern near Otmoor, reputedly the inspiration for the chess game in Lewis Carroll’s Alice in Wonderland. Locally, for example in the Chilterns and in the former Wychwood Forest, woodland relic hedgerows provide evidence of assarting of ancient woodland. In short, hedges are amazing.
Much of the value that a hedge has for wildlife depends on when and how frequently it is cut. Hedges that are cut once every 3 years yield 1.5 - 2 times more hawthorn and blackthorn flowers than those cut annually. This increased flower abundance attracts more pollinating insects such as hoverflies, bees and butterflies and more hawthorn, blackthorn and black berries are provided for overwintering wildlife (e.g. farmland birds and small mammals), especially if hedges are cut in late winter, rather than Autumn. We know that less than half of UK hedges are in good condition partly due to neglect and unsympathetic management, including over-frequent annual trimming with mechanised flails. Without intervention this can lead to a slow death of the hedgerow. Grants are available for planting new hedgerows, including the Woodland Trust’s MOREhedges scheme, and hedges in poor condition can be rejuvenated using traditional methods such as hedge-laying, coppicing to fill the gaps and stimulate new growth from the base of hedgerows.
National CPRE is calling for Government commitment to increase hedgerow cover by 40% by 2050. The 1997 – 1999 CPRE Oxfordshire Hedgerow Survey concluded that there was approximately 7,820 km of hedgerow in Oxfordshire. For Oxfordshire, a 40% increase would see an additional 3,128km by 2050 – or 108km a year, which sounds ambitious. However, equally distributed across the county (there are 235 parishes in Oxon), it’s only about 0.5km per parish per year, for the next 30 years! To the get the ball rolling, CPRE and Wild Oxfordshire are really excited to be working with the community groups and parish councils of Kidlington, Watlington and Eynsham, the Wychwood Project and local hedgerow hero Nigel Adams to not only plant new hedgerows but rejuvenate exhausted ones. We won’t be delivering 3,138km, but it’s a start and we are hoping to create an inspiring and helpful community project template to encourage others to take action for hedgerows on their patch.
Although hedgerows are an iconic feature of our farmed landscape, they are more subtly woven into our built-up areas, winding their way around gardens, allotments, water courses, recreation grounds and churchyards. Furthermore, hedgerows are a significant element to providing natural habitat and a refuge for wildlife in new developments. Existing hedgerows must always be retained and used to inform the layout and the design of the greenspace. Existing connections between these features should be retained and new links of mixed, native species hedgerow should be added to enhance and extend ecological networks.
So, how healthy are the hedgerows in your corner of Oxfordshire? Take part in the ‘Great British Hedgerow Survey’ run by the People’s Trust for Endangered Species (PTES): https://hedgerowsurvey.ptes.org .This survey provides a health check for your hedges and gives tailored management advice to help ensure this precious habitat can thrive in the future and don’t forget to submit your records to TVERC as well.
If you are surveying or enhancing your parish’s hedgerows, we would love to hear from you contact: roselle@wildoxfordshire.org.uk
