A number of surveys have been carried out of hedges in Devon. These include:
South Devon AONB hedge survey 2002
174 hedges were surveyed across the AONB. The report estimates that the AONB contains 4,060 km of hedges, with an average of 12.4km per square kilometre. Ash and elm were the main hedgerow trees recorded, although about 60% of hedges had no trees at all.
Devon Hedgerow Surveys 2007 -2009
This report gives the results of random sample surveys carried out across 10 parishes in Devon by The Farming and Wildlife Advisory Group (FWAG) and Exmoor National Park. The Hedgelink standard hedgerow survey methodology (see Survey methods) was used and 1,308 hedges were surveyed. The results are summarised in this presentation.
Huntsham hedge survey 2011-2012
The Huntsham Society surveyed 9 hedges within a 1km2 block immediately NW of Huntsham (which is in the east of the county, in Mid-Devon). The Hedgelink survey methodology was followed (see Survey methods). The survey found the hedges to be exceptionally species-rich, with a minimum of 12 woody species per 30m length and a maximum of 17 species.
Blackdown Hills hedge survey 2013
A GIS and field survey carried out by Will Dommett in conjunction with the Blackdown Hills AONB service . The aim was to evaluate whether the network of hedges within the AONB could provide an economic driver for their long term management through provision of sustainable woodfuel. On the plateau land it was estimated that there are 11.34 km of hedge per square kilometre, on the slopes 13.07 km per km2: overall, across all landscape types, the average was 11.68 km per km2. Conservatively, the research suggested hedges could provide enough sustainable woodfuel to heat 562 typical farmhouses, approximately 42% of all farm properties in the AONB. For further information please contact Will Dommett at email@example.com.
A standard procedure for surveying hedges to record their basic parameters and their condition for biodiversity has been published by Defra on behalf of Hedgelink as the Hedgerow Survey Handbook (2007). This is linked to an online database, allowing secure storage of data, easy analysis, and sharing of information across the UK.