MAPS REVEAL HEDGEROW WEALTH
England’s historic hedgerows would wrap around the world 10 times, shows new high-tech aerial technology
Hedgerows are a precious wildlife habitat and England has a lot of them, a new and highly accurate survey reveals.
Hedgerows have been used to divide fields across Britain since the Bronze Age, keeping farm animals contained. But they are also vital for wildlife, like ribbons of minirainforest, say conservationists.
Now, a remarkable new map tells us exactly how much hedgerow we have in England: a startling 242,300 miles (390,000km), which is enough to circle the world 10 times.
Who did the counting? Scientists from the UK Centre for Ecology & Hydrology (UKCEH) used LiDar technology – lasers mounted on aircraft – to make 3D scans of the countryside. The result is the first accurate map of England’s hedgerow network. It shows that the highest densities of hedgerow are in Cornwall, with an astonishing 5km of hedgerow per square kilometre. Surrey has the lowest density at 1.2km per square km.
Hedgerows are valuable to nature because they allow wild animals the opportunity to move around under cover. They offer a rich variety of micro-habitats for plants, birds, invertebrates and mammals. And they absorb surprisingly large amounts of carbon dioxide, too, locking up this greenhouse gas in soil, roots and woody matter.
Britain lost half its hedgerows between the 1940s and the 1990s due to changes in farming practices. Despite the losses, the numbers still impress – England has much more hedgerow per square kilometre than France, for example. But many are now in a poor state. Well-maintained, dense hedges are more biodiverse than neglected ones: wild animals won’t stay in gappy, overgrown hedges because they can’t hide from predators. Researchers hope their mapping will now be used as a tool to guide planting and restoration of these crucial wildlife habitats.