It may be that a dead hedge is just that, your once carefully manicured box hedge which has now been ravished by the box moth.  However, in terms of managing your woodland, a dead hedge may have a different meaning. Here, a dead hedge may be a barrier to an area of new planting, it may be a way to ‘persuade’ people to keep to a footpath, or keep away from a pond / stream.   The dead hedge will be made from the bits and pieces that have be culled in clearing and thinning operations within the wood, material that foresters sometimes refer to as ‘lop and top’ and tree surgeons call ‘arisings. It can also include material cut from brambles and climbers such as ivy, honeysuckle and Old Man’s Beard (Clematis). Using natural materials to create barriers (and indeed) a habitat in a woodland is a way of using ‘waste’ in an ecologically sound way.  It saves having to remove trimmings from the site and offers opportunities to ‘top up’ the hedge if desired.  Obviously diseased materials should not be used.   Creating a dead hedge from clippings and trimmings is a way of using natural materials, rather than plastic & other materials that do not readily decompose.  A dead hedge will be an effective barrier for a period of time but it will break down sooner or later as bacteria and fungi break down the woody remains (lignin and cellulose).  The disappearance of the hedge will take time as the branches twigs etc are largely off the ground, so relatively dry and decomposition is facilitated by warmth and wetness. After its initial ‘construction’, the hedge will become part of the woodland, it will be colonised by some plants and it will offer shelter, nesting sites for birds and small mammals, and a ‘home’ to many different invertebrates, such as woodlice, beetles, even certain species of bumblebees.  As the hedge deteriorates, that is, decomposes, so the soil will gain in humus and fertility as the nutrients from the decaying wood etc are released through the detrital food chains.   Another way of using / recycling bits from pruning, clearing etc is by Hugelkultur.   Hugel beds are basically raised beds with a difference - they are filled with rotting wood and other biomass.  They are packed with organic material, nutrients and air pockets. Such beds can be an effective way of creating a productive area for growing fruits and vegetables in your woodland.  There is a woodlands blog about hugelkultur here. Large chunks of wood e.g. sawn up tree trunks can be stacked up in small piles and will over time make an excellent home for many invertebrates but especially xylophagous (wood eating) insects, for example,  saproxylic beetles.  These are beetles that live / eat in dead wood.  In the UK, some 600+ beetle species (from 53 different) families are associated with deadwood. Some feed on the deadwood itself (often with the aid of symbiotic bacteria in their gut), others feed on the fungi that are gradually ‘dissolving’ the wood.  Ants and wasps sometimes make their nests in dead wood.   Using wood to increase the organic content of the soil is good in terms of  carbon sequestration,  improving soil fertility,  water conservation and  productivity.  

Dead hedges are piles of branches and twigs arranged to form a barrier which are increasingly used as a way to dispose of the material that arises from thinning or clearing operations in woodlands. Tree surgeons call this waste material of saplings and side branches "arisings" whereas foresters tend to call it "lop and top". Using surplus branches in this way is good for wildlife - especially for small mammals and birds - because it gives them somewhere to shelter that is protected from predators and from the wind and rain. It's also good for insects: dead hedges in effect create a linear eco-pile. Recently we at woodlands.co.uk have been using dead hedging as a way of guiding the public to stay on public footpaths and to discourage people from walking across sensitive areas of a woodland. In many situations the dead hedge needs to have gaps left in it for deer paths and for managers and owners to get around the woodland. The idea is that the material in the dead hedge will rot away in ways that are good for ecosystems but this takes quite a few years as the branches are largely off the ground - it is becoming quite common to keep a dead hedge maintained by regularly putting more foliage and saplings on top. When constructing one of these barrier hedges you soon realise just how useful it is to build it very near to where the branches are, as an enormous amount of time and energy can be taken up in moving branches around your woodland. Depending on the site, the alternatives to creating a dead hedge are often unattractive - smelly bonfires, carting material off-site or leaving a forest-floor that is impenetrable by foot. Visiting a heavily used council woodland in Highgate in London recently I saw how effective dead-hedging can be in protecting areas of woodland from being trampled. Circular dead hedges were also being used to protect ponds from dogs - I saw a tightly built pile of cut branches woven between hazel posts which had created a barrier so that the tadpoles survived being persecuted by dogs - in this case labrador-German-wire-haired crossbreed. Dead hedging is also a very useful activity for volunteer groups in woodlands because the activities involved are fairly safe - hand cutting of small diameter branches and arranging these into piles. Such projects have a clear purpose but also a very visible result so volunteers feel they have achieved something useful in building a dead hedge. Brambles that have been cut can also be put on top but often the dead hedge becomes a lattice work which will be colonised by brambles that are very much alive - much depends on how much light there is and whether brambles are already established in that part of the woodland.