Building a Dead Hedge from Coppice Brush

If you have spent a winter coppicing hazel, ash or willow, you will know the problem. The poles are useful — hurdles, bean poles, stakes, firewood — but the brash is another matter entirely. Piles of leafy, springy branches that refuse to lie flat, that spring back when you walk on them, and that seem to multiply the moment your back is turned. Burning it feels wasteful and smoky. Leaving it heaped in the corner of the wood looks untidy and smothers the ground beneath. A dead hedge is the answer, and it is one of the most satisfying jobs in woodland management.

What a Dead Hedge Actually Is

A dead hedge is a linear barrier built by stacking cut branches between pairs of stout upright stakes. The brush is laid roughly horizontally, criss-crossed and packed tightly so it forms a dense, self-supporting wall. It is not a fence in the conventional sense — there is no wire, no rails, no nails. The structure holds itself together through friction and the sheer volume of material packed between the stakes.

In a working wood, dead hedges do several jobs at once. They mark boundaries and compartment edges, they keep deer and rabbits out of coppice regrowth, they slow the movement of people across sensitive ground, and they provide an enormous amount of edge habitat for invertebrates, small mammals, birds and amphibians. Best of all, they consume the brash that would otherwise be a nuisance, and over five to fifteen years they quietly rot down into a raised ridge of rich, crumbly woodland soil.

Choosing Your Line and Gathering Materials

Position comes first. A dead hedge works best along a boundary you actually want to reinforce: the edge of a ride, the perimeter of a newly cut coupe, the line of an old fence that has rotted out, or a path you want to steer people away from. Follow the natural contour where you can, as a hedge on a curve looks intentional and sits better in the landscape than a stark straight line.

You will need two sorts of material:

• Stakes — straight, sturdy poles about 1.5 to 1.8 metres long and 5 to 8 cm in diameter. Hazel, ash, sweet chestnut and field maple all work well. Chestnut is the most durable, easily lasting a decade or more in the ground.
• Brash — everything else. Leafy tops, side branches, twiggy material, cut lengths of any size that will fit between the stakes. Mixed species and mixed sizes make the tightest, longest-lasting hedge.

Do not be tempted to use only one species of brash. A uniform heap of soft willow will slump and rot quickly, while a mix of hazel, oak, birch and thorn packs down into something almost solid.

Setting Out the Stakes

Drive your stakes in pairs, roughly 60 to 90 cm apart, with the pairs spaced every 60 cm or so along the line. A mallet or a small post driver makes short work of this in soft ground; in stony or compacted soil, use a crowbar to make a pilot hole first. Aim to sink each stake about 30 to 40 cm into the ground, leaving a metre or more standing proud.

If the hedge is to be more than about 1.2 metres tall, lean the stake pairs slightly inward toward each other. This gives the completed hedge a trapezoidal profile that is far more stable than a vertical wall, and it sheds rain rather than trapping it in the middle. On soft ground you can also weave the tops of opposing stakes together, but for most situations a straight pair is perfectly adequate.

Building Up the Layers

Now the real work begins. The principle is simple: lay brash horizontally between the stakes, butt ends facing outward where possible, and pack it down firmly with your boot as you go. Start at the base and work upward in layers of 20 to 30 cm.

A few practical points make a great deal of difference:

• Put the thickest, woodiest material at the bottom. It rots slowest and forms the structural core of the hedge.
• Alternate the direction of the branches — some pointing left, some right — so they lock together rather than all sliding one way.
• Fill the gaps. Twiggy material and small side branches are the mortar in this wall. Push them into any hollows before adding the next layer.
• Stand on it. A dead hedge should be compressed to roughly half the volume of the loose pile you started with. Tread it down regularly.
• Keep the top slightly domed so water runs off rather than pooling in the crown.

Taller hedges of 1.5 metres or more are useful where deer pressure is heavy, but even a knee-high hedge of 60 cm will shelter ground flora, protect coppice stools from browsing and hide a great deal of brash. Build to the height your material allows rather than chasing a target, and resist the urge to make it neat. A slightly ragged profile weathers better and looks more at home in the wood.

Finishing Off and Looking After It

When the last of the brash is in, tidy the ends of the hedge by weaving a few flexible stems back through the final stake pair, or simply trim the protruding twigs with a pair of loppers. Cut any stakes that stand more than 15 to 20 cm above the top of the hedge — long protruding tops look untidy and can catch on clothing — unless you want them as a perch for birds, in which case leave a few and you will soon see wrens and dunnocks using them.

A finished dead hedge needs almost no maintenance, but a few minutes each winter will extend its life considerably. Walk the line and push back in any brash that has worked loose. Replace stakes that have rotted through, using fresh chestnut or hazel. If the hedge sags in the middle, add a new pair of stakes to support the belly of the structure. As the interior rots down, top it up with the next season's brash.

The Slow Reward

Within a season, the hedge will be alive with life. Solitary bees nest in the sunny south-facing side, beetles and woodlice work through the interior, and small mammals tunnel in at ground level. Fungi appear along the damper sections. After a few years, the base will have settled into a low mound of dark, friable leaf mould — some of the finest soil in the wood, and perfect for planting ferns, wood anemone or dog violet along the foot of the hedge.

Eventually the hedge will collapse into a fertile ridge, and you will have a decision to make: rebuild it alongside, or let it become a habitat pile and start a new line elsewhere. Either is fine. What matters is that nothing has left the wood. The nutrients, the carbon and the habitat all stay on site, cycled back into the soil from which they came. That, in essence, is what good woodland management looks like.