BTCV Handbooks Online

Book:	How & Why
Chapter:	How to manage dunes
Section:	Hands-on techniques
Metadata:	Details	Buy this book

Dune Stabilisation

Digging Up

Marram grass (Ammophila avenaria) is themost common plant used in dune restoration.

Young plants (those with fibrous roots) transplant better than older ones. They are best obtained from the downwind side of mobile dunes.

Don't denude an area, but collect only one or two clumps per square metre.

Loosen a clump of marram with a spade or a fork, then pull the plants up by hand if possible. Get as much rhizome as possible with each plant, preferably 30cm or more. Shake the plants gently to get rid of excess sand. Tread back the disturbed soil to reduce erosion.

Keep the roots covered and out of the sun - if they dry out, the plant will die.

Transporting

The easiest things to carry the plants in are clean old plastic sacks. Put all the plants into the bag the same way round. Make sure the plants are shaded and moist. Heel them in if they need to be stored for more than a few hours (see How to Plant Trees).

Planting

A sharp dibber is the best tool for planting. Bare hands are good in dry sand.

Make a hole deep enough to get at least 15cm of root into damp sand, whilst planting as near as possible to the depth the grass was originally growing at.

Where is is uncertain how healthy an in-dividual plant is, plant a couple in each hole.

Replace the sand firmly and make sure all roots are thoroughly covered.

Tug the plants to check that they are firmly planted.

Judge space according to the availability of plants. 45cm between plants is adequate.

On exposed sites, trim the growth to about 10cm so they are not loosened by the wind.

To plant a slope, start at the top and work downwards to avoid trampling on what you have just planted.

Plant the whole of a dune face, not just part of it, otherwise erosion problems will be encountered.

Don't plant within 2m of the high water mark because marram has low salt tolerance. Below this height sand couchgrass (Agropyron juncei forme) or lyme grass (Elymus arenarius) can be used.

Dune Fencing

For details of fencing techniques, see How to Build Fences. The following are special types of fencing adapted for sandy areas.

Access Control Fences

Where sand build-up is to be avoided, post and wire fencing is the easiest and cheapest.

Straining posts must be very well made. Dig the hole quickly and put the sand in one heap to reduce drying out.

Sand does not compress much with tamping, so replace the sand in layers about 5cm thick and water each layer until it is thoroughly moist.

Do not strain wire more than is absolutely necessary.

Where access control is to be combined with sand trapping, chestnut paling or dutch fencing reinforced with strained wire are best.

Sand Trap Fences

There are many different designs, mainly determined by the availability of materials. When using branches, ensure they are dead otherwise they may take root.

The fence should stand 0.7m to 1.2m high and have a porosity (proportion of holes) of about 50%. To decide on fence alignment, take note of the prevailing wind direction. It should normally run at right angles to the wind.

An abrupt end to a sand trap fence can cause scouring round the end. A short section of dutch fence will avoid this.

Boardwalks

The design depends on ground conditions and the materials available. Where the path may need to be relocated periodically, use duckboards - wooden slats attached to rails. Avoid running boardwalks or duckboards up steep slopes.

Dune Thatching

Dune thatching acts as a low wind barrier to trap sand and protect newly planted vegetation. It is only effective by itself in small areas and should generally be combined with marram grass planting.

Work from the top of a slope downwards. The top branches should not project above the top of the slope, or the wind will catch them.

Follow contours closely and keep the thatching an even thickness, since any projecting branches will catch the wind.

Push the branches well into the sand. When thatching a blowout, work down in concentric circles and finish by blocking the entrance.

Thatching A Blowout

Where public pressure is intense, run occasional wires across the thatching, staked down at either end, to hold the brush in place.

For more information:

On access work in dunes, managing vegetation and dune wildlife refer to Sand dunes - a practical handbook by A Brooks & E Agate (1986) BTCV.

For more about the principals of dune management refer to Coast Dune Management Guide by DS Ranwell & R Boar (1986) Institute of Terrestial Ecology.

This information is believed to be correct but does not obviate the need for further enquiries as appropriate.

This is not a comprehensive statement of all safety procedures to ensure the health and safety of all users.

No responsibility is accepted by BTCV for accidents or damage as a result of its use. This information can assist you to gain National Vocational Qualifications in Environmental Conservation with BTCV.