Dynamic Dunescapes Dune Management Case Study

UXO, Scrub Clearance and Scrapes, Braunton Burrows, 2021-22

Sand dune system:

Braunton Burrows, North Devon

Case Study Subject:

Removal of unexploded ordnance, followed by areas of scrub clearance to remove vegetation and turf scrapes to expose bare sand

About The Dune System Habitat Management Intervention
Site Background Information:

The Braunton Burrows dune system is recognized as an internationally important site for plants.  It is the core area of a UNESCO Biosphere Reserve, a Special Area of Conservation (SAC) and a Site of Special Scientific Interest (SSSI), and it is within the Area of Outstanding Natural Beauty.  The Burrows contain almost one third or all native vascular plant species.  It is a refuge for many rare species, including sand lizard, great crested newt, round-headed club rush, petalwort and the amber sand bowl snail. In recent decades, the dunes have become increasingly overtaken by scrub and dense vegetation growth, including large areas of sea buckthorn which flourishes to the detriment of every other plant.

The area has a long history of been used by the military as a training and exercise ground. From 1943-1944, large reaches of the Burrows and the beaches were used as a training ground for American forces, to assist in preparations for the D-Day landings on the beaches at Normandy. Exercises used live ammunition, tanks, artillery and explosives. After the war, a clear-up operation rid the area of most of the ordinance, although many items from this time have remained buried in the dunes.

In total, Dynamic Dunescapes will restore 60 of Braunton Burrow’s 1,000 acres, including creating 20+ hectares of bare sand at points identified by ecologists to best support biodiversity. This amounts to around 3% of the site.

What was the issue/change you hoped to make?

To support both bio-abundance and biodiversity in the dunes by removing scrub and creating more bare sand habitat and mobile sand.

What was the suggested intervention?

To clear scrub and vegetation, including scraping the top layer of turf to create bare sand areas covering up to 5 hectares. We planned to remove roots and all remaining vegetation to create a clean ‘bed’ of sand.

Early successional habitat is necessary for a wide range of both endangered and protected plant species as well as common ones. Bare sand areas also benefit animals such as lizards and snakes, insects and ground-nesting birds, including skylark, meadow pipit and stonechat.

What did you do and how?

The first stage was to select the physical location for the restoration works.

Factors in selecting locations included knowledge of:

  • The flora on site and judgement as to where interventions will most benefit dune species as well as rare dune species.
  • Visitor use numbers and patterns, and expectations on how interventions in differing locations might be received by members of the public.
  • Awareness of existing protected or rare species that need to be located and protected so that they are not damaged or lost due to the works.
  • Archaeological sites that need to be protected.
  • Any current or historic military use of the site and if unexploded ordinance (UXO) surveys need to take place.
  • Suitable locations to place removed material from the scrapes – if possible so they do not stick out on the landscape.

The second stage was to find contractors with experience and discuss methodologies for clearing scrub and scraping depending on whether UXO are found on site. Contractors were briefed regarding protected species and attend UXO safety talk at the MOD base. On sites with UXOs, where dense scrub needed to be cut to allow the UXO surveys, the contractors are instructed not to break the surface of the ground.

Scrub can be flailed or, if the stems are too thick, they can be cut using tree shears.  A forestry mulcher can also be used but creates large amounts of debris and mess that is difficult to tidy up, resulting in soil enrichment. Scrub is then burnt on site or removed from site for disposal elsewhere. Locations for burn piles must also be UXO surveyed. Options for chipping for biomass as well as firewood were researched. Once the scrub was cleared the UXO surveys could take place.

On completion of the UXO surveys, the root-plates and roots could be pulled out using excavators.  The turf was peeled back to remove the vegetative layer and create a clean bed of sand which is, so far as is possible, free from any roots or twigs. Locations to place the removed materials need to be as close to the scrape site as possible to keep costs down. These piles were capped with clean sand - preferably 1m over any humus-rich soil or roots to prevent regrowth.

At Braunton Burrows, two tractors were used with heavy duty flails – a standard size tractor, and a compact tractor to help to flail tight slopes and handle the heavily undulating terrain. Very steep slopes were cut using a robotic flail. The tree shears were mounted on a 15 ton swing shovel.  Two 14 ton+ swing-shovels were used to scrape and two standard tractors towed two 30 ton tipper trailers to remove the scrapings.

The MOD UXO Team (29 EOC Clearance Group) comprises of more than 20 staff, and Welfare Units were provided to give them shelter, water, a food preparation area, toilets and office.

This work occurred between October 2021 and February 2022. It was completed during the winter months to best avoid disturbing bird breeding seasons.

How was the site / intervention monitored?

Plant species were recorded using quadrats.  Photos of sites where scrapes were planned were taken before and after works.  Some drone footage was also taken, but this was half-way through the works.

What modifications, if any, did you make to your initial plan and why?

Initial plans did not manage the UXO risk. When scrub has wide stems and big roots systems, the resultant scrub removal works are deep and effectively scrapes, which meant that we had to account for scraped areas where this scrub had been removed.

Highlight any issues/obstacles & how you overcame them?

We had for classifications of scrub to help contractors bid for the works but this proved unhelpful and two classes would be easier – high and low categories, depending on whether they can be cut with a flail or not. Cutting with tree shears is slow and therefore expensive.

How much did the intervention cost?

The total cost was £248,328.

Breakdown: Scrapes at c. £10k/ha. Low scrub c. £750/ha. Dense scrub c. £5-7k/ha

What size was the area of the intervention?

36 hectares of scrub cut, 10 hectares of scrapes created.

What else went well?

Working in close collaboration with MOD and Christie Estates (the landowner) has been worked well.

Engagement Measures
How were the public and others engaged?

We had six A4 informational signs placed around the work areas. Contractors talked to visitors when possible. The site Officer talked to anyone walking in the work areas. The landowner's Facebook page proved a useful place to share information with the community. Technical Support Andy Byfield also gave a talk in the village to the community half way through the works. We were also reliant of key local actors, who were supportive of the works, to engage with concerned voices in the community.

How were communities or volunteers involved?

A public talk was given, a GCN course was run and sand lizard monitoring volunteer opportunities provided.

How were schools or local organisations involved?

Devon Birds led a guided walk across the work site, we hosted a volunteer day, and also three school visits to site (although these visits were not to the work sites).

Is the intervention working?
Please describe how. What has changed?

Works were completed in Feb 2022 – it is too soon to gather data.

However, scrub cutting and sand scraping have proved very effective methods of dune restoration. Plantlife’s smaller-scale trials on the Burrows in 2014 and 2018 have seen huge numbers of rare plant species colonising the bare sand scrapes.

Media

Credit: Dynamic Dunescapes:

A digger removes large areas of turf exposing bare sand
Areas of bare sand are created which will support specialist dune biodiversity for many years to come
A man in military uniform stands next to an area of sand that has been scraped exposing historic artefacts
The MOD EOC 29 group locate and excavate items buried in the dunes prior to conservation works taking place
An old box sits on a sand dune with the word TNT clearly visible
Historic unexploded objects were located and disposed of safely by MOD EOC 29 group
A man stands beside large shears used on trees
Tree shears
A collection of military artefacts that are aged from decades underground are laid out on sand
CREDIT_ Dynamic Dunescapes. Shown_ A selection of the WW2 military artefacts found prior to conservation works taking place

Credit: Dave Lincoln/MOD:

An area of cleared sand shows two military items uncovered
Two WW2 3 Inch HE Mortars uncovered during the ground surveys
A man in a high vis jacket walks over a grassy dune with earth monitoring equipment
MOD 29 EOC Clearance Team surveying the landscape prior to conservation works taking place
An aerial view looking own on diggers removing turf from sand dunes
Contractors creating the scrapes and creating much-needed sandy habitat
An aerial view of the large scrapes created,
An aerial view of the large scrapes created, exposing bare sand for the rare plant and reptile species that need this habitat type
Showing the scale of some of the turf scrape sites
Showing the scale of some of the turf scrape sites
An aerial view of sna dunes with some diggers and a small patch of removed scrub being burned
In some instances scrub removed was burned on site.
A digger and a tractor with a trailer are shown removing waste vegetation removed from site.
Removing scrub from the site