peatland restoration in the UK

The North Pennines AONB Partnership has been restoring peatlands for nearly 20 years. The North Pennines AONB Partnership have developed a five-step process to restoration designed to address each feature of degraded upland blanket bogs in northern England.

A water channel actively eroding the peat and acting as a barrier to revegetation (Photo: North Pennines AONB Partnership)

STep 1: Hydrology

The restoration of site hydrology is the crucial first step in restoring a bare peat site. Sites with active drainage channels will continue to erode making re-vegetation difficult to accomplish. There are a variety of techniques that can be used to prevent running water causing further or new erosion within the site, these include:



Photo: North Pennines AONB Partnership

PEAT DAMS

If there is sufficient peat on site and if the gully is accessible to a digger, peat can be taken from ‘borrow pits’ and placed in the gullies. This is similar to grip blocking in that it will act as a leaky dam.


Photo: North Pennines AONB Partnership

COIR ROLLS/
HEATHER BALE DAMS

Used on degraded peat sites to slow water move-ment in eroded gullies. Best used in shallow water channels where peat is still present. Should be keyed into the eroded channel to reduce water movement, hold water during drier months and trap sediment.


Photo: North Pennines AONB Partnership

STONE DAMS

Used on large gullies (over 2m wide) that have either a peat base or eroded down to the mineral layer. Stone is flown in by heli-copter, to avoid damaging the bog with vehicles, and is dropped along the gully in pre-determined loca-tions to form dams. Trap sediment and slow water movement during high rainfall, keeping the water on the peatland longer.


Photo: North Pennines AONB Partnership

WOODEN DAMS

These can be used when there is still peat at the bottom of the gully. They are constructed of hardwood planks and fencing posts. These are leaky dams that slow the water and slow water during high rainfall.


Any grips or drains created in the peat which are still actively draining water from the peatland are also blocked using peat dams created by excavators. These are made by scooping peat out from within the grip, forming it into a dam and then placing vegetation back over the top. Watch the video to see grip blocking in action:

Grip blocking Yorkshire.MP4

Grip blocking in Yorkshire, UK (Video: North Pennines AONB Partnership)

North Pennines AONB Partnership

Step 2: Slopes

Steep bare peat faces known as haggs actively erode, releasing carbon, drying the peat and preventing revegetation. Slopes greater than 45° can be re-profiled to speed up colonisation from the base and halt erosion. A digger is used to peel back vegetation on the top of the slope, re-profile the exposed peat to a more gradual angle and then replace the vegetation from the top back over the newly re-profiled slope.

Not all slopes can be re-profiled in this way. Accessing peat haggs with a digger can be difficult because of the deep gullies between them, and this technique is only used where the surrounding area is vegetated to prevent causing unnecessary damage to bare and degraded areas.

Reprofiling prevents more peat being lost to erosion, reducing the carbon emissions and watercourse colouration which occur as a result.

A digger re-profiling a hagg, the newly re-profiled slope is to the left of the image and the eroding hagg to the right (Photo: North Pennines AONB Partnership)


Freshly cut sphagnum-rich brash and brash spreading (below) (Photo and video: North Pennines AONB Partnership)

Brash spreading x24.mp4

Step 3: Heather Brash

Covering bare peat with Sphagnum-rich heather brash is a crucial part of peatland restoration in Northern England. Heather brash acts as a mulch, insulating the bare peat from frost heave, protecting it from erosion through wind and weathering, and providing a seed source and growing medium for new plants.

Heather brash is typically sourced as locally as possible to the restoration site from areas with a suitable mixture of heather, cotton grasses and Sphagnum moss. Tracked machinery is used to cut and bag the brash and it is then airlifted to the restoration site to prevent damaging the sensitive ground with vehicles. The brash is then spread by hand using pitchforks.

Heather brash has proven to be a highly effective method of revegetating bare areas, with results seen within a year or two of restoration. Preventing further erosion limits the carbon emissions released into the atmosphere as a result, mitigating climate change.

An aerial view of a restoration site, brash has been spread at the bottom of the image and bags of brash waiting to be spread at the top.
(Photo: North Pennines AONB Partnership)

A site shortly after brash spreading ...
(Photo: North Pennines AONB Partnership)

... and then again two years later
(Photo: North Pennines AONB Partnership)

STEP 4: Re-Vegetation

To encourage and speed up re-vegetation of bare peat, several things can be added. Lime and phosphate fertiliser can be applied in very small quantities to improve the soil conditions. The lime raises the pH slightly, making it less acidic and more hospitable for new plant growth. Small amounts of fertiliser give the colonising vegetation a much-needed temporary boost but will not damage the surrounding bog vegetation. Both are applied either by hand or machinery.

A seed mix made up of moorland species typically found in the surrounding area including heather and wavy hair grass can also be applied after the lime and fertiliser have had time to take effect. This increases the speed at which plants begin to spread over the bare areas and ensures the desired vegetation grows.

As well as moorland seed, whole plug plants of moorland species can be planted in bare areas to speed up revegetation. This is most commonly done with cotton grasses, but other plants such as crowberry can also be used. The plugs are grown by specialist nurseries and planted in restoration sites by hand.

Re-vegetation means that further peat erosion is limited and the water holding capacity of peatlands is restored. Ultimately, it is hoped that restored peatlands will eventually recover to the point at which they can begin actively forming peat and sequestering carbon again.

Lime spreading using a Softrak
(Photo: North Pennines AONB Partnership)

Seed spreading by hand
(Photo: North Pennines AONB Partnership)

Cotton grass plug plants a year after planting
(Photo: North Pennines AONB Partnership)

Sphagnum capillifolium (Photo: North Pennines AONB Partnership)

Step 5: Sphagnum
re-establishment

Sphagnum moss is a vital feature of peatlands that contributes significantly to their ability to hold water, mitigating flooding, and form peat, mitigating climate change.

The final step in the process of peatland restoration is the reintroduction of Sphagnum moss to areas from which it has been lost or is declining to further speed up the process of revegetation. This restoration technique can also be applied to degraded sites which do not yet require more drastic interventions but have begun to decline with patches of bare peat, a limited vegetation community and a loss of Sphagnum to help reverse the process of degradation and prevent further decline. Sphagnum mosses can be added in several different forms to the wetter areas of sites to help retain water and prevent the bare peat from drying out.

Sphagnum moss can be reintroduced as clumps, plugs, pellets, beads, fragments, gel or slime. The most commonly used techniques are clumps, plugs and pellets.

Photo: North Pennines AONB Partnership

CLUMPS

Clumps are handfuls of Sphagnum moss collected from healthy donor sites and transplanted into restoration sites by hand. They are a highly effective technique for re-establishing Sphagnum moss relatively quickly.

Photo: North Pennines AONB Partnership

PLUGS

Plugs are strands of Sphagnum moss grown by specialist nurseries which are planted in restoration sites by hand. Although much smaller than clumps, they are also a highly effective technique.

Photo: North Pennines AONB Partnership

PELLETS

Pellets are spores of Sphagnum moss coated in clay which breaks down once spread onto moist ground. They are spread over restoration sites by hand or machinery but are much slower to become established.

Photo: North Pennines AONB Partnership

BEADS, GELS & SLIMES

Beads, gels and slimes are fragments of Sphagnum moss suspended in various substances to allow for easy spreading by hand or spray pump. These methods are also much slower to become established.


Sphagnum fragments being spread onto a heather cut
(Photo: North Pennines AONB Partnership)

Sphagnum clumps can be broken into fragments for spreading over larger areas of bare peat or on heather cuts carried out as part of a moorland management regime. The fragments can be spread onto the peat surface or beneath the layer of cut vegetation to provide protection from weathering and provide a growth medium. Each fragment will develop into a new Sphagnum plant.