Blanket Bog Track Trial Moor House NNR
in Partnership

## Context

Blanket bog is a wetland habitat that requires specific conditions to develop: more than 160 "rain" days per year, low evapotranspiration, relatively low fluctuations between annual summer maximum and winter minimum temperatures and underlying geology that allow the peat to spread and "blanket" the landscape.

Association (MA), Natural England Not surprisingly, these conditions are 
(NE) and peatland partnerships like not common on a global scale which North Pennines AONB Partnership is why this habitat is globally rare.  The have been working to improve UK holds roughly 15% of the world's peatland functionality by repairing blanket bog and the importance of oxidising and eroding bare peat, this habitat for plants and animals has blocking gullies and grips to raise the been known for a long time.  More water table and reduce erosion as well recent research has shown that this as filter the water for free and slow the habitat can influence raw drinkingflow off moorland to attenuate peak water quality, freshwater invertebrate flows and mitigate flooding. This work communities and the setting down/
across blanket bog habitat improves release of carbon into the atmosphere. 

eco-hydrology, but also makes the moorland wetter and more fragile and We are unsure how a warming climate prone to damage with use. 

will impact upon the carbon stored within blanket bog. However we know from studies of the peat cores that blanket bog has the ability to withstand some changes in climate as a result of individual plant and moss species different responses to water saturation, with for example, species that prefer drier conditions dominating in periods of reduced rainfall.  The less damage that occurs to blanket bog hydrology on any given site through anthropogenic effects, the greater the likelihood that the area in question will be in a condition to respond naturally to changes in temperature and The uplands have multiple uses and are patterns of rain-fall that are expected managed for sheep grazing, grouse under a warming climate.

shooting, and other leisure and visitor activities such as fell running, walking, The importance of deep peat as a mountain-biking and orienteering. 

carbon store and potential to sequester Vehicle access is often required for day further carbon if in good health has to day shepherding and grouse moor become a major agenda item in management activities like predator the English uplands. The Moorland control, vegetation management, putting out grit for grouse to aid digestion and getting shooting visitors and their equipment to areas of the moor on shoot days. Access is also required to work on peatland restoration areas. Routes and tracks created and maintained for land use are often subsequently also used by leisure visitors as they provide an easier aid to navigate otherwise difficult Open Access terrain. They can also facilitate emergency services to reach casualties in inhospitable places as well as to get wildfire fighting personnel and equipment out to hard to reach places. Vehicle access across blanket bog is therefore essential for land use. 

However, stone constructed tracks on deep peat have been found to result in compression and compaction of the peat impeding natural hydrological flow. It is in no ones' interests to damage peat bog surfaces or their properties and a pragmatic solution to help balance the conservation, economic and social land use needs of these areas is required. With increased knowledge of the hydrological function of deep peat and factors that affect its health, a partnership of MA, NE and North Pennines AONB Partnership investigated novel track technology including wooden and mesh surfaces to help prevent damage.

## The Mesh And Wooden Track Trial

The MA, NE and North Pennines AONB sponsored a research project carried out by a PhD student from the University of Leeds on the Moor House - Upper Teesdale National Nature Reserve. 

This track was constructed from The site is deep peat with healthy hardwood planks spaced to leave a gap functioning blanket bog in favourable the same width as the plank connected condition.  Its Water Table Depth (WTD) 
together with folded steel links which is typically at or within 10cm of the also act as the main running surface. 

surface for more than nine months of A plastic grid was spread on the cut the year which supports a representative vegetation to spread the load of the assemblage and abundance of blanket plank construction laid on top. John bog plant species. 

Carrick designed, supplied and laid the track free of charge for which the Given the sensitivity of the site it is project partners are very grateful.

perfect for testing new approaches to and measuring the impact of vehicle 

- 
A section that remained unsurfaced 
track design on blanket bog. 

which was also driven on (albeit light use) by the argocat. 
The experimental design included:
The tracks were laid in Summer 2013 

- 
Plastic mesh track laid and driven on by 
and allowed to settle in, on the advice of 

an argocat (but also suitable for quad 
the track manufacturers, before driving 

bikes)
started in Spring 2014. 

- 
A heavier duty wooden construction suitable for heavier vehicles such as 
Vehicle use of the tracks followed a 

4x4s
variable driving schedule until Autumn 
2015, incorporating five different sections, each representing a different intensity of track use. These were designed to mimic use for moorland management on a working driven grouse moor. This included sections of 10 passes per week, both loaded and unloaded from July to October. A range of peat physical and hydrological properties, and vegetation characteristics were measured before and after the tracks were laid and then during the driving.

| Treatment	          | Weekly Usage	                                | Total No.	        | Topographic	           | Track Type	              | Vehicle Type	             | Additional Information   |
|----------|--------------------------------|--------|-----------|--------------|-------------|--------------------------|
|          | (passes over track per week)   | Passes | Positions |              |             |                          |
|          |                                |        |           |              |             |                          |
| PWEEK.AL | 2 (April - End July, October - | 412    | S1,S2,S3  | Plastic Mesh | Agrocat     |                          |
|          | April)                         |        |           |              |             |                          |
|          | 10 (End July - October)        |        |           |              |             |                          |
| PWEEK.AH | 2 (April - End July, October - | 412    | S1,S2,S3  | Plastic Mesh | Agrocat     | Vehicle Weighted         |
|          | April)                         |        |           |              |             | (End July to October)    |
|          | 10 (End July - October)        |        |           |              |             |                          |
| PWEEK    | 2                              | 156    | S1,S2,S3  | Plastic Mesh | Agrocat     |                          |
| PMONTH   | 0.5                            | 38     | S1,S2,S3  | Plastic Mesh | Agrocat     |                          |
| PDELAYED | 2 (from February 2015)         | 76     | S1,S2,S3  | Plastic Mesh | Agrocat     |                          |
| U        | 0.5 (stopped April 2015)       | 24     | S1,S2,S3  | Unsurfaced   | Agrocat     | Driving over vegatation, |
|          |                                |        |           |              |             | no surface track         |
| W        | 10                             | 780    | S3        | Wooden Beams | 4x4 Vehicle | 30m length of track      |
| C        | 0                              | 0      | S1,S2,S3  | Unsurfaced   | None        | No driving or track,     |
|          |                                |        |           |              |             | Undisturbed hillslope    |
|          |                                |        |           |              |             | control                  |
| Characteristics	              | Plastic Mesh Track	                             | Articulated Wooden Track                                   |
|--------------|-----------------------------|------------------------------------------------------------|
| Total Length | ~1.5 km                     | ~0.3 km                                                    |
| Manufacturer | Terram                      | John Carrick                                               |
| Material     | UV Stabilised HDPE          | Oak Planks (n = 94), Steel Links (n = 186), HDPE Underlay  |
| Dimensions   | 2.5 m x 15 m (section size) | 3.2 x 0.15 x 0.1 m (single plank)                          |
|              | 0.0145 m (thickness)        | 0.45 x 0.28 x 0.1 m/thickness - 0.05 m (single steel link) |
| Weight       | 2 kg m                      |                                                            |
| -2           |                             |                                                            |
|              | 184 kg m                    |                                                            |
| -2           |                             |                                                            |
|                                                                       | Properties Measured	   | Importance to blanket bog functions                                |
|-----------------------------------------------------------------------|---|--------------------------------------------------------------------|
| Water Table Depth / surface moisture                                  |   | WTD within 10cm of surface supports bog pant species and main-     |
| tains anaerobic conditions in peat allowing peat formation.           |   |                                                                    |
| Bulk density of peat/permeability                                     |   | Compression has the potential to reduce or restrict flow of water  |
| through peat interrupting functionality leading to probable drying    |   |                                                                    |
| and peat structural change                                            |   |                                                                    |
| Vegetation/bare peat %                                                |   | Blanket bog plant assemblage perpetuates blanket bog function      |
| ensuring moisture is retained and no oxidation at the surface occurs. |   |                                                                    |
| Bare peat should be avoided.                                          |   |                                                                    |
| Overland flow                                                         |   | Roughness of the surface created by healthy vegetation, especially |
| mosses, slows flow so erosional force of water and mobilisation of    |   |                                                                    |
| carbon is minimised. Drowning of plants should not occur. Moor-       |   |                                                                    |
| house has natural overland flow which increases with rainfall.        |   |                                                                    |

## Results

height decreased on the unsurfaced 

## Wtd - Little Effect

section probably due to flattening by vehicle use.

Hydrology is central to the functioning of peatlands. The water table up to a distance of 10m from either side of the 

## Compression

track edge shows little change after mesh and wooden track installation and use. Therefore carbon storage There was natural variability in peat bulk is unlikely to be affected in the short density across the site but compression term. The trial covered a year with of the peat following track installation wetter conditions and a year with drier and use was not evident with bulk conditions. Peat soil moisture content density actually decreasing overall after varied only slightly. 

driving. There was a small compression impact of the 4x4 track but this may be a result of it being laid at the outset 

## Driving Frequency

with a normal tractor not low pressure equipment which was used for the The mesh track at heaviest use tolerated mesh site preparation.

10 passes per week for three and a half months (End July - Oct) loaded with The peat surface did not remain even 
225kg to mimic carrying guns and after track laying and was sometimes equipment to butts compared to the lower where the wheels of the vehicle unsurfaced track which was subject passed. Increased driving frequency to two passes per month protected did not influence the extent of peat only by its dwarf shrub layer. Even surface lowering. (Max. average drop at this rate of use, driving had to be measured was 6cm) This may have led stopped on the unsurfaced section due to small scale changes in peat structure to damage to the turning area - a key and the formation of channels for consideration for vehicle use. 

overland flow of water which could be problematical in some situations. 

## Vegetation

Surface peat demonstrates natural variability of permeability with Vegetation re-growth will depend to horizontal flow typically known to be a degree on the original vegetation faster than vertical flow. The effect of composition and abundance and site the mesh track on permeability showed preparation technique used prior to variability but generally vertical flow laying. However, the recovery rate of slowed and horizontal flow speeded bryophyte (mosses) compared with up. However, neither trend was related vascular plants was found to be faster. 

to driving frequency and they were Driving frequency did not affect regenerally insignificant from a statistical growth or abundance of key species point of view.

on the mesh track but vegetation 

## Results Continued

The lowest percentage of bare peat was 

## Rutting

in the most frequently used section. This suggests that the track prevented Both track surfaces offered protection rutting and braiding that occurs on from damage to the peat surface. 

non-surfaced tracks.

Rutting did occur on the lower section and turning area of the no-surface route section after 24 passes. This had 

## Overland Flow

very light use during the trial (twice per month) and was stopped early (12 
There was less overland flow in the months not 18) due to the damage control area where vegetation was being caused. It is precisely this damage disturbed least i.e. no site preparation that practitioners and conservationists or driving. Frequency of use or track seek to avoid by finding a pragmatic type did not affect overland flow but solution.

naturally occurring overland flow was seen to channelize, especially where the track was at the bottom of the 

## Bare Peat

slope and at times of higher rainfall. Diverting overland flow down the mesh No vegetation survey was carried out surface is not desirable and a balance immediately after the tracks were between preparing track route before laid and compared to the survey of laying and leaving enough vegetation vegetation before preparation started. 

roughness is important.

It is therefore not clear what caused bare peat but it could be:
N.B. For more detail, please see the inside back cover for the full a) the natural result of removing the scientific report reference. 

canopy revealing patches with no moss layer. However, only 1-2% cover (after driving) of bare peat was evident in the unsurfaced treatment where no vegetation removal took place and there was no evidence of bare peat recorded in the vegetation survey before site preparation on the track routes. 

b) mechanical scalping during site preparation and/or c) the effect of driving coupled with overland flow. 

## Conclusion

Both the wooden structure for 4x4 use and the plastic mesh had little effect in the physical and hydrological properties of the peatland within the timescale of the trial. Hydrological properties remained intact even with increased driving frequency and loading of vehicles. 

Driving seemed to have little negative The 4X4 track also proved successful impact on blanket bog vegetation for not interrupting hydrological community on both types of track function to any great extent within surface which showed signs of the timescale of this trial but there recovery since site preparation even is some vegetation loss beneath the with frequent use. The unsurfaced structure.  
route had a very high density of possibly cushioning vegetation However, the trial was only short term coverage, yet showed evidence that and therefore long term effects are vegetation height was lowered with still unknown and may be the subject a suggestion of a wheel rut profile of future research. 

forming across the track cross-section even with light use.

A review of the hydrological impact of existing stone tracks on deep peat 

## Consent

in The North Pennines and Cheviots was also undertaken as part of this From the results, Natural England collaborative work. Although caution 
(NE) is content to continue to give is needed in interpreting the results, and renew time-limited consents moisture content around older stone 
(typically five years) for mesh tracks tracks (15 years or more) was lower on designated blanket bog sites as implying that there could be an a pragmatic solution to the balance increasing impact on the hydrological between required access and function (connectivity) over time/age conservation objectives.

of the track. When the track runs parallel to the contours - cutting across flow pathways - the effect is NE consent does not give planning seen to be greatest on the downhill permission and each local planning side of the track. 

authority may interpret mesh surfacing differently.  Each local planning authority should be contacted in advance of any track installation.

## Acknowledgements

The Project Partnership would like to thank the following: The research student, Kathryn McKendrick-Smith for her hard work and commitment and Leeds University for supervising and supporting her. To John Carrick of Carrick Contractors Ltd for supplying and installing the 4X4 track and for his continued interest throughout the time of the project. To Martin Furness for facilitating access to Moor House NNR. To Bev Ridley for her driving of the Argocat. We would also like to thank the MA members who allowed Kathryn to access and study some of the existing tracks on sites around the North Pennines.

For further reading on this study see: McKendrick-Smith, K., Holden, J., and Parry, L. (2017) The Impact of Tracks on Blanket Peat Ecohydrology - Summary Report, University of Leeds.

Blanket Bog Track Trial Moor House NNR
in Partnership