Monday, November 5, 2018

The Importance of Peat...


Over the last few weeks you may have seen that whilst the summit path works have been completed, the diggers have still been busy on the top of the hill. This is because we are continuing to work with the specialist restoration contractors Conservefor, this time to restore the damaged peatland habitats on the plateau of the hill.

But what is all the fuss about? What is peat, and why is it so important?

Peat is a type of soil which is formed in places where rainfall is high and temperatures are just about high enough for plants to grow, but no so high to allow the dead plant matter to decompose quickly. Lack of oxygen and acidic conditions help to slow the rate of decomposition further, leading to an accumulation of peat over time, at a rate of around 1mm per year. These conditions allow for the preservation of organic materials within the peat, and so the peat becomes a time capsule and a direct connection to the past. Cores taken down through the peat contain pollen from the plants which inhabited the surrounding countryside up to 5000 years ago! Many of you will have heard of Lindow Man, or Pete Marsh, a local lad who was murdered and dumped in a peat bog around about 90AD, and whose preserved remains can now be seen in the Museum of Manchester. The lack of oxygen and acidic conditions of the bog meant that even the parasitic worms in his stomach were preserved!


Carpet of brightly coloured bog mosses
On Pendle, the peat is mainly made up from Sphagnum moss or 'bog moss', a group of species which range in colour from yellow and acid green through to vibrant reds and earthy brown and form a living carpet over the surface on the peat.  

Sphagnum mosses can hold up to twenty times their weight in water and have antiseptic qualities which were highly prized during the First World War as a dressing material. The following was written by Mrs A M Smith, a member of the Edinburgh War Dressing Supply organisation, in 1917:

The doctors and the nurses

Look North with eager eyes,

And call on us to send them

The dressing that they prize

No other is its equal---

In modest bulk it goes,

Until it meets the gaping wound

Where the red life blood flows,

Then spreading, swelling in its might

It checks the fatal loss,

And kills the germ, and heals the hurt-

The kindly Sphagnum Moss

So over time, the bog mosses continue to grow and peat is slowly formed. The high carbon content of peat means that like its drier, harder, older cousin coal, peat can be burnt as a fuel once it has been dug and dried. There is evidence of peat cutting up close to the summit, this would have been done by hand with special long narrow spades to form brick shapes, which were then brought down the hill on pony drawn sleds.

Why do we need to restore the peat on Pendle?

Peatland restoration aims to restore the moorland habitat covering the peat in order to ensure the peat continues to form. Damage to the vegetation has been caused in various ways – fire, grazing, and feet have all contributed. Once 'holes' are formed in this layer, the soft peat is very vulnerable to being washed and blown out by the wind and the rain.

Damage to vegetation leaves the underlying peat vulnerable to erosion.

The peatlands themselves are an important part of our upland landscapes and are home to many speciality species such as the aptly named Cloudberry, as well as our much loved upland birds – curlew and dunlin, meadow pipits, sky larks, raven and golden plover. They have an intrinsic value which forms part of why Pendle is so important to so many people, and habitat restoration is one of the three main reasons for undertaking this work.

Erosion of the peat soils releases carbon into the atmosphere. The peat is also washed off the hill in rivers and streams, where it then silts up important spawning gravels and needs to be removed from our drinking water. Recent work by the University of Leeds shows that over 40% of the UK's population rely on peatlands for their drinking water sources, and so we need to ensure they are kept in as good condition as possible.

Restoring moorland habitats also helps to manage local flood risk. Eroded gullies through the peat allow water from severe local rainfall events to run quickly off the hill, adding to the total amount of water reaching rivers and streams all at the same time. 'Slowing the Flow' of water down off the hill helps to reduce the risk of all the water ending up at the same place at the same time.

And how are we doing it?

Back to those diggers! Right up on the summit where there are areas of bare and eroding peat, the contractors have 're-profiled' the edges of the peat. The contractors carefully peel back the vegetation layer, reduce the angle of slope on the edge of the peat and then roll the vegetation back into place, stretching it out to cover as much bare peat as possible. This will be covered with chopped heather in the winter and seed will be added next spring.

Digger working on the edges of the peat, with coir logs already in place.

 

To help to slow the flow of the water down the gullies, coir logs (nets filled with coconut husk), peat and timber dams are being installed. As the speed of the water is reduced, it also drops the peat it is holding, helping to reduce siltation downstream. The sides of the gullies are also being re-profiled to stop water erosion removing more peat during high rainfall events.

 8 tonne digger down in one of the gullies on Barley Moor, showing the scale of the problem!

So if you are up on the hill, you might just see some diggers performing these delicate operations, and if not you will see the results of their efforts. If you want to get involved with the intricacies of peatland restoration, join one of our volunteer days, and in the meantime you can see some live footage on this film we shot in the centre of the Forest of Bowland in February this year.