Blanket bog is only found in a few cool and wet parts of the world. Mosses and other plants break down over time to create a layer of peat which forms a habitat that dominates the landscape of upland Scotland. The peatlands host an assortment of wildlife, including iconic moorland breeding birds such as the hen harrier, golden plover and red grouse and plants such as heather, butterwort, bog asphodel and of course sphagnum moss.
There is however, a more fundamental attribute to peat that makes it essential in the landscape. The sphagnum moss which drives peat formation holds significant amounts of water and releases it very slowly. This means it filters towards the lowlands over a long period of time, so provides a degree of natural water regulation preventing downstream flooding.
The peat formed also plays a crucial role in slowing the effects of climate change. Organic matter barely decomposes in cool, waterlogged conditions, which means that the carbon stored in the generations of plants and animals that make up the peat is locked away. That’s many millions of tonnes of carbon that would otherwise be released into the atmosphere.
The National Trust for Scotland (NTS) has embarked on work to restore peatland habitats at Goatfell, Ben Lawers and Ben Lomond. Surveys revealed damage to natural drainage systems and erosion caused by past agricultural practices. In the 1940’s, deep drainage ditches were dug throughout the bogs as it was thought if the peat bogs could be dried out, the land would provide suitable conditions for crop growing. It was never a success but has now left large ditch scars across the landscape which now require attention.
We spent this week on Ben Lomond with Alasdair Eckersall, property manager and senior ranger with the National Trust for Scotland. He took us to see these ditches, some of which must have been at least 6 feet deep. He showed us areas where the restoration had already begun and how it was having a positive effect.
The idea was to remove the dark, oxygenated peat from the ditch surface to reach the milk chocolate coloured peat below. A large square hole was then dug down below the drain level which would be filled up with large building blocks of good peat to form a dam. The dam will form a solid wall in the drain, unable to be penetrated by water. The excess water backed up by the dam will then overflow into a side ditch and this will allow water to collect in a reservoir and slowly lap over the sides, gradually water-logging the surrounding landscape.
We built these dams approximately every 4m down the ditch line. It almost reminded me of a canal lock like Neptune’s Staircase, and the dams immediately began to work, filling up the reservoirs. The darker peat is unable to block water flow as it has been aerated so becomes waste material which can be transferred into these reservoirs along with any sphagnum moss to encourage future growth.
The mountain bog restoration work is just one of the nature conservation projects which form part of Loch Lomond & The Trossachs National Park’s five flagship ‘Wild Challenges’. They also include improving woodland habitats, increasing the number of red squirrels and black grouse, and the removal of non-native invasive species.
I have attached a link to some SNH peatland action videos for some more information if anyone is interested – http://www.snh.gov.uk/climate-change/taking-action/carbon-management/peatland-action/peatland-action-videos/
We also had the chance to practice some of our site specification drawings and costings by carrying out surveys at The Harry Lauder Memorial walk in Argyll, the Beinn Dubh hill path, the Callander Crags and Duncryne Hill (The Dumpling).
Our week was finished off with a visit to Craigmore, our first path site up at Aberfoyle. It was really cathartic returning to site over a month later to see the path with fresh eyes. We got to see the effects that water has had on the path now we have had all this rain and how successful all of our drainage features are. The vegetation growth and transplanted turfs are lush and green and other than a few ‘tweeks’ here and there, we were all really pleased with how it’s looking. It has been really good for us as a team to see that all the hard work we put in has been worth it and have a sense of pride over our first project.