Schiehallion 25: a lasting legacy

As the Trust celebrates 25 years of caring for East Schiehallion, we reflect on all that has been achieved on this special mountain – and what more is to come.

In many ways, Schiehallion can lay claim to being the most famous mountain in the UK. Admittedly, it may not have the highest peak kudos or mass appeal of Ben Nevis, Yr Wyddfa (Snowdon) or Scafell Pike but Schiehallion’s curious mix of rare geology, recovering habitats, scientific history and cultural identity give it a depth of interest that few other mountains can match.

Anglicised from the Gaelic, Sìth Chailleann, meaning ‘Fairy Hill of the Caledonians’, Schiehallion’s distinctive, cone-shaped summit rises high above the waters of Loch Rannoch in Highland Perthshire.

Since 1999, the Trust has cared for the 871ha East Schiehallion estate which extends across the eastern flanks of Schiehallion to the wilder Gleann Mòr to the south. A designated Site of Special Scientific Interest, the whole area holds an incredible diversity of habitat and species: calcareous grassland, upland heath, peatland and regenerating woodland that between them are home to ptarmigan, black grouse, ring ouzel, mountain hare, pine marten and golden eagle.

Changing landscape

Over the past quarter of a century, Trust staff have got to know every rock, hump and hollow across the mountain. And the landscape has begun to respond to the care and attention it has received.

Perhaps most apparent to the thousands of walkers who reach Schiehallion’s boulder strewn summit every year has been the realignment of the main mountain path onto a more sustainable and less intrusive line. The terrible scarring of the previous path (pictured above left) has also been repaired. Today, this ‘new’ 4km section of path is carefully maintained to prevent erosion that could potentially damage surrounding habitats.

But Schiehallion is not just about high mountain ridges. The Trust has also established the Braes of Foss Loop, a 1km all-abilities path that enables those less physically able to immerse themselves in the surrounding landscape.

The path also offers visitors an opportunity to see how new native woodland can regenerate over time. In 2017, the Trust established the Heart of Scotland Forest Partnership, a coordinated and large-scale regeneration of the landscape together with neighbouring estate owners, community bodies and nature conservation partners. The aim is to restore and connect pockets of native woodland across 3,000ha of land between Schiehallion and Loch Tummel.

As part of this mountain woodland project, more than 12,000 native trees have been planted at Schiehallion, beginning the gradual regeneration of 40ha of native woodland. Many have been grown from seed collected locally, creating a tree stock that is perfectly suited to the environment.

Engagement with the local community and visitors is another key component of the work at Schiehallion. Working with volunteers, the Trust has hosted numerous tree planting schemes and created an educational nature club for students from Fairview School in Perth.

Most recently, Trust staff have been involved in Connect Outdoors, a pilot educational hiking programme in partnership with Tiso and MhÒr Outdoor. The aim is to introduce people from under-represented communities to the outdoors in a way that inspires long-term and meaningful engagement with the natural world.

Weighing the world

Of course, Schiehallion’s appeal long precedes the Trust’s current involvement. Coincidentally, this year also marks the 250^th anniversary of astronomer Nevil Maskelyne’s experiment to determine the density of the Earth – which used Schiehallion as its muse.

In 1774, Maskelyne developed an idea, first proposed by Sir Isaac Newton, of observing how much the gravitational pull of a large mass, in this case a mountain, affects a pendulum. Following a lengthy search for candidate mountains, Schiehallion was chosen due to its unique symmetry. Of equal importance was its relative isolation as there would be no interference from the gravitational pull of other mountains.

At observation stations built on the north and south slopes of the mountain – of which stone ruins remain today – Maskelyne’s team hung a pendulum to determine whether the gravitational pull from the mountain would draw it away from the vertical pull of the Earth below. As he predicted, Maskelyne observed a clear pull towards the mountain, deviating the pendulum away from true vertical.

But that wasn’t the end of the experiment. It was then necessary to map the entire mountain – a task bestowed on mathematician Charles Hutton, who calculated the mountain’s volume using thousands of precise longitudinal and elevation readings. To make this complex endeavour more manageable, Hutton connected readings at similar altitudes together by drawing lines to form rings. These rings were the very first contour lines – another claim to fame for Schiehallion!

Using Maskelyne’s measurements of the angles of deviation of the pendulum, alongside knowledge of the mountain’s volume from Hutton’s calculations, the scientists were able to extrapolate the relative density of the Earth – and all within 20 per cent accuracy of modern-day calculations.

Next steps

Over the next 25 years, the Trust will continue to work towards creating a natural tree line on the mountain, reducing browsing pressure so that native pine and oak woodlands can continue to re-establish on the lower slopes and species such as aspen, birch, rowan and willow can return and climb the mountain’s broad flanks.

The ambition is for this natural tree line to gradually give way to areas of montane scrub, with sparser coverage of dwarf birch, juniper and montane willows at higher altitudes – a low-density woodland that will provide outstanding habitat for a variety of species.

To help achieve this, the Trust will remain an integral member of the Heart of Scotland Forest Partnership and work with partners to deliver volunteering and training opportunities. Engagement work will also continue, with particular focus on supporting those who experience barriers to accessing the outdoors to connect with wild places.

These efforts will be aided considerably by  the Trust’s East Schiehallion Mountain Woodland Project Manager, Tom Corke who is overseeing an exciting mountain woodland project that will bring so much to the biodiversity of the landscape.

“Schiehallion is a fascinating place and the Trust’s work here has come a long way over the past 25 years,” says Tom.

“In time, this woodland restoration work will create a seed source that will allow for natural regeneration of the landscape without the need for planting in the future. I can’t wait to see that ambition become a reality.”

• This article first appeared in the Spring 2024 edition of the John Muir Trust Journal. If you would like to receive our Journal twice a year please consider joining the Trust as a Member.
• Read more about mountain woodland.