Trees with Altitude

Tom Bowser, Head Ranger of Argaty Red Kites, explores the value of montane woodland and discovers an exciting new restoration plan to return small trees to the mountain environment.

“Trees don’t grow at altitudes of over 500 metres.”

It’s a comment that we frequently hear. Have we become so used to barren hillsides, devoid of life, over-grazed and strip-burned to the knuckle that we can no longer imagine a time when our landscape looked any different? The truth is that it did once look different. Very different. The word ‘scrub’ is often used dismissively. “It’s just scrub,” is an excuse used to negate the natural value of small trees and shrubs when they are removed to make way for development, or cleared because they form dense impenetrable thickets. However, the importance of ‘scrub’ for biodiversity is immeasurable.

When it comes to altitude many of our hills were once cloaked in ‘montane’ tree species. Often windhewn and skeletal, these diminutive plants evolved to withstand the vagaries of the elements and previously created a buffer zone between the lush woodlands of the glens and the mountain summit. Typical montane species include dwarf juniper, downy, woolly and mountain willow, dwarf and downy birch.

Eared willow and downy birches at Loch nam Eun

There is far more to montane woodland than we may appreciate. Foliage may sometimes be sparse, but tenacious roots can stabilise entire hillsides, guarding against flooding and erosion. Where it thrives so too do rare mosses and lichens, alpine flora and its numerous associated invertebrates, micro-organisms and small mammals. This is turn provides food and shelter for other birds and mammals, and ideal hunting ground for golden eagles, buzzards and hen harriers.

Sadly, due to extreme grazing pressures, montane woodland has almost entirely vanished. The charity, Trees for Life (TFL), hopes to change modern perceptions of how our uplands should look. In 2008, they bought Dundreggan, a 4000-hectare sporting estate near Loch Ness. After decades of over-grazing, all natural regeneration had stopped. TFL began an ambitious 50-year project to restore life to Dundreggan. “Our first challenge was dealing with grazing pressure,” says Doug Gilbert, Dundreggan’s Operations Manager. “We fenced the boundary so sheep didn’t stray from common grazings and impact on native woodland remnants. Deer were an issue too. Our stalkers reduced the population from around 350 to roughly 150. To protect planted trees, we build deer fences. Historically, deer were woodland animals. Ideally, we wouldn’t keep them out of our woods, but we can’t control numbers on neighbouring estates. In the short term fences are the only practical solution here.”

With the grazing animals excluded, birch, oak, hazel and pine are already regenerating on the heatherclad hillsides. This spring, TFL began the next phase of their work, planting some 10,000 rare montane species. They aim to re-establish an area of Dundreggan on Beinn Bhan, some 500-600 metres above sea level. Having raised £20,000 to finance the project, planting is now well underway.

“By 2058, we want woodland to cover around 60% of Dundreggan,” says Doug. “Some of that will be regeneration, but most will come from replanting. We have a native tree nursery and our staff and volunteers collect seed from up high to grow on before planting out the young trees. We hope that woodland habitats will stretch right over the hill and down into Glen Affric.”

Polytunnels at the Dundreggan nursery

“We aim to demonstrate the importance of upland forest. Presently native woodland covers only 4% of Scotland and that’s simply not enough. Trees can store carbon for centuries and absorb up to 50 times more water than open upland habitats, mitigating against downstream flooding. Their purpose goes further than that, though. Presently lowland forest areas are disconnected. Our wildlife is trapped. If animals and birds wish to move between woodlands, they have to travel across open ground, risking predation. If we can bring scrub back to the uplands, we can change this; we’ll link forests and create corridors for wildlife to move through.”

Climate change hangs over us like a black cloud and our biodiversity continues to crash. A burgeoning forest of wind-sculpted, waist-high trees fringing the regenerating woods of Caledonia would help with both of these problems. Scrub is never ‘just’ scrub, and montane woodland, Scotland’s weather-battered, wind-hewn bonsai trees, is another vital link in the ecological big picture.

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Published in Think Like A Mountain: Inspiring stories from the rewilding world. Issue 08 September 2019.

Dundreggan is Trees for Life’s flagship rewilding site, and a biodiversity hotspot with a growing reputation as a ‘lost world’ due to the many rare species discovered there. More than 3,300 species have been discovered at the forest restoration site – including 11 species never recorded before in the UK.

Featured image shows eared willow montane woodland.