There’s something ecologically fascinating about edges. We tend to put our habitats into separate boxes – woodland, moorland, heathland, wetland – and draw lines around them. But often it’s the fuzzy bits between them that are most interesting.
Unfortunately, these are also the bits that get forgotten, which is why it’s particularly heartening to hear the news from Scottish charity Highland Birchwoods that it’s about to start a new Mountain Woodland project, planting 500,000 trees above the commercial treeline.
In our highest mountain areas, the tops are too cold, windy and exposed, and the growing season too short, for trees to establish. Instead, you find heather, bilberry, and other dwarf shrubs. But the natural boundary between this habitat and the woodland or forest lower down isn’t a hard line. Moving up the slope, the dominant forest cover changes from taller trees to lower-growing species such as rowan, juniper and willows, and then into montane scrub, with gnarled and twisted little trees, clinging on at the upper limit of their range, as well as low-growing or even prostrate species specifically adapted to the habitat such as dwarf juniper and birch, and montane willows.
This fuzzy, scrubby zone has been all but lost, probably due to grazing and browsing by sheep, goats and deer, and due to “muirburn” (burning of old growth on moorland to encourage new growth) and is now probably our rarest native woodland habitat. It’s not just the trees that are important here – though some of these, such as the woolly willow, are extremely rare. Associated with the habitat are unusual communities of tall herbs such as alpine sowthistle, globeflower and others that are today only found on inaccessible rock ledges. There are specialised invertebrates found on the willows and juniper.
Fortunately, there are remnant patches, and in recent years there has been great work going on in Scotland through an Action for Mountain Woodlands project to survey and record these, educate people about their value, and involve volunteers in propagating trees and planting new areas of montane scrub. The new project will pick up where this left off, with funding from Heritage Lottery Fund to help restore this natural fringe in three key areas of Scotland.
Last week I was lucky enough to visit one. At the Forestry Commission’s centre in Glentrool, in the Galloway Forest Park, south west Scotland, volunteers have created a mountain garden, where visitors unable to complete the hike up to the treeline can see many of the characteristic species of montane scrub on a miniature mountain slope. Nearby, on the slopes approaching the Merrick, the highest point in the Southern Uplands, a ten hectare area has been cleared of spruce and replanted with mountain woodland trees. Cuttings and seeds have been collected from montane species and grown on. Ultimately the aim is to replace nearly 3000 hectares of high elevation conifer plantation with new mountain woodlands of broadly native character, as well as conserving and cherishing the remaining fragments of montane scrub.
Inspirational to see, and a great reminder that our native trees and woods come in all kinds of shapes and sizes, and that biggest isn’t necessarily best.
Sian Atkinson, Conservation Communications & Evidence Adviser