Dundreggan nursery offers a lifeline for rare trees
At the Dundreggan tree nursery, we focus on growing the rare and hard-to-grow species of the Caledonian forest. Growing aspen has been a theme for Trees for Life since we started 30 years ago. Before Dundreggan, we had a small nursery in the grounds of Plodda Lodge, near Glen Affric. Indeed, the nursery at Plodda was set up because we wanted to grow local provenance aspen for planting in and around Glen Affric, and we couldn’t get it anywhere else.
For much of the time since, we have grown aspen from locally collected root cuttings. Aspen shoots, or ‘suckers’, from cuttings, however, are all clones of their parent. And trees do best when they are genetically diverse.
Growing aspen from seed allows for this genetic variation and it is much less time-consuming at the propagation stage. But finding local seed isn’t easy. Aspen doesn’t flower regularly like other trees, and even when it does, the males and females are often too far apart for pollination.
Inspired by the work of charity Coille Alba, today at Dundreggan we are producing local provenance aspen seed ourselves. To create our polytunnel ‘seed stand’, we have to find aspen trees in the wild that are known to flower. From these, we collect cutting material and then graft the cuttings onto young aspen trees. Moving these into the polytunnel, we ‘stress’ the trees to encourage flowering. Once they’re in flower, we collect pollen from the male trees and apply it to the female flowers - all of which hopefully results in seed catkins ready to collect in April and May each year.
This approach undoubtedly involves a lot of work, but it makes a big difference. Even a few catkins can potentially yield thousands of seeds and this means we can grow plenty of aspen seedlings ourselves, as well as supplying other nurseries too. In the last year, we have dispatched 12,000 aspen trees grown from seed, whereas from cuttings it was never more than two or three thousand a year. We’re planning to gradually extend the seed stand and hope that it will be able to make a significant difference to the supply of local provenance aspen across the Highlands in the future.
As well as making big strides in returning aspen to the landscape, since the nursery moved to Dundreggan we have specialised in growing montane scrub plants. These ‘wee trees’ grow at high elevations, and include dwarf birch, and dwarf willows such as downy willow and the rare woolly willow.
Montane scrub is a habitat that’s virtually missing from the Scottish landscape. Populations of dwarf willows, in particular, are often isolated and fragmented, and sometimes in poor condition due to overgrazing. So it can be difficult for our existing montane plants to regenerate. Some of the most important work the nursery has been involved with is setting up seed stands for rarer species of dwarf willows such as downy willow and whortle-leaved willow. And we grow these trees not just for Glen Affric and Dundreggan, but in collaboration with estates in other parts of the Highlands too.
With the seed stands, planted from cuttings from parents in the wild, we ‘capture’ the genetics of the wild populations. Even if there are further losses of plants in the wild, at least we have not lost their unique DNA. By producing seed in these stands, we can grow plants of local provenance to establish new populations and enhance those that need it in the future.
There is still a lot of work to be done in this area, but we are making progress and seeing the results. New montane willow populations are now thriving in the central Highlands, in places like the Cairngorms and Monadhliath mountains, as well as closer to home.
People are often surprised by how small Dundreggan nursery is. But when it comes to developing new techniques to save and restore the Caledonian forest - our reach is significant. It’s this tangible rewilding impact that has kept me at Trees for Life for the last 20 years - and still excites me today.
If you’re interested to learn more about our work at the nursery, you can book a tour at visitdundreggan.co.uk
Dundreggan tree nursery is kindly funded by Arcadia Trust and Brown Forbes Memorial Fund.
