Craigengillan Aspen Arboretum and Agroforestry Trial
Much of Eadha’s aspen work has focused on Galloway where through a partnership with the Forestry Commission, Eadha was tasked to map and collect samples of all remaining aspen clones growing wild in the district for conservation and propagation. Eadha has been seeking a site to establish and showcase the full collection of Galloway clones. Eadha has a good relationship with Craigengillan Estate having supplied aspen trees to their Jubilee Woodland Project in the past. Through discussions with the estate, an area of land was identified as suitable for establishing this collection.
An exciting new project was then scoped for Craigengillan which exploits the unique characteristics of the aspen tree to serve a range of multiple purposes. Exploiting its strategic location at the gateway to Galloway and the Forest Park, the site is an ideal location to host the Galloway clone collection and to develop a unique demonstration project for aspen agroforestry. Aspen clones can vary widely in their characteristics (form, vigour, colour, timing of flushing etc). Planting the clones together at a single site offers an ideal opportunity to conduct growth trials to identify superior clones for vigour which can be preferentially propagated for productive woodland projects effectively create an arboretum. The site is and will remain organic pasture for sheep and cattle. Prior to planting the estate reseeded the site with a native grass mix.
During 2020, a total of thirty four fenced enclosures were installed by East Ayrshire Woodlands across the 7 Ha field at 24m centres. Within each enclosure, five trees of each clone from the collection were planted. The trees were protected in 1.2m tubes.
We are also planning to undertake a phase 2 project during 2021 replicating the planting again to double up the number trees.
In time the fenced enclosures will protect any sucker growth from grazing by livestock. Aspen is one of the most nutritional dense tree species hence its high palatability. When the suckers have grown to a certain size, the enclosures could be opened, allowing livestock to graze on the suckers benefiting from the supplementary nutrition.
Pollarded aspen in Norway, with branches tied to trunks to dry for winter fodder
The estate is actively managing its woodlands and thinnings are used for the estate biomass heating system. After 15 years of growth the aspen trees could also be coppiced to provide woodfuel. In this case the fenced enclosures would be used to protect the regrowth of each coppiced clump. This would be undertaken on a rotational system to ensure a continuous supply and creating a diversity in age classes across the site. A selection of leader stems would then be selected for protection in tubes enabling the fence to be moved to another clump and so on.
Some of the aspen trees could be allowed to grow on to maturity creating further diversity and providing larger diameter timber. Some of the trees could also be pollarded and it would be interesting to compare the suitability of different clones for this.
C18th century etching of aspen pollard
The planting of aspen will also have many other benefits. Once the trees mature, they will provide shelter for the sheep and enhance the landscape. The clumps will also provide a home for wildlife. Aspen supports more rare biodiversity than any other native tree species in the UK. The trees may also benefit the soils, improving drainage and increasing rainwater infiltration, reducing flood run-off. The trees will also sequester 110 tonnes of carbon in their lifetime (if left uncut).
Thanks to Daisy Whytock from the East Ayrshire Coalfield Environment Initiative for the Drone Footage