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As one of the partners in Cairngorms Connect, we've been carrying out enrichment planting of native broadleaves across Glenmore Forest Park. Over the summer, alongside Cairngorms National Park Volunteer Rangers and local volunteers, we removed the protective tree tubes from aspen trees that had successfully established and outgrown them.

Aspen is one of the most palatable species to deer, so to help it become established we used plastic tree tubes to protect it. Now collected, these protective tubes will be recycled. We have since introduced biodegradable tubes to our forests and land in an effort to work more sustainably.

Enrichment planting is carried out where species would struggle to recolonise without our help. This planting of aspen, alongside natural regeneration and ongoing deer management similar to that at Ryvoan Pass, helps to restore and expand our native woodlands. 

Currently, aspen is mainly found in small and fragmented stands. A rare part of the Caledonian Forest, aspen (Populus tremula), with its leaves on long, flattened stalks (petioles) that flutter even in a gentle breeze, is known as the ‘tremlin tree’ in Scots.

Aspen leaf

In Scotland, aspen flowering is rare with the last major flowering event in 2019 being the first for 23 years. As a result, it is difficult for aspen to spread and recolonise through wind pollination and subsequent seed dispersal.

However, aspen has another very interesting way of regenerating: the extensive root system of mature trees sends out shoots known as suckers. These suckers remain connected to the parent tree, receiving nutrients from it and effectively forming clones. Our young aspen have already begun to do this.

Sets of clones can be distinguished from one another by a variety of traits — everything from exhibiting a different colour variation to the time the leaves change in autumn.

Aspen tree in autumn

The coming weeks are a great time to see some of the vibrant shades of yellow that aspen can display. In addition to providing stunning colours to the autumn landscape, aspen supports a range of insects, lichens and mosses as well as birds and mammals. These include UK Biodiversity Action Plan (UK BAP) priority species, specifically the dark-bordered beauty moth, aspen hoverfly, aspen bristle-moss and blunt-leaved bristle-moss.

UK BAP priority species are those that have been identified as being the most threatened and requiring conservation action.