SNH is very concerned about this serious threat to a tree of great importance to our natural heritage. We are working closely with Forestry Commission and other Scottish and UK bodies to develop a greater understanding of the threat, and to determine an appropriate response. For further information please see www.forestry.gov.uk/chalara
These are the woods of our richer soils, often hidden away in dens and gullies, and as such they have a very restricted distribution throughout Scotland. Ashwoods are typically moist and shady, and wherever they occur they form rich assemblages of woodland plants including many rare and colourful species. In the uplands, they can represent real oases of biodiversity with a wide range of associated species in an otherwise barren landscape.
The largest ashwoods occur on limestone, i.e. on well-drained, base-rich soils, but the type is also found on more acid poorly-drained soils where there is flushing of nutrients. Often these latter are just small fragments of woodland with irregular margins or narrow strips along flushes, riparian tracts, outcrops and steep banks. Characteristically, these woods are dominated by ash, but may also feature wych elm, oak and hazel, and alder may be present where the ground is wetter. In the north-west of Scotland ash is often scarce, but the type is represented by some of the most westerly European examples of coastal hazel scrub that is rich in lichens and higher plants.
Because of the strong association in distribution between this woodland type and limestone, many ashwoods contain archaeological features that point to people's long historical involvement with ashwoods such as small quarries, the remains of lime kilns and other relicts of an industrial past. Many of these woods have been treated as coppice in the past, others have been wood-pastures, but most now have a high forest structure.
Most ashwoods are probably ancient, and they are amongst the richest habitats for wildlife in the uplands, notable for bright displays of flowers such as bluebell, primrose, wood cranesbill and wild garlic. Many rare woodland flowers occur in upland ashwoods, such as dark red helleborine and whorled Solomon's seal. Ashwoods also harbour a rich invertebrate fauna, which may include uncommon or declining species. The alkaline bark of old ash (and elm where it still survives) supports an important lichen flora, particularly the Lobarion community. Amongst the breeding birds are redstart, wood warbler and, in north-west Scotland, redwing.
Upland mixed ashwoods are included in the Scottish Biodiversity List of habitats and species that Scottish Ministers consider to be of principal importance for biodiversity conservation in Scotland. They are also protected under the European Habitats Directive .
There are some wonderful examples of this woodland type to be visited in our National Nature Reserves such as:
Rassal Ashwood is one of Scotland's few natural ashwoods and the most northerly in Britain. The underlying limestone creates unusually fertile soils, which support many flowering plants. The woodland was once managed to provide feeding for grazing sheep and cattle, and many trees show signs of historical pollarding or repeated harvesting.
Glasdrum Wood This wild woodland climbs from the seashore near the head of Loch Creran up the slopes of Ben Churalain. The changes in altitude and the presence of both acid and lime-rich rocks make for a rich variety of trees, plants and insects. The reserve is also notable for a range of butterfly species, including the rare chequered skipper .
Clyde Valley Woods This reserve features gorge woodland that's typical of the Clyde Valley. The steep gorges have protected the rich mix of ash, oak and wych elm trees from felling and grazing. There is a wide variety of bird life, including warblers, flycatchers and redstarts, and in spring, colourful carpets of bluebells and primroses greet you.
Ballachuan Hazel Wood is a Scottish Wildlife Trust reserve in Argyll. The Atlantic hazel woodland cloaks a low ridge overlooking Cuan Sound. It is a site of international importance for its lichen flora, with many species depending on the hazels. The wood has rich ground flora and is a good site for breeding birds and summer migrants.
Last updated on Tuesday 18th December 2012 at 14:03 PM. Click here to comment on this page