• About us
  • Objectives
  • Biodiversity
  • News
  • Events
  • Contact us
  • Useful Links

Upland Ash Woods

Upland mixed ashwoods comprise a broad range of woodland types on freedraining base-rich soils. Ash Fraxinus excelsior is usually a major species, but oak Quercus spp., elm Ulmus spp., and birch Betula spp., may also be locally abundant. Yew Taxus baccata may also form stands in an intimate mosaic with the other major tree species and alder Alnus glutinosa may occur where there are transitions to wet woodland. Many of these woods are ancient, but ash is a vigorous colonist of open ground and secondary upland mixed ash woodland can form rapidly. The name upland mixed ashwoods reflects the abundance of this type of woodland in upland Britain rather than the altitude at which sites may occur. Many sites may be found just above sea level, for example Castle Eden Dene in County Durham. Upland mixed ashwoods are generally taken to equate to three particular communities of the National Vegetation Classification (NVC): W8 ash Fraxinus excelsior - field maple Acer campestre - dog’s mercury Mercurialis perennis woodland; W9 ash Fraxinus excelsior - rowan Sorbus aucuparia - dog’s mercury Mercurialis perennis woodland; and W13 yew Taxus baccata woodland.

Mixed ashwoods are amongst the richest habitats for wildlife in the uplands, notable for flowers such as bluebell Hyacinthoides non-scripta, primrose Primula vulgaris, wood crane’s-bill Geranium sylvaticum and wild garlic Allium ursinum. Many rare woodland plants and trees occur only in ash woodlands and the habitat may be particularly rich in lichens and invertebrates.

Current status

There is no precise data on the total extent of upland ash woodlands in the UK, but in the late 1980s the Nature Conservancy Council estimated that the total extent of ancient semi-natural woodland of this type was 40 000 to 50 000 ha. Over the last fifty years it has declined in area through clearance, overgrazing and replanting with non-native species. A crude estimate places the total area of upland ashwood at 67 500 ha.

Within the North East, examples of W8 or W9 type woodlands are thought to be found in all districts. It is therefore likely that examples of upland mixed ashwoods are found within each local planning authority area in the Region, with overlap with other types of lowland mixed deciduous woodland. Particularly important examples of upland ash woodlands are found in the upland valleys and ravines of the North Pennines and Border Uplands/Northumberland National Park, and within coastal denes on the Magnesian Limestone of east Durham. Many of these sites are designated as SSSIs and one site, Castle Eden Dene, is a Special Area of Conservation (SAC).

Threats

  • Overgrazing by domestic stock, deer and rabbits, leading to a loss of ground flora, difficulties in regeneration of tree species and changes to the woodland structure.
  • Invasion by tree species which are not native to ashwoods, such as sycamore Acer pseudoplatanus. Invasion by bracken Pteridium aquilinum reduces or prevents the regeneration of tree species.
  • Dutch elm disease has changed the structure and composition of many woods since the early 1970s.
  • Nationally, quarrying threatens some sites.
  • Intensive farming methods have led to a simplification of the landscape and removal of field boundaries which caused greater ecological isolation of woodlands.
  • Semi-natural woodlands have declined in many areas over the last 60 years as a result of replanting, development and conversion to grazing. Recent changes in policy (eg by the Forestry Commission) have greatly reduced the amount of inappropriate planting that takes place in woods.

Opportunities for protection and enhancement

  • Enhancement through fencing to eliminate/reduce grazing; supplementary planting, bracken spraying, gap creation, scarification etc to encourage natural regeneration of tree species; creation of links between existing woodlands and boundary features to reduce the effects of habitat fragmentation.
  • The Forestry Commission’s Woodland Grant Scheme gives grants for the planting of new woodlands. The Annual Management Grant and Woodland Improvement Grant make payments for the management of existing woodlands.
  • The New Native Woodlands in National Parks Challenge scheme and the Jigsaw Challenge within the North Pennines are targeted at creating new native woodlands, extending and linking existing semi-natural ancient woodlands.
  • The Northumberland National Park enters into woodland management agreements with landowners to secure the management of existing woodlands.
  • Castle Eden Dene is managed as a National Nature Reserve (NNR) by English Nature.
  • A number of other woodland sites, such as Hawthorn Dene on the Durham Coast, are managed as nature reserves by conservation bodies.
  • New areas of native woodland are being created by the Great North Forest and the Tees Forest.