Gill and clough woodland
Sensitive management and replanting of woodland and scattered trees can benefit certain birds in the uplands.
Gill and clough woodlands
Most of the uplands below 600 metres would have historically been covered by broadleaved woodland. However, in many upland areas, woodlands are now confined to steep-sided valleys, ravines and gills or cloughs.
Although some bird species, notably wading birds, avoid woodland in the uplands, sensitive management and replanting of woodland and scattered trees can benefit certain other birds.
Extensive planting of conifers is generally of little value for upland biodiversity.
- Identify suitable areas for the recreation of new woodland and the planting of scattered trees. Where necessary seek specialist advice.
- Identify areas of existing woodland and maintain and restore native tree and shrub species.
- Grant aid may be available from statutory conservation agencies and through agri-environment schemes.
Benefits to wildlife
Gill/clough woodland has a characteristic community of plants and wildlife
Upland woodlands consisting of native tree species, for example sessile oak, birch, rowan and ash, can be rich in a variety of specialist insects and plants. Woodland flowers, for example bluebell, primrose and wild garlic, can also be found. A number of rarer species such as herb paris may be present too. Patches of ancient woodland can support a high diversity of ferns, lichens and bryophytes.
Gill/clough woodland can provide important feeding habitat for birds
Berry-bearing trees and shrubs such as rowan, juniper and hawthorn are an important source of food for a variety of birds. These berries can provide a source of food for ring ouzels after the breeding season and can be used as a winter food source for black grouse.
Gill/clough woodland can provide important nesting habitat
Tall, open woodland can harbour a distinctive group of breeding birds including redstarts, pied flycatchers and wood warblers. Scrub can be important for species such as black grouse, nightjars and stonechats.
Where to create new woodland?
- New woodland is best created next to existing woodland where natural regeneration can reduce establishment costs.
- Sites which are of current high nature conservation should not be chosen for new woodland creation.
- Consideration should be given to existing species interest - woodland can be detrimental to breeding waders and also to ring ouzels which prefer un-wooded, steep-sided gills or cloughs.
- If black grouse is a target species, plant low density scattered trees.
- On steep-sided slopes, which are dominated by bracken, planting trees can often be the simplest and most cost-effective method of enhancing conservation value.
- Where natural regeneration is preferred, grazing will need to be excluded to allow seedlings to develop.
- Natural regeneration should only be chosen if there is a nearby seed source, for example if the site is next to existing trees and shrubs.
- Although this method of establishment can take many years to achieve results, natural regeneration is a low cost and minimal management technique. Resulting woodland will be natural and have a diverse structure.
Planting young saplings rapidly establishes trees. This allows trees and shrub species to be introduced for a particular conservation purpose, for example, planting berry producing species for birds.
- Choose species that naturally occur in the area and are suited to the local soil and climatic conditions.
- There is a high financial and management cost with planting. Resulting woodland may have a less natural appearance than naturally regenerated woodland.
- When planting saplings within bracken stands, clear the bracken immediately surrounding the sapling, approximately 1m, to aid establishment. Protect the saplings using plastic tubes.
- Planting can be used in combination with natural regeneration, particularly in establishing species that may be slow to colonise, such as oak.
- Planting broadleaved trees near stands of conifers can be beneficial for black grouse which feed on birch buds, as well as berries of rowan and hawthorn.
- Planting of scattered trees at a low density is beneficial for the widest variety of wildlife.
How to manage
- Where natural regeneration is chosen, grazing will initially need to be excluded to allow seedlings to develop. Fencing can be expensive, particularly on larger sites. Rotationally fencing small areas for 10-15 years will reduce costs and encourage a habitat mosaic. Planted saplings can be protected from grazing with tree guards.
- Winter grazing is a particular threat to establishing saplings, which may be preferentially browsed.
- Management of grazing will depend to some extent on what the species objectives are for any given site. Light grazing can be beneficial for some species of woodland plants as it reduces competition and shading effects. Ground disturbance associated with grazing can create bare patches ideal for seed germination.
- Heavy grazing can lead to a reduction in shrub cover that results in a loss of nesting and foraging habitat for some bird species, and can reduce floral diversity. Birds such as redstarts, tree pipits and pied flycatchers prefer an open wood with little shrub cover (<30-40 per cent), which is provided by low to moderate stocking densities as part of a woodland grazing regime.
Other management considerations
- Burning is a common management tool in the uplands, but is very detrimental to woodland. Fires should not be allowed to spread into woods or areas next to woodland where regeneration is desirable.
- Deadwood should be left in situ to provide habitat for specialist insects, fungi and bryophytes.
- Avoid supplementary feeding of livestock near areas of woodland. Providing winter housing for livestock may reduce their need to utilise woodland as shelter.
- Rhododendron is a major problem in many areas and needs to be controlled and eliminated where possible.
- Where black grouse are present, care needs to be taken with fencing. Many grouse can die by flying into certain types of fence. In such areas mark new and existing fences.
- The number of nest sites for bird species such as pied flycatchers and redstarts, can be enhanced by the provision of nest boxes.