Published in support of the UK Biodiversity Action Plan for black grouse

Woodland

Black grouse will feed, nest and lek in native woodland (principally Scots pine and birch), which provides a mosaic of small-scale habitats. Efforts to increase the area of native woodland, especially in Scotland, should benefit black grouse in the long term.

Black grouse will also use young conifer plantations (before the tree canopy closes), and second-rotation forestry (replanted following clearfelling operations), though less is known about how to manage second-rotation areas for black grouse.

Whether in a plantation, semi-natural woodland or moorland fringe, trees can benefit black grouse, but there can be too many of them. Five factors affect the degree to which woodland can support black grouse:

  • woodland size

  • tree spacing

  • species composition

  • availability of heather, bilberry and herbaceous plants on the woodland floor
  • location of new woods
  • Woodland size
    The size of any woodland patch determines whether it can support all or most of the habitat requirements for black grouse. Forestry plantations, in particular, will often provide just one habitat in a mosaic of resources within a landscape. A woodland of over 200 ha (1280 acres) is likely to support black grouse for many of its needs, but small woodland patches of just 10 ha (64 acres) may also provide a vital resource, depending on the surrounding habitat.

    Tree spacing

    The woodland structure is also important. Black grouse select young stands of conifers between planting and 20 years old. They also favour open, mature woodlands where the tree density is between 5 and 200 stems per hectare, and a canopy cover of less than 20%. For best conditions, over 40% of the total woodland area should remain open ground. This allows development of a thick cover of ground vegetation, where adults and young can feed, as well as open areas for lek sites.

    Pearce-Higgins et al. (2007) correlated lek occurrence, lek size and changes in lek size with forest structure, both positively in terms of the amount of pre-thicket forest cover, and negatively in terms of closed canopy cover. In their study, forest maturation alone accounted for 58-78% of the decline in the black grouse population.

    The woodland edge is particularly important for black grouse, as their gateway to other habitats. A good shrub layer will help, ideally 20 to 50 metres wide (66 to 164 ft), which can be created either by planting outside existing plantations or by felling up to 80% of existing trees along the woodland fringe.

    Mature plantations are homogenous and have minimal value for black grouse. However, these can be opened up by:

    1. Widening rides and creating open ground
    2. Thinning tree cover at the edge of compartments
    3. Protecting and establishing broadleaf trees
    4. Retaining and creating marshy/boggy areas
    5. Safeguarding lekking sites in clearings and on tracks

    The density of trees that black grouse require is low compared to that typically planted for forestry. A sufficiently low average tree density may be achieved across a large site by planting some parts (such as those on drier ground or away from the edge of the forest) at a higher density.

    Forestry plantations can provide food and nest sites for black grouse until the canopy closes and shades out heather and bilberry. Chris Gomersall (RSPB Images 5275000-00030-002)

    Species composition
    Trees and shrubs provide shelter for black grouse, but also food in the form of buds, catkins and fruit, principally from birch, rowan, hawthorn, juniper, willow, larch, Scots pine and alder. Larch is important to greyhens in spring and can influence their breeding success.

    Woodland vegetation
    Management to provide open woodland for black grouse often requires restrictions on grazing, to permit the regeneration of plants on the woodland floor. Managing grazing, whether by livestock or wild animals, provides a dilemma for black grouse conservation, because this is traditionally achieved using fences. However, large fences - especially those designed to exclude deer - are responsible for the deaths of many black grouse. Thus, to sustain black grouse populations in woodland, exclusion without fencing is necessary, or at the very least with marked fencing.

    Livestock should also be excluded from woodlands, especially during the winter. In native woodland, some controlled grazing, or mechanical cutting of heather and bilberry, may be useful after 10-15 years of exclusion, to prevent the vegetation becoming too thick. Research is underway by the RSPB and FCS to increase knowledge of the potential role of managed grazing in woodland.

    Black grouse chicks can drown in drainage ditches within forestry, so efforts should be made to fill ditches with tree brash, where an objective of forestry management is black grouse conservation. These shallow wet areas will encourage the growth of ground flora, providing insects for black grouse chicks.

    Location of new woods
    Young conifer plantations can benefit black grouse, but should not be planted on habitats that are already good for black grouse (and other upland species), such as heather moorland and in-bye grazing land. The value of maturing plantations and second rotation woodlands for black grouse can be increased by:
    1. Planting at low density, and/or leaving large gaps between blocks.
    2. Including fringes of broadleaf species, such as rowan, birch and hawthorn, to provide winter food.
    3. Leaving sparse tree cover at the forest edge to encourage ground vegetation.

    Grants
    There are a variety of grants available for woodland management to help black grouse; click on the relevant link below.