Oakwood is broad-leaved, semi-natural woodland that is dominated by long established oak trees. This habitat becomes established in damp, humid conditions with high precipitation levels & acidic soils derived from granite or other base-poor rocks (NIBG, 2000).

Key Characteristics

  • Site: Moist, high rainfall levels
  • Soil: Base-rich, variable depth, moderately free draining/poorly drained acid soils, flush of nutrients
  • Main species: Sessile oak & pedunculate oak
  • Other species: Downy birch, holly, rowan & hazel
  • UK: 70,000-100,000 ha
  • NI: 2,350 ha (<1,400 ha pre-1900)

Habitat Description

  • Within Northern Ireland oak woodland is predominated by two species of oak: Sessile oak Quercus petraea & pedunculate oak Q. robur. Sessile oak is more common but they often hybridize.
  • Downy birch Betula pubescens is common in the canopy.
  • Most of the Oakwood in NI can be assigned to two NVC: W11 Quercus petraea – Betula pubescens – Oxalis acetosella & W17 Quercus petraea – Betula pubescens – Dicranum majus woodland.
  • The main understory assemblages include holly Ilex aquifolium, rowan Sorbus aucuparia & hazel Corylus avellaria. In recent centuries, non-indigenous species such as beech Fagus sylvatica & sycamore Acer psedoplantus have become components (Translink Biodiversity Audit, 2008).
  • Typical oak woodland plants in the ground layer include wood anemone, bramble, ferns, bracken, greater wood-rush, bluebell with a variety of mosses & lichens.

Current Status in UK & Northern Ireland

Precise data on the extent & status of oakwood in the UK is lacking but estimates are within the range of 70,000 to 100,000 ha (JNCC, 2001).

An estimated 2,350 ha of oakwood remains in NI, but only 1,400ha is mature (NIEA, 2005).

Such woodlands occur in the north-east, on less base-rich soils, in rocky & damp areas (BTCV, 2009).

A large proportion (2,000ha) of oakwood is in private ownership & a small proportion (350ha) is in public ownership (EHS unpublished estimates, based on Graham, 1975). The latter estimate includes oakwood in NNRs, ASSIs & Forest Nature Reserves (FNR). It is a probable underestimate as it excludes an estimated 2,700ha of woodland classified as plant conservation (i.e. semi-natural woodland habitats within productive planted woodland areas) by the Forest Service.

As a result of tree planting & natural woodland regeneration, the NICS (2000) reported an 11% increase in the extent of woodland & scrub between 1988 & 1998.

Oakwood in NI has generally been unmanaged, often used for livestock grazing & sheltering.

Oakwoods are under threat from physical damage from domestic & wild animals (e.g. squirrels & deer), habitat loss & fragmentation by deforestation, climate change & air pollution, which can potentially kill old & veteran trees. Nutrient enrichment from spray drift, agricultural runoff or game bird rearing & inappropriate woodland management, disease, such as Sudden Oak Death & invasive species such beech, rhododendron & Japanese knotweed, may change the composition of woodlands.

 Key Designated Sites

Oakwood is common in the Sperrins, north-west on metamorphic rocks & in County Fermanagh on sandstone. It is also found in areas of less-base rich soils of Counties Antrim, Down & Armagh.

  • Altmover Glen
  • Banagher Glen
  • Breen Oakwood
  • Craigagh Wood
  • Creighton’s Wood
  • Glenarm Wood
  • Tow River Wood

Further Information