Many of the bogs that would have characterised the lowland areas have been drained to allow for agricultural improvement, though some important wetlands remain. These bogs were formed on water-logged sites where bog moss accumulated, building up to form thick peat deposits. The bogs have been much disturbed by centuries of turf-cutting, drainage and reclamation however, those that survive contain mixtures of bog mosses with drier banks of heather and bilberry often being colonized by willow or birch scrub. Some areas of abandoned cutover bog contain deep pools. The small fragments of remaining bog in Ring of Gullion are valuable wildlife habitats whose conservation is clearly dependent on continuing environmentally sensitive farm practices.
Heathland in the Ring of Gullion covers approximately 12% of the area making it one of the largest dry heaths in Northern Ireland, recognised by its designation as a Special Area of Conservation. The heaths form on thin acidic soils overlying granitic rocks and is home to colourful gorse and bracken in the autumn.
The heaths themselves are very variable. Slieve Gullion is by far the largest area of heather moorland and consists of a fairly pure stand of ling, with scattered bilberry. Other areas around the lower hills of the ring-dyke, as at Mullach Bán Mountain, Ummeracam and Ballard, have a much greater diversity of habitats and plants.
Drier heaths are characterised by ling heather and western gorse. Cross-leaved heath is more typical of wetter areas, forming wet heath communities with deer grass, bog asphodel and cotton grass.
Within the Ring of Gullion trees and small woods are significant landscape features and valuable wildlife habitats. In the farmed countryside small groups of trees in shelter belts or hedges provide beneficial shelter for stock and help to screen farm buildings. On the steep slopes of valleys and hillsides small semi-natural woodlands of hazel and ash with sycamore, oak, rowan and willow are notable features. Willow, birch and alder scrub is typical of cutover peatland in the valley bottoms. The most mature woods are those which have been planted in old estates notably at Killevy Castle, Hawthorn Hill and Forkhill.
Forestry covers about 6% of the area, is a major land use and is of mixed coniferous species – mainly sitka spruce, lodgepole pine, japanese larch and scots pine. The variety of species planted in irregular blocks with areas of unplanted hillside and pre-existing broad-leaved trees combine in many cases to produce attractive landscape features and pleasant areas for forest recreation.
Ancient woodland sites include Aughanduff, Carrive Grove and parts of the lands of Slieve Gullion Forest, Killeavy Castle and Fathom Forest. The Woodland Trust’s ‘Ancient Woodland Inventory’ records that of Forest Service’s 1403 hectares of land in the area, some 920 hectares are planted with a mixture of conifers and broadleaved trees.
Forest Service works to the UK Woodland Assurance Standard and replants at least 5% of felled areas with mixed species broadleaved trees and leaves 10-20% open space to promote biodiversity, new or replanted forests under this Standard comprise more than 75% of one species. It also manages unplanted areas for nature conservation with Forest Nature Reserves on Camlough Mountain and at Hawthorn Hill.
Located at Slieve Gullion, Slieve Gullion Forest Park is owned and managed by Forest Service and has a range of including Courtyard Centre and café, an 8 mile scenic drive, woodland trail, an ornamental walled garden and toilet facilities. There is also a waymarked trail, from the scenic.
A fen is a marsh, rich in specialised plants and organisms. Cashel fen is the easiest to be seen. They occur where vegetation on low-lying, frequently flooded, alkaline soils have been grazed for centuries or cut regularly. The grazing stalls succession, a natural development, to wet woodland, known as a Carr and a diverse fen flora develops. It is home to a diverse range of vegetation and organisms such as newts and frogs. A fen develops through grazing and cutting and its preservation depends on active management to prevent scrub encroachment. Fens on nature reserves and private land are cut to remove biomass, (a biological material derived from living, or recently living organisms), and to prevent succession to scrub.