NVC community W4 is one of the woodland communities in the British National Vegetation Classification system, characterised by a canopy of downy birch over a field layer of purple moor-grass or other calcifugous herbs on a peaty substrate. It usually forms as a secondary woodland over partially drained bogs or wet heaths.
W4 Betula pubescens-Molinia caerulea woodland is widely distributed, but rarely extensive, throughout the lowlands and the upland fringes of Britain. It occurs on moist, peaty, rather acidic soils, particularly on or around peat bogs that are drying out, usually as a result of drainage, although it can also be found on acidic mineral soils in suitable locations. Its characteristic (constant) species are downy birch (occasionally replaced by silver birch), purple moor-grass and various types of Sphagnum moss. [1]
The habitat is typically a rather open woodland canopy, mainly of birch but often with some alder, willow and oak, with a typically sparse shrub layer that may contain some hawthorn and alder buckthorn. The field and ground layers are sometimes formed of either a lawn of Sphagnum or a taller sward of purple moor-grass or, on less moist soils, a dense cover of bracken. [2] In the less common W4b subcommunity, various rushes and sedges are abundant. There are no tall trees in a W4 wood, as downy birch grows only to about 20 m and it is not long-lived, so there is usually an abundance of dead and decaying trees, giving the habitat a "moribund" look. [3] [1]
Fungi are often abundant, with birch polypore on the rotting tree stumps and tawny grisettes and various types of Russula on the boggy ground. [4]
The types of bog-moss that occur in the Sphagnum-dominated stands often reflect the conditions that were present before the tree cover. Sphagnum recurvum agg. (flat-topped bogmoss etc.), feathery bogmoss and red bogmoss suggest raised mires or schwingmoors, while blunt-leaved bogmoss and spiky bogmoss typically occur in places where there is some base-rich surface water. Fringed bogmoss is perhaps the most characteristic of W4 woodland, as it is shade tolerant and frequent here. [5] [6]
Birch woodland (usually W4 but sometimes W10 or W16) is often considered problematic on heathland nature reserves, particularly as the decomposing leaf litter can suppress the ground flora. [4] [7]
There are three subcommunities: [1]
Betula woodlands have long been recognised on the Continent, [8] where the European Union lists several similar habitat types, the closest to W4 being EUNIS habitat G1.5 - Broadleaved swamp woodland on acid peat. [9] Woodland very similar to W4 occurs on the peaty soils of lower Normandy and Brittany, where it is considered a wet pedunculate oak-birch woodland with characteristically fluctuating water levels. [10]
In Britain, an important early study was by Duncan Poore at Woodwalton Fen in the 1950s. This showed how the birch had colonised the ground around Whittlesey Mere shortly after it had been drained, and the tree cover was fairly uniformly composed of 85 year-old specimens at the time of survey, dating the establishment of the wood to around 1865. [3] In 1962 Sinker also described how birch woodland is part of the hydrosere around some of the meres in the Shropshire-Cheshire plain, forming a distinct band between the wet fen and the dry oak woodland beyond. [2] At first this was thought to be a natural and fairly stable ecological feature, [11] but later it was found to have been triggered by 19th century drainage operations, as at Woodwalton. [12] [5]
Acid woodlands, with varying proportions of birch, are more common in County Durham than in many other counties. A study by Gordon Graham in the 1970s and 1980s described two broad communities, WOC2 and WOC3, which encompass both upland and lowland birch woods, but they are not described as being significantly different to the more acid types of oak wood. [13]
Askham Bog is small area of peat bog and Site of Special Scientific Interest situated within the Vale of York in North Yorkshire, England. It lies to the south-west of York, north of Copmanthorpe and near Askham Richard and Askham Bryan. It is regarded as one of the most ecologically diverse sites in Northern England.
Moorland or moor is a type of habitat found in upland areas in temperate grasslands, savannas, and shrublands and montane grasslands and shrublands biomes, characterised by low-growing vegetation on acidic soils. Moorland, nowadays, generally means uncultivated hill land, but also includes low-lying wetlands. It is closely related to heath, although experts disagree on what precisely distinguishes these types of vegetation. Generally, moor refers to highland and high rainfall zones, whereas heath refers to lowland zones which are more likely to be the result of human activity.
NVC community W2 is one of the woodland communities in the British National Vegetation Classification system. It is one of seven woodland communities in the NVC classed as "wet woodlands".
Lough Derravaragh is a lake in County Westmeath, Ireland, north of Mullingar between Castlepollard, Crookedwood and Multyfarnham.
The Portlethen Moss is an acidic bog nature reserve located to the west of the town of Portlethen, Aberdeenshire in Scotland. Like other mosses, this wetland area supports a variety of plant and animal species, even though it has been subject to certain development and agricultural degradation pressures. For example, the Great Crested Newt was found here prior to the expansion of the town of Portlethen. Many acid-loving vegetative species occur in Portlethen Moss, and the habitat is monitored by the Scottish Wildlife Trust.
Lambert's Castle is an Iron Age hillfort in the county of Dorset in southwest England. Since 1981 it has been designated as a Site of Special Scientific Interest (SSSI) on account of its geology, archaeology and ecology. The hillfort is designated a scheduled monument together with a bowl barrow, the sites of a post-medieval fair and a telegraph station. The site was on the Heritage at Risk Register but was removed in 2022 as a result of the Hillforts and Habitats Project.
NVC community W11 is one of the woodland communities in the British National Vegetation Classification system. It is one of the six communities falling in the "mixed deciduous and oak/birch woodlands" group.
Cors Caron is a raised bog in Ceredigion, Wales. Cors is the Welsh word for "bog". Cors Caron covers an area of approximately 349 hectares. Cors Caron represents the most intact surviving example of a raised bog landscape in the United Kingdom. About 44 different species groups inhabit the area including various land and aquatic plants, fish, insects, crustaceans, lichen, fungi, terrestrial mammals and birds.
A wet woodland is a type of plant community. It is a biodiversity habitat in the United Kingdom as part of the British National Vegetation Classification system.
The Wilderness is a Site of Special Scientific Interest which is located on the Isle of Wight, England. It is close to the village of Rookley in the valley of the River Medina. The Wilderness is an area of wet woodland over a quite deep peat soil with adjacent areas of unimproved acid grassland and wet grassland. The SSSI covers an area of 12.59 hectares, the boundaries being reset in 1984 to exclude an area of grassland which had been artificially improved.
Sphagnum girgensohnii, commonly known as Girgensohn's bogmoss, Girgensohn's sphagnum or common green peat moss, is a species of peat moss with a Holarctic and Indo-Malesian distribution. First described by Edmund Russow in 1865, it is a relatively robust moss species characterised by its green to straw-coloured appearance and distinctive branching pattern. The species typically grows in shaded, damp woodlands and on the edges of mires, forming loose mats particularly under birch and willow trees, and can be found from sea level to elevations of 2,200 m (7,200 ft). While it shows a mainly northern distribution pattern and is especially abundant in subarctic regions, it occurs throughout Europe from Portugal to Russia, being more common in upland areas. Despite facing threats from habitat degradation and land-use changes, S. girgensohnii is assessed by the IUCN as Least Concern due to its extensive range and stable populations, though it receives legal protection under various national and international frameworks, including the EU Habitats Directive.
Frog Wood Bog is a Site of Special Scientific Interest in the Teesdale district of County Durham, England. It lies alongside Bedburn Beck, approximately 3.5 km west of the village of Bedburn.
Ireland is in the Atlantic European Province of the Circumboreal Region, a floristic region within the Holarctic.
The Georgenfelder Hochmoor is a raised bog (Hochmoor) in the German Ore Mountains of central Europe, not far from Zinnwald-Georgenfeld. It is part of a larger bog or moor complex, that lies to the south, mainly on the far side of the Germany's national border in the Czech Republic and which, since time immemorial, has been known simply as "The Lake". The Georgenfelder Hochmoor is one of the oldest nature reserves in Saxony.
NVC community W17 is one of the woodland communities in the British National Vegetation Classification system. It is one of the six communities falling in the "mixed deciduous and oak/birch woodlands" group.
Bewick and Beanley Moors is the name given to a Site of Special Scientific Interest (SSSI) in north Northumberland, in the north-east of England. The moors are asserted to be of national importance by Natural England for the extent, quality and diversity of upland types including heaths, fens, wet grassland, flushes, mires and blanket bogs, together creating an extensive mosaic habitat supporting an exceptional community of amphibians. The moors are important, too, for their relict juniper woodland and scrub.
Trichophorum cespitosum, commonly known as deergrass or tufted bulrush, is a species of flowering plant in the sedge family. It was originally described by the Swedish naturalist Carl Linnaeus in 1753 as Scirpus cespitosus, but was transferred to the genus Trichophorum by the Swedish botanist Carl Johan Hartman in 1849, becoming Trichophorum cespitosum.
The Mouds Bog Special Area of Conservation or SAC is a Natura 2000 site based close to the Hill of Allen and to Newbridge, County Kildare, Ireland. The qualifying interests by which it is protected as an SAC are the presence of three habitat types: the presence of active raised bogs, the presence of degraded raised bogs still capable of natural regeneration, and the presence of depressions on peat substrates of Rhynchosporion vegetation.
The Red Bog Special Area of Conservation or SAC is a Natura 2000 site in County Kildare, close to the town of Blessington in County Wicklow, Ireland. The qualifying interests by which it is protected as an SAC are the presence of a specific habitat type: transitional mires and quaking bogs.
NVC community W5 is one of the woodland communities in the British National Vegetation Classification system, characterised by a canopy of alder over a field layer of sedges and reeds, often over a peaty substrate. It is a form of primary woodland around freshwater lakes and bogs, or as a component of river valley wetlands, and is one of seven woodland communities in the NVC classed as wet woodlands. It was once very common but is now rare and localised.