Rainforests aren’t always in the Tropics – John Lamb, senior conservation officer for the Lancashire Wildlife Trust, is finding these vital habitats much closer to home
On the recent David Attenborough series Wild Isles, you will have heard about and seen images of temperate rainforests, known as Atlantic or Celtic rainforest, as well as Atlantic, upland and western oak woods.
Celtic Rainforest is a colloquial term, it refers to the temperate rainforest of Great Britain and Ireland.
We have all heard of tropical rainforests, but our temperate rainforests can receive as much, or even more rain, than their tropical cousins – but here the rain is cool and refreshing rather than hot and humid. Temperate rainforests occur in mid-latitude, temperate zones, in places which receive heavy rainfall due to an oceanic climate.
Temperate rainforest is a globally rare habitat in both hemispheres. It forms part of the natural range of mammals, such as pine marten and red squirrel, and provides habitat for migrant birds such as pied flycatcher, redstart, tree pipit and wood warbler, which thrive in the insect-rich conditions that rainforests offer.
The chequered skipper, a rare butterfly in the UK, is only found in the mild, damp and grassy habitats at the edges of rainforests in western Scotland.
As David Attenborough highlighted in Wild Isles, such woodland is home to the ash-black slug – the largest land slug in the world, which can be found in some ancient woodlands in Lancashire.
The British Isles once supported large expanses of temperate rainforest across the western fringes from the west coast of Scotland, down through the Lake District, Yorkshire Dales, Forest of Bowland, South and West Pennines and through a great swathe of central Wales, to Dartmoor, Exmoor and Bodmin Moor in south west England, as well as on the Isle of Man and in Ireland.
Unfortunately, the vast majority of our rainforests were replaced by coniferous plantations and sheep grazed pastures. Now they cover less than one per cent of the British Isles and are clinging on as small remnants. Unlike lowland oak trees that provided timber for the Royal Navy, people saw the twisted and stunted oaks of our rainforests as useless “scrub oak”, good only for firewood or converting into charcoal.
There are notable examples of surviving rainforest in Scotland on the islands and shores of Loch Maree, Loch Sunart, Loch Lomond, and the remote Taynish Peninsula in Argyll. In Wales, they occur on steep-sided riverine gorges in Snowdonia and mid Wales. In England, there are examples in the steep-sided riverine and estuarine valleys in the South West, including the valleys of the River Fowey in Cornwall and the Dart in Devon, with Wistman’s Wood on Dartmoor being the most famous example of temperate rainforest in the British Isles. And closer to home there are the Borrowdale Woods in the Lake District.
Lots of rain and relatively small annual temperature variations make temperate rainforest an important habitat, a key indicator being an abundance of mosses, liverworts, lichens and ferns, especially polypody ferns (Polypodium species). Rainforests are damp woodlands – so damp that plants grow on other plants, without being parasitic, and are known as epiphytes. The ground and exposed rock surfaces can be covered in mosses and liverworts, which rise up the trunks of the trees, festooning the horizontal branches and even growing up into the canopy.
Temperate rainforest is a habitat of European importance, defined in the UK government’s Habitats Directive as “Acidophilous Quercus petraea woods of Britain and Ireland”, of which the best examples are designated as Special Areas for Conservation (SAC). The Joint Nature Conservation Committee describe it as “old sessile oak woods with Holly Ilex aquifolium and Hard Fern Blechnum spicant in the British Isles”.
There is a site of European importance in Lancashire, for which old sessile oak woods is the primary feature. Calf Hill and Cragg Woods is on north and south-facing slopes of a valley on millstone grit on the northern edge of the Forest of Bowland.
In addition, the national importance of the West Pennine Moors was recognised in 2016, when it was designated as a Site of Special Scientific Interest (SSSI). As well as upland habitats and birds, the SSSI designation includes upland oak woodland as a feature and lists Stronstrey Bank, Lead Mine’s Clough, Dean Wood, Tiger’s Clough, Hall Wood and Longworth Clough as ancient woodland dominated by oak.
In 2005, Lancashire County Council commissioned Lancashire Wildlife Trust to map areas of upland oak woodland in the West Pennine Moors together with adjacent precursor vegetation that could be targeted for the creation of new native woodland. The survey covered 96 woodland units in 35 clusters and identified 169.5 hectares of upland oak woodland and 276.3ha of upland oak woodland precursor vegetation.
When these clusters are added to the sites highlighted above, together with other sites that Wildlife Trust staff are aware of, the list of potential rainforest sites in Lancashire is approaching 100.
In February this year, the national office of The Wildlife Trusts announced they had negotiated a £38 million deal with Aviva to acquire suitable land for the creation of new temperate rainforests, and Wildlife Trusts in Devon, Gwent, the Isle of Man and North Wales are already in the process of buying over 133 hectares (330 acres) of land. Here in Lancashire, we are identifying the best places to target before approaching the landowners to discuss options.
