Tamar Valley

Tamar Valley Area of Outstanding Natural Beauty covers approximately 190 square kilometres along the valley of the River Tamar and its tributaries in the borderland between Devon and Cornwall. Designated in 1995, it is one of the smaller and less well-known AONBs in England, but contains a landscape of exceptional richness and historical depth. The Tamar has formed the boundary between Devon and Cornwall for over a thousand years, and the valley retains an intimate, sheltered character with wooded creek valleys, orchards, market gardens, and small riverside settlements. The AONB is distinctive for its industrial heritage, centred on what was once one of the richest metal-mining districts in the world, now recognised as part of the Cornish Mining World Heritage Site. The tidal section of the Tamar and its tributary creeks are designated as a Special Area of Conservation.

The Tamar Valley supports important wildlife along the tidal river, in the ancient woodlands of the valley sides, and in the wetland habitats of the estuary. The tidal Tamar and its tributaries, including the Tavy, Lynher, and Tiddy, support internationally important populations of common and grey seals, and the estuary is a major nursery area for fish including bass, mullet, and flounder. Otters are present throughout the river system and are regularly seen in the tidal creeks. The ancient oak woodlands support wood warblers, redstarts, pied flycatchers, and significant dormouse populations. Common and lesser horseshoe bats use the valley woodlands for foraging, roosting in historic buildings and mine adits. Barn owls hunt the valley farmland. The river supports white-clawed crayfish in upper tributaries and Atlantic salmon migrate upstream in autumn.

The Tamar Valley's sheltered, mild, and humid climate supports outstanding botanical diversity, particularly in the ancient woodland habitats that line the valley sides. The oak, ash, and hazel woodlands drape the steep creek banks and support the mosses, liverworts, and polypody ferns characteristic of Atlantic temperate rainforest. Notable bryophyte communities include nationally rare oceanic species found only in areas of high humidity and clean air. The estuary fringes support saltmarsh communities with sea purslane, cord grass, and common reed. The valley farmland retains some traditional orchards with varieties of Tamar Valley cherry, damson, and apple, reflecting the market gardening and fruit-growing tradition of the valley. Riverside meadows with meadowsweet, yellow iris, and purple loosestrife occur along the non-tidal sections. Ancient hedgerows on valley sides support a rich hedgerow flora including primrose, violet, and bluebell.

The Tamar Valley straddles the geological boundary between the Devonian and Carboniferous rocks of Devon and the highly metamorphosed Devonian and igneous rocks of Cornwall. The Dartmoor granite to the east and the Bodmin Moor granite to the west both drove the intensive mineralisation that made this region one of the world's richest metal-mining areas. Hydrothermal fluids associated with granite intrusion deposited rich veins of copper, tin, arsenic, and silver in the Devonian country rocks, particularly in the Gunnislake and Calstock areas. The valley itself is a product of river incision through the upland plateau, with the Tamar and its tributaries cutting deeply into the surrounding landscape. The tidal section of the river is a ria, formed by the drowning of the lower valley as sea levels rose after the last ice age. Quarrying for Devonian slate provided a local building material seen throughout the valley's architecture.

The Tamar Valley benefits from a mild, wet Atlantic climate, sheltered from the strongest south-westerly winds by the surrounding uplands of Dartmoor and Bodmin Moor. The valley position means that temperatures are moderated by the surrounding land masses, and the sheltered creek valleys can be significantly warmer than surrounding upland areas. January averages are around 6 to 7 degrees Celsius, and frost is relatively uncommon at valley floor level. Summers are warm, with July averages around 17 degrees Celsius, and the valley can be several degrees warmer than exposed coastal areas. Annual rainfall averages approximately 1,000 to 1,100 millimetres, somewhat higher than the coastal fringe due to orographic enhancement as airstreams rise over the adjacent uplands. The humidity of the valley, combined with the mild temperatures, creates ideal conditions for the Atlantic woodland flora including mosses, ferns, and lichens.

The Tamar Valley's human history is dominated by the metal-mining industry that made it one of the most productive mining regions in the world during the 18th and 19th centuries. Copper and tin had been worked in the area since prehistoric times, but the 18th and 19th centuries saw industrial-scale extraction transform the landscape and society of the valley. At its height in the mid-19th century, the Tamar Valley and surrounding mining districts produced the majority of the world's copper and significant quantities of arsenic, arsenic being a by-product of tin and copper smelting. The mines attracted engineers, entrepreneurs, and workers from across Britain and overseas, and Cornish mining expertise was exported worldwide. The distinctive engine houses and chimney stacks of the pumping and winding engines still dot the landscape as monuments to this industrial heritage.

Tamar Valley was designated an Area of Outstanding Natural Beauty in 1995, reflecting recognition of the combination of outstanding natural landscape quality and exceptional cultural heritage concentrated in a relatively small area. The designation was the culmination of advocacy by conservation organisations concerned about the loss of the valley's distinctive character to development pressure. Part of the AONB's industrial heritage landscape was inscribed as part of the Cornwall and West Devon Mining Landscape World Heritage Site in 2006, bringing international recognition to the mining heritage. The Tamar Valley AONB Partnership, hosted by Devon County Council, coordinates management in partnership with Cornwall Council, Natural England, the Environment Agency, and community groups. The AONB team works with landowners on ancient woodland management, orchard restoration, and the maintenance of the tidal estuary.

The Tamar Valley Discovery Trail is a 35-kilometre walking route following the river from its source to the tidal limit at Gunnislake. The Tamar Valley Line railway, one of Devon's scenic branch lines, follows the Tamar estuary from Plymouth to Gunnislake and provides car-free access to the valley. Calstock, a village on the Cornish bank of the Tamar, is accessed by ferry from Cotehele or on foot from the railway viaduct station. Cotehele House and its quay, owned by the National Trust, is one of the finest Tudor manor houses in the south-west and includes a restored Tamar sailing barge, the Shamrock. The Morwellham Quay open-air museum recreates Victorian industrial life at a former mining and shipping port. Mount Edgcumbe Country Park, at the mouth of the estuary near Plymouth, provides formal gardens and coastal walking.

The Tamar Valley is accessible by car via the A390 and B3257 on the Cornish side and the A386 in Devon. The Tamar Valley Line railway from Plymouth to Gunnislake provides regular passenger services, and the Calstock viaduct crossing is a landmark engineering structure. Plymouth, just beyond the southern boundary, provides the main gateway city with a full range of accommodation, restaurants, and transport links. Ferry services operate seasonally across the Tamar between Devon and Cornwall at various points. The AONB Discovery Centre at Tavistock, just outside the AONB boundary, provides visitor information and interpretation. Cotehele and Morwellham Quay are the main managed visitor attractions within the AONB. Cycling is possible along some valley tracks and the Tamar Valley cycle network, though the hilly terrain limits access in places.

Conservation priorities in the Tamar Valley AONB include the management of ancient woodland, the restoration of traditional orchards, the protection of the internationally important estuarine habitats, and the preservation and interpretation of the mining heritage. The ancient woodland management programme addresses the need for active management to maintain habitat quality, including coppicing, invasive species control, and deer management. Traditional orchard restoration is a significant community-led initiative, reviving the Tamar Valley fruit-growing heritage. Marine and estuarine conservation focuses on maintaining the SAC designations for seals and habitats, managing recreational disturbance, and improving water quality in the tidal creeks. The mining landscape management works with Historic England and the World Heritage Site management body to conserve engine houses and other structures. Sustainable transport initiatives leverage the railway as a low-carbon access route.