Castle Down

Castle Down (Tresco)
Site of Special Scientific Interest
Shown within Isles of Scilly
Area of Search	Cornwall
Grid reference	SV885160
Coordinates	49°57′48″N 6°20′40″W / 49.9632°N 6.3444°W / 49.9632; -6.3444Coordinates: 49°57′48″N 6°20′40″W / 49.9632°N 6.3444°W / 49.9632; -6.3444
Interest	Biological and Geological
Area	58.1 hectares (0.581 km²; 0.224 sq mi)
Notification	1971 (1971)
Natural England website

Castle Down is a windswept plateau of maritime heath in the northern part of the island of Tresco, Isles of Scilly. The area has a number of designations including Castle Down (Tresco) Site of Special Scientific Interest (SSSI); is part of the Isles of Scilly Area of Outstanding Natural Beauty; part of the Isles of Scilly Heritage Coast; and part of Plantlife's Isles of Scilly Important Plant Area. There are a number of Schedule Ancient Monument's ranging in age from Bronze Age cairns (or burial places) to castles built in the 16th and 17th centuries to protect the anchorage of New Grimsby harbour.

History

There is a long history of human habitation with 66 cairns (usually burial sites) dating to the Bronze Age.^[1] In addition, within 100 m (328 ft) of the southern boundary of the SSSI, there is an Iron Age field system, associated hut circles and large middens covering 3 ha (7.4 acres). The huts are 5 m (16 ft) to 20 m (66 ft) apart and have diameters ranging from 5 m (16 ft) to 7 m (23 ft) while the middens are up to 11 m (36 ft) long, 10 m (33 ft) wide and 1 m (3.3 ft) high. (grid reference SV 888156) The field system was reused in the 19th century.^[2]

The artillery fort on the highest point of the west side of Chapel Down, and now known as King Charles's Castle (grid reference SV882161), was built between 1548 and 1554 in the reign of King Edward VI (1537–53). It was built to guard the northern, deep water approach, to New Grimsby harbour, although it proved to be badly sited to fire on ships below, or to withstand attack from the landward side. For a short time it was the main stronghold in the islands but was replaced by Star Castle on the Garrison, St Mary’s in the 1590s. It was later used as a quarry for the building of the nearby fort known as Cromwell’s Castle. The name, King Charle's, comes from the occupation by Royalist forces – the Parliamentarians took Tresco in 1651 by landing on the other side of the island.^[3] In March, 1651 a Dutch fleet arrived off the islands demanding reparations from Royalist privateers. The Dutch threat was countered by Admiral Robert Blake who captured the islands from the Royalists in June. The round tower of Cromwell's Castle (grid reference SV881159), built on the site of a previous blockhouse, was completed the following year to guard the deep water approach to New Grimsby harbour. It was updated around 1740 with a platform built for cannon on the seaward side.^[4]

In 1652 the Parliamentary Survey of Scilly reported a row of shallow pits and spoil heaps (grid reference SV884164) following, in part the line of a tin lode. The pits were mostly 1.8 m (6 ft) to 2.4 m (8 ft) deep with some shafts to 7.3 m (24 ft). At the western end was an adit. The mining started in the 1640s and ended by 1652 and was said to be of no value.^[5]

Piper’s Hole is a deep cavern reached by scrambling down the north coast cliff. The cave consists of a 20 m (66 ft) long boulder–filled passage leading to an underground pool. With the arrival of tourism in the 19th century a punt was kept there and was used to take tourists to the inner chamber.^[6]

Geography

Castle Down is the name given to the northern part of the island of Tresco and is a 35 m (115 ft) plateau of coarse–grained Hercynian granite. The southern edge of the Late Devensian ice sheet probably reached the northern islands of the Isles of Scilly about 18,000 years BP (before present) and there are glacial outwash gravels on the northern part of the downs with erratic pebbles.^[6] Raised beach deposits are exposed on the cliffs between Cromwell’s Castle and Grimble Porth. The thin skeletal podzolic soils and extreme exposure to salt laden winds have led to the development of a wind–pruned, lichen–rich, “waved” maritime heath dominated by heather (Calluna vulgaris).

Wildlife and ecology

The northern part of Tresco is designated as the Castle Down (Tresco) Site of Special Scientific Interest for its waved maritime heath, its lichen flora, a breeding colony of Common Tern (Sterna hirundo) and for its geology. The SSSI was first notified in 1971, re–notified in 1986 and covers most of the higher land and cliffs to the north of the inhabited area of the island.^[7]

Flora

Due to the thin, low nutrient podzolic soils and exposure to salt laden winds the vegetation is pruned into a low growing, ankle height, heather carpet. Waved heath is so called because the plants form ‘waves’. On the windward side of the plant there is bare ground and exposed roots with the leaves and flowers concentrated on the sheltered side. The heath is species poor with western gorse (Ulex gallii) and some bell heather (Erica cinerea), which becomes dominate on the southern side of the area. Other species found on the heath are common bird’s-foot trefoil (Lotus corniculatus), English stonecrop (Sedum anglicum), heath bedstraw (Galium saxatile), lousewort (Pedicularis sylvatica) and tormentil (Potentilla erecta). Forty five species of lichen have been recorded including rare Heterodermia communities. The only European sites for H. propagulifera are in the Isles of Scilly.^[6]^[7]^[8]

Fauna

Peter and Myrtle Ashmore investigated Piper’s Hole in 1993 and amongst the cavernicolous fauna found a springtail new to Britain, Onychiurus argus, a troglophile species known from caves in Belgium, France and Spain.^[6]

References

↑ "Monument No. 303361". Pastscapes. English Heritage. Retrieved 25 November 2012.
↑ "Monument No. 303447". Pastscapes. English Heritage. Retrieved 25 November 2012.
↑ "King Charles's Castle". English Heritage. Retrieved 25 November 2012.
↑ "Cromwell's Castle". English Heritage. Retrieved 25 November 2012.
↑ "Monument No. 303450". Pastscapes. English Heritage. Retrieved 25 November 2012.
1 2 3 4 Parslow, R. (2007) The Isles of Scilly. New Naturalist Library. London: HarperCollins
1 2 "Castle Down (Tresco)" (PDF). Natural England. Retrieved 25 November 2012.
↑ Lousley, Job (1971). The flora of the Isles of Scilly. Newton Abbot: David & Charles.

External links

Isles of Scilly

Inhabited islands	St Mary's St Agnes (and Gugh) Bryher Tresco St Martin's

Uninhabited islands	Annet Bishop Rock Crim Rocks Eastern Isles English Island Great Ganilly Gweal Norrard Rocks Pednathise Head Rosevear Round Island Samson St Helen's Teän Western Rocks White Island Zantman's Rock

Settlements	St Mary's: Hugh Town, Holy Vale, Longstone, Maypole, Normandy, Old Town, Pelistry, Porthloo, Rocky Hill, Telegraph and Trenoweth St Martin's (and St Agnes): Higher Town, Middle Town and Lower Town Tresco: New Grimsby and Old Grimsby

Topics	Environment History People Schools Transport

Biological Sites of Special Scientific Interest in Cornwall and the Isles of Scilly

Summary	Summarised data for all sites (biological and geological)

Cornwall	Aire Point to Carrick Du Amble Marshes Baulk Head to Mullion Bedruthan Steps and Park Head Boconnoc Park and Woods Bodmin Moor, North Borlasevath and Retallack Moor Boscastle to Widemouth Brendonmoor Breney Common Bude Coast Cabilla Manor Wood Caerthillian to Kennack Carnkief Pond Carrick Heaths Carricknath Point to Porthbean Beach Carrine Common & Penwethers Chyenhal Moor Cligga Head Coombe Mill Coverack to Porthoustock Crow's Nest Crowhill Valley Dozmary Pool Draynes Wood East Lizard Heathlands Eglarooze Cliff Gerrans Bay to Camels Cove Godrevy Head to St Agnes Goonhilly Downs Goss and Tregoss Moors Greenamoor Greenscoombe Wood, Luckett Grimscott Gwithian to Mexico Towans Hayle Estuary & Carrack Gladden Kelsey Head Kennack to Coverack Kernick and Ottery Meadows Loe Pool Loggans Moor Lower Bostraze and Leswidden Lower Fal & Helford Intertidal Lymsworthy Meadows Lynher Estuary Malpas Estuary Marazion Marsh Meddon Moor Meneage Coastal Section Merthen Wood Minster Church Mullion Cliff to Predannack Cliff Nance Wood Newlyn Downs Ottery Valley Park Wood Penhale Dunes Pentire Peninsula Phoenix United Mine Plymouth Sound Shores And Cliffs Polruan to Polperro Polyne Quarry Porthgwarra to Pordenack Point Rame Head & Whitsand Bay Red Moor Redlake Meadows & Hoggs Moor Retire Common River Camel Valley and Tributaries Rock Dunes Rosemullion Rosenannon Bog and Downs St Austell Clay Pits St John's Lake St Nectan's Glen Steeple Point to Marsland Mouth Swanpool Sylvia's Meadow Talland Barton Tamar–Tavy Estuary Tintagel Cliffs Treen Cliff Tregonetha & Belowda Downs Tregonning Hill Trehane Barton Trelow Downs Trevose Head and Constantine Bay Upper Fal Estuary and Woods Upper Fowey Valley Ventongimps Moor West Cornwall Bryophytes West Lizard

Isles of Scilly	Annet Big Pool and Browarth Point Castle Down (Tresco) Chapel Down Eastern Isles Great Pool Gugh Higher Moors and Porth Hellick Pool Lower Moors Norrard Rocks Peninnis Head Pentle Bay, Merrick And Round Islands Plains and Great Bay Pool Of Bryher & Popplestone Bank Rushy Bay and Heathy Hill Samson Shipman Head & Shipman Down St Helen's St Martin's Sedimentary Shore Teän Western Rocks White Island Wingletang Down

Neighbouring areas Sites of Special Scientific Interest in Devon Sites of Special Scientific Interest in Somerset

Geological Sites of Special Scientific Interest in Cornwall and the Isles of Scilly

Summary	Summarised data for all sites (biological and geological)

Cornwall	Aire Point to Carrick Du Baulk Head to Mullion Bedruthan Steps and Park Head Belowda Beacon Boscastle to Widemouth Boscawen Bude Coast Caerthillian to Kennack Cameron Quarry Carn Grey Rock and Quarry Clicker Tor Quarry Cligga Head Coverack Cove and Dolor Point Coverack to Porthoustock Crocadon Quarry Crow's Nest Cuckoo Rock to Turbot Point Cudden Point to Prussia Cove De Lank Quarries Duckpool to Furzey Cove East Lizard Heathlands Folly Rocks Gerrans Bay to Camels Cove Godrevy Head to St Agnes Great Wheal Fortune Greystone Quarry Gwithian to Mexico Towans Harbour Cove Hawkstor Pit Hingston Down Quarry & Consols Kennack to Coverack Kingsand to Sandway Point Lidcott Mine Loe Pool Lower Fal & Helford Intertidal Luxulyan Quarry Meneage Coastal Section Mulberry Downs Quarry Mullion Cliff to Predannack Cliff Penberthy Croft Mine Penlee Point Penlee Quarry Pentire Peninsula Polyne Quarry Polyphant Porthcew Porthleven Cliffs Porthleven Cliffs East Rame Head & Whitsand Bay Roche Rock Rock Dunes Rosemullion Rosenun Lane South Terras Mine St Agnes Beacon Pits St Erth Sand Pits St Mewan Beacon St Michael's Mount Stepper Point Stourscombe Quarry Swanpool Tater-du Tintagel Cliffs Trebetherick Point Tregargus Quarries Trelavour Downs Tremearne Par Trevaunance Cove Trevone Bay Trevose Head and Constantine Bay Viverdon Quarry West Lizard Wheal Alfred Wheal Gorland Wheal Martyn Wheal Penrose Yeolmbridge Quarry

Isles of Scilly	Castle Down (Tresco) Chapel Down (St. Martin's) Peninnis Head (St. Mary's) Porth Seal (St. Martin's) Porthloo Shipman Head & Shipman Down (Bryher) St Martin's Sedimentary Shore Teän Watermill Cove White Island

Neighbouring areas: Sites of Special Scientific Interest in Devon Sites of Special Scientific Interest in Somerset

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