Area: 72.3 hectares.
Name changed from Chercombe Bridge Old Quarry, site boundary extended. Part owned by the National Trust.
Description and Reasons for Notification:
This site presents an extensive example of ancient semi-natural woodland developed almost wholly on limestone and calcareous soils, a habitat rare in Devon. Two disused limestone quarries, Chercombe and Broadridge, show important exposures of the Devonian limestones and have yielded a wealth of fossils.
The site lies between 15 and 70m altitude in the valley of the River Lemon, which flows west to east, cutting a steep-sided valley. Soils of the valley sides are thin, clayey, calcareous earths, and in the valley bottom drainage is restricted.
There are various stand-types within the wood, the principal canopy trees being ash Fraxinus excelsior, pedunculate oak Quercus robur and beech Fagus sylvatica with small-leaved lime Tilia cordata, field maple Acer campestre and sycamore A. pseudoplatanus also present. Alder Alnus glutinosa is common beside the river. Wych elm Ulmus glabra is present throughout but most of the tall trees are dead. Small areas have been planted with broadleaved trees, but in general the woods have a semi-natural structure. The shrub layer is very varied and includes areas of old hazel Corylus avellana coppice, with wild service-tree Sorbus torminalis, spindle Euonymus europaeus, wayfaring tree Viburnum lantana, guelder rose V. opulus, dogwood Cornus sanguinea and crab apple Malus sylvestris. The ground flora is species-rich and luxuriant, with many species characteristic of woodland on calcareous soils. The most notable species are butcher’s broom Ruscus aculeatus, spurge laurel Daphne laureola, southern woodrush Luzula forsteri, bird’s-nest orchid Neottia nidus-avis, wood vetch Vicia sylvatica, small teasel Dipsacus pilosus and wood small reed Calamagrostis epigejos.
Broadridge Quarry forms a large clearing in the woodland. Plants typical of calcicolous grassland which is a rare habitat in Devon, grow on the ledges of the almost sheer rockface. Rock rose Helianthemum chamaecistus, wild thyme Thymus drucei, dropwort Filipendula vulgaris and fragrant orchid Gymnadenia conopsea are found along with the mosses Grimmia orbicularis, Gymnostomum viridulum and Camptotheciuin lutescens.
The fast-flowing River Lemon contains salmon Salmo salar, stone loach Noemacheilus barbatulus and bullhead Cottus gobio, and with its associated alder woods is an important component of the site.
The fauna has not been studied in detail, but a wide range of woodland birds breed here, and the dipper Cinclus cinclus nests in the river bank. Butterflies include the white admiral Limenitis camilla.
Chercombe Bridge Quarry is the type locality of the Devonian Chercombe Bridge Limestone (late Eifelian-Givetian age). The lowest horizons exposed comprise shaley limestones with a rich Eifelian trilobite fauna. Broadridge Quarry is complementary in providing the best exposures of the upper horizons on the Chercombe Bridge Limestone. Both quarries are richly fossiliferous and show good examples of coral and stromatoporoid/coral bioherms or ‘reefs’, and are important in displaying facies variations which occur in the Middle Devonian of South Devon.