Area: 50.4 hectares.
In Dartmoor National Park. Nature Conservation Review site. Part of Hawns Wood and High House Moor SSSI has been incorporated into the site. Remainder of Hawns Wood and High House Moor SSSI to be included with Central South Dartmoor SSSI.
Description and Reasons for Notification:
This site is an example of an ancient upland Oakwood. It supports a rich lichen and moss flora and high numbers of breeding bird species.
Within an altitude range of 160 metres to 280 metres the woodlands cover the valley slopes at the confluence of Broadall Lake and Ford Brook with the River Yealm. The parent rock is mainly granite but slates occur in the southern part of the site; the soils are shallow and generally well drained. Boulder-strewn ground occurs in some areas, whilst the water courses are typical of Dartmoor’s streams, being fast-flowing and nutrient-poor.
The woodland is dominated by pedunculate oak Quercus robur, occurring with beech Fagus sylvatica on the lower slopes. Heavy grazing has led to an impoverished shrub layer with hazel Corylus avellana, holly Ilex aquifolium and rowan Sorbus aucuparia are scattered throughout. The ground flora is characterised by creeping soft-grass Holcus mollis, sweet vernal-grass Anthoxanthum odoratum, bramble Rubus spp., bluebell Hyacinthoides non-scripta, wood-sorrel Oxalis acetosella, tormentil Potentilla erecta and herb robert Geranium robertianum. Bracken Pteridium aquilinum is scattered throughout, forming dense stands in places. In some parts, where drainage is impeded or seepage flushes occur, marshy vegetation has developed, with willows Salix spp., alder buckthorn Frangula alnus, purple moor-grass Molinia caerulea, yellow pimpernel Lysimachia nemorum, marsh violet Viola palustris and bog mosses Sphagnum spp. are present.
The site’s cool and moist conditions have enabled a profuse growth of mosses to develop. Common species of the sward are Rhytidiadelphus squarrosus and Thuidium tamariscinum, while many boulders carry a mat of mosses including Isothecium myosuroides,Dicranum scoparium, Polytrichum formosum and Plagiothecium undulatum. The well lit trees and a high rainfall have also enabled a luxuriant epiphytic lichen flora to develop, characterised by the Parmelietum laevigatae community. There is a profuse growth of Usnea species and the site is also the richest locality in south west England for the rare Graphina ruiziana. Cetrelia cetrarioides, a rare lichen widespread in Dartmoor woodlands, is also frequent here. The riverside banks support abundant ferns including royal fern Osmunda regalis and Tunbridge filmy-fern Hymenophyllum tunbrigense; both local species.
The woods support a breeding bird community highly representative of upland oak woods. Species present include buzzard Buteo buteo, wood warbler Phylloscopus sibilatrix, pied flycatcher Ficedula hypoleuca and redstart Phoenicurus phoenicurus; while dipper Cinclus cinclus and grey wagtail Motacilla cinerea nest alongside the water-courses. A diverse invertebrate fauna is present which includes the silver-washed fritillary Argynnis paphia and green hairstreak Callophrys rubi butterflies. The mammal fauna includes red deer Cervus elaphus and fallow deer Dama dama as regular visitors.