Bincknoll Dip Woods

Also within

Wiltshire County North Wessex Downs Scenic Area

Condition (Natural England)

Habitats

Ancient woodland, Coppiced woodland, Fast flowing river and stream

Geology & landscape

Rock Type: Chalk, Greensand

Landscape processes: Fluvial

Description

Description This wooded area is of considerable importance due to the presence of populations of nationally and internationally rare mosses. There also exists a variety of other bryophytes and typical woodland vascular plants. The site comprises two blocks of woodland located on a steep north west facing escarpment. Outcrops of Lower Chalk occur at highest levels but most of the terrain is composed of Upper Greensand and Gault Clay. Streams issuing intermittently from beneath the chalk flow within a system of short but deeply incised valleys. The lower and middle slopes support semi natural ancient woodland, much of which is derelict hazel coppice. Here the tree canopy is comprised largely of mature pedunculate oak but with ash, field maple, silver birch and goat willow also occurring commonly. Beneath this is a diverse shrub layer of elder, blackthorn, hawthorn, spindle, guelder rose, young English elm and abundant hazel. The upper slopes are in part dominated by beech but elsewhere are characterised by frequent ash and sycamore. The woods hold at least 39 species of common bryophyte such as the mosses Kindbergia praelonga, Zygodon viridissimus and Amblystegium serpens and the liverworts Frullania dilatata, Lophocolea bidentata and Metzgeria furcata. Shaded vertical chalk faces beside a sunken trackway provide earth filled crevices supporting occasional specimens of the extremely rare moss Barbula glauca. These chalk cliffs constitute the only currently known British locality for this inconspicuous species which grows to a maximum height of only 3 mm. It has never been recorded outside Europe and is very rare throughout the majority of its range. Another rare moss, Pylaisia polyantha, occurs commonly on the bark of elder bushes in damp, well sheltered woodland. It is frequently present in sizeable patches measuring several square centimetres and is usually most vigorous on the higher elder branches at the point where they narrow into twigs. P. polyantha is widely distributed in high latitudes of the northern hemisphere but is rare in Britain. The ecological requirements of both mosses are incompletely understood and future monitoring at this locality may produce much valuable information. The ground flora contains a diversity of herbs characteristic of ancient woodland, including abundant bluebell Hyacinthoides non-scripta, dog's mercury Mercurialis perennis and ramsons Allium ursinum. Smaller numbers of wood anemone Anemone nemorosa, yellow archangel Lamiastrum galeobdolon and herb paris Paris quadrifolia also occur. Within the shadier areas of the wood, ferns such as broad buckler fern Dryopteris dilatata, lady fern Athyrium filix-femina and soft shield fern Polystichum setiferum are a prominent feature. Typical woodland grasses and sedges include wood false brome Brachypodium sylvaticum, giant fescue Schedonorus giganteus, pendulous sedge Carex pendula and remote sedge Carex remota. The fauna of Bincknoll Dip Woods has not been studied in detail but the area is likely to support a varied bird population and many invertebrates. Of particular importance to the latter is the presence of damp stream sides, large standing trees and frequent fallen dead wood.

Species mentioned

Plant communities