Harpsden Wood

Site of Special Scientific Interest · 51.5178, -0.9069

Condition (Natural England)

Favourable (4)
UnitFeatureConditionArea (ha)Assessed
SU758806 Favourable 7.0 2011-08-04
SU760803 Favourable 16.18 2011-08-04
SU760806 Favourable 16.18 2011-08-04
SU762804 Favourable 6.22 2011-08-04

Geology & landscape

Rock Type: Chalk

Description

Area, 25.83 hectares 63.83 ac Description Harpsden Wood supports a range of woodland stand types reflecting the underlying geology and has a rich flora with over40 species associated with a long continuity of woodland cover. It also contains populations of plant species with are stricted distribution in the Oxfordshire Chilterns. This ancient wood occupies a plateau and adjacent north facing slope of a dry valley. It lies mainly on the acidic clay with flints though Upper Chalk underlies the northern slopes and the eastern edge. Two contrasting soils are associated with the parent material; on the plateau there is a sandy clay with flints and pebbles of the Berkhampstead complex and, on the slopes, a dry, silty, chalky brown soil of the Coombe series. The major part of the wood has a high forest structure composed of a mosaic of the acid pedunculate oak ash beech and oak beech types with variable numbers of oak, ash, cherry and birch. It has a sparse understorey of shrubs including holly, elder and hazel. Brambles are locally dominant in the field layer and there are frequent patches of tufted hair grass Deschampsia cespitosa and foxglove Digitalis purpurea. Some areas with impeded drainage support goat willow together with soft rush Juncus effusus, yellow pimpernel Lysimachia nemorum and two species relatively uncommon in the Chilterns, great wood rush Luzula sylvatica, a species of acid soils mainly found in the north and west of Britain and pendulous sedge Carex pendula which prefers acidic, but base rich heavy, often clay, soils. In contrast the northern slope supports calcareous pedunculate oak ash beech woodland with whitebeam and old maple standards and an underwood of hazel coppice, dogwood, guelder rose, wayfaring tree, spindle, privet, honeysuckle and, rarely, old coppiced wych elm stools. Ash is regenerating freely where there are openings in the canopy. The ground flora is very diverse and includes woodruff Galium odoratum, dog's mercury Mercurialis perennis, sanicle Sanicula europaea, goldilocks buttercup Ranunculus auricomus, wood barley Hordelymus europaeus and, on the leached clay soil at the foot of the slope, common cow wheat Melampyrum pratense, a species of restricted distribution in the Chilterns. Other locally uncommon plants occur in deep beech litter on the northern slope. Broad leaved helleborine Epipactis helleborine, which occurs sparingly in woods throughout Britain, is present in a number of localities and is very variable in form, partly dependent on the intensity of light available. Another orchid, the green flowered helleborine Epipactis phyllanthes, a self pollinating plant restricted to woods in Southern England, is found in one area. The narrow lipped helleborine Epipactis leptochila, a plant not recognised as a separate species until 1921 and with an uncertain distribution in Britain, has also been recorded. Two uncommon plant species which feed on decaying plant material and have fungal associates in their rootstocks, also occur, bird's nest orchid Neottia nidus-avis has a widely scattered, but localised distribution in Britain, whereas the less common yellow bird's nest Hypopitys monotropa is more strictly associated with the southern chalk.

Species mentioned

English name
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Latin name
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IUCN / Red List Type Family
tufted hair grass Deschampsia cespitosa LC grass poaceae
wood barley Hordelymus europaeus VU grass poaceae
foxglove Digitalis purpurea LC herb plantaginaceae
broad-leaved helleborine Epipactis helleborine DD herb orchidaceae
narrow-lipped helleborine Epipactis leptochila VU herb orchidaceae
green flowered helleborine Epipactis phyllanthes LC herb orchidaceae
woodruff Galium odoratum LC herb rubiaceae
yellow birds nest Hypopitys monotropa DD herb monotropaceae
yellow pimpernel Lysimachia nemorum LC herb primulaceae
common cowwheat Melampyrum pratense VU herb orobanchaceae
dog's mercury Mercurialis perennis LC herb euphorbiaceae
birdsnest orchid Neottia nidus-avis VU herb orchidaceae
goldilocks buttercup Ranunculus auricomus LC herb ranunculaceae
sanicle Sanicula europaea LC herb apiaceae
soft rush Juncus effusus LC rush juncaceae
great wood rush Luzula sylvatica LC rush juncaceae
pendulous sedge Carex pendula LC sedge cyperaceae

Plant communities

W12 — Beech wood

Fagus sylvatica-Mercurialis perennis woodland

Hedera helix, Acer pseudoplatanus, Ilex aquifolium, Betula pendula, Betula pubescens, Carpinus betulus, Corylus avellana, Fagus sylvatica, Quercus robur, Aesculus hippocastanum, Fraxinus excelsior, Prunus avium, Sorbus aria, Taxus baccata, Ulmus glabra, Buxus sempervirens, Sambucus nigra, Viburnum lantana, Viburnum opulus, Euonymus europaeus, Cornus sanguinea, Ligustrum vulgare, Clematis vitalba, Crataegus monogyna, Daphne laureola, Carex flacca, Carex sylvatica, Mnium hornum, Plagiomnium undulatum, Fissidens taxifolius, Brachythecium rutabulum, Kindbergia praelonga, Thamnobryum alopecurum, Tamus communis, Anthriscus sylvestris, Heracleum sphondylium, Sanicula europaea, Arum maculatum, Arctium minus, Mycelis muralis, Solidago virgaurea, Cynoglossum officinale, Alliaria petiolata, Campanula trachelium, Lonicera periclymenum, Silene dioica, Euphorbia amygdaloides, Mercurialis perennis, Geranium robertianum, Hypericum hirsutum, Iris foetidissima, Ajuga reptans, Glechoma hederacea, Lamiastrum galeobdolon, Stachys sylvatica, Teucrium scorodonia, Allium ursinum, Hyacinthoides non-scripta, Chamerion angustifolium, Circaea lutetiana, Epilobium montanum, Cephalanthera damasonium, Neottia nidus-avis, Neottia ovata, Veronica chamaedrys, Rumex sanguineus, Anemone nemorosa, Ficaria verna, Ranunculus bulbosus, Fragaria vesca, Geum urbanum, Rosa canina, Rubus fruticosus agg., Galium aparine, Galium mollugo sens.lat., Galium odoratum, Urtica dioica, Viola riviniana, Anisantha sterilis, Arrhenatherum elatius, Brachypodium sylvaticum, Bromopsis ramosa, Dactylis glomerata, Deschampsia cespitosa, Melica uniflora, Milium effusum, Poa nemoralis, Poa trivialis, Asplenium scolopendrium, Dryopteris dilatata, Dryopteris filix-mas

W14 — Beech wood, Wood pasture

Fagus sylvatica-Rubus fruticosus woodland

Hedera helix, Salix caprea, Acer pseudoplatanus, Ilex aquifolium, Betula pendula, Betula pubescens, Corylus avellana, Fagus sylvatica, Quercus robur, Fraxinus excelsior, Pinus sylvestris, Prunus avium, Sorbus aria, Sorbus aucuparia, Taxus baccata, Ulmus glabra, Sambucus nigra, Ruscus aculeatus, Ligustrum vulgare, Carex remota, Carex sylvatica, Luzula pilosa, Mnium hornum, Dicranella heteromalla, Dicranum scoparium, Fissidens taxifolius, Brachythecium rutabulum, Hypnum cupressiforme, Isothecium myosuroides, Kindbergia praelonga, Plagiothecium denticulatum, Plagiothecium undulatum, Pseudotaxiphyllum elegans, Thuidium tamariscinum, Atrichum undulatum, Polytrichum commune, Polytrichum formosum, Arum maculatum, Lonicera periclymenum, Moehringia trinervia, Stellaria media agg., Euphorbia amygdaloides, Mercurialis perennis, Hypericum pulchrum, Lamiastrum galeobdolon, Hyacinthoides non-scripta, Circaea lutetiana, Epipactis helleborine, Oxalis acetosella, Digitalis purpurea, Anemone nemorosa, Ranunculus repens, Geum urbanum, Rubus fruticosus agg., Rubus idaeus, Galium odoratum, Galium verum, Urtica dioica, Viola riviniana, Agrostis capillaris, Agrostis stolonifera, Brachypodium sylvaticum, Bromopsis ramosa, Dactylis glomerata, Deschampsia cespitosa, Deschampsia flexuosa, Holcus lanatus, Holcus mollis, Melica uniflora, Milium effusum, Poa nemoralis, Poa trivialis, Schedonorus giganteus, Pteridium aquilinum, Dryopteris dilatata, Dryopteris filix-mas

W15 — Beech wood, Wood pasture

Fagus sylvatica-Deschampsia flexuosa woodland

Hedera helix, Acer pseudoplatanus, Ilex aquifolium, Betula pendula, Betula pubescens, Fagus sylvatica, Quercus hybrid, Quercus petraea, Quercus robur, Pinus sylvestris, Sorbus aucuparia, Taxus baccata, Calluna vulgaris, Rhododendron ponticum, Vaccinium myrtillus, Ruscus aculeatus, Carex pilulifera, Luzula pilosa, Luzula sylvatica, Mnium hornum, Orthodontium lineare, Dicranella heteromalla, Dicranum scoparium, Leucobryum glaucum, Hylocomium splendens, Hypnum cupressiforme, Kindbergia praelonga, Plagiothecium undulatum, Pseudotaxiphyllum elegans, Rhytidiadelphus loreus, Thuidium tamariscinum, Polytrichum formosum, Tetraphis pellucida, Calypogeia fissa, Diplophyllum albicans, Gymnocolea inflata, Lepidozia reptans, Cladonia fimbriata, Cladonia squamules, Lonicera periclymenum, Hyacinthoides non-scripta, Chamerion angustifolium, Oxalis acetosella, Rubus fruticosus agg., Melanpyrum pratense, Agrostis capillaris, Deschampsia flexuosa, Holcus lanatus, Holcus mollis, Molinia caerulea, Poa nemoralis, Blechnum spicant, Pteridium aquilinum, Dryopteris dilatata