Ancient Woodland Indicator Plants

Large-leaved Lime and Wych Elm at Casey’s Copse and Rook Clift, nr. South Harting, West Sussex. Part I 28.10.25

Casey’s Copse from footpath

Rooks Clift from footpath

I have visited Casey’s Copse and Rook Clift several times this year; in the Spring, the Summer and now the Autumn. Theses sites were new discoveries for me this year. They will join my list of favourite sites in Sussex, that I love so much, I visit them every season every hear e.g. The Mens, Ebernoe Common, Eridge Rocks, Eridge Park, Newtimber Holt. I first visited Casey’s Copse with a friend who knew the site.

OS Maps © Crown copyright as accessed 22/10/25

I reached these woods by bus and train. I get the train to Chichester and then the 54 bus to South Harting. The South Harting bus only goes 5 times a day; so careful planning is needed! It is about an hour walk from South Harting to the bottom of Rooks Clift; I walk along the footpaths and trackways along the flat arable fields of the scarp foot (from road just before Knightsfield). It is possible to reach Rooks Clift along he South Downs Way, but that takes about three hours as the walk is extremely undulating. The 54 bus will drop you off where the B2141 crosses the South Downs Way; whilst it is not an official stop most drivers will drop you off there.

These sites are west South Downs escarpment ancient woodland. Some of these western scarp wood appear to be very old, possibly primary, from such evidence is available. South-East of East Harting ancient woodland (with Ash, Wych Elm and Large Leaved Lime …) occur. Francis Rose (1995) The Habitats and Vegetation of Sussex. The Booth Museum of Natural History, Brighton Borough Council p.9

Rose’s comment that these scarp woods are possibly primary, suggested that this woodland may have been part of the “wildwood” that covered the Downs until the dip slope woods were cleared for sheep farming, from the neolithic (ca. 5000-4000 BCE) onwards. see: Peter Brandon (1998) The South Downs

Until the late 1980s Large-leaved Lime was regarded as introduced in Sussex, but is now thought by Francis Rose and others to be native on the downland scarp in West Sussex. … Since 1987, when coppiced T. platyphyllos stools were discovered at Springhead as detailed in Briggs (1990), around 30 sites have been found on the scarp in Hampshire and W. Sussex. Most trees are within ancient copses surrounded by wood banks towards the foot of the scarp. Some border old tracks and a number perch upon ancient parish boundaries. The Sussex Rare Plant Register of Scarce & Threatened Vascular Plants, Charophytes, Bryophytes and Lichens (2001) Mary Briggs, Paul Harmes and Alan Knapp et. al pp. 100-101 Available on line Sussex Botanical Recording Society

List of native Large-Leaved Limes from the Sussex Rare Plant Register:

Map from Natural England Open Data Sites of Special Scientific Interest England

Casey’s Copse is within the Harting Down SSSI; Rook Clift is its own SSSI, just to the east of Harting Down SSSI near Treyford

The SSSI citation for Harting Down does not mention the presence of Large-Leaved Lime; but the citation was last revised in 1980; 45 years ago. Many SSSI specifications are very old now, and don’t represent current knowledge of sites. The Rooks Clift citation is much more accurate, and is more recent (1997); although it misses out the huge amount of Solomon’s Seal on the slopes of the stream valley.

From South Harting SSSI specification: Longer-established woodland occurs throughout the site, with a varied composition according to soil type and aspect. Beech Fagus sylvatica is common and becomes dominant on the scarp-face and valley sides. Oak Quercus robur and ash occur with yew on the deeper valley loams. The ground flora is quite sparse beneath the densest canopies, but
elsewhere includes bramble Rubus fruticosus, ivy Hedera helix, dog’s mercury Mercurialis perennis and false-brome Brachypodium sylvaticum.

From the Rook Clift SSSI specification Rook Clift is a small wooded combe on the scarp slope of the South Downs. The soils are predominantly calcareous in nature, overlying the chalk of the Downs. Deeper soils occur at the foot of the slope, and also the course of a stream, arising within the wood. This site is an ancient woodland which remains in a semi-natural condition. Large leaved lime Tilia platyphyllos dominates the canopy, together with ash Fraxinus excelsior and some beech Fagus sylvatica. Large leaved lime is a nationally scarce tree, with its natural range concentrated on the limestones of the Wye Valley and Peak District. Thus the high concentration of mature coppice stools, occurring on chalk, make this site nationally important and unique within West Sussex and the South Downs Natural Area. The canopy of large leaved lime, together with some beech casts a heavy shade, and as a result the shrub layer is poorly developed with scattered whitebeam Sorbus aria and yewTaxus baccata.

The field layer is dominated by vernal species such as ramsons Allium
ursinum and bluebell Endymion non-scripta, or shade tolerant species including dog’s mercury Mercurialis perennis, spurge laurel Daphne laureola and sanicle Sanicula europaea. The steep sided valley around the steam is more open with a canopy dominated by ash and wych elm Ulmus glabra. Here the field and ground layers are more developed with stands of hart’s tongue fern Phyllitis scolopendrium and soft shield fern Polystichum setiferum abundant, and opposite-leaved golden-saxifrage Chrysosplenium oppositifolium common along the stream side.

Both Casey’s Copse and Rooks Clift are designated by Nature England as ancient and semi-natural woodland. Looking at the Nature England ancient woodlands maps, it is clear that ancient woodland on the South Downs is mostly confined to the escarpments. There is much woodland in the Harting Down SSSI, but the dip slope woodland is not ancient.

Map from Natural England Open Data Ancient Woodland

Looking up to the scape-slope woodland before reaching Casey’s Copse, green-orange Beech and dark green Yew stand out from the dying Ash.

Casey’s Copse

The boundary bank at the scarp foot of mostly coppiced Ash. Scarp foot coppiced Ash seems to be less effected by Ash dieback than the maidens on the scarp slopes. Features like this tell us that most ancient woodland included much human intervention

Some of the coppiced Large-Leaved Limes:

Looking through dead/dying Ash maidens toward Beech:

Coppiced lime with a maiden Ash next to it

Looking though Soft Shield Fern at Beech

A Fox Skull next to a Long-leaved Lime leaf. In English folklore Long-Leaved Limes are associated with love, fertility, and justice. I hope the fox had lots of cubs!

A seemingly very ancient coppiced Long-Leaved Lime

Some of the lichens on this lime: Pertusaria leioplaca, Graphis scripta s.l. (Writing Lichen); Pertusaria pertusa (Pepper Pot Witing). All of these are common on smooth-barked trees like Beech, Sweet Chestnut and Lime

Walking along a hollow-way trackway at the foot of the downs, on gault clay. Trees: Hawthorn, Field Maple, Hazel

Hedgerow, from when the hollow-way ends.

One of a flock of about eight Yellow Hammers in the hedgerow

Path to the base of the bostal up Rooks Clift

Coppiced Ash along the path

Rooks Clift

Trackway up the north side pf the clift (variant of cleft, geographical: meaning a fissure or break)

Beech on the edge of the steep slope into the valley (clift) formed by a stream fed by a chalk spring

Yew

Soft Shield Fern

Beech

False Brome

Dogs Mercury

Fungus (probably Armillaira sp.) in the process of deliquescing

Going down the south side of the clift

Solomon’s Seal – extremely abundant

At this point if I had turned south and walked on I would have come to the grove of ca. 80 Long-Leaved Limes; but if I had done that I would have had to have walked back to South Harting as it got dark; that did not feel safe, so I am returning to Rook Clift on Saturday – watch out for Part II of this post!!!

Wych Elm

young Wych Elm tree (leaves to left; leaves on right, Hazel))

View from the south side f Rooks Clift to the north side: Beech and dying Ash

Hazel

Sunken trackway bedside the path on south side of clift

full of Harts-tongue Fern; extremely abundant, as in many South Downs hanger woods

Bank of sunken trackway with coppiced Beech

Back to the scarp foot path

White Poplar

Getting dark – back along the hedged trackway

Getting darker -past a field of Sunflowers

Terrible photo of a Raven at dusk

For most of the afternoon I had heard Ravens kwaaking overhead; it gave Rooks Clift a more Poe-like Ravens Clift feel!

Notable vascular plants of medieval woodland shaws north-west of Cowfold, West Sussex. Low Weald. 23.10.25

Above: South-facing edge of the east-west rectangle and the weest facing edge of the north rectangle of the L-shaped unnamed shaw

Below: Shaw shown with pink line. OS Maps © Crown copyright as accessed 22/10/25

This shaw has no name. I visit it frequently because it has a special charm; it encapsulates the essence of the small parcels of ancient woodland in the Low Weald; a landscape that has preserved its medieval patten of fields, hedgerows, shaws and woodlands. To get to it I walk through Bushygrove and Bakers shaws, named shaws of a similar character to this unnamed shaw. I take the 17 bus from Brighton to Cowfold to reach it.

A shaw is a strip of woodland usually between 5 and 15 metres wide. Shaws mostly form boundaries between fields. They are usually composed of semi-natural woodland and often have diverse woodland ground vegetation similar to other semi-natural woodlands in the area. In the Low Weald shaws may be the relicts of former larger woods, or they may have developed from narrower hedgerows. A look at the Natural England map of ancient woodland shows how many shaws in West Sussex are semi-natural ancient woodland

Map from DEFRA Open Data Ancient Woodland

All sections of text in italics are quotations; sources given at the end of the quotes.

Most of the Wealden hedgerows – including shaws (narrow belts of woodland remaining when fields have been cut from woodlands) – are likely to date from the time of medieval assarts (fields derived from the general, unplanned clearance of woodlands and unenclosed commons by individuals). In Mid Sussex, as elsewhere in the Weald, there are relatively few hedgerows stemming from the formal enclosure of fields. The Weald appears to have a significant proportion of species rich/ancient hedgerows, revealed by the frequency of indicator species such as field maple, spindle and hazel. However, the data is not yet available to assess with any degree of accuracy the number, length and type of hedgerows in Sussex and its Districts. Mid Sussex District Council (2005) A Landscape Character Assessment For Mid Sussex.

Shaws are important relicts of long-lost woodland: In 1210 Beeding Manor had outlying farms in Cowfold and in 1256 the Bishop of Chichester’s chase extended down the whole East side of Cowfold Parish across to the Southwest corner and from there to near the centre of the northern boundary of the Parish. By 1257 the Cowfold tenants, customary and free, formed a distinct group. A large proportion of the Parish was woodland or orchards and remained so until the mid 18th century. Cowfold Parish Council. (2024) Cowfold Neighbourhood Plan 2019-2031. p.9

I am writing this post to “big-up” the biological importance of small, especially unnamed, shaws: to draw attention to the beauty of small patches of woodland. They are greatly under threat from development. There are many new housing development in-between the South Downs north of Brighton and the High Weald, in the Low Weald, transacted by the A281 (Pyecombe to Horsham) and the A273 (Pyecombe to Haywards Heath. As I travel on the 17 bus on the A281 or the buses 270,271, or 272 on the A273, I see the continuous building of new housing, and plans for housing are continually presented to planning authorities e.g. The Argus (21/02/25) Plans for dozens of homes near Cowfold are revealed

Sussex sits between two immovable features—the coast of the English channel and Greater London. In many places, it is the only ribbon of truly green land preventing unbroken concrete from connecting the two. … we have a legal commitment to net zero, but we are building homes in the middle of nowhere whose occupants are wholly reliant on a car to go anywhere. Andrew Griffith MP Arundel and South Downs Hansard Housing Developments: West Sussex Volume 679: debated on Monday 7 September 2020

The Low Weald lacks the higher level of protection of the South Downs, which is a National Park, and the High Weald, a National Landscape (area of outstanding natural beauty), not that that necessarily offers between protection in practice to the South Downs and High Weald

I became aware of this shaw from a map of Wild Service Trees

in Dave Bang’s excellent book.(2018) The Land of the Brighton Line: A Field Guide to the Middle Sussex and Southeast Surrey Weald 018 ISBN: 978095486382

This unnamed shaw has large maiden trees – Wild Service, Pedunculate Oak, and Ash – with an understory of Field Maple, Hazel, Hawthorn, Wild Cherry and Midland Thorn. Wild Service, Midland Thorn and Wild Cherry are ancient woodland indicators.

It’s ground flora includes the ancient woodland indicators Bluebells and Wood Anemone, in the Spring, and Butchers Broom, all year round. In a nearby stand Spurge-Laurel and Wood Spurge can be found.

This blog does not attempt to be a full survey of the vascular plants in this shaw; it is just the things I found particularly noticeable.

Ancient Woodland Indicators visible in Autumn

Sorbus torminalis Wild Service Tree

Trunk. This trunk of a maiden Wild Service Tree is covered in lichen so it hard to see the trunks morphology

Most Wild Service Trees have few lichens from my experience, but on the side which gets most light this tree had abundant lichens.

This trunk in the shaw shows the typical bark of Wild Service Tress; many Wild Service Trees in the Low Weald have been coppiced into two trunks. (e.g. the large Wild Service Tree in Furzefield Wood nr. West Grinstead and the numerous Wild Service Trees of West Wood nr. Burgess Hil)

Leaves and fruit

Crataegus laevigata, Midland Thorn

Trunk and leaves

Fruit

Midland Thorn has two (or more) seeds in their haws, whereas Hawthorns have only one

This Midland Thorn Flower on 29/04/25; with twin stigmas

Prunus avium Wild Cherry

Wild Cherries can be identified just by their trunk morphology which is so characteristic. However, in spring their white flowers are very characteristic; and in summer so are their berries. However, ripe berries are almost immediately eaten by birds; if you are lucky enough to see them, they make a very nice fruity snack on a walk

This species mostly develops single, straight trunks with a thin, smooth purplish-grey bark that becomes grey-brown with horizontal fissuring and peeling when old. Tree species | European Atlas of Forest Tree Species – Prunus avium

Wild Cherry flowers from a tree in Baker’s Shaw; 400m south of this (unnamed shaw) in the Spring

Malus sylvestris, Crab Apple – Fruit.

Theses crab apples trees were in Bushygrove Shaw. Crab Apples are easiest to identify in Autumn when their fruits are on the forest floor; just look up and you’ll see the tree(s) they came from. This autumn is a “mast year” when fruits from trees are abundant.

Ruscus aculeatus Butchers Broom

Butchers broom is a shrub which grows under trees in ancient woodlands; it’s leaves and flowers are very characteristic. Butcher’s broom leaves are not true leaves but are actually flattened stems called cladodes, with sharp spikes on the ends of the cladodes. Its flowers bloom in very early spring; and female flowers produce berries in Summer, which persist into Autumn

Butchers broom is known as an ‘ancient woodland indicator’. This is because it doesn’t colonise new habitats or spread easily to new woods; where it is growing, the wood has usually been there for a very long time. … Look beneath the deciduous trees, even in the more shaded areas.

Butchers broom is quite unlike any other British plant. It is a short evergreen bush growing up to about two feet high and all the leaves end in a pointed spike; one of its old English names is ‘knee holly’. In early spring, the tiny, pale green six-petalled flowers sit in the middle of the leaf and show that these leaves are, technically, flattened stems.

Butchers broom was used to scour butcher’s blocks until the nineteenth century. The spiky leaves seem ideal for getting into the cuts of old wooden blocks to clean them. New Forest National Park Butchers Broom

Fruit:

Ancient Woodland Indicators seen on other visits:

Euphorbia amygdaloides Wood Spurge seen on 29.08.24 in Baker’s Shaw; 400m south of this (unnamed shaw)

Anemonoides nemorosa Wood Anemone 16.04.25

Carex sylvatica Wood Sedge – seen on 29.08.24 in Baker’s Shaw; 400m south of this (unnamed shaw)

The locations of Bushygrove and Baker’s Shaws

Map above from iNaturalist community. Observation of Euphorbia amygdaloides from Cowfold, Sussex observed on 29/08. Exported from https://www.inaturalist.org on 25.10.25 showing Bushygrove and Bakers Shaw

Detail of Bushygrove and Bakers Shaw

Hyacinthoides non-scripta Bluebell in Spring 29.04.25

Daphne laureola Spurge-Laurel

In Baker’s Shaw; 400m south of this (unnamed shaw)

Mercurialis perennis Dog’s Mercury – viewed 29.04.25

Other vascular plants in the Shaw

The large maidens, with “white” lichen-covered bark, are Ash, Pedunculate Oak (and Wild Service)

The understory is Hawthorn, Field Maple, Hazel, Holly (and Midland Thorne)

Quercus robur Pedunculate Oak

Pedunculate Oaks leaves and acorns in autumn are very distinctive. In some areas of the Low Weald, especially on the Greensand Ridge there are Sessile Oaks, e.g. at Rakes Hanger, near Liss (hanger in West Sussex)

A useful guide from Natural Resources Wales

Pedunculate Oak; tree with yellow-brown leaves

Trunk of Pedunculate Oak. The sides of trunks which receive most light are often covered in lichens. This maiden Oak is on the edge of the shaw

This Oak also has a beautiful fingus growing on it:

Phaeotremella foliacea Leafy Brain

Fraxinus excelsior Ash

This maiden Ash, on the edge of the Shaw, is typical of an Ash with Ash Dieback Disease, with no leaves (in October, whilst Ash is deciduous, you would except to see some leaves)

When Ash has leaves their leaves are very characteristic; as are their samaras.

Samaras are the winged, single-seeded fruits, commonly called “ash keys, that can be seen in Autumn and Winter within the shaw were healthier Ash showing these features:

Ash is an extremely important tree for lichens; it is the tree species with the second highest diversity of lichens, according to the British Lichen Society

Ash dieback will kill up to 80% of ash trees across the UK. At a cost of billions, the effects will be staggering. It will change the landscape forever and threaten many species which rely on ash.

Varicellaria hemisphaerica is a rare UK lichen, and it is on the Ash on the south-facing edge of the shaw; this Ash is dying

Acer campestris, Field Maple

Crataegus monogyna, Hawthorn

Corylus avellana Hazel

Taxus baccata English Yew, in Baker’s Shaw

A Pin-Head lichen, ancient trees, and spring flowers at Marstakes Common, South Chailey. 22.04.25

“Markstakes Common is a small nature reserve with a mix of landscapes; grassland, ancient woodland, wood pasture and mire. Past use is likely to have been bracken harvesting, rough pasturage and ad hoc extraction of timber” Friends of Markstakes Common

I first visited Marstakes Common in the winter of 2022: Markstakes Common & Chailey Commons. Tress, Fungi, Bryophytes, Lichen and Slime Molds. 06.12.22

Marstakes us a wonderful location with much biological interest; this post focusses only on lichens and vascular plants.

The most interesting thing I saw was Calicium viride; a pin lichen, growing on Oak. I saw it just outside the boundary of the commons in ancient woodland between It’s apotothecia is ca. 1-2mm long and is pin shaped. Theoretically “common” but incredibly difficult to see. On acid barked broad leaved trees in ancient woodland. Look out for bright green granular thallus – looks like Psilolechia lucida, but P. lucida on grows on rocks. So, if you see something like P. lucida on a tree, it might be C. viride. Pin 1-2mm long so probably need 20x hand lens or macro camera.

Soon after entering Marstakes Common, I saw a huge ancient birch, Fagus sylvatica. On it was the tiny lichen, Enterographa crassa

“A distinctive species often dominating large areas of trunk in pure mosaics of small interlocking waxy brown thalli, spotted with small dot like apothecia, which often line up in dendritic patterns. Very common in south western and Irish woodlands on humid shaded trunks. Rare to the north and east” British Lichen Society Enterographa crassa

Enterographa crassa is very difficult to see, as it is the colour of bark. It often occurs in large patches. It’s tiny apotothecia form in lines that look like lirrelate apothecia (writing-like apothecia), but they are lines of dots 0.1-0.2mm across.

Marstakes has many beautiful trees, including Ancient Oaks, Birches, Hornbeam, Wild Cherry and Midland Hawthorn. Hornbeam (when in the middle of woods, not a boundary tree), Midland Hawthorns and Wild Cherry are ancient woodland indicator plants.

Wild Cherry (Gean), Prunus avium

Ancient Hornbeam, Carpinus betulus

Midland Hawthorn, Crataegus laevigata, with Bluebells, Hyacinthoides non-scripta, another Ancient Woodland Indicator Plants

Flowers of another Midland Hawthorn

Midland Hawthorn has two styles; ordinary Hawthorn only has one. A style of an flower is an organ of variable length that connects the ovary to the stigma.