Part IV     Natural History

Chapter 12: Habitats

 

The landscape around us is not a ‘natural’ countryside.  It has been created by farmers.  Whether we own our land or are tenant farmers, we are only here for a short time really and we must use our land in the best way we can.  That’s good stewardship … The look of the country matters to me and to a lot of my colleagues.  The look can either be ‘suburban tidiness’, which I do my best to avoid, or it can be more of a variety without causing problems agriculturally … In the past I suppose farmers were motivated by the commercial aspects, but more and more of them are now taking an interest in conservation and that is good – it is good public relations for the farming industry as a whole.

Dorset farmer Mike Chandler in Haworth (1987)

 

The natural history of Prestwood is intimately bound up with its geology (see Chapter 2) and economic history.  The parish is largely situated on a clay plateau cut by steep dry valleys exposing chalk soils.  Economic exploitation of the area over centuries has resulted in an environment quite unlike that which existed before man first occupied it.  The original “wild wood” has long disappeared, along with most of the animals that lived there.  Nevertheless there are still substantial areas of woodland and most of these have survived for centuries.  Some areas, in fact, may have been continuously wooded since Neolithic times, although they have been continually reshaped by the activities of man, selectively cutting mature trees and brushwood, planting new trees, hunting, and so on.

Apart from the woods, the only other large-scale habitats in Prestwood parish are agricultural fields and areas of housing development.

 

Typical local scenery - woods, pasture fields, and housing development: Perks Lane seen from Hockey Field

 

The fields were created for agriculture and have been actively managed for a very long time for the production of crops or for grazing animals.  Whatever wildlife and plants survive there do so, by and large, because they do not unduly interfere with this economic business.  Where there is intensive cultivation or high stocking levels, agricultural land can be virtually a wildlife desert.  Farmland at any one time divides down into a number of distinct types in the parish: arable (important for native annual plants that only grow where the soil is regularly disturbed), unimproved (unfertilised) grassland, improved pasture, impoverished grassland that has been over-exploited, and derelict wasteland.  These can be further divided according to the soil-type, particularly between those on chalk and those on clay, the latter also varying between the less fertile “sandy clay with pebbles” and the more fertile “clay-with-flints”.

One might think that the wide swathes of housing could be written off as far as wildlife was concerned, but at least half this area is occupied by gardens and interstitial remnants of “wasteland”, trees and grass, that enable certain plants and creatures to thrive.  For certain birds and insects, gardens, as long as they are not laid to hard-standing, now constitute the most important habitat in the parish.

Apart from these three large-scale habitats, there are smaller habitats that are often crucial for the natural history of the parish.  One of the most important of these is the hedgerows.  Prestwood is fortunate to have preserved a good many of its ancient hedgerows, some of which almost certainly date back over a thousand years where they mark old boundaries or route-ways.  Not only do these contain plants that are relics of the old woods and provide food and nesting-places for birds, but they also constitute an interlocking network of corridors for small mammals, bats and invertebrates to disperse through the parish.  Many of the roads and tracks are bordered by such hedges, and they may also provide roadside banks and verges giving sanctuary for plants and creatures displaced from the fields by modern agriculture.  Where trees have survived to maturity in the parish, this is often because they were part of hedgerows (or marking the boundaries of woods).  Mature trees are not only aesthetically pleasing and a crucial part of the Chilterns scenery, but they also provide unique habitats in themselves for some of the rarer invertebrates such as beetles.  Moreover, like the hedgerows, these trees, some of them 200 years old or more, provide a visible sign of the history of the area of a vintage seldom attained by man-made structures.  Other boundary markers consist of old flint or brick walls.  There are very few of these in the parish, but some harbour plants that grow nowhere else locally.

One essential resource for wildlife is water.  While the parish has no running water such as streams or rivers, it has dozens of ponds, ranging in size from a couple to hundreds of square metres.  Even the smallest, if in good condition, will be used by amphibians, reptiles, birds and mammals.  Some plants grow uniquely in and by such ponds, and aquatic invertebrate life may be extremely rich.  Marshland also has its own flora and fauna.  The clay plateau would at one time have had many permanently wet areas, but these have been almost all drained for agriculture or housing.  A few ponds have a small area of marsh, and a couple of other marshes have survived in old woodlands or derelict fields.

Most of these ponds were originally man-made, but so were all the ancient hedgerows, and all other parts of the countryside have been radically modified by man.  As such, they need regular maintenance to survive, as all land in the parish, given only a short time (just a few decades) would naturally revert to woodland – good for some creatures, but poor for overall diversity and the open scenery that most people value.  A lot of emphasis is placed today on planting trees to protect the environment, but they will not be more than plantations, without the genuine ecological value of ancient woodlands, for many centuries.  Grassland, properly maintained, can be as valuable, or more so, than such plantations, both for environmental benefits and for wildlife.  Because they have adapted over many centuries to countryside management by man, many species would now not be able to survive without the special conditions provided by our interference, so that nature conservation involves considerable work and cannot, except in special circumstances, be simply a matter of letting things "go wild". 

Another obviously man-made habitat, but one also of historic interest, is the orchard, once such a feature of Prestwood.  The orchards were also associated with a particular flora and fauna.  Very few orchards survive nowadays and it is important that these few should be preserved.  If new orchards can be grown as well, so much the better, particularly if some of the old fruit varieties of the past can be re-introduced, as long as they do not displace wildlife-rich grasslands.

A few places in the parish, of various habitat types, are richer in plants and creatures (what in modern parlance is called “biodiversity”) than others, by the accident that they happened to have received more favourable treatment from the point of view of conservation.  This is usually a chance by-product of their economic use by man.  Particularly rich sites are small in extent and have survived precariously, but they give us an experience of what our countryside could be like if our economic exploitation of it could be tempered with some thought for the needs of conservation and aesthetic value.  These special places need targeted preservation.  They include the only local nature reserves in the parish, Prestwood Picnic Site at the bottom of Perks Lane, and the churchyard of Holy Trinity at the very centre of the parish.  The first was earlier managed by Wycombe District Council, and now by the Chiltern Society, with the help of Prestwood Nature, to preserve and enhance its natural history interest.  Although small, it is a delightful place to rest or take a ramble.  The second, even smaller in extent, no more than an acre, has recently been designated a Local Wildlife Site for its unique, and internationally important, acid grassland with an unusually large concentration of rare waxcap fungi.

We should not, however, confine our attention to these special areas of high “biodiversity”.  Isolated as they often are from other similar sites, their impact on the countryside generally is minimal, being more like zoos that exhibit the variety, colour and excitement that used to be more widespread.  Most people of a certain age these days can just remember fields of orchids and clouds of butterflies as a feature of any walk through the British countryside.  This experience, sadly, is no more.  It could, however, be revived if the semi-natural areas that still exist (almost all the land, in fact, that has not been built on or is still in active agricultural use) were to be sensitively managed to encourage a variety of plants and wildlife.  This must, of course, be a matter of a trade-off between our economic needs and the value we place on having a pleasing and exhilarating environment.  The choice is ours – but we have only a short time in which to make it, because almost every acre of open space within the parish is under threat in some way and could disappear as semi-natural habitat in a matter of years.

These threats are numerous.  They include:

·          Pressure to build more houses and widen roads, along, of course, with more car parks.

·          Intensive agriculture (especially monoculture), including use of herbicides and pesticides.

·          Loss of traditional farming practices such as fallow, summer hay-making, and hedge-laying.

·          Disappearance of a local economy supporting traditional small-scale farming.

·          Pollution.

·          Introduction of alien species.

·          Loss of economic use (e.g. ponds).

·          Poor management or neglect.

·          Over-exploitation (such as over-abstraction of water).

·          Drainage of wetlands.

·          Further fragmentation of already tiny natural habitats.

·          Over-tidiness and excessive management.

·          Inadequate government support for conservation at international, national and local levels.

·          Lack of public appreciation of the value of wild areas, diversity of wildlife, and certain conservation       measures, as well as lack of awareness of the potential for environmental improvement in their own back-      yards and surrounding streets.

·          Lack of value placed on a rich and diverse countryside as an essential element in our quality of life.

·          Growth of traffic (including the fact that most people can neglect their local environment and travel to       designated “beauty spots” or “nature reserves” in their leisure time).

·          Recreational activities conflicting with the needs of wildlife.

·          Pest damage (e.g. grey squirrels, deer, rabbits, edible dormouse).

·          Public overuse or misuse of certain spaces, especially those closest to housing.

·          Irresponsible dumping of waste (including green garden materials).

The impact of some of these will be discussed below in the context of different habitats, but what they all have in common is that they stem from a failure in our modern society to value and take responsibility for the countryside, as against economic development, short-term hedonism, and other social activities.  The following chapters are intended to make clear what we still have that we should value, the potential for improvement, and how precarious is the preservation of what currently exists.  At the microscopic level of the single parish, rather than the grand sweep of national or world trends, it is easier to understand the complex relationships that exist between biodiversity and human history.

Nanfan Wood, ancient woodland regenerating after substantial felling in the early C19 ^th

Woodlands

 

These woods are not the Forest; each is moored

To a village somewhere near.  If not of to-day

They are not like the wilds of Mayo, they are assured

Of their place by men; reprieved from the Neolithic night

By gamekeepers or by Herrick’s girls at play.

And always we walk out again.

Louis MacNeice “Woods”

 

Like the Chilterns generally, a substantial proportion (about 15%, or 309 acres) of Prestwood parish, in accordance with its name, is woodland.  Most of this woodland has been continuously so for at least several centuries, and perhaps since before the arrival of man.  Even in medieval times, however, parts of the then larger area of natural woodland were being actively managed.  A steep bank and ditch, originally medieval, still marks one edge of Lodge Wood, where it backs on to the equally ancient route-way now known as Honor End Lane.  It was mentioned in medieval manuscripts as the “Priest’s Wood”, having been the benefice of the priest to the Hampden Estate.  Solifluction has reduced most such boundary features to virtually nothing over time, but, in this case at least, its survival has been ensured by its finding a modern use as a roadside drainage ditch.  With the bank inside the ditch, this feature was designed to keep stock in, rather than to keep creatures out, and it was reinforced by laying the boundary shrubs to form a dense hedge, even more effective, if well-maintained, than the modern barbed wire fence, and certainly far more attractive and environmentally friendly.  (You can still see the effect of laying in the form of large horizontal boughs, although this management has now been discontinued for centuries and the boundary hedge is no longer impenetrable.)  When it was maintained by the priest, then, it would have been partial pasture with trees.  We know from medieval manuscripts that the wood was part of the land the priest was allowed to exploit economically - pasturing animals such as pigs that fed on acorns and beech-mast, cutting brushwood and so on: for he received no salary for his services and must maintain himself.  In later centuries our woodlands lost their pasture function and the boundaries were maintained to keep stock out from the woods, which were coppiced for fence stakes, furniture, basketry and firewood, and owners no longer wanted animals browsing off the young growth.  (Old pasture woods were characterised by scattered large trees with open grassy glades and the trees were managed by pollarding above browsing height to provide small branches to be cut as poles.  No such pollard trees survive in the parish, but a couple of superb old pollard beeches can be found in the woodland of Little Hampden Common, just north of the parish, because this survived longer as common land and therefore was still used for pasture until only a couple of centuries ago.  Even more impressive examples survive at Burnham Beeches.)

 

Pollard beeches, Little Hampden Common

 

After medieval times our Prestwood woodlands became closed woods, largely without open grassy areas, devoted to supplying timber and, later, coppiced small wood for furniture-making.  Trees were harvested for timber, originally piecemeal but in later centuries by clear-felling, so they were not allowed to grow very old, except where they formed part of the boundary, while regular coppicing (about every seven years) and cutting of brushwood would have provided a circulating patchwork of sunlit clearings favourable to a ground flora of primroses and violets.

Whatever the original use of our woodlands, this has long been obscured by the more recent dominance of the chair industry that started around the beginning of the nineteenth century.  This led to massive uniform plantings of Beech, the most suitable wood for this purpose.  These trees have now reached maturity and dominate woodlands throughout the Chilterns, so much so that they are almost synonymous with the Chiltern landscape and one would think that they had always been so, so natural do they appear sometimes with specific beech-associated ground plants and fungi.  For the most part, however, the ground is bare apart from leaf litter and patches of moss, so dark is the shade under these trees (although bluebells can survive and flower before the leaves expand to cut out the light), while in recent decades there has been a large increase in the density of holly (producing no berries in the shade), making some areas impenetrable.  The old beech flora is now rare and best sought on steep chalky slopes where leaf litter is less able to accumulate and forestry operations less likely.

Julius Caesar in his Commentaries claimed that there was much timber in Britain except for beech, but this was almost certainly a superficial judgement on limited evidence, as Plot (1676) contests, observing that "there is such plenty [of beech] in the Chiltern, that they have now there-about scarce any thing else".  Early woods must certainly have contained much naturally generated beech (long used for making bowls and furniture, and for charcoal), although, as one would expect from woodlands that had survived for millennia, there would have been a mixture of many species.  Most of these likewise had traditional economic uses – oak (for buildings and ships), ash (for poles and firewood), yew (for bows), hornbeam (for charcoal or products requiring particularly hard wood, like bowls and coffins), rowan (for its fruits), birch (for brooms), willow (for baskets), hazel (for stakes and nuts), wild cherry (for its fruits and decorative timber), and wild service (for its fruit).  There may have been trees that no longer grow here at all, such as native limes and box (which still grows nearby at Chequers as either a native or at least established for many centuries).

These early woods, less densely shady than the present beechwoods, and with a wider variety of ages of trees preventing a uniform roof of foliage, would have had plenty of light reaching ground level (particularly if they were pasture woodlands or where sections were coppiced) and hence a good variety of lower plants.  Access to remove timber or to hunt deer also meant the upkeep of open rides that encouraged a variety of flowers and insects, and prevented a smothering of the ground flora by brambles.  In the best of our old woods many of these native ground plants survive as indicators of this history, although often in small numbers or in limited areas.  They are plants that do not readily colonise new areas and are therefore absent from newly-created woodlands, or from clear-felled sections where the forestry work has severely damaged the soil.  These include primrose, bluebell, wood-sorrel, enchanter’s nightshade, yellow archangel, yellow pimpernel, green hellebore, moschatel, coralroot, wood speedwell, and sanicle.  They survive where the shade or bramble have not crowded them out, despite the fact that the old rides have declined to tracks no wider than a metre or two.  That these are the old rides is often indicated by their being depressed below the level of the surrounding woodland by centuries of use, or by following a ditch or bank that was an ancient boundary marker.

 

Yellow pimpernel

The planting of beech did not entirely eradicate the native trees, although it came preciously close to doing so.  For one thing, local residents would have still valued other trees (like hazel) for purposes other than the furniture industry.  The boundaries of the woods were also maintained, and this usually meant the survival of a many different species at the wood-margins.  This means that today we have the best chance of finding a good range of trees by walking along the edge.

Until recently a mature Wild Service tree survived in Lodge Wood but it was felled (probably by mistake in an attempt to widen a footpath across which it leaned).  Two younger specimens still grow in the parish, not in woodland, but in a large ancient hedge (see below).  These trees always seem to have occurred in small numbers, at least in the last couple or three centuries.  They spread most easily by suckering, as the elm does, despite the fact that they can produce plenty of fruits, which are edible and used to be known as “chequers”.  These are red berries, like those of the rowan and the whitebeam (to which they are related by being in the same genus Sorbus – the Latin name that was corrupted into Old English as syrfe to become the modern “service”).  They need a frost, as the medlar does, to soften them, when their taste apparently has “hints of apricot, sultana, overripe damson and tamarind” (Mabey 1996)!  They were apparently much more common in the past because archaeological evidence indicates that these tiny fruits were collected in sufficient quantity to be a staple food in Neolithic times.  They were on sale in local markets in the C18^th.  Why they were called “chequers” is unclear, but it is most likely because they were often fermented to make a wine, sometimes fortified with spirits, that was then sold at inns.  The standard sign for such inns used to be a chess- or draughts-board - one of the standard games played at them, giving rise to a number of Chequers Inns.  One such inn survives in Prestwood today. (Although it was after the Angevin family of Elias de Scaccario - Italian for “chessboard” - who lived there in the C12^th, that the prime minister’s country residence of Chequers, not far from Prestwood, was named.  The family name was probably derived from their role in the Exchequer at the time, itself so named from the checked cloth on the table of that office.  So this famous house has nothing to do with the tree or pubs!)  One may hazard a reasonable guess that it was the widespread planting of beech and the management of Chiltern woodlands for timber that meant that the spreading of the wild service tree by suckering became a nuisance to well-ordered plantations, and its failure to regenerate readily by seed spelled its demise.  Perhaps, now that the demands for large quantities of beechwood have disappeared, it would be a good chance to reintroduce this interesting and historic tree (from local stock) to those of our woods that are managed with an eye to conservation.  In fact, cuttings have been taken from Prestwood's surviving wild service trees by the National Trust in order to grow on and restock woodlands on the Ashridge Estate with this now rare species.

 

Wild service with unripe "chequers"

 

In the C19^th and the first half of the C20^th, plantations were commonly created of foreign pine, fir or larch, which supplied a fast-growing source of easily worked timber, and hence a more rapid return for owners' investments.  These were used to feed the saw-mills, but some of these plantations have survived.  These plantations, after ten or twenty years, tend to be dark and have virtually no ground flora, and they are not popular with modern conservationists.  Where they have been grown more spaciously, in small groups or avenues, they can be quite scenic and valued by local residents (such as the fine avenue of pines on Ninneywood Farm extending from Crooks Wood to the cow-pond).  They are also used by sparrowhawks for nesting, and can be popular with certain other birds, particularly coal tits and goldcrests.  There are also sometimes associated fungi and insects that are of interest.  Many of these plantations were new woods, although some were created within the ancient woods after clear-felling of beech.  There are substantial plantings, for instance, of larch and Sitka spruce in Lodge Wood, which are gradually being reduced by the current owner, the Woodland Trust.  One C19^th pine plantation at Nanfan Wood was cut a long time ago, although the odd tree survives: when it was in its prime, it became a famed local landmark, people appreciating the exotic dark rows of evergreens as a scenic feature.  Later plantations have also been felled more recently, such as that in Atkins Wood.  Those planted to replace the WWII prisoner-of-war camp in Peterley Wood are now mature and due to be felled (some have already fallen).  Such plantations have lost their economic value and the foreign evergreens are now replaced by mixtures of native trees.

            Fungi are a prominent feature of most of the woodlands.  There are more species of fungus associated with woodland than plants or animals.  Almost three-quarters of all our fungi are associated with woods and trees, as against just 11% of our vascular plants.  This includes both those fungi that grow on the trees themselves or on decaying wood, and those that sprout from the ground in woods.  The latter’s mycorrhiza (like roots, but really the subterranean main body of the fungus, the toadstool being the equivalent of a fruit on a green plant) spread underground in a complex association with the roots of trees, some of them only associating with a particular kind of tree.  While the fungi are dependent on this association, receiving sugars and other substances that only green plants can manufacture with their chlorophyll, in exchange they supply vital nutrients like phosphorus to the plants with which they live, as only the fungi can extract such minerals efficiently from the soil.  (According to Watling, 2001, “More than 85 per cent of the world’s vascular plants are mycorrhizal: their roots have established an intimate liaison with at least one fungus”.  One can therefore say that most life on this planet is made viable only by the existence of the fungi, which is not surprising because our plants evolved in a world where fungi were already prevalent and the two kingdoms evolved together.)

The soil-sprouting fungi emerge mostly in the autumn, as long as it has not been too dry, and can astonish with the sudden appearance of huge numbers overnight, as well as with the sheer variety of shapes, colours and textures.  Some species can be found dependably year after year, but others only “fruit” occasionally, presumably when conditions are just right.  The joy of fungus-hunting is that you never know what surprise awaits you.  You can go to the same wood year after year and still find new species.  After many years of walking Lodge Wood, for instance, it was only in 2000 that I came across a magnificent specimen of a large shaggy bolete (the type of fungus that has round pores beneath the thick spongy cap instead of linear gills like the mushroom), a species I had never seen before, the rare Strobilomyces strobilaceus, or "old man of the woods".  Not often seen, it appeared in a number of woods in the region that same year (Angling Spring Wood, Hampden Common), so that the sequence of weather conditions that season must have just suited it.  Without that happy coincidence, we would never have known it was there.  Fungi are essentially hidden creatures of the dark, growing inside the soil or wood, and they only appear in the light very temporarily as "toadstools" when they feel the time is right for producing spores and creating new progeny.

 

Deathcap

Fly agaric

The unpredictability, mystery and hint of danger (a few are indeed deadly poisonous if eaten) that surrounds toadstools make them a unique and fascinating subject for study, although precise identification is not always easy, often impossible without microscopic study.  More than any other group of organisms, they are associated with a vast range of uncommon chemical compounds that both give the edible species their unique and interesting flavours (like the beautiful bluish strong-smelling aniseed toadstool found in Lodge Wood), but also make others dangerously inedible or hallucinatory.  A few, like the deathcap (to be found sometimes in Peterley Wood, for example), have a cocktail of chemicals that can attack just about every function of the body.  The air of mystery surrounding toadstools is best symbolised by the fly agaric, its striking bright red cap dotted with white scales, pictured as the haunt of fairies in so many children’s books.  It was used by early tribes for ritual hallucinatory experiences, but without appropriate preparation it is also deadly poisonous.  As long as we leave well alone, the fly agaric can be admired and appreciated for its sheer beauty and power when we walk through the birches with which it grows in Lodge Wood, Lawrence Grove, Prestwood and Kingshill Commons and elsewhere.

The trees present in most or all of the parish’s woods are: English elm, beech, hornbeam, pedunculate oak, silver birch, goat willow, wild cherry, rowan, whitebeam, holly, field maple, sycamore and ash.  The commonest of these, because of the C19^th plantings, is beech, which is dominant in all the major woods.  It has a large suite of fungi and creatures associated with it, reflecting the fact that it was always a major native species before it was planted in monocultures.  Look out particularly for the beechwood sickener Russula mairei with its bright red cap, the southern bracket Ganoderma australe, often covered with a dense sprinkling of cocoa-like spores, the rhinoceros-horned smaller relative of the stag-beetle Sinodendron cylindricum, whose grubs live and feed in the rotten beech-wood for three years, or the fuzzy cylindrical galls of Hartigiola annulipes that stand erect on the leaves in late summer, caused by the larvae of a tiny gall-midge.  Among the birds, jays, bramblings and great tits particularly enjoy beechnuts through the winter.  While the beech seeds itself abundantly and the woods are full of young saplings, these are almost universally ring-barked by grey squirrels, who enjoy the rising sweet sap beneath the bark in spring, so that very few of these saplings will become mature trees.  (The beechwoods were planted, of course, long before the squirrel was introduced in the early C20^th and displaced the red squirrel that, until then, was a regular inhabitant of our woodlands, and less of a threat to our trees.)

The tree that has most other associated, however, is the venerable Pedunculate Oak, which at one time was probably more numerous than the beech, but was selectively felled for timber and, being slow-growing, less often replanted.  (For more on the ecological relationships of trees and other plants see the first chapter of " Ecological Flora of the Central Chilterns" (Marshall 2019), available on the Prestwood Nature website www.prestwoodnature.org.)  It is present throughout the parish and can make a claim to be the most characteristic indigenous tree, given that the majority of our beech trees were planted.  Some species particularly associated with it have even taken its name - oak bush-cricket, pale oak beauty moth, oak longhorn beetle, oak milkcap fungus.  Familiar oak-users, of course, are the five gall-wasps whose larvae cause the artichoke, marble, knopper, cherry and spangle galls to be seen on most oak-trees of an appropriate age.  Grey squirrels and jays eat the acorns (as did the wild boar and domestic pigs in medieval times).

 

Acorns

Oak galls: upper pair, marble gall, one showing chamber inhabited by a single grub; lower, oak-apple with multiple emergence holes

Another very characteristic and ubiquitous tree, which seeds itself abundantly and soon colonises new ground, especially on the plateau clays, is the Silver Birch. Like the oak and the beech, it supports a large suite of other creatures, including the birch shieldbug and the grey birch moth.  Several tits also feed both on the birch seed and on the small insects that inhabit the foliage.  A renowned and beautiful fungus always associated with birch is the fly agaric, but there are many more - the very common brown roll-rim, brown birch bolete Leccinum scabrum and lots of milkcaps and brittlegills.  The common bracket fungus on birch is the birch polypore, with a smooth pale brown cap and white pores underneath.

A tree that readily seeds itself is the Goat Willow .  Although found scattered in woods it will grow almost anywhere.  Many insects feed on it, some causing the red galls often to be found on the leaves.  Its most valuable role, however, is as the food-plant of the rarely seen purple emperor butterfly.  The male butterflies keep to the tops of tall woodland trees, especially oaks, where they mate with females, but the latter then scatter widely looking for willows on which to lay their eggs.

Two common trees are close relatives of the rare wild service - rowan with its ash-like leaves and bright red berries, and whitebeam, whose leaves flash their white undersides in the wind at the edge of most woods.  The rowan prefers acid soils, the whitebeam chalk ones.  Wild cherries and hornbeam are characteristic trees in our area, both with distinctive trunks.  The cherry's trunk is conspicuously ringed with lines of pores.  The grey trunk of the hornbeam has darker vertical streaks that tell it apart from the beech, although its toothed leaves also contrast with the beech-leaf's smooth margins.  The fruits of the hornbeam are very distinctive with large ragged bracts, hanging in dense clusters.  Yew, our only native evergreen tree, occurs in a number of woods on the chalk (Peterley, Longfield, Crooks and Acrehill).  Wych and small-leaved elm are sometimes seen, although they no longer grow into mature trees because the Dutch elm disease strikes them down when they reach about fifteen years, so they are never now more than shrubs.  Even so, they are important as the food-plant of the uncommon white hairstreak butterfly, which still has colonies in our region.  Downy birch, which has more regularly toothed leaves than the silver birch, grows in wet areas of Lodge Wood, Peterley Wood and Lawrence Grove.  Aspen, whose leaves loudly rustle in the slightest breeze because of their flattened stalks, is rare.

One introduced tree that has been with us for centuries is now very common in our woodlands, especially young second-growth woods, and that is the sycamore.  In autumn almost all the leaves carry a multitude of black patches, the sign of the tar-spot fungus.  More recently it has been joined by Norway maple, which has more jaggedly cut leaves.

Below the tree canopy and at the wood-edges a number of shrubs are commonly seen; most abundantly bramble, of course, especially where there is not sufficient light for anything else.  It would be even more dense in our woods if it were not one of the food-plants of the increasingly common roe deer.  Hazel and field maple are also typical of wood-margins.  Other shrubs to be seen are red currant, gooseberry, raspberry (whose abundance in the Chiltern woods was noted as early as 1676 by Robert Post), field- and dog-roses, gorse, blackthorn, dogwood and elder.  Honeysuckle (and, on the chalk, traveller’s joy) is usually to be found straggling over these shrubs.  Look out too for guelder-rose (not a rose, but it has clusters of bright red berries) and its close relative the wayfaring-tree (only on the chalk).

 

Wayfaring-tree

Guelder-rose

In many parts of our woods there are few or no ground-level plants (except mosses), especially under thick-set beeches.  In lighter spots, along rides or in glades, however, there are many that please the eye - in spring the lesser celandine, dog-violets, wood-sorrel, goldilocks buttercup and primrose (this latter now much reduced but still in good numbers in Acrehill Wood); in summer the foxglove, woodruff, yellow pimpernel, yellow archangel, sanicle, wood speedwell and St John's-worts.  Bluebells, of course, are common, but restricted to the clay tops with deeper humus, where they usually grow in dense colonies with no other flowers.  Another patch former is dog's mercury, an undemonstrative green plant with separate male and female flowers.  It is able to cope with greater shade, as do the ferns - mainly male-fern and broad buckler, with bracken taking over where the chalk is leached out.  In the latter acid areas, often water-logged, the main other plant consists of the huge clumps of tufted hair-grass, perhaps with some slender stems of remote sedge.  The drier areas with chalkier soils, however, support a number of special grasses, uncommon in many parts of the country but here quite prevalent - wood melick, wood millet, wood meadow-grass and wood barley.  In Lawrence Grove another grass, wood small-reed, still grows.  They are often accompanied by wood sedge and hairy woodrush; in the least spoiled parts, a close relative of the latter, southern woodrush, is also often found, with its erect triangular splays of tiny nut-like fruits.

Of the less common plants, Borrer's male-fern, lady fern and soft shield-fern can still occasionally be found, while narrow buckler-fern is confined to one small patch in one of the wettest parts of Peterley Wood.  In Longfield Wood can still be found a few bird's-nest orchid and green-flowered helleborine, but the deer and slugs seldom allow them to flower.  Violet helleborine is doing rather better and grows in several woods.  White helleborine occurs at one site.  But many of these rarer plants have been lost in the last fifty years - stag's-horn clubmoss, common wintergreen, wood anemone, great woodrush, coralroot, wild angelica, nettle-leaved bellflower, yellow bird's-nest - although all but the first two still grow at some places just outside the parish.  While our woodlands are still numerous, their flora is very depleted compared with a hundred years ago, whether from neglect or insensitive forestry operations.

Woodlands are vital as shelter, food and habitation for many insects, birds and mammals, quite apart from those mentioned in connection with specific trees above.  Most of the badger setts in the parish are situated in woodland, and most of the foxes hole up there too.  The foxes, as well as stoats, weasels and tawny owls prey on the abundant wood mice and bank voles, as do the polecats, recently returned naturally to the area after being exterminated centuries before.  Both roe deer and, more recently the introduced muntjac, are common in our woodlands, on which they depend for cover.  Grey squirrels are rife in all woods.

 

Red fox

Polecat (photo by Mike Collard)

 

Both green and greater spotted woodpeckers, and nuthatches, are quite common, too, exploiting the older trees for insect grubs as food and for nesting-holes, and the treecreeper is sometimes seen.  Their numbers are limited, as are those of many wood-boring beetles, by the lack of really old trees, the result of regular felling for timber in the past.  Our warblers tend to nest in woodlands, as do the tawny owl, rarely seen but commonly heard after dark, and the jay, a large and attractive but shy bird.

Now that the woods are losing their economic value there is a chance for them to be managed for their wildlife.  Some trees could be left to reach a grand old age, allowed to decay gradually in situ instead of being cleared away.  Similarly plenty of dead wood should be left on the ground.  This may well increase the variety of creatures to be found in the woodlands, none of which is currently notable for its insects.  Many of our rarer insects depend on dead or rotting wood, in which their larvae live - often for far longer than they exist as adults.  They include many colourful hoverflies, craneflies and beetles (such as the bright red cardinal beetles or the impressive stag-beetle).

Our ancient woods tend towards two types according to whether they are on the chalk slopes or the clay plateau.  In terms of the ‘National Vegetation Community’ classification (Rodwell 1991) there is a tendency towards either the Fagus sylvatica-Mercurialis perennis woodland (W12), particularly on the thinner soils of the chalk slopes, or the Fagus sylvatica-Rubus fruticosus woodland (W14) on the plateau.  Both are dominated by tall beech (Fagus sylvatica), but they differ according to whether the understory is dominated by bramble ( Rubus fruticosus ) and holly (W14) or by dog’s mercury (Mercurialis perennis) plus a greater variety of shrubs and ground-level plants (W12).  The difference between the two is not clear-cut and they intergrade, especially as the clay soil can wash down the slopes and obscure the influence of the chalk.  The difference is also obscured by man’s interference.  Without this we would, of course, not have mono-cultural beechwoods at all! 

 

Lodge Wood, which I have already mentioned frequently, is unique in that it descends the hillside across all four of the geological strata in Prestwood.  One short walk will bring you through the whole subtly changing vegetation sequence.  Until recently (1985) part of the Hampden Estate, the 63-acre wood is now divided in ownership.  The lower section (33 acres) on chalk, the northernmost, was purchased by the Woodland Trust in 1991 and renamed Pepperboxes Wood, after an unusual building on the wood’s northern boundary (just outside the parish).  The rest, on the plateau clays, is split between two owners. 

The wood is clearly marked on Jeffereys’ 1768 map and is certainly ancient, as it is mentioned in medieval documents and gave its original name (Priest’s Wood) to Prestwood itself.  It was one of the best examples in the Chilterns of plateau beechwood on leached soils, but suffered from clear-felling in 1970 and the subsequent planting of beech, larch, western hemlock and Sitka spruce.  It was briefly given SSSI (Special Site of Scientific Interest) status in 1976, but was deleted in 1981, when it was found that much of the special botanical interest had been destroyed.  This was the site of the last small patch of stag's-horn clubmoss, now extinct in the parish, where it grew with heather, a plant now also gone from there and almost from the parish.  Further damage to the remaining mature trees, made vulnerable by clear-felling, was caused by storms in 1990.  Nevertheless enough interest remains (especially a good range of woodland fungi) for it still to be designated a Local Wildlife Site.

 

Lodge Wood in winter

While Lodge Wood is at the northern tip of the parish, the other chalk-slope woodlands are all in the western half.  The largest of these (42 acres) is Nanfan Wood, also a Local Wildlife Site, the remnant of a much more extensive woodland stretching far to the north in Victorian times.  All but its north-east quarter is shown as woodland in Jeffereys’ 1768 map and can be considered to be ancient.  The remaining section was open field until at least 1883, was then planted to pine, since felled, and now consists mostly of young-growth trees, largely sycamore, beech and wild cherry.  Like Lodge Wood the soil has been subject to solifluction from the clay on top and leaching, so that the flora is not conspicuously calcicole (chalk-loving).  Originally used for coppicing and forestry, the current owners (Wren Davis Ltd) manage it for its wildlife and scenic value. 

Near the eastern side of Nanfan Wood lies another 5-acre piece of ancient woodland, Stonygreen Wood, again the property of Wren Davis Ltd.  Also a beechwood, with whitebeam and cherry, the steeper part has a thick understory of hazel, hawthorn and elder and ground cover of dog’s mercury and ivy.  There is some dead wood.  To the south of the public footpath where it enters the wood coming from Stony Green is a large old quarry which has some large sarsens and, at one time, an exposure of the chalk rock, now obscured. 

Stretching south from this wood is a line of woods, along the eastern crest of the Hampden Road valley, that has had a chequered history and was probably not woodland for a substantial time in the C18^th and 19^th.  The first section around Stonygreen Hall (and belonging to that estate) had been wooded at the beginning of the C19^th but was later felled and later replanted.  The next section south of the Hall was probably more consistently wooded in the C19^th, when it was an open mixed wood, but now it is wholly planted to beech, with cherry, elder and dog’s mercury.  To the south of this again, the boundary marked by the remains of an old hornbeam hedge, is the older Meadsgarden Wood, once more the property of Wren Davis Ltd.  This was a larch plantation in the early part of the C20^th, but it is now wholly beech, with an understory of holly and elder, except for Corsican pines planted at the southern tip.  It is partially covered with bramble.  Roe deer are particularly common here.  At its north-west corner, where the public footpath enters the wood, there is a very old hornbeam, part of the boundary hedge row, which may be almost 200 years old (and looks it!), a very good age for this species of tree.

            Longfield Wood (24 acres) lies on the same eastern side of the valley as the above sequence, but a little further south.  Parts have been extensively felled in the past.  It is now divided up among a number of private landowners.  As far as can be ascertained it has always been wooded and it has some plants that are strongly indicative of an ancient pedigree, especially a good stand of wood barley.  An older name for the wood is Botchet Wood, probably meaning “beechwood”, from the Old English boece, beech.  (The term ‘bodger’ for a wood-turner working beech may itself be from the same origin.)  This is interesting because it may mean that this wood at least had a large proportion of beech before the supposed golden age of beech-planting in the C19^th.  Longfield Wood has a good ground flora in parts, and it is a classified as a Local Wildlife Site.

There is one remaining wood on the chalk slope.  This is Acrehill Wood on the western side of Denner Hill.  Although small (just five acres) it is an ancient wood.  There are no really old trees.  It has recently been neglected, becoming crowded with scrub growth and dark, and with only small numbers of flowering plants surviving, apart from a numerous, though declining, population of primroses (probably the greatest concentration in the parish), particularly at its bottom end (the most calcareous part).  Here also the uncommon spurge-laurel still grows.

 

Atkins Wood in autumn

The other woods in Prestwood are on the plateau clays, although Atkins Wood, on the eastern boundary, partially occupies the top of a chalk valley.  The chalk here, however, has been wholly covered with clays washed down from above, and the valley part was in any case partially planted to larch and fir, just recently harvested and beech replanted.  It is part of what was once a more extensive woodland.  The 16-acre wood is largely beech, with little ground flora apart from patches of bramble and a little grass.  A very large oak stands in the middle of its western edge and some good old laid hornbeam form the southern boundary.  There is a good range of mosses and fungi.  A large sinkhole can be found by the northern boundary, its sides too uniformly steep to have been a quarry.

William Grover owned this wood in 1841 and there is a record of a sale of timber from the wood which provides evidence of the composition of the wood at that time.  Half the value was in beech timber, which must therefore have been the dominant tree.  Although no number of trees is given, it can be estimated from the bill of sale to be over 1,000.  There was also a large amount of coppice (also beech?) in the form of 2,842 “tellers” (coppice poles), which would have been used in the chair industry.  The most valuable tree, however, was oak, at 2s 6d a foot, of which there were 139 specimens.  The remaining native hardwoods included 33 elm, 29 ash, 25 "poplar" (presumably aspen), 19 cherry, and 18 sycamore.  There appeared to be one chestnut.  There was also a large larch plantation with 812 trees.  At this time the wood was slightly larger, by a couple of acres or so, than it is now, with an extension at the south-west corner.  Part of the wood was possibly felled about 1825, as Bryant’s map of that time seems to show, while the first Ordnance Survey map of 1820 shows a complete wood.  If the larches were planted at this time, then they were no more than about 16 years old at the time of sale and were probably used for fence posts.  Only 47 years later, in 1888, 120 loads of beech timber were again sold, followed in 1894 by a further 75 loads and in 1905 by “100 loads of well-grown beech timber”.   Assuming these were planted about the same time as the larch (c 1825), then these would have been 65-80 years old and therefore reasonably mature trees.  While the previous sale of beech in 1841 had reached £500 for that species alone, in 1905 only £114 was realised, on which the land agents Vernon & Son commented “ Considering the somewhat depressed state of the chair trade we consider the prices obtained to be quite satisfactory ”.

There are three remaining ancient woods on the clays.  The largest of these is Peterley Wood, once part of the Peterley Manor estate.  Its distinctive shape, a square northern section with two ‘arms’ of woodland extending down to Peterley on either side of the Manor itself, indicates how the monks in medieval times cleared and drained the heart of a much larger wood, which probably extended as far as what is now Wycombe Road and may have included Lawrence Grove.  The main section of the wood still has a large marshy area with yellow pimpernel and narrow buckler-fern, but the number of marsh plants has decreased markedly in recent years.

 

Narrow buckler-fern in Peterley Wood

A typically streaked trunk of hornbeam

The wood, which is just over 30 acres, is predominantly beech, with hornbeam, cherry, oak, birch and rowan, and little ground cover except for some good patches of bluebells in parts.  Almost surrounded by housing, there is fairly intensive use by walkers, especially dog-walkers, cyclists, children, and some illegal motor vehicles, which keep the main tracks very bare.  There is nevertheless a good variety of fungi and birds, and some old lime-trees and a particularly large Turkey oak on the northern boundary.  A growing patch of ramsons, or wild garlic (a native plant in some woods) was not there in the early 1980s and arose from garden escapes.

The end of the eastern ‘arm’ extends beyond the old woodland and is largely scrub with invasive garden species, like periwinkle and garden yellow-archangel, which carpet the ground and stifle any growth by native plants.  The western arm was used to house prisoners of war in the Second World War and the remains of the concrete bases of the bunkers are still detectable, while much of it was subsequently replanted with Scots pine.  The pines are now mature and due to be felled (some have fallen naturally already).

Across Peterley lane from Peterley Wood lies Crook’s Wood (7 acres), a narrow “dog’s leg”, with a crook in the middle that might have contributed its name.  Its original shape is now obscured by a much later plantation, Long Plantation, which borders it on the west side and extends much further, all the way to Heath End.  This was a C19^th pine plantation, used to supply timber for the sawmill situated at Heath End.  On its eastern side Crooks Wood is bordered by a secondary young-growth woodland, over what used to be pasture land, which once had abundant common spotted orchids.  These still grow sparsely in open areas of the wood.  The only mature beech trees are in the original Crooks Wood section, and here one can clearly trace the embankments that mark its previous boundaries, while there are some impressive old laid hornbeams marking the southern edge.

 

Common spotted orchid

Coralroot

 

Citers Wood is a small 7-acre patch that was once part of Peterley Corner Farm.  Originally beechwood, many of the mature trees have been removed and it is overrun with bramble.  There are a few recently planted conifers.  Neglected for many years, it has lost two rare plants that grew there in the 1960s – coralroot, which is now extinct in the parish, although it grows at Cryer’s Hill to the south and in Piggotts Wood to the west, and green hellebore, now confined to just a single site elsewhere in the parish.  The overgrowth of bramble suits foxes, that often den here, but it has restricted the diversity of plants.

There remain a few recent woods, although two of these have existed for over 150 years.  In 1850 Lawrence Grove, across Wycombe Road from the parish church, was shown on the map as a conifer plantation.  It seems to have been wooded at various times in the more distant past too (known variously as Dishet and Dicket Wood, probably from “ditched wood”, in some surviving medieval manuscripts).  It is not shown on Jefferey’s C18^th map, but does appear on a 1767 map of the bounds of Peterley Manor, where it appears to be part of an enlarged Peterley Wood.  It has been felled several times since 1850 and is currently made up of maturing beech of 50-100 years in the western part and young saplings in the eastern part, with a boundary of older trees.  There is one old oak on its southern boundary that probably exceeds 200 years.  It has some vegetation indicative of established woodland – wood meadow-grass, the only clump of wood small-reed in the parish, and much gorse.  It is likely therefore that this small wood of 11 acres is of ancient origin, but has had a mixed history of use as scrub, native woodland and plantation, possibly created out of common-land (which may itself have been partially wooded).  The use of “grove” usually indicates more of a scrub environment than of trees.  There is a good understorey of young trees, but the south-western corner adjacent to housing has been used for the dumping of large quantities of garden refuse endangering the survival of the native flora.  The wood is used by tawny owls and deer, but the two grasses mentioned above are the only uncommon species recorded.  A section with silver birch often provides a good display of fly agarics.

The other wood which is not shown on Jeffereys’ map, but was in existence as broad-leaved woodland in 1850, is Lawrence Grove Wood .  This wood only has a few indicators of old woodland, although it does have a good patch of woodruff, many violet helleborines and 150-200 year old beeches on the northern boundary.  A fallen beech at one edge was over 200 years old.  It also has a boundary bank and layered trees on two sides like the ancient woods.  This wood is therefore likely to have been in existence since the late C18^th.  Like Lawrence Grove it has been used commercially for timber in the past, so that the central part of the wood lacks older trees.  It is a private wood, owned by Wren Davis Ltd, and currently used to raise pigs in a small enclosure.  The origin of the name is confused.  It has been assumed that it was named after the large field to the north of it, called Lawrence Grove, but the use of “grove” in a field name is unusual and may reflect either that it was at one time part of an area of scrub and young-growth trees that included the current wood, or else was itself named after the currently wooded area when it was a “grove”!  And who was Lawrence?  With one field and two woods still named after him, he must at some time have been an important figure in the area, but there is no record of such a person.

There are a few patches of more recent deciduous woodland, none of them with a name.  The oldest of these, and the largest, is a plantation of oak and birch at the south end of Peterley Avenue that must have been planted in the early part of the last century.  There are also very small patches (less than 5 acres) of very recent woodland that have grown up in the last few decades in various parts of the parish, most of them developing from scrub that has invaded disused grassland, mostly dominated by ash and sycamore.

There are few solely coniferous plantations today in the parish – just a small patch of larch at Newhouse Farm, a tiny roadside grove of pines at Thimble Cottages, and a rather desolate grove at the western end of the Brickfields.  There are, however, some plantations within the older woods described above, and they are not entirely without natural history interest.  For instance, larch may be associated with several other species, such as the shiny yellow larch bolete fungus Suillus grevillei, the paler yellow larch woodwax fungus Hygrophorus lucorum, the yolk-yellow "egg-shell" slime-mould Leocarpus fragilis, the larch ladybird Aphidecta obliterata, the larch longhorn beetle Tetropium gabrieli, and the larch case-bearer moth Coleophora laricella.  Somehow these insects and the spores of the fungi manage to invade along with the planted trees, or are able to find them after planting.

 

Egg-shell slime mould on fallen larch (photo by Penny Cullington)

Orchards

Orchards, as a natural habitat, are man-made park woodlands - grassland among spaced out trees, the latter confined to fruit-bearing tress that are not so long-lasting as our native beech and oak.  They may therefore combine some features of both open grassland and well-lit woodland.  After burgeoning around the end of the C19^th and the first half of the C20^th, now only oddments remain – mainly at Andlows Farm, Collings Hanger Farm (restored by Wren Davis Ltd), the corner of Greenlands Lane (now part of Woodlands Farm),  beside the Polecat Inn (recently partly damaged by the rebuilding of the pub), with much reduced remnants at Cherry Tree Farm, Idaho Farm and Stockens.  A much larger orchard survives just outside the parish boundary south of Nairdwood Farm, now known simply as the “Old Orchard”, which used to be run by a local family, the Tilburys.  There is only one-twelfth of the number of orchards today in this region as existed before the Second World War (Prowse et al 1967).

Old varieties of fruit may sometimes be preserved in such orchards, and these are an important part of the heritage of the parish.  There is a particularly fine tall old Hazel Pear-tree beside the Polecat, which flowers and fruits plentifully.  A similarly old large apple tree stands behind the pub.  The grassland in these orchards may preserve old meadow flowers, such as pignut at the Polecat and corky-fruited water-dropwort at Collings Hanger.  Older cherry trees often support the spectacular bright yellow “sulphur polypore” fungus or “chicken-of-the-woods”.

Old orchards lack the straight lines of close, uniform, heavily pruned trees of the modern equivalent.  The mixed trees were allowed to grow high and gnarled, while cattle or other stock were allowed to browse beneath, and people could rest or picnic in the flowery sward.  They were places where nature and humanity were equally at home, whether in harmony or in conflict, as in the continual battle waged against the birds that share our liking for the sweet blood-juice of the ripe cherry.  The cherry-harvest supper with cherry-pie was a communal event for the whole village.

Where the old trees are allowed to survive, and where the dead trees are allowed to rot down while standing, such trees become valuable resources for insects whose larvae live in decaying wood.  These include a rare orchard specialist the noble chafer, which has recently been rediscovered in north Bucks, and may still linger on somewhere in our orchard trees too, as the adult beetle only appears for a few days and is hardly ever seen.  A survey in 2019 using pheromones to attract it was unfortunately unsuccessful.

To carry on the orchard tradition of the area Prestwood Nature has set up a new orchard off Greenlands Lane, preserving both the habitat and many endangered local varieties of cherry, apple, pear and plum.  Many of the trees were funded by local residents.  The grass beneath is managed to develop into a wildflower meadow, where once just coarse grasses and docks dominated.  It is a community orchard with open access to all.  Particularly interesting old local fruit varieties are the Prestwood Black and Nimble Dick cherries, the Bazeley apple, the Aylesbury prune, and a Hazel pear grown from cuttings from the old tree beside the Polecat Inn, which has, for the moment at least, survived modernisation of the premises.

 

Old orchard by Greenlands Lane, with many old trees, but in need of renewal

Hedgerows

 

In time, no doubt, a self-spraying weed will appear, causing the last of the hedgerows to disappear, so that sparrows, which formerly fetched four-for-a-farthing, will become costlier than grouse.

JHB Peel “Country Talk”

 

Hedgerows are important habitats for trees, shrubs and herbaceous plants, many of them survivors from woodland which is now less suitable.  Hedgerows near the bottom of Rolls Lane are very old and protected (Local Wildlife Site) for the sake of important local populations of green hellebore and moschatel.  Winifred Peedle, in her 1939 essay (see Chapter 10), knew of the Green Hellebore under the hazel here and stated that she had known of it first in the late 1920s, coming every year in spring to see it flowering.  She observed that “Last season the hedge was cut very low, and the plants had very little shelter.  This year the flowers were a little later in coming out, and they were not so large as they usually have been.”  The hedge is still cut relatively low, but it is managed to ensure the survival of this plant, which is probably native to this site and reflects a time long past when woodland descended to the road (it is still not very far away, but neither it nor moschatel survive there now).  The long-lasting green flowers are unusual – the apparent petals are really sepals (the green bracts that enclose the petals of a flower like the rose or poppy), and the petals are reduced to tiny tubes of nectar that attract the early bees.  It presumably uses scent rather than colour to attract the bees, an adaptation to the dark conditions in woodlands where it more normally grows.  Green hellebore survives as a woodland plant nowadays only in Piggotts Wood to the west of the parish and Gomms Wood at Cryers Hill to the south.

The Moschatel (pronounced musk-a-tell) also has a largely green flower, again reflecting its usual dark habitat in woods.  It is tiny and easily overlooked, especially tucked up well under the hedge – it can be far more conspicuous as large patches in some nearby woods (e.g. Rignall and Cockshoots to the north, Rook Wood beyond Great Missenden).  The flower-heads have a unique structure, making up a cube with a single flower on each of the four faces and a fifth on the top face.  It is known by some people as the “town hall clock” for this reason.  Like much of nature, the real gems are hidden away from us in miniature to reward only the persistently curious.  It has a faint smell of musk (the origin of its name) which is strongest in the early evening, attracting various small flies, but it rarely sets seed and therefore does not spread very easily.

 

Green hellebore

Moschatel

 

Probably the most ancient hedge in the parish is Nanfan Hedge , the wide, tall, prolific hedge that runs all the way from Nanfans to the NE corner of Nanfan Wood.  This was a major boundary of the old Nanfan farm that was probably the first established in this area in Anglo-Saxon times.  Other field boundaries nearby are also ancient and were also part of the original farm.  The main hedge, however, also once formed an old parish boundary (since moved).  In places it is wide enough for what are clearly two hedgerows with a space between, so it is likely that at one time a track followed the centre of the hedge (now replaced by a footpath along the field edge to the west).  Going by the mixture of tree species and their variety it can be estimated that the age of the hedge is certainly a thousand years.  While it would originally have been managed to keep it shorter and denser as an effective fence, many of the trees have now been allowed to grow tall and there are some fine ash, beech, hornbeam, oak and cherry trees.  Two rare native species still grow in this hedge - the rare "chequers" tree or wild service, and the grey-leaved succulent plant orpine, which has pink flowers in late summer.

The ancient green lane, Hobbshill Lane (which forms in part the eastern boundary of the parish), is also bordered by excellent hedgerows on each side.  Special plants here include the native pale lady’s-mantle Alchemilla xanthochlora, which is rare in this part of the country.  It also grows in Hampdenleaf Wood near Little Hampden, just north of Prestwood, but Hobbshill Lane is one of only two sites in Prestwood parish (the other being Hangings Lane, also an old route, now a minor road).  It can look very similar to the garden lady’s-mantle A.mollis, which frequently escapes in this area and is also seen in hedgerows, but it can be told by not having softly-downy upper sides to the leaves, hairs growing only on the undersides.

Apart from such rarities, hedgerows also harbour, much more commonly, colourful flowers that brighten up the waysides.  After the lesser celandine, and the early and common dog-violets, foxglove, red campion, greater stitchwort and bluebell make a patriotic combination of red, white and blue, which may be further enhanced by the yellow archangel, wall lettuce and goldilocks buttercup.  Several umbellifers (plants with large heads of small, usually white, flowers, and much-divided, feathery, parsley-like leaves) also enjoy the special environment a hedge provides – protection from the worst weather while being open to the sun.  These include cow parsley, the first to flower, followed by bur chervil (particularly noticeable in the Hampden Road area), the late summer-flowering hedge parsley, and hemlock with purple-spotted stems warning of its poison juices.  (Not forgetting that coarse relative, hogweed, which grows in hedgerows and every sort of rough or waste land, but which is just as much enjoyed for its nectar by the flies and beetles that often swarm on the platforms provided by these heads of flowers.)  One should not overlook, either, that delicate grass, the wood melick, which appears to enjoy the hedgerow habitat as much as its native woods, and can make a fine display with its little brown flowers appearing too heavy for such slender stalks waving in the breeze.  Hedge bindweed, honeysuckle, traveller’s joy, sometimes black bryony and less often white bryony, scramble over the hedges themselves.

 

Pipistrelle

Male blackbird

 

Hedges also provide shelter and food for an abundance of insects, birds and mammals, including bats like the pipistrelle that is still commonly seen in the late evening swiftly manoeuvring after moths and other insects.  The taller hedges provide hunting places for the pipistrelle at night and roosting places during the day.  The preserve of blackbirds, song and mistle thrushes most of the year, the haws and holly berries attract flocks of redwings and fieldfare in the winter, to the consternation of the residents vainly trying to keep them at bay from their precious food reserves.  The song thrush has declined very considerably in numbers of late, that may be associated with the poisoning by gardeners of their primary food, the snails and slugs, although there does seem to have been a slight resurgence of numbers in the last year or two.  The mistle thrush, although it comes less often near dwellings, is holding its own quite well, and its powerful song can often be heard from the tallest hedgerow trees.  The nightingale and turtle dove, however, are long gone.

Thicker hedges provide nesting-places for many songbirds.  Magpies, too, prefer to nest in the tops of the taller hedgerows.  While they will raid the nests of other birds, a pair nesting in my hedge in 2001 had to fight off a grey squirrel intent on stealing their clutch!  A prolonged attack by the male was only converted to success by its mate finally losing patience and leaving the nest to join in the tail-pecking, which proved too much for the squirrel and it fled pursued by two irate birds.  The magpie, which has certainly become more evident recently, is often blamed for the decline in numbers of songbirds, but the wood pigeon is equally, if not more, vulnerable, with its simple platform nest usually easily observable, and it continues to thrive.  The maligning of the magpie is just a continuation of that old gamekeeper’s prejudice against all competitive predators.  (See Obee 2009.)

Hedgerows have been planted from at least Saxon times to border tracks and fields.  Easier and less costly to erect and maintain than fences because they could be left to care for themselves, they provided resources for villagers such as firewood and fruit, and they also provided very efficient barriers, especially if laid.  Laying was accomplished by cutting almost entirely through a sapling and then bending it over, intertwining it with neighbouring laid stems.  The horizontal stem throws up vertical shoots along its length, making a very dense impenetrable hedge.  Hedges laid in the past are quite readily detectable by the horizontal stems that, over the decades and centuries, become substantial trunks lying parallel to the ground.  As was stated above, wood-edges were often treated in the same way to prevent stock wandering in from the fields and browsing the coppice.  Traditionally hedges were kept cut back fairly low so as not to impede hunting, but over the last century many have been left to grow to six metres or more.  The enclosure of the commons around 1860 resulted in the carving up of the land into fields that were also defined by the planting of new hedges.

Old hedges and laid wood-edges can be seen all over Prestwood, which has been fortunate in not having too many of its old hedges eradicated.  (In other areas, the decline of mixed farming has often meant that it was more economical to work larger fields, rooting out the old hedges that previously divided them.)  In 1850 there were about 100 kilometres of hedgerow in the parish.  Detailed comparisons with 1900 Ordnance Survey maps show that over 16 kilometres (16%) were lost during those fifty years, almost entirely due to the creation of larger fields for cultivation.  At the same time, however, about 19 kilometres of new hedgerow were planted, largely as a result of the enclosure of the commons.  While Prestwood ended up with a slightly greater length of hedgerow in 1900 than in 1850, there was still a clear loss, in that the those that were lost were virtually all ancient hedgerows that had existed for many centuries, some for a thousand years.  The newly planted hedgerows could not match these in diversity of species and the amount of cover for wildlife that they provided.  The mid-C19^th hedges across the old commons, moreover, were mostly removed during the building boom a century later, although a few remnants are still traceable.  (A notable example of such a trace is the line of old oaks and one beech along Westrick Walk through the main housing estate, the remnant of an old hedge that marked part of the southern boundary of Prestwood Common.)

Between 1900 and 2000, almost a third of all hedgerows were destroyed (some 32 kilometres) – the same annual rate of loss as in the previous fifty years.  Most of these were due to building, however, and very few to agricultural change.  While 1850-1900 had seen a similar rate of hedgerow creation to compensate for the losses, this was not so in the twentieth century, when only about 7.5 kilometres of new hedgerow were planted.  The end result was that by 2000 Prestwood parish had only 75 kilometres of hedgerow, three-quarters of that existing 150 years before.

Discontinuance of the traditional hedgerow maintenance, regularly re-laying and coppicing, has resulted in the shrubs often becoming more like individual trees, out-competing smaller intermediate saplings, the hedge then becoming “gappy” and eventually just a line of trees.  Traditionally, a few trees were always left to grow tall in each hedge, often as boundary markers, making the hedge a better habitat for birds (providing song-posts for instance), helping create more satisfying scenery, and ensuring that some mature trees survived.  Because our woods have traditionally been working woods, few really old trees have been left within them, so what old trees there are in the parish are almost entirely in hedgerows or on the margins and corners of woods where they helped mark the boundary.

Hedges also provide corridors for wildlife – cover for smaller creatures as they travel from one area to another, to find food, a mate or a new home.  The more interconnecting hedgerows there are, the easier is it for wildlife (and shade-dependent plants) to disperse and colonise new areas when necessary – for instance if a previous territory is destroyed.  A good network of dense hedges therefore contributes to a thriving ecology and biodiversity.  It is particularly important for the hedgehog, whose numbers have declined as its territories have become divided up.  Woods and semi-natural grasslands in the parish countryside around Prestwood and Kingshill are still quite well connected by such hedgerows providing the crucial links past the no-go areas of open fields.  A vole, hedgehog or fox at Ninneywood farm in the south of the parish, for instance, could, by following hedgerows, woodlands and areas of scrub, reach any other part of the parish as far as the northern tip at Lodge Wood, over the west to Denner Hill and Bryants Bottom, and to the east at Atkins Wood, with only a very few roads to dash across now and again under cover of darkness.

Prestwood Nature has surveyed all the hedges in the parish.  On average, it has been found, a hedge acquires one more woody species in a length of 30 metres roughly every hundred years.  (Hooper, 1974.)  This fact gives us a rough-and-ready guide to the dating of hedges, by counting the number of different woody species in sample sections of 30 metres.  Where a hedge is long enough, several samples may be taken and the results averaged for a more accurate result.  The method does not work well for relatively young hedges, because they may have been planted with a mix of species, but the older the hedge the more reliable it becomes.  Other clues to an old hedge may also exist, for instance the existence of a ditch and/or bank along it, or evidence of past laying.  The greater the mix of species, too, the denser and the more suitable it generally is as a wildlife habitat, so that such a count can be used not only to estimate the historic longevity of a hedge but also its biodiversity value.

Of 169 hedges in total, 132 contained six or more species per 30m.  Of these, 29 had eight or nine species (i.e. probably dating back to early medieval times) and 8 hedges had ten or eleven species, which would take their origin back to Saxon times before the Norman conquest.  The most common species, growing in over three-quarters of all hedge-sections surveyed, was the hawthorn.  Wild roses grew in two-thirds.  Four more species were found in half or more of the hedge-sections: hazel (58%), holly (56%), elder (54%) and blackthorn (50%).  Ash was present in well over a third (38%), and four more species were in a quarter of hedges (wild cherry, hornbeam, field maple and oak).  Other common trees were sycamore (21%), dogwood (17%), beech (12%) and whitebeam (11%).

Species particularly associated with the older hedges were beech, hornbeam, oak and whitebeam.  These are slow colonisers and the existence of any of them in a hedge is a good sign that it may be old.  Another good sign was the existence of any of the less usual native species (those occurring in fewer than 5% of all hedges) – trees like rowan, apple, elm or yew, and shrubs like broom or red currant.  One very old hedge near Hotley Bottom (nine species in 30 metres) contains the only example in the parish of Midland hawthorn.  It differs from the common hawthorn in its less divided leaves, flowers with two styles, not one, and haws often with two stones.  (This list of species associated with older hedges is radically different from that given in Rackham, 1986, whose studies were carried out elsewhere than the Chilterns.  This shows that such associations can be locally specific, and one should beware of generalisation to other regions.)

 

Midland hawthorn: less-cut leaves, two stigmas per flower

Hawthorn: deeply cut leaves, one stigma per flower.

 

There were also two species that were more associated with the poorer hedgerows.  These were elder and hawthorn.  Both occurred very often in the higher-scoring hedges, but they were especially dominant in the low-scoring ones.  Elder is a well-known “weedy” species that soon colonises new habitats, especially those where there is not too much established competition, so that the sparser hedgerows suit it well.  The hawthorn, on the other hand, is the commonest shrub to be planted in field hedges these days (and, much earlier, at the time of the Enclosures), so it is the one most often encountered in recent hedges, sometimes forming an almost mono-cultural hedge.

Hedges are under threat from two directions.  Those beside cultivated fields often suffer from chemical and fertiliser sprays.  The latter increase the nutrients in the soil beneath the hedge and encourage an over-growth of nettles, cow parsley, cleavers (or goosegrass) and ground ivy that can swamp more sensitive native plants.  Hedges beside roads, on the other hand, are often under threat from road-widening and other “tidying” operations, as a result of which the parish has lost several species, such as ragged robin and leopard's-bane.

Special mention should be made of Hornbeam before we leave this habitat.  While the prime constituents of a hedgerow in the past were the "thorns" (haw- and black-thorn), Hornbeams were also planted because of their ready response to laying.  For this reason, it is one of the most characteristic trees of our parish hedgerows. Its unusual fruits are beloved of jays and nuthatches.  It is also associated with two rare fungi – the milkcap Lactarius circellatus, and the bolete Leccinum carpini .  Its hard wood (it was also known as “hardbeam” and “horn-“ refers to the same quality) was difficult to work, so it was often left in boundary hedges, laid or pollarded, to become old and handsome, although it cannot reach the sort of age attainable by beech or oak.  By 200 years its boughs are cracked and its bark is riddled with beetle holes, still admirable but largely for its grotesqueness rather than stateliness.  When used as timber, hornbeam supplied the parts that needed to be especially durable, such as the machinery of windmills or cider-presses, cobblers’ lasts and axles, parts that now would be made of iron rather than wood.  (See Howkins and Sampson 2000.)

 

Lactarius circellatus only grows with hornbeam trees

Ancient trees

 

O if we but knew what we do

When we delve or hew –

Hack and rack the growing green!

Gerard Manley Hopkins “ Binsey poplars: felled 1879 ”

 

Because of local woodland industries in the past, few really old trees survive in the parish.  They occur mainly in two different habitats - either in hedgerows and woodland boundaries, especially at the corners of fields or woods, where they were left as landscape markers; or in parkland where they were deliberately planted to become landscape trees.  Parkland trees are often the most impressive, well spaced to give plenty of room to grow, but past fashions at the time of planting favoured imported species, so there are often disappointingly few native trees.

On the basis that trees gradually get bigger as they grow older, the dating of trees is usually based on the girth (distance around the trunk) at about chest height.  Girth is a better guide than height because the latter often reaches a plateau (or even decreases from die-back) once the tree is fully mature, while the girth always goes on increasing, however imperceptibly.  Interpreting girth-sizes, however, is problematic, because the rate at which a tree grows varies with its age (its growth slows down as it gets older), its situation (trees in the middle of a wood grow taller and slimmer than those at the edge, hedgerow trees grow larger because of less competition from other trees, and lone trees in parkland grow fastest of all), the soil type, region of the country, and the species.

One can get an idea of local growth-rates, however, by measuring trees whose date of planting is known approximately from historical evidence or by counting tree-rings on felled trees.  I have used both methods for a variety of trees growing in different situations.  The results showed that a hedgerow oak or beech (the most commonly available trees) reaches an average girth of about three metres in its first 150 years.  In an open field it might reach 3.5 metres.  The slightly slower growing lime and horse chestnut in an open situation reach about 3.25 metres, while the slower yew reaches about 2.9 metres and the Scots pine no more than 2 metres in 150 years.  A free-standing wellingtonia in Prestwood Park, on the other hand, reached a massive 5 metres.  This local landmark, on the top of the hill, was unfortunately cut down in 2020.

Most of the datable or felled trees were around 150 years, so that it was more difficult to obtain a fix on growth-rates beyond that age.  A few younger specimens showed that a field oak might reach 2.5 metres in its first 100 years, but then its growth slowed down.  A hedgerow beech had reached 2 metres in the same period.  A hedgerow cherry had reached 2 metres in 60 years, but thereafter the growth-rate appears to slow down, attaining 3.25 metres after 150 years (although few will survive that long).

Most trees will have reached maturity in 150 years.  By then they will have an impressive trunk and crown and have gained a shape and character of their own, contributing to the scenery and beginning to excite admiration for these long-lived organisms that see so many generations of us come and go.  On the basis of the above evidence, therefore, it is generally worth regarding any tree of 3 metres girth with particular respect.  By this time, it will be a flourishing wildlife habitat in its own right, particularly if it is one of the truly native trees, that can have a hundred or so species of insect associated with it in some way.  After this age, too, the tree will often start to gain features such as a hollowing trunk, rough bark, broken branches, and fissures that increase its accessibility to insects, fungi, ferns, lichens and birds.  It has been proposed that ancient trees should be recognised as habitats in their own right and qualify as potential Sites of Special Scientific Interest (Green 2001).  Some of the rarest beetles are those whose larvae live in the decaying wood of ancient trees. 

Not all types of tree will attain a grand old age.  A cherry, a hornbeam or a birch that has reached 200 years will generally show extreme evidence of decline, with huge fissures, a multitude of beetle holes, and broken boughs.  An oak or beech, on the other hand, can be still in its prime after 300 years, and may only start to look as if it is reaching senility after some 600 years.

In a survey of all the larger mature trees in the parish to which I could readily gain access I measured altogether 208 trees.  By far the greatest number of these were oaks, 95 in all.  The fact that so many oaks had survived to maturity indicates not only their longevity, but also the respect that has always been accorded this tree as a quintessential English landmark, so that they are more often left to grow than any other tree.  Although many beeches have now reached maturity from the early Victorian plantings, the oaks were probably more frequent before that time, and therefore dominate among the oldest trees.

The oldest measured oak grew in the private grounds of Rickyard Cottage on Denner Hill.  This magnificent specimen was somewhat difficult to measure because almost half of it had recently been split off and collapsed after recent storms, but I estimated that when it was whole the girth would have been some 6.6 metres.  This would have made it a truly ancient tree that would have begun its life somewhere around late medieval times, perhaps about the time that Richard II died.  There was already a well-established farm settlement there at that time, and it would have been a notable feature of the farm for many centuries; probably, going by the land contours nearby, with a pond at its foot.  The sad story, however, is that the tree was very much weakened by the effect of that first storm and another violent storm in 2000 brought the rest of this magnificent edifice to the ground.  The largest and most ancient oak in Prestwood is therefore no more.

The largest remaining oak lies on the very boundary of the parish (or to be strictly accurate, just beyond it) at Honor End where Grim's Ditch reaches a field corner.  The oak standing here is 4.4m, still in good health and covered in untold lichens both common and uncommon.  Not much smaller is another oak of 4.3m on the north side of Prestwood Park; it has lost a major bough and is hollow, but will stand for much longer yet, as the loss of the what is dead tissue at the heart of a tree (all the living tissue is in the bark and just beneath it) decrease its weight and makes it less vulnerable to wind-throw, as well as providing excellent homes for many creatures.  Several ancient trees mark the southern boundary of Prestwood Common (as along Westrick Walk mentioned above) and these include an oak of over 4.2m on the boundary between Widmere and Dell Fields, just south of Lodge Lane, equalled by another standing by the barns at Stonygreen Farm.  All these trees are at least 250 years old (in other words, they were acorns around about 1750, when Thomas Gray, in another part of Buckinghamshire, composed his Elegy in a Country Churchyard ).

 

The oak on Wycombe Road by Hildreths Garden Centre

 

The next largest surviving oak has a girth of 4.1 metres.  It is situated at the corner of two hedges beside Wycombe Road, at the southern end of Hildreths Garden Centre car park.  It is an imposing tall tree in full health.  It was with considerable pleasure that I once listened to a mistle thrush singing its clear loud notes from the very top of this tree.  Very nearly at the geographical centre of the parish, this tree might stand as a symbol of the parish itself, and I hope it can be left to attain another 250 years or more.  (Although, who can tell what the ravages of climate change will bring in that time - one fears for all these majestic old natural monuments.)

Prestwood Park has many fine old trees and we know their age exactly, as they were planted at the foundation of Holy Trinity in 1850 or thereabouts.  They include horse-chestnuts, the largest over 4m, sweet chestnuts and limes at 3.8m (one of the limes carrying a bunch of mistletoe in its topmost branches), more oaks also of 3.8m, a beech of 3.7m, an ash over 3.5m, Turkey oak 3.4m, and a Lucombe oak of 3m.  The last is rather special.  It is a cross between Turkey and cork oaks and holds its leaves through the winter, only dropping them in spring when ready to flower and grow new leaves.  Its bark is slightly soft, showing its relationship to cork.  It is one of the progeny of a breeding experiment at Lucombe Park in Devon in the C18^th.  These descendants of the one original were sold all over the country for planting in parks, but most have not survived so long.  The Prestwood Park Lucombe oak is one of few to be seen in the county today.  (I have seen some others near Halton.)

 

Lucombe oak, Prestwood Park

 

Of all these old oaks, only the Lucombe oak and those in the old Prestwood Common hedge are covered by Tree Preservation Orders.  The conferment of TPOs rests on individual applications and is exceedingly haphazard.  Very few of those with such protection qualified as older trees in this survey.  (Such orders can, of course, enable younger trees to survive to become the ancient ones of future centuries.)

Given Prestwood’s famous association with the cherry, it was cheering to discover 21 mature wild cherries, especially as they rarely last 200 years.  The bark of the younger cherry is very distinctive because of the horizontal bands of breathing-pores (lenticels), but in the old trees the bands become obscure as the whole trunk takes on a dark purplish-black colour and develops huge craggy fissures.  Many of them are completely hollowed out, but the tree is still very much alive, producing leaf and fruit, as the living part of the trunk is the wood just beneath the bark.  The wild cherry is particularly attached to clay soils over chalk, which is why it is a particular feature of this area.  Cherries rarely exceed 4 metres in girth, and one locally reached 3.6 metres, before it died, standing by an old pond in a field by Hangings Lane.  Another notable cherry, although a "mere" 2.7m stands along Green Lane and is sufficiently celebrated for neighbours to have planted spring bulbs around its base.

Old trees, especially those that are becoming stressed with age, are important for a good number of our rarer fungi, often specific to particular types of tree.  There are many species associated with oak and beech, although they will usually be evident only on those beyond the age of the ones we currently have in the parish.  The wild cherry is particularly associated with the rather beautiful large bracket fungus “Chicken of the Woods” or sulphur polypore, Laetiporus sulphureus, which when fresh is a striking yellow or orange on top and white beneath, growing out from the trunk at various heights.  I have seen it on the old cherries at Idaho Farm and next-door in the grounds of Idaho Cottage.  It also commonly grows on oak and yew.  Another striking bracket on oak is the beefsteak fungus, which oozes juice that is convincingly blood-like and is coloured just like steak.  It is edible and can be cooked just as one would a slice of meat.

 

Chicken of the woods on old cherry tree, Idaho Farm

Beefsteak fungus on old oak, Hobbshill Lane

 

Grasslands and Scrub

 

‘Tis spring; come out to ramble

The hilly brakes around,

For under thorn and bramble

About the hollow ground

The primroses are found.

…

Or littering for the fields of May

Lady-smocks a-bleaching lay …

AE Housman, from “A Shropshire Lad”

 

Grasslands are strongly influenced both by the underlying geology and their history of use.  In Prestwood most grasslands are improved or semi-improved pasture with a very restricted number of flowers and a small range of the more nutritious grasses favoured for stock.  (Improvement of pasture to increasing stock yields has a long history - Post (1676) mentions the sowing of rye-grass in the Chilterns along with nitrogen-fixing herbs like clover and sainfoin.  The most degraded grasslands today tend to be the horse paddocks, where intensive grazing leads to an increasingly bare community with coarse plants like creeping thistle, dock and ragwort.  Of somewhat greater interest are those agricultural fields used for hay-making, although the tendency in modern times to cut early for silage, not allowing the grass to dry in the field and for flower-seeds to develop, has much reduced the biodiversity of these habitats, too.  A traditional hay meadow can be a riot of summer colour with ox-eye daisy, common cat's-ear, yellow rattle, buttercups, orchids, a large variety of grasses and butterflies, but such a sight has more or less disappeared these days.  The Hay Pole field beside Hangings Lane was our last remaining ancient hay meadow (with abundant cowslips, betony, devil's-bit scabious, pignut and much else) but that was recently destroyed to create horse pasture.

The sites we shall concentrate on here are those that have had little agricultural use, at least in the last few decades.  They vary considerably according to whether they are on chalk or clay.  In this parish they are few and small in area, although the few that remain are highly significant from the point of view of wildlife and conservation.  Altogether they only comprise some 50 or 60 acres (less than 4% of the non-built-up area), whereas pasture and other “productive” grasslands of limited natural interest occupy nearly half the non-built-up area of the parish.

 

Betony, left, and devil's-bit scabious, right, are indicators of ancient meadows

Chalk grasslands

 

… it has always seemed to me that just as the air is purer and fresher on these chalk heights … so do all colours and all sounds have a purity and vividness and intensity beyond that of other places.  I see it in the yellows of hawkweed, rock-rose, and bird’s-foot-trefoil, in the innumerable specks of brilliant colour – blue and white and rose – of milkwort and squinancywort, and in the large flowers of the dwarf thistle, glowing purple in its green setting; and I hear it in every bird-sound, in the trivial songs of yellowhammer and corn-bunting, and of dunnock and wren and whitethroat.

WH Hudson “A Shepherd’s Life”

 

The Chilterns are famed for their chalk grasslands, which were traditionally maintained as short turf by sheep-grazing, although these were generally much smaller flocks than those that Hudson cared for on the Wiltshire downs and the vast expanse of rolling hills one sees there was never replicated in the Chilterns.  There was some sheep-grazing in Prestwood, too, in the past, but flocks rarely reached over 100.

The grasslands tend to shade into scrub where grazing is less intensive, as part of a natural succession to woodland, if there is no control on the invasion of woody species.  The mixture of short-turf, longer grass, scrub and wood-edge shade encouraged a large variety of plants and their associated invertebrates, especially a number of uncommon orchids and butterflies.  The chalk soils, rich in calcium but impoverished in terms of certain other minerals, suited a special suite of plants that were unique to this habitat, especially on the steeper slopes where richer humus could not accumulate.

Some of this habitat was converted to arable land with the decline of sheep-grazing, some to improved pasture for cattle, and only small patches remain of the native chalk grassland.  These tend to revert to scrub and woodland without management, although for the first half of the C20^th rabbits helped to graze such patches.  Myxomatosis, a highly contagious viral disease, decimated the rabbit populations in the 1950s, and they only returned to something like earlier levels in the last decade or so.  Myxomatosis is still present at lower levels, but a new virulent threat, rabbit viral haemorrhagic disease, is now sweeping the country.

In one way or another the parish of Prestwood lost all its natural chalk grassland by the time of the second world war, except for some on the western slope of Denner Hill, which have largely been decimated by uncontrolled scrub.  What sites we have left are impoverished survivors from that time, radically altered in one way or another, although there are still a number of places where one can see such plants as quaking grass, salad burnet, hoary plantain, basil thyme, marjoram, yellowwort and greater knapweed.  With these it is common to see the marbled white and small heath butterflies.

The only site with anything like the variety of species of plant one might expect is Prestwood Picnic Site, also known as Prestwood Nature Reserve (less than two hectares), run since 1976 as a nature reserve with full public access by the Bucks County Council and the Wycombe District Council, joint owners of the site, and since 2013 managed under licence by the Chiltern Society.  The list of notable species recorded for this site is 314, including 164 locally rare species (particularly plants and insects), much larger than any other natural habitat in the parish.  Before the war it was still a pristine grassland site that had never been fertilised, although the southern part of the site, on the steep slope down to Perks Lane had been sold off in the 1930s for housing development and therefore lost entirely.  Just after the war the remaining part was used by Graham Britt, a former bus-driver from London, to set up a business dealing in used caravans and cars and scrap metal.  He himself lived in a caravan on the site until 1974.  He kept goats there – the comfrey that is still present was introduced to feed them.  The land became severely degraded and parts of car bodies are still regularly unearthed, including a series of hub-caps pressed into the ground along the main path up the slope (used by thrushes, according to Fisher, 1989, as anvils for smashing snails).  In the war a wooden bungalow had been built at the bottom where the car park is now, used by a London eye surgeon as a country retreat, but this was subsequently demolished (Fisher 1989).  Since the site came under positive management the turf has been restored and the scrub of dogwood, which had threatened to swamp the whole site is now kept to reasonable proportions, valuable in its own right as a slightly different habitat.  There is a car park and a picnic area, with an interpretation board, at the western end of the reserve, at the bottom of the steep slope.  (Oddly, alien shrubs have been planted here, when equally good native ones might have been used.)  On the grass bank beside the car park the alien speedwell, slender speedwell Veronica filiformis, has found its way in, an interesting addition to the overall diversity of plants.  It is very inconspicuous, low amongst the grass, and does no harm to the natural vegetation.

The chalk slope, warm in its south-western exposure to the sun, is important for butterflies (Butterfly Conservation, and particularly the late Ron Beavan, were involved with the creation of the reserve).  There are shrubs of common buckthorn, one of a limited number of places in the parish for this food-plant of the brimstone butterfly caterpillar.  When it emerges as an adult, the butterfly does not confine itself to the site and wanders widely across the parish, often visiting gardens.  The abundant dogwood is also the food-plant of the green hairstreak butterfly, a rather rarer creature, which in some years can be seen flying over the reserve in good numbers.  It is a Jekyll-&-Hyde sort of insect because its wings are dark brown above and bright green beneath, so that it changes its appearance as it flies and settles, the brown alternating with flashes of green in the one case and the green dominating in the other when it folds up its wings, disguising itself amongst the leaves.  This is the only place in Prestwood parish where this butterfly can be seen.  Dingy and grizzled skippers, brown argus and dark green fritillary are all still present.  Unfortunately, the horseshoe vetch that used to be the food-plant of the beautiful chalkhill blue butterfly has entirely died out, so that butterfly has been lost.  The Duke of Burgundy fritillary is seen occasionally, but despite the large number of its food-plant cowslip, has not in recent times established a permanent colony, although measures are being taken to encourage it. 

Caterpillars of the striped lychnis moth (subject of national plans to conserve it) have been found on dark mullein here (its only wild food-plant).  Glow-worms are regularly seen, although nowhere near as abundantly as in the late 1970s.  It also provides a habitat for the tiny snail Abida secale, which is a priority species for protection in the Bucks BAP, and the lapidary snail Helicogona lapicida.  Numerous other uncommon insects have been recorded, such as false slender-footed robberfly (first Bucks record) and long-winged conehead.  At night the black ground beetle Cychrus caraboides emerges to prey on the snails that are active at this time.  Although one of our larger beetles, up to 19mm long, its foreparts are narrowed for getting into shells.  Among some interesting Hemiptera (true bugs) the tree-hopper is particularly distinct.  In 2018 the main bank was extensively colonised by the immigrant ivy bee Colletes hederae, which flies later than any of our other bees, when ivy begins flowering.  In September, the males can be seen swarming in hundreds over the burrows excavated in the soil by the females in the previous October, waiting to mate with the new females as they emerge.  The females lay eggs in the burrows and stock them with pollen as food for their larvae.

The yellow ant is conspicuous among several species here because it creates the ant hills that can make walking somewhat laborious.  Geraldine Fisher (1989) describes them:

There are many ant hills here, some very large.  A few are two to three feet across; some are new, some may be as old as two to three hundred years.  There was little change through the winter months but when spring came there was much activity.  What a gardener might call ‘a fine tilth’ was being thrown up from inside and this settled among the new spring growth of grass covering the ant hill.  Some appeared to have large portions of the hill knocked off thus exposing the soft finely aerated soil inside.  As badgers enjoy eating ants and their larvae I suspect one of these was the culprit.

 

Green hairstreak   Ivy bee (male)

Dingy skipper   Abida secale (actual length c.7mm)

This was once a regular haunt of the common lizard, which has not been seen since 2006, although the slow-worm is still present.  Fisher (1989) reports her first sight of the lizard here:

Last year on 2^nd August 1987, I caught a fleeting glimpse of the common lizard -  Lacerta [now Zootoca] vivipara – darting up the side of an anthill in the hot midday sun.  It seemed to be about 5 inches long.  On 21^st November 1988 I saw again a quick darting movement on the same anthill.  I waited and within a minute there came a tiny lizard no more than two inches long.  It seemed to have lost the point of its tail, but this can grow again.  We were enjoying an unusually warm sunny spell for November and so I saw it again on six further days until the weather became very cold on 16^th November.  It seemed to become quite used to me and would keep perfectly still while I sketched and photographed it.  One day I sat by its anthill fortress and leaned close on one elbow waiting for it to reappear.  After a minute it came and stared at me with its little black beady eye.  It seemed like a miniature dinosaur with its prehistoric head.

 

Male common lizard

 

The site is particularly special, however, for its plants.  Many of them are rare in the area and occur in Prestwood only at this one place.  The most obvious flower in the spring is the cowslip, which still grows quite commonly around Prestwood, and here exists in fabulous numbers.  Some parts of the turf are completely dominated by its leaf rosettes, and the mass of colour when it is in flower is a sight worth travelling far to see.  In 2003, the newly-formed Prestwood Nature local conservation group counted 95,000 cowslip plants at this site!  Winifred Peedle, writing in the thirties, observed that

The bank in Spring and Summer is always a mass of colour.  In Spring the deep blue dog violets thickly cover it.  Later the cowslips bloom abundantly, with stems shorter than those growing in the neighbouring meadows.

She mentioned in addition, however, that

One half of the bank has been sold, and this part has been fenced off and is now kept private.  This half has not been cleared for over 15 years.  Hawthorn, bramble, wild rose, whitebeam and wild cherry have been allowed to grow freely.  They almost cover the bank, but fewer flowers grow there now.  The best orchids grew there.  The cowslips were finer, and I have often found coloured cowslips growing there before the bank was enclosed.  This colouring was due to pollination by the bees.

There is much to comment on here.  Occasional orange-brown flowers can still be found among the cowslips today, and this may be a natural variation. By pollination by the bees she may have meant cross-fertilisation with garden varieties of this colour, which is certainly a possible source and may be the more likely explanation.  If so, it goes to show that our gardens have influenced natural populations of plants for a considerable time.  This process is still happening today, even more so given that there are now gardens right up to the southern fence of the reserve.  A variety of plants of garden origin can be seen on the site, although fortunately none of them have yet got out of control.  Hybridisation between the cowslips and a small population of primroses growing in the scrub on the northern side of the reserve also produces a range of plants intermediate between the two, some first generation crosses (“false oxlips”) and others back-crosses between these hybrids and primroses.  Such hybrids were the origin of our garden polyanthus.

The early spring violets mentioned by Miss Peedle were sweet and hairy violets, which emerge before their relatives.  The sweet is easy to distinguish by its smell, and it is also the only species that regularly has white flowers.  The hairy violet only occurs at one other site in Prestwood.  They are followed by the early (or wood) dog violets and the common dog violets, which are often found flowering at the same time as the cowslips and primroses in that archetypical spring display of fresh blues and yellows that so raises spirits dampened by winter.

 

Cowslips at Prestwood Picnic Site, early May

 

Miss Peedle also mentions the orchids that grew best in that part of the site that was enclosed.  Altogether her list of flowers includes six orchids: white helleborine, early purple orchid, man orchid, pyramidal orchid, fragrant orchid, and bee orchid.  Of these only the bee (“rare” in Miss Peedle’s time) still occurs at the site, in good numbers, although the location of the flowers is unpredictable year from year.  It is strange that she does not mention the common spotted orchid, which is now the most frequent orchid and gives a fine display in July to replace the cowslips.  Unlike most orchids, however, the common spotted is capable of colonising new sites, and the demise of the more sensitive ones may have left a niche for it to fill.  It is inconceivable that Miss Peedle would have missed it if it were there in the thirties, although it is of course possible that it was omitted from her list by pure oversight.  (She mentioned the harebell in her text, but it was missed from her summary list.)  The pyramidal orchid still occurs and had a particularly good year in 2019.  None of the other orchids in her list now occur at all in the parish, except white helleborine.

 

Common milkwort

Bee orchid

Man orchid

 

The man orchid no longer occurs in the county and was always rare, so that the county recorder for botany, Roy Maycock, has doubts about her identification of this plant.  It is not that difficult to identify, however, and his only suggestion of a plant that might be confused, because of a certain similarity in the flower, is the common twayblade, which does occur there.  Druce (1926) said that the man orchid was very rare in the county and had only one record, from Revd. Harpur-Crewe near Wendover in the 1860s.  On the other hand, it is not a very conspicuous orchid from a distance, and it tends to hide its remarkable flowers under the shade of scrub, so that it could easily have been overlooked if it occurred in only small numbers.  Miss Peedle records it only as being seen “occasionally”.  There is no evidence of a botanist visiting this site before the second half of the C20^th, as Miss Peedle’s other orchids are not mentioned among Druce’s lists of sites for them.  There is no doubt, however, about the identification of man orchid growing at the north edge of Longfield Wood in the 1950s and into the 1960s, although now extinct there (personal communication from George Lewis).  This site is only a hundred metres across the valley from the Picnic Site, and it would not have been at all surprising for it to have grown in both places, connected as they were by open downland in the 1930s.

"In Summer there are milkworts, blue and pink, clustered bellflowers, scabious, knapweed, thistles and harebells all growing abundantly, and at the bottom of the bank there are masses of rose-bay willowherb.

Each year on August Bank Holiday, prizes are given for the best collection of living wild flowers.  The chalk bank is one of the favourite hunting grounds for treasures.  The children have been asked to pick only the amount they will require.  After the children have finished picking, there are still hundreds of flowers left".

All these flowers are still conspicuous in the summer, as Peedle described, except the harebell, which has surprisingly gone.  She found them growing all up the bank, plants at the top “ growing on a hard lump of chalk, with just a thin layer earth ” being only 2 inches high, whereas those at the bottom on “loamy soil at least 1 foot above chalk” reached 2 feet, although in both cases the flowers themselves were the same size.  Miss Peedle’s account gives an idea of the abundance of flowers in those days, something one very rarely sees, even at the better sites, today.  All her orchids, for instance, except the bee and the man, she listed as “frequent”.

Other flowers she recorded are also no longer there.  I mentioned above the disappearance of the horseshoe vetch, but also gone are the rock-rose, which she said was abundant in places, and betony (also "frequent").  On the other hand, there are a few chalk grassland specialities that do grow there now in good numbers that she did not list.  There is no reason to doubt that the delicate long-stalked cranesbill had always been there, nor the Chiltern gentian.  Was the bank grazed from time to time by sheep, one wonders, and did they selectively eat off these plants, along with the common spotted orchids?  If so, why were other plants so abundant?  If there were no grazing, then how was the turf maintained?  It would be very useful to know more about the management of this site in the late C19^th and early C20^th.

Miss Peedle did record common agrimony, although she did not differentiate the fragrant agrimony, which Druce (1926) said was very local.  Both occur on the site nowadays, the rarer species probably more abundantly.  It is distinguished by glands on the leaves that produce its fragrance, although this can sometimes be difficult to detect, and it is more reliable to look at the seed-heads, which are less clearly grooved and have bushier spines, the outer ones of which turn back.  This plant is generally uncommon, although I have also seen it beside one of the chalk fields on Denner Hill and on clay at the Brickfields.  It is quite possible that this plant was not distinguished in whatever textbook Miss Peedle used, although it is also possible that it is a later invader, as it prefers the scrubby areas that grew markedly in extent during the war and afterwards.

 

Chiltern gentian

Sweetbriar

It would be tedious to give a full list of the 257 plants on the site, but most notable are: thyme-leaved sandwort, imperforate St John's-wort, long-stalked cranesbill, autumn and Chiltern gentians (plus hybrids between the two - see McVeigh et al. 2005), chalkhill eyebright Euphrasia pseudokerneri , musk thistle, bee orchid, sweetbriar, kidney vetch, common restharrow, common milkwort, clustered bellflower, ploughman’s spikenard, and yellowwort.  Many of these are specific to chalk grassland, as also are the hairy violet, dewberry, salad burnet, fairy flax, wild basil, and basil thyme, all common at this site.  On the southern boundary native hazel is mixed with introduced filberts that have larger nuts, with which it had hybridised to produce intermediate forms (Marshall 2015).  Near them there is also a rare wild pear tree, which has tessellated bark and small hard fruits.

Immediately north of the Picnic Site is a large field (Mead's Garden) with no public access belonging to Wren Davis Ltd.  It is managed under Countryside Stewardship.  Although it had been agriculturally improved in the past it is now left to recover its former chalk grassland ecology.  It is improving from year to year and has many cowslips, large wild thyme (strangely absent from the Picnic Site), common milkwort, common broomrape, greater butterfly-orchid, tor-grass, meadow cranesbill and many other chalk turf plants.  It is also good for butterflies and day-flying moths like Mother Shipton and burnet companion.  Only the absence of scrub limits its interest in comparison with the Picnic Site.

About a kilometre north of the Picnic Site, lies Stonygreen Bank on chalk sloping below Stonygreen Wood, recognised as a Local Wildlife Site.  Also owned by Wren Davis Ltd., it has been kept unfertilised and clear of any scrub for a considerable time, although it may have been more actively farmed at one time.  Here there are still a few interesting plants such as clustered bellflower, sainfoin, small scabious, white helleborine and bugle.  A public footpath goes up the bank into the wood.

 

Sainfoin

Grass vetchling

 

Further north again is a field, Stony Bank, north of Hangings Lane, which is also on chalk.  Although it is unmanaged and covered in rank grass, grass vetchling, blue fleabane, yellowwort, agrimony and fragrant agrimony, red bartsia and gorse have been recorded here.  Among insects is the grey damsel bug.  Grass vetchling is almost impossible to spot if not in flower (late June), because the leaves are so like the long grass among which it grows.  The flowers, however, are a brilliant crimson and show up at a distance, even though quite small.  The plant is fairly abundant across this field.  It also occurs on one field on the west side of Denner Hill, but here the grass is grazed, and the plant occurs in a dwarf form.  Blue fleabane has not been seen elsewhere in the parish, although it occurs at Hampden Bottom.

South of the Picnic Site, on the other side of the Perks Lane housing, is the Perks Lane Cowslip Meadow, once renowned for its display of cowslips, orchids and for other chalk grassland plants, but no longer of interest because of intensive sheep grazing.

There used to be extensive chalk grassland on the west side of Denner Hill above Bryant’s Bottom.  One can still find eyebright and yellowwort here, but there were more interesting records from the 1960s, especially green-winged orchid.  Up to at least the 1970s glow-worms were to be easily found on these slopes.  Most of this land has been left to return to scrub and the grassland is fast disappearing.  Roessel’s bush-crickets, however, appreciate the longer grass and low bushes.  They are common here, the first place I saw them in the parish.  They were once a rare species confined to the south coast, but with recent warmer summers have much expanded their range.  They are now to be found in many areas of tall grass and scrub in the parish.  Acrehill Field south of the Gate public house, once had the second-best display of cowslips in the parish (about 25,000 plants), both in the open grassland and in the scrub spreading down from the top.  Primroses spread from the neighbouring Acrehill Wood, and occasional cowslip/primrose hybrids were seen (false oxlip).  Small scabious, green-winged orchid and autumn lady’s tresses were once to be seen here, but no longer survive.  Other chalk grassland species have also disappeared and, along with them, the butterflies for which this field was once famed.  It demonstrates the need for continued good management for chalk grassland and all its riches to survive.

 

Acid and neutral grasslands

At the time of the commons, heathy grasslands, interspersed with gorse scrub, would have been a familiar habitat in the parish on the clay plateau.  The clay-with-flints tends to give a richer, more water-retentive soil, the pebbly-clay-with-sand a rather nutrient-poor one.  Now almost all this land has been either built over or has long been farmed and lost any of its natural character, especially through the addition of nutrients to produce a better sward or crops.

One field on the pebbly clay that has been left unmanaged for some time is Widmere Field behind the housing on Lodge Lane.  It is mixed in character, with long grass, patches of bramble scrub, and young trees, intrusions of garden throw-outs at the margins and a plantation of grey poplar on the west side.  It is intensively used by dog-walkers and others, although lack of management has caused the most damage.  The grass is of a heathy type that is not evident elsewhere in the parish outside Holy Trinity churchyard, with the pretty brown bent grass, slender St John’s-wort, greater bird's-foot trefoil, heath speedwell and harebells (a plant that strangely grows both on heaths and chalk downs).  There is also that indicator of old unfertilised meadows, the small white umbellifer, pignut.

 

Pignut

Harebell

 

 

The bright yellow butter waxcap toadstool still survives here, although the short grass it needs is continually getting smaller in extent, along with other fungi like yellow club, saffron milkcap, dusky puffball, and the purple-and-yellow "plums and custard".  Several rare beetles have been recorded.  This field would be well worth preserving as a locally rare example of its kind.  There would, however, have to be some control of dog-soiling, which is occurring to such an extent that the field could soon become over-nutrified and poisoned (quite apart from the dangers to children playing there from the diseases spread by dog faeces and the general unpleasantness for walkers).  Even if only 40 dogs a day use it (and it may well be more as many daily users bring two, three or more dogs), the small 8-acre field can be estimated to receive a ton of excrement a year.  Similar problems occur at all open spaces that are close to housing, especially when the rate of dog-ownership (often large ones) is as high as it is in Prestwood.  This problem is easily avoided if owners were careful to clear up after their dogs.

Some private land attached to housing may also support small areas of relatively unspoilt grassland.  One such field, on rather neutral soil on the western side of Peterley Wood, has common spotted orchids, and there may be others that are not visible from rights of way.  Some of these fields, abandoned agriculturally, are no longer drained and have regained some of their original marshy character, with soft rush and greater bird’s-foot-trefoil.  There is a promising unspoilt meadow behind Idaho Cottage and Idaho Farm, although I found it had a disappointing shortage of flowering-plants among a large range of the coarser grasses like Yorkshire fog, probably because it is cut too early in the year, preventing the establishment of seeds. It has also had a mixed history of usage, including sheep-grazing some years before, which has prevented the establishment of any one vegetation type.

To the north of these is a meadow belonging to Michaelmas Farm which is somewhat degraded by use as a horse paddock, but which preserves more of what would probably have been the original flora on the dampish clay-with-flints here.  This includes the yellow rattle subspecies stenophyllus, which is rare in the south of Britain, and a little pignut.  Previous occupants of the farm had mentioned orchids growing here, although I have seen no evidence of this.   In 2001, however, amongst long herbage, I did discover a patch of star-of-Bethlehem that looked native.  The large white flowers are exceptionally beautiful and showy, and occur in large loose sprays.  They may have been considered to have been “orchids”.  This is a rare plant which usually occurs only in small numbers, except where it is obviously a garden escape.  Druce (1926) gave it to be “local and rare” in meadows and pastures in Bucks and thought that it might well be native to the area.  He had found it sometimes in meadows well away from houses and remarked that it similarly appeared to be native at some sites in Oxfordshire and Berkshire as well.  There has been some argument about whether this is a true native, but the most up-to-date authority Stace (2019) states that it is native in eastern England. Referring to Oxfordshire, Killick et al (1998) record it as possibly native, and note that recent records appear to show that it is increasing in the southern Chilterns.  In the Michaelmas Farm site, it is possibly native (the fact that it had never been recorded from here before would be explained by the fact that it is private land with no footpath).  The bottom of the field, however, has piles of builders’ rubbish and the cluster of plants might have originated from a bulb dropped from garden rubbish being transported across the field.  There is virtually no way of deciding its status, and in these circumstances it would be better to err on the side of caution and ensure that these plants, in their currently natural-looking setting, are conserved by not cutting that part of the field until well after seeding (e.g. July).  If the field could be left ungrazed in the early part of one year, it might be found that there are other patches of this plant, which flowers May-June, and this would then strongly point to its being native rather than an adventitious introduction.  Since I surveyed this field the ownership and management have changed.

Other meadows have been preserved behind the Polecat Inn, and these have plenty of pignut, an indicator of old unimproved grasslands.  Pignut also grows in a small area of rough grass beside the pond at Peterley Manor Farm, a relict of the former cow pasture there, although the surrounding fields are now cultivated.  It is now illegal to dig up pignut without permission of the landowner, but in the past villagers used to dig up the brown “nuts”, which are tubers up to 20cm below the ground, either to peel and eat raw, when they apparently tasted like young hazel-nuts, or to use in stews with rabbit, when they were something like parsnip (Mabey 1996).

Fryer’s Field, between Collings Hanger Farm and the parish church, has been consistently used as cow pasture for a long time and has had very little fertiliser added to it.  It appears unexceptional in its flora except for one plant that grows abundantly here and nowhere else in the county.  This is the clumsily named corky-fruited water-dropwort, a relatively unremarkable white “umbellifer” (i.e. one of the parsley family that has broad white clusters of little flowers, like the familiar cow parsley), which I prefer to call "Prestwood parsley".  The plant is distinguished by smallish “umbels” or flower-heads; two types of leaf, the lower well-divided but the segments quite broad, and the upper with very long and narrow segments; seed-pods that have a “corky” base (although this can be difficult to see); and (the feature I use mostly in the field as a quick way of identifying the plant) stalks to the fruits that are rigid and very thick, although they are more flexible and of normal width when in flower – this gives the seed-heads in particular a very solid and coarse appearance.  It occurs in large numbers in certain places near the coast in Hampshire and Dorset, but the Prestwood site is very far removed from any of these.  While Fryer’s Field is the centre of the Prestwood colony, the plant also stretches into the orchard at the north end of the field and beyond, and into Prestwood Park on the south side, where it can be seen beside the footpath.  It has also recently spread into the roadside verges beside the field and the orchard (and north to Giles Gate and east along Lodge Lane), and south of Prestwood Park into Hockey Field.  The plant was not noticed before 1998, although there is every sign that it has been there a very long time.  This may have been because there is no public access to the main field and that it only recently spread into Prestwood Park (where I first noticed it).  It could be that the succession of warmer summers has made its habitat more like those on the south coast and that this has favoured its expansion.  A sample survey carried out in 2008 in Fryer's Field and the Orchard led to an estimated 144,000 plants in those two fields alone (Marshall and Marshall 2009).

 

Corky-fruited water-dropwort "Prestwood parsley"

Lady's-smock or cuckoo flower

 

Although it is common and not specific to unaltered grassland, mention should be made of the lady’s-smock, cuckoo flower to some, that graces many of our slightly damper grasslands with its very pale mauve flowers in late spring.  While it is often seen in ungrazed meadows, it is just as happy on garden lawns and grassy roadsides, growing right into the heart of the Lovell estate south of Prestwood High Street.

All the above grasslands were outside the old commonland.  The only ones to survive from the commons themselves are the recreation grounds at Kingshill Common and between Nairdwood Lane and Grims Dyke at Prestwood.  These are kept closely mown for their football and cricket pitches.  While this ensures that no flowering plant of note occurs, it can be appropriate for certain rare fungi that grow only on unfertilised old grasslands.  Most of these are waxcaps, Hygrocybe species, that are brightly coloured and nestle like gems in the short turf, unable to grow higher than the motor-mower’s blade.  Kingshill Common, with the cricket pitch in the centre, has myriads of these in the outfield in autumn, after the cricket season: bright red, glutinous green, pure white, pink, and deep chrome yellow.  At least fifteen different species of Hygrocybe occur here, along with other species of short pasture, and numerous others, more associated with woodlands, that grow under the small trees at the edge of the commons.  At Prestwood Common the ground is mainly taken up with football pitches and here nothing can survive the stamping of boot-studs, but in the narrow bands of longer grass beside the pitches some of the same pasture fungi grow, including five wax-caps.  Here again there are trees along the edge: fly agaric sometimes appears under the birch and the rare Boletus albidus under oak.

Another area of grassland that is relatively unchanged since 1850 and is kept closely mown in part is in the parish churchyard.  The longer grass, that is mown infrequently, harbours a thriving colony of lady’s-smock.  The short grass close to the church has an exceptional array of wax-caps.  Twenty-three species have so far been recorded, making it a site of international importance as a "waxcap grassland", a habitat that is rare and endangered worldwide.  It has recently been declared a Local Wildlife Site.  Since it was described in an article in British Wildlife (Marshall 2017) the churchyard has become a place of pilgrimage by naturalists from a great distance, as far even as New Zealand.  The species here include the pointed pink cones of pink or ballerina waxcap Hygrocybe calyptraeformis, a species that is the focus of special conservation programmes, and is found in a few other old churchyards in south Bucks (Fortey, 2000).  As it matures the edge of the cap splays out and turns up like a pink tutu.  With the waxcaps grow a weird range of other fungi like clubs and corals, while the plants in the turf, among mosses and lichens, are typical of heathland pasture and are rare in the Chilterns - heath speedwell, tormentil, heather, harebell, heath bedstraw.

 

Pink waxcap with drab bonnet behind

Tormentil

 

The churchyard is a rare survival of the type of acid grassland that would have dominated Prestwood and Kingshill Commons.  Even in garden lawns, if they have not been fertilised or treated with moss-killer or fungicide, some remnants of this grassland can be found, even in the centre of Prestwood, including a number of waxcaps, although never to the extent of the churchyard.

 

Golden waxcap (photo David Cann)

Parrot waxcap

Snowy waxcap

 

Some of the waxcaps found on the Lovell Estate in Prestwood

 

 

Ponds

 

The frogs that were peeping a-thousand shrill

Wherever the ground was low and wet,

The minute they heard my step went still

To watch me and see what I came to get.

Robert Frost “Pea brush”

 

General condition

Prestwood Parish was traditionally well endowed with ponds.  Thirty-seven current, or recently existing, ponds that are either long-established or extensive, i.e. not including the large number of garden ponds of recent construction, have so far been identified.  None of them involve particularly large bodies of water, the largest being no more than a fifth of an acre in extent.  Almost all of these (34 in total) are at least one hundred years old and they are a heritage from a past when ponds were integral to the life of a rural community.  At least 67 ponds were in existence in the same area in 1900.

Not all the ponds, however, are currently thriving.  Of the 39 in a preliminary survey in 1995-96, six could be considered to be in excellent or very good condition, five good, five quite good, two moderately good, and sixteen were in poor to very poor condition, while five had either disappeared altogether or were irrecoverably spoiled within the last thirty years.  Eighteen ponds in decent condition is not a bad situation for a single small parish, but many of the others could be rescued (given the resources) and some have substantial wildlife and amenity potential which means they ought to be conserved.  Left as they are the neglected ponds are only eyesores and would soon disappear altogether, as many others have in the past.  The initial survey was followed up with more intensive studies by myself with Eric Hollowday (an expert on microscopic aquatic life), Julie Carey and Andy McVeigh (then with the county council ecology team), David Hillas and Christine Jolly Prestwood Society) and Val Marshall; and subsequently revisited by Mary Campling and Holly Bennett (with specific emphasis on amphibians).  As a result, three of the ponds were restored by Prestwood Nature from poor to very good condition, one (Sheepwash) with the help of a grant from the Chilterns Conservation Board and Great Missenden Parish Council, one on Denner Hill with a grant from Bucks County Council, and the ditch opposite Collings Hanger Farm, again with a grant from the Parish Council.

The reason for much of this neglect was the loss of economic function.  Most ponds were created to water livestock, either for all the local residents on common land (which survived in the parish well into the nineteenth century) or on privately-owned farms.  Thirteen were certainly, or probably, old common ponds.  Fifteen were probably long-established farm ponds.  The rest comprised a miscellany that includes a unique example of a shallow field pond on a clay hill-top, three woodland ponds which may be semi-natural in origin (one of which is now nothing more than marsh and the others fast becoming so), and a very deep concrete-lined depression reputed, erroneously, to be an old cockpit, and still so-named (which has since been re-landscaped by the Kingshill Society with a grant from the Chilterns Conservation Board).  Three were of more recent construction (one near the site of a former farm pond), and four are water-filled former clay- or chalk-pits.  Some may have originated from pits dug to extract clay for brickmaking.

Hardly any of these ponds currently keep their original function for livestock, the exceptions being one at Ninneywood Farm that, at least until very recently, was being used by cattle, and another at Newhouse Farm that survived as a goose pond (for amenity value rather than as an economic venture).  Two more survive (although not very well from a wildlife perspective) because they are maintained by the highways department as drainage ditches.  Those ponds that are in reasonably good order have survived only because of the attentions of the landowner or, in the case of those still on common land, because of the care of neighbouring households.  This has not been from any economic motive but purely to maintain or revive their scenic and ecological value.

There are two major threats to these ponds.  One is a general drying out of the clays so that the ponds hold water for shorter periods, with damage to the impervious puddled-mud bottoms, and the other is encroachment from trees, scrub or invasive plants, that tend to convert the ponds to marsh and eventually dry land.  Most or all of the original common ponds and the old farm ponds too, were filled by rainwater and run-off from fields or buildings, although there is some suggestion that the Sheepwash is spring-fed.  They would have had a seasonal cycle of deep water towards the end of the winter and decreasing levels through the summer.  In the more built-up areas natural run-off has often been obstructed and the disturbance of the clay has also dried it out, so that water is absorbed more quickly.  If they remain dry for an extended period, the soil and clay beneath shrink and become ineffective in holding water, weakening the pond even further.  This is a long-term trend that is impossible to counteract except by the costly expedient of digging the ponds deeper, restoring their foundations, and creating routes for drainage from surrounding areas.  Ponds formed by rainwater filling former clay-pits would always have been in greater danger of drying out and few of these have survived.  Ponds in better condition only occur among the old common and farm ponds (42% and 53% respectively).  Part of the reason for this may be that they were not entirely dependent on rainwater, but were sensibly sited where the contours encouraged collection of run-off as well.

Encroachment by vegetation is in theory a simpler matter of management, involving regular cutting back or extraction of invading plants.  This may need to be done every few years or even annually in the case of alien plants of garden origin that are capable of spreading throughout even the largest pond (e.g. Wibner and Kiln Corner Ponds).  The danger of introducing such aliens to natural ponds may not always be apparent to gardeners, who may think the disposal of excess water-weed and ornamental grasses adds to the value of the pond rather than its destruction.  The problem with some of Prestwood’s ponds is that they have been neglected for many years and now need major, and costly, surgery to remove large trees and thick sediments of rotting leaves.  At least 21 ponds have a serious problem of encroachment. 

A further possible source of decline is pollution, and some of those ponds near roads or well-used paths do have the obvious eyesore of dumped rubbish.  Although unsightly, dumping actually does little actual damage in most cases.  There are only two obviously polluted ponds in the area, one because of oil and other waste runoff from the road for which it serves as a drainage ditch, and the other from farm waste.  Occasionally there has been more serious dumping, of builders’ waste or scrap farm machinery.  One old pond has been completely filled in by a gross act of this kind and another has been seriously depleted.  The pond at Peterley Manor Farm was restored (to excellent condition moreover) from being a waste-pit for rusting machinery only by exemplary effort on the part of the current owner, Roger Brill.

 

Peterley Manor Farm Pond (known as Lloyd's Pond in the C19^th), one of Prestwood's best surviving ponds

 

There may, however, be less obvious pollution associated with road run-off, as is possibly indicated by the findings (below) in regard to numbers of rotifer species, which were generally absent or extremely low for ponds directly beside roads or major tracks.  Even a relatively small distance from a road, 30 or 40 metres, on the other hand, seems to have been sufficient to prevent such an effect.

All but one of the old ponds with adequate amounts of water were tested for their pH.  (It was not possible to gain access to one pond on private land.)  Most of the ponds are neutral or acid, with an average of 6.6 (pH7 = neutral).  There was some association of acidity with a high degree of leaf humus and over-shading, but by no means all the acid ponds were in this condition.  Different levels of acidity are associated with different micro-fauna, some confined to acid habitats and others to alkaline.

With regard to conservation it has to be recognised that different kinds of pond serve different needs - one more pleasant to look at may be less attractive to wildlife, one with a good number of plants may be good for some creatures but not all kinds, and so on.  It is important to preserve variety, rather than to try to manage all ponds according to a single plan. An example of this is a shallow field pond on Denner Hill, so shallow it looks hardly worthy of being called a pond.  Yet it had the best assembly of micro-fauna of any of the ponds examined in the parish, many of the species not known to occur in the others.

 

Overview of the Flora

With no rivers or streams in the parish, ponds are the only sites where aquatic or marshland species can be found and are therefore vital for their survival in the area.

Forty-four truly native species using the open water or marshy areas have been recorded.  By far the most common are yellow flag and common duckweed (both in 13 ponds), soft rush (10), and floating sweet-grass (9). Also quite common are water-starworts Callitriche spp. , which have been recorded from eight ponds.

Water-crowfoot Ranunculus aquatilis agg. was present at five ponds (including R. aquatilis, R. hederaceus, & R. peltatus, the last-mentioned having temporarily gained a foothold in a new pond on Denner Hill in 1998-99), and sedges Carex spp. at four (including Carex pendula at two sites,  C. remota at one, and C. hirta, until recently, at another). Water plantain was present at four ponds.  Bittersweet is also a common member of marshland communities, although equally common on drier soils.  Other plants that often use the marsh areas but which also grow in quite different habitats include lady’s-smock, yellow pimpernel, celery-leaved buttercup, redshank (4 ponds), bracken, docks, and willows (growing in the water at four sites).

Other frequent wetland plants are great willowherb (5 ponds), and bulrush Typha latifolia (3 ponds).  Strangely, there is only one reed-bed, in the roadside ditch opposite Collings Hanger Farm.  This was formerly a much larger farm pond at the corner of the old Prestwood Common and one spectator in the early C20^th noted clouds of butterflies coming there for minerals and salts in the mud.

 

 

None of the aquatic plant species present in the parish is especially notable in a national context.  This is not surprising given the limited area of wetland and the fact that the ponds are highly dispersed.  Only yellow pimpernel and celery-leaved buttercup are somewhat more notable.  The latter survives at two sites only and could easily be eliminated from the parish.  This has already happened in the recent past to ragged robin Lychnis flos-cuculi. The nationally rare star-fruit used to grow at Hatches Pond, but this was filled in during the 1960s and the plant is no more in the parish (and endangered nationwide).

Even the commoner aquatic species often grow at only one site in the parish.  Over half the total list of aquatic species is surviving in this perilous way, which could make the loss of even one pond a disaster.  Marsh marigold has already disappeared from its last site as a native plant.  Twelve ponds contain species that grow nowhere else in the parish, and one of these (Brickpits) has almost disappeared because of a lowering of the local water-table.  One pond (Wibner) had five species not growing elsewhere, another (Peterley Manor Farm) had four, and the marsh in the centre of Peterley Wood had two unique species.

Fourteen native species were known to grow in the parish as a result of deliberate introduction, but only eight of these grow in ponds other than the two garden ones included in the survey.  The most frequent (in three ponds) is marsh marigold.  Hornwort (two ponds), bogbean, white water-lily, fringed water-lily, and greater spearwort also occur.  Another two native species were present in natural ponds: nodding bur-marigold and curled pondweed, of which the former has now disappeared.  As native species they may be capable of blending with the rest of the aquatic community and achieving a balance with other plants, but this does not always happen, and some introductions, even of native species, can take over a pond and completely destroy its character.  There is always a possibility that introductions of supposedly native species are actually foreign strains that are more vigorous, although it may also be the case that ponds where introductions are made lack the natural predators that might otherwise keep them under control.

 

Marsh marigold (photo Val Marshall)

Wibner Pond 1995, choked by variegated reed sweet-grass

 

Finally, the aquatic flora of the parish contains nine introduced exotics, readily available from garden centres.  Most are extremely prolific and incompatible with ponds of such limited size as exist in the parish.  The most frequent was Canadian pondweed, recorded from four ponds (including both garden ponds).  The variegated reed sweet-grass Glyceria maxima var. variegata was in two ponds, from one of which (Wibner) it has to be cleared regularly if it is not to turn the whole pond into a single-species marsh.  Curly waterweed was also present in two ponds, and that particular bugbear, parrot’s-feather Myriophyllum aquaticum, has been introduced with it in one of these and also another pond.  (There are three native species of Myriophyllum that look just as attractive and are compatible with a mixed aquatic community.)  In the last few years, the area has been invaded by least duckweed, which has got a hold in two ponds.  It tends to create almost complete surface-cover, preventing light getting into the pond for the other creatures, which the native duckweed tends not to do so thoroughly.  Of the two other common introduced surface-plants, ivy duckweed is also present in two ponds, although it does not constitute a nuisance, and the water-fern has not so far been recorded, although it can be seen at local garden centres, like the two Lemna species, growing with other aquatic plants, and it is probably only a matter of time before it, too, will be present.  Like least duckweed it is capable of covering the whole surface of a pond.  We shall also be lucky if the New Zealand pigmy-weed does not also find its way eventually into one of our ponds, as it already has done outside the parish at Penn Street, Gerrards Cross and Pitstone Fen nature reserve.  This can only be removed by destroying the whole pond.

Overview of the Fauna

The common frog actively used at least fourteen of the ponds, and had been present in another two.  The smooth newt has been observed in ten ponds and the palmate newt in seven.  Great crested newts have been found in Peterley Manor Farm, Idaho Cottage and Wibner Ponds, and survive in the first two.  They have also been reported from time to time in garden ponds, although these are usually too small to hold permanent populations.  Common toads have been recorded at three ponds (Sheepwash, Peterley Manor Farm and that beside Hildreths Garden Centre), although they are also widely recorded in gardens and woodland some way from water.

 

Frogs in a Prestwood pond

 

Great crested newt outside breeding season (no crest!). Photo by Peter Daltry.

 

The main limitation on the existence of amphibians, given water of adequate depth, appears to be disturbance by water-birds.  One pond used as a goose-pond was not able to support amphibians, and most where mallard are regularly observed (twelve ponds) contain neither newts nor frogs, despite otherwise appearing suitable, except for the Sheepwash which is large enough to accommodate small numbers of the ducks.  (Mallards mainly eat water-plants, but have been observed preying on frog spawn.)  The other seemingly incompatible species, the stickleback Gasterosteus aculeatus , occurs in just one pond, which would otherwise be expected to provide a good breeding-ground for frogs and newts.  (The stickleback normally eats very small creatures such as water-fleas, but it may perhaps also take spawn or very small tadpoles.)  Domestic ponds may suffer predation of amphibians by cats, blackbirds and even the occasional grey heron.

Many birds, of course, use ponds as a vital source of drinking- and bathing-water.  Those particularly associated with water are mallard (above), moorhen (five ponds), willow warblers at one pond where there is a good stand of willow, and swallows, which occur in large numbers at two of the large open ponds, continually criss-crossing for flies.  Coot only frequent much larger ponds that exist outside the parish (e.g. Deep Mill).  The only other two vertebrates noted using ponds are the grass snake, seen in or by three ponds, and roe deer, which have been seen coming to drink at one quiet farm pond well away from footpaths.

 

Pair of mallards

Moorhen

 

The most conspicuous and attractive insect pond-users are the dragonflies.  They have been observed at only thirteen of the ponds, although others will no doubt be used on an occasional basis.    The most frequently recorded are the southern hawker Aeshna cyanea , which often ranges far from water as well, including gardens, although ponds are essential for breeding, and the azure damselfly Coenagrion puella .  Another familiar blue damselfly Enallagma cyathigerum is also frequent, as is the common darter Sympetrum striolatum, whose males are red and the females brown.  At least five other species have been noted, including the less common emperor dragonfly Anax imperator, larvae of which were found in the large garden pond at Hughenden Chase and in another garden pond near Hotley Bottom, while adults have been seen around a new pond at Rickyard Cottage.

 

Right: male southern hawker Above: great diving beetle (photo by Peter Hodge)

 

Water-bugs are also familiar to most people, especially the surface-living pond-skater Gerris lacustris, recorded at ten ponds.  Lesser water-boatmen are also frequent ( Corixa punctata, and possibly other Corixa spp., plus Callicorixa praeusta and Hesperocorixa linnaei, moesta, and sahlbergi).  The larger water-boatmen also occur (not only the common Sigara dorsalis, but also S. distincta, less common in this part of the country than elsewhere, preferring large ponds such as Peterley Manor Farm where it was recorded; S. limitata, another local species which recently colonised both the new pond at Rickyard Cottage and the nearby Dennerhill Pond after scrub clearance; and S. lateralis, also recently colonising the Rickyard Cottage pond).  Backswimmers (Notonecta spp, including N. glauca, N. maculata, and N. marmorea ssp.viridis) are common.  Particularly notable are the saucer bug Ilyocoris cimicoides, recorded at the ponds at Hughenden Chase and Dennerhill; Plea leachi, a distinctive water-bug without an English name, which is generally considered rare in Buckinghamshire, but occurs in both the pond by the Garden Centre and the new one at Rickyard Cottage; and most importantly the tiny Microvelia pygmaea, a nationally “notable” species which is still rather rare, although possibly increasing.  The latter was found in 2002 in Peterley Manor Farm Pond.

The water-beetles are the other main group of insect water-inhabitants.  They have been found at sixteen ponds so far.  They include the great diving beetle Dytiscus marginalis , the screech beetle Hygrobia hermanni, and eleven other species, including the scarcer Haliplus heydeni in the Garden Centre Pond and Enochrus ochropterus in Dennerhill Pond.  The commonest species is Hydrobius fuscipes. 

Other beetles are associated with pond margins and marshy conditions.  These include Elaphrus cupreus , a ground beetle often associated with pond-edges, found by Woodlands Pond, Stenus pubescens, typical of ponds on clays (Lodge Wood), and less common species like the rove-beetles Quedius maurorufus (Lodge Wood) and Oxytelus fulvipes (Cherry Tree Pond), and the further ground beetles Acupalpus dorsalis (Lodge Wood) and Amara plebeja (garden pond).  Most of these are not averse to using the water itself at times, being able to negotiate the surface-film or crawl along the bottom of shallow water.

Still other beetles may be found on water-plants, such as the cardinal beetle Pyrochroa serraticornis , orange ladybird Halyzius 16-punctata, and the soldier beetles Rhagonycha testacea and R. lignosa, all of which have been found on floating sweet-grass in the middle of Cherry Tree Pond.  The water ladybird Anisosticta 19-punctata was recorded on bulrush at Cockpit Hole before its reconstruction.  Even more significant was the rare reed-beetle Donacia marginata discovered to be living plentifully on bur-reed at Peterley Manor Farm Pond.  These beetles shine splendidly in the sun with changing hues of green and purple, although when approached they soon drop to the bottom of the plants and disappear from view.

A number of flies (Diptera) use ponds for their larval stage.  These include the common mosquito Culex pipiens , which is probably present in all the smaller ponds, although even more prevalent in water-butts and troughs.  Craneflies, hoverflies (especially the yellow-and-black striped Helophilus pendulus) and long-legged flies are frequently recorded in association with the ponds in the parish.  Wasps and bees regularly patrol the ponds and use them for drinking.  Mayflies have been recorded at five ponds, and the larva of a caddis fly at another (a limnephilid species).  Helophilus pendulus has aquatic larvae, as also have the drone flies, Eristalis species, of which five different species are commonly seen in the area.  Most of these larvae prefer organically rich ponds, especially those “polluted” by manure or rotting leaves.

 

Helophilus pendulus hoverfly

Giant ram's-horn snail

 

Two species of water-snail are very common in the area, Lymnaea peregra and L. stagnalis.  The large ram's-horn snail Planorbarius corneus (an introduced species) also occurs in two ponds. Ten other species have been recorded, including the uncommon freshwater limpet Acroloxus lacustris.

            The larger crustacea include the water slater Asellus aquaticus and the freshwater shrimp Gammarus pulex, each recorded from the same six ponds.  The smaller crustaceans include the ubiquitous water-fleas.  Daphnia obtusa has been recorded from 16 ponds, and four other species from once to four times each.  Chydorus sphaericus is also common (7 ponds).  The copepods are almost as common, Cyclops spp. being recorded from 13 ponds, and a Canthocamptus sp. from one.  Ostracods have also been noted in three ponds.

            Twenty-seven different species of rotifer have so far been collected in the ponds of Prestwood.  The commonest are Lepadella patella (10 ponds), Lecane bulla (5), Anureaopsis fissa (4), Mytilina mucronata (4), Synchaeta pectinata (3), Keratella brevispina (3), Squatinella tridentata (3) and Testudinella patina (3).  Notable observations were Keratella ticinensis (from 2 ponds) and Collotheca campanulata (both first records for the county), and Asplanchna girodi (a relatively large rotifer, over half a millimetre in length, characteristic of lakes and very large ponds, but in Prestwood found in the small shallow field-pond on Denner Hill). 

Protozoans were identified in thirteen ponds, flatworms in four, nematodes in one, other worms in two, green hydra Chlorohydra viridissima in two, water mites in two, and leeches also in two.

 

Biodiversity

It is abundantly clear that, even within a relatively small, and more or less uniform area (a single parish), there is a considerable variety of pond habitats.  If one also included the large number of small artificial garden ponds (only one of which was included in the survey), one would undoubtedly add to this variety.  Even the smallest, least promising, patch of water may hold species that do not occur elsewhere in the area.

Not all the ponds that appear to be good for the diversity (number of different species) of one group of creatures is necessarily good for another.  The diversity of micro-fauna, in particular, was neither correlated with the diversity of the flora nor of the macro-fauna (although surveys of the micro-fauna were only carried out for those ponds with adequate levels of water, and these generally had higher numbers of plants and all had some macro-fauna associated with them).  The diversity of flora (all species, native and introduced) did have some association with the diversity of the macro-fauna, however.  Of the 16 ponds with above-average levels of fauna, 13 were also above average for plants.  The diversity of native plants alone did not produce such a strong association (only ten of the ponds with good fauna had above-average numbers of native species).  It is therefore a good variety of plants generally that encourages a range of fauna, rather than the existence of native species.

Of the 34 ponds that could be rated, just six were above average for all three main groups (flora, macro-fauna and micro-fauna).  These exceptional ponds were that by the Garden Centre, Lodge Wood, Wibner, Peterley Manor Farm, Denner Farm and Hughenden Chase.  (At the time of the main surveys, Sheepwash had not been restored and was only marshland.)  All had some species present that were unique within the parish.  Four had the snail Lymnaea peregra associated with them.  Five were also used by dragonflies, water-bugs and water-beetles.  The common rotifers Anureaopsis fissa and Lepadella patella were found in three and five of these ponds respectively.  All but one of these ponds are carefully tended by their owners or by the householders whose land abuts the ponds.  Three are ancient farm ponds, one an old common pond, and one a large, recently constructed, garden pond with a concrete foundation.  The sixth is a woodland pond, in danger of drying out if not maintained, but it has apparently never held a great deal of water and used to be known as “the bogs” (personal communication from John Parker).  Its membership of the group is marginal for both the flora and the micro-fauna, but it has enough unique features to be important for conservation.  Peterley Manor Farm pond (originally called Lloyd’s Pond) stands out in this group for having all five of the amphibians known in the parish, lake limpet, four uncommon water-bugs (including the extraordinarily long thin water-measurer) and three uncommon beetles.

It is remarkable that three of this top group of ponds had no amphibians present.  It was presumably no accident that two of these ponds contained fish - in one case sticklebacks and, in the other, introduced goldfish.  The same two ponds were also remarkable among the top group in apparently lacking water slaters and freshwater shrimps, species that might also form the prey of fish, especially at the egg or larval stages.  The third pond had only shallow water which often deteriorated to marsh, which may have been inappropriate for amphibians, although its cool shady woodland location and high acidity may also have made it less attractive.

Six further ponds were very close to joining this top group.  They were above average for two groups of species and average for the third.  These were Kiln Corner Pond, Prestwood Lodge, Dennerhill (after clearance), Cockpit Hole, the shallow field-pond on Denner Hill and the small garden pond.  All had a good diversity of plants, including celery-leaved buttercup at Dennerhill.  Again, all had some unique species for the area.  Five also had molluscs present and were frequented by dragonflies (most notably the bright blue emperor on Denner Hill), and three contained aquatic bugs.  All contained frogs and four also had newts.  Like the top group, four of these ponds were carefully tended, one by staff at the school in whose grounds it lay (since unfortunately totally neglected and now little more than a patch of mud), one by neighbours (also now unmanaged), and two by the landowners.  One is a type of pond unique in the parish, a shallow field pond that is unimpressive to view, but in surprisingly good condition and with an outstanding variety of rotifers.  The last (Cockpit Hole) was a bulrush marsh with a substantial depth of water, although open water had declined to a small area and is very muddy; it has more recently been restored and has more open water.  Its origin is in doubt, being reputed to have once been a cockpit, but this is very unlikely.  It is clearly shown as a pond on C19^th maps, and is too large and deep a depression to have been created solely for highway drainage.  It is most likely that it originated as a swallow-hole, where the ground collapsed above an underground chasm.  The pond on Denner Hill, since it was restored, is particularly notable for its water bugs and beetles, with the best assemblage of any pond in the parish, including six uncommon species of bug and seven of beetles.

Surveys therefore clearly show the importance of local people taking care of the ponds on their land or close to their property.  Very few of the longstanding ponds in the area have survived in a reasonable state without regular intervention.

Another feature emerging from these surveys is the existence of certain “indicators” for quickly identifying ponds likely to be in good order as wildlife habitats.  One of these would be the number of aquatic plants present (over three).  Particularly significant aquatics are water-plantain and rushes other than the prevalent soft rush.  Other indicators of the ponds in our top groups would be the presence of moorhens, great crested newt, mayflies and caddis-flies, dragonflies (especially the larger species), aquatic bugs other than the ubiquitous pondskater Gerris lacustris, larger crustacea (water slater, freshwater shrimp), and any molluscs other than Lymnaea stagnalis.  Microfauna especially associated with the best ponds included the green hydra, and the rotifers Anureaopsis fissa, Lepadella patella, Squatinella tridentata, Synchaeta pectinata, and perhaps Lecane bulla.

It is surprising that the two commonest amphibians in our survey (frog and smooth newt) do not feature in this list of indicator species.  This is for two reasons.  One is that the presence of fish in some of the best ponds has limited their presence there.  The other is that both the common frog and the smooth newt proved to be surprisingly tolerant in the water conditions they would accept, so that their presence does not necessarily indicate a thriving pond.  (Both species, it should be noted, spend much of the year away from ponds, often visiting them only to breed.  As a result, frogs were found visiting year after year, in large numbers, certain ponds that had declined below the level of viability.)

It is also perhaps surprising that water-beetles do not appear in the list.  This again may be due to the wide range of tolerances exhibited by this group as a whole, helped by the fact that they generally have the ability to fly from one pond to another if conditions in one become unsuitable.

 

Sheepwash Pond 2011 after restoration by Prestwood Nature.  The gorse returned naturally from old buried seed.

 

 

Disturbed Land

 

And down … the furrow dry

Sunspurge and oxeye

And lace-leaved lovely

Foam-tuft fumitory.

Gerard Manley Hopkins “The woodlark”

 

It may seem surprising at first to think of disturbed land as a natural habitat.  Humans, however, have been present for millennia, continually disturbing the countryside – felling trees, draining and tilling soil, making homes and gardens, hunting and gathering, and so on.  Arable fields, in particular, have been in existence for so long that certain annual plants able to colonise new conditions more quickly than others found in them ideal conditions to thrive.  Probably these plants had once been quite rare, exploiting the sudden acquisition of light and bare ground that came with a fallen forest tree, for instance, flowering and seeding in a short time and spreading their seed widely enough, so that wherever the next tree fell there would be some seed lying in the soil to take advantage.  When we made our fields and ploughed them every year, these plants were ready to take over and suddenly became some of the commonest plants around, the so-called “arable weeds”. 

For thousands of years they blossomed, as waves of red poppies, yellow marigolds and blue cornflowers breaking up the golden seas of ripening corn.  They were not always welcome to the farmer – the poisonous darnel (a grass like rye), harvested with the wheat, could kill whole families from the resulting bread.  Even the harmless plants were a nuisance if they could not be separated from the harvested crop.  By and large, however, farmers had to put up with them, until the advent of chemicals, especially in the latter part of the C20^th, that could be used selectively to kill unwanted plants other than the target crop.  This improved the profits of farmers, but created a crisis for a whole range of plants suddenly finding themselves under threat.  Many of these former weeds became extinct in the last century.  Others survive in very small numbers in limited areas.  While we may not bemoan the passing of darnel, others that used to brighten up our fields, like Venus’s looking-glass or pheasant’s-eye, or at least provided some interest, like the fluellens or shepherd’s needle or ground pine, have been missed.  Corncockle was recorded at an unspecified location in Prestwood in 1964 but has not been seen since.  The corn poppy has managed to survive and now and again one still sees fields of crops beautified by its scarlet flowers, and so have certain “weeds” like charlock and the mustards (although surprisingly infrequently in Prestwood), but corn marigold and cornflower died out in the parish.

The survival of these plants depends on the intensity of use of herbicides and the type of herbicide used (general or specific).  Most arable fields, although they cover nearly 500 acres, or 27% of the non-built-up area in the parish, now contain a very limited number and range of annual plants.  Some can still be seen, however, when you go to collect your “pick-your-own” fruits at Peterley Manor Farm, where the chemicals used are generally selective and not so devastating.  They include corn spurrey, heartsease, field pansy, wild mignonette, and creeping yellow-cress.  Many, however, of those recorded in the last century have failed to survive into this.  The really common arable weeds remaining in the parish are: common poppy, common fumitory, common orache, common chickweed, redshank, knotgrass, shepherd’s purse, scarlet pimpernel, common vetch, sun spurge, fool’s-parsley, field bindweed, field forget-me-not, red dead-nettle, cleavers, pineappleweed, scentless mayweed, groundsel, parsley-piert and common couch.

 

Common fumitory

Sun spurge

Scentless mayweed

The existence of a good number of arable weeds ensures a good food-supply for birds, so that they too h ave been set back by the weeds’ demise.  Use of insecticides against insect pests has also taken away the subsistence of the insectivorous birds, so that numbers of birds of all kinds on arable farms have plummeted.  The conversion from haymaking to silage has also reduced the potential for ground-nesters to breed on farmland.  This has particularly affected the skylark.  John Priest of Ninneywood Farm noted (personal communication, May 2001):

The bird that I miss the most is the skylark, which used to be quite common here 50 years ago.  They have a wonderful song as they soar high into the sky.  There are none in this area any more.

Fortunately, more sympathetic farming in recent years, promoted by Environmental Stewardship grants, has enabled the skylark to make a comeback and it can be heard once more in the parish over various fields each year.  Its song is synonymous with an English summer, and a countryside without it seems strangely empty.  When Robert Louis Stevenson (1875) walked by our parish in the C19^th he called it the "country of larks".

Farmland, both pasture and arable, can also provide habitat and food for a variety of animals.  John Priest (above) continued:

There are usually quite a number of muntjac deer about and also some roe deer, but I haven’t seen a roe deer this year yet.  We have a badger sett on the farm which has been used as long as I can remember.  We had a young badger hiding under one of the old chicken-houses the other day.  There are a great number of foxes about which occasionally steal our ducks and chickens.  We haven’t seen any hedgehogs for several years , but seem to have as many or more rabbits about than 50 years ago despite frequent outbreaks of myxomatosis.  There are also plenty of grey squirrels and earlier this year we had a Glis glis (edible dormouse) under the floorboards of our farmhouse.  We managed to trap it alive and release it.

Edible dormice have been reported from households in various parts of the parish, where they may invade lofts and have to be removed because of the noise and damage caused.  Grey squirrels will also do this from time to time and they are also very common in gardens, attracted particularly by bird-feeders.  Muntjacs, with their characteristic high-rumped posture, rabbits, foxes and badgers also enter gardens on the fringe of the countryside, although the latter two do so almost exclusively at night.  Wood mice may also make their homes in gardens, sheds and out-houses, and do little harm, as they are not inclined to nest in houses (although they may come inside in search of food), unlike the house mouse, of which I have received no records in the parish.  Brown rats may also use gardens, especially if there are nesting sites beneath sheds etc.  The odd one is really no problem, but they need to be removed if they start to nest, as a colony of rats is not something that most of us are prepared to live with!

 

Edible dormice take advantage of bird-feeders

Polecats have returned since gamekeeper predation declined (photo by Mike Collard)

 

Many insects, of course, use our buildings as shelter in the colder months, like hibernating butterflies, ladybirds and green lacewings, or enter our houses in search of food, whether it is the blow-fly seeking meat carelessly left out, the clothes moth leaving one with a drawerful of holey jumpers, wood-boring beetles seeking out unvarnished furniture, or mosquitoes looking for us!  The most serious pests are those that occasionally enter wholesale, like the nest of ants under the floorboards or a wasps’ nest under the sink.  When we ourselves have invaded so much of the world, it should be no surprise that the more enterprising natural species find the conditions we provide sufficiently similar to their natural requirements for them to strike back, some of them living much more prolifically as a result than before we intervened.

In Chapter 10 we saw how the pheasant farms (and chicken runs) attracted not only foxes, but stoats and weasels.  These are rarely seen, but are probably still quite common.  Polecats, too, have recently returned to the area after an absence of several centuries. While the name of the Polecat Inn is often assumed to be evidence of polecats in this area at one time, it actually derives from an old family name (see Chapter 7) and thus has no significance at all in relation to natural history.  Nevertheless the polecat would have been common until the nineteenth century, when it was exterminated in this part of the country, becoming largely confined to Wales and the Welsh borders before its natural spread back to Prestwood.

Our gardens provide similar conditions to farms, although in miniature and under even more intensive control.  Some gardeners are happy to retain certain harmless weeds.  While no-one wants the pernicious ground elder, I must say that I enjoy seeing both the small toadflax, fumitory and petty spurge when they spring up uninvited, and even the common dandelion is colourful in spring.  Some, however, are a mixed blessing.  Sleeping beauty (Oxalis corniculata) is a pretty yellow flower, but it can be difficult to control.  It finds acceptable habitat between paving-stones and along roadside kerbs.  Our streets can indeed be very colourful with continual invasions of alien species that are fortunately harmless, like purple toadflax, various South American fleabanes, love-in-a-mist, tutsan, garden grape-hyacinth, and spotted medick, along with many other more or less temporary visitors living beside our native groundsel, daisy, dandelion, red and white dead-nettles, whitlow-grass, great mullein and so on.  The latest coloniser of our area is the dainty grass water bent, which probably came with foreign plants into Hildreth's Garden centre, is now well-established there, and has colonised streets in the centre of Prestwood.

 

Sleeping beauty   Water bent at Hildreth's

Love-in-a-mist beside Kiln Road   White dead-nettle - a native quite at home in residential areas

Gardens are also the common haunt of a number of birds, especially when artificial food is provided, or there are “natural” areas where fruits, seeds and insects are allowed to remain.  In late winter when fruits have become scarce in the countryside, gardens are the last refuge of several species.  Results of the Buckinghamshire Bird Club Garden Bird Survey show that fourteen species occur regularly in over two-thirds of gardens in the county – robin, blue tit, blackbird (all three of these in virtually every garden in the survey), chaffinch, great tit, collared dove, greenfinch, dunnock, woodpigeon, magpie, starling, wren, house sparrow and song thrush.  The last species, however, has declined from 90% to 70% of gardens in the last five years.  All these occur regularly in gardens in Prestwood, along with long-tailed and coal tits, jackdaws and redwings.  The survey is carried out only over the winter months, so that house martin, swallow, swift and various warblers do not feature.

Less frequent visitors include the handsome bullfinch, the colourful goldfinches and nuthatches, and the striking great spotted woodpecker.  Jays and green woodpeckers come to the larger gardens.  We once had a pheasant strutting across the lawn, and people with fish ponds dread the visit of a grey heron.  If one keeps an eye on the sky, red kites, reintroduced recently to the Chilterns and now thriving once again locally, may be seen soaring even above houses and gardens.  These birds in centuries past were common scavengers around human habitations, even in the centre of London, but they were eliminated by senseless persecution of all things predatory (even though, unlike the other hawks, they take mostly carrion along with a few small mammals).  The sparrowhawk, on the other hand, is a more frequent garden visitor, entering quickly and suddenly by flying low over a fence or hedge, hoping to surprise an unaware songbird on the bird-table or preening in a bush.  Unless they are lucky enough to catch a bird, often a blue-tit or a wood pigeon, one does not see much of them, but if successful they will often stay around to eat the prey and then one gets a great chance to admire an impressive small hawk at close quarters.  Although commoner generally, the kestrel is less often seen around gardens.  Owls may also visit the larger gardens and farmyards, but are less often seen because of their nocturnal habits.  Tawny owls are quite frequent in the area and often heard near houses, while John Priest has noted little owls at his farm.  Altogether over 37 years I have recorded 56 birds in my garden on the edge of the Prestwood estate.

The distribution of some of our garden birds is quite intriguing.  In my garden on the south-east corner of the Lovell Estate I only occasionally see a starling, but go over to the west side and they are abundant.  House sparrows are regular with us, but in Little Kingshill John Obee tells me he rarely sees one.  Jackdaws are common around Prestwood High Street (and in Great Missenden), but only passers-by with us.  It is interesting, too, that pied wagtails are common around recreation grounds and other wide expanses of grass in built-up areas, but I never see them in my garden.

 

Our commonest garden birds

 

Robin

Blue tit

Female blackbird "anting" on a hot day

 

 

 

 

Some less common garden birds

 

Song thrushes have declined as a result of insecticides, including slug pellets that poison their favourite food   Goldcrests like shrubberies and evergreens

Jackdaws nest in the centre of Prestwood   Green woodpeckers like large lawns with ants

 

Some birds use gardens regularly as nesting-sites if they include thick shrubbery or trees, or if nesting-boxes are provided (popular with tits but known even to host spotted flycatchers).  House martins, swifts and swallows are also dependent on buildings for their nest-sites.  They are particularly fond of farm-buildings.  Numbers have decline in recent decades, particularly of swifts, which are now rarely seen.

 

As far as insects go, gardens provide a chance of flowers and shrubs that may be rare in the wider countryside, especially since the disappearance of the flower-filled hay meadows, the weedy arable fields and the neglect of some of the woodlands.  They are therefore often visited by insects, especially flies and bees seeking nectar, even though they may breed elsewhere, and others find niches that are relatively rare in the “wild”.  I have therefore recorded more uncommon insects in my one small garden than at any other site in the parish!  This is partly because I spend more time there, but the insects still have to visit the garden to be seen.  For instance, I have recorded 91 different hoverflies in the parish, 51 of them in my garden.  In contrast, I have only recorded 23 at the Picnic Site.  It was in my garden, too, that I first recorded hornets and also the new immigrant wasp now resident here, Dolichovespula media, which I first saw in 1991, having spread gradually over a few years from the extreme south-east where it entered from the European mainland.

Median wasp (photo by Bob Fastner)

 

           

As more land succumbs to housing, the proportion that is garden (as opposed to woodland or grassland etc) increases, and the greater the dependence of wildlife, at least at some point in their life cycle, on garden habitats.  Even as we want our gardens to be aesthetic and comfortable to our own needs, one can always leave some corners unkempt and provide useful micro-habitats like ponds (preferably without fish but with plenty of vegetation), tree-stumps, log-piles, ivied walls, long grass, nectar-providing flowers, or a derelict patch.  Fertiliser and insecticide should be used sparingly, if at all.  The use of insecticide, for instance, creates a vicious circle, whereby predatory insects are destroyed with the target species, leaving the garden unprotected the following year and thus demanding ever more insecticide.  Thus the use of slug-pellets kills the hedgehogs, slow-worms and thrushes that feed on them.  For those special crops, like prize roses and broad beans, it is better to encourage natural insect and avian predators and to use mechanical means to remove the most damaging infestations rather than general applications of chemicals.  As Prestwood writer JHB Peel (1970) said “ … birds can kill pests without poisoning people … And … birds have a second advantage over insecticides; they sing. ”  Even better for our wildlife are those gardens where the owners appreciate variety and “disorder” rather than uniform flower-beds and weed-free soil, obtaining gratification from observing the animals, birds, and insects that soon abound in any environment which is not rigidly under control, and happy to forego regular human geometry.  (We are the only species that apparently prefers squares and straight lines, as against the natural spiral.)  This is, of course, easier for those gardens that are not used for food production, although even allotments can be more or less wildlife-friendly.

Wastelands provide another undervalued habitat.  While gardens usually provide contrasting small-scale habitats in close proximity – trees, hedges, scrub, open grass, tilled ground, compost heaps, wood-piles etc – wastelands provide larger areas of more or less open ground where large numbers of thistles, docks, and many other plants are able to flourish, producing foliage, flowers and seeds that sustain a vast number of birds and insects. The coarser weeds are best suited in the larger arena. While wastelands constitute one kind of disturbed land, they are much less disturbed in another sense, that of human presence.  They therefore provide an area where wildlife is relatively free and unrestrained, as well as finding food in abundance.

 

Goldfinches will go anywhere there are teasels or thistles

Hoary cress beside Sprinters car park

 

The demise of the brickyards off Honor End Lane originally left a large area of such “wasteland”, the Brickfields (including the edges of the Sports Centre car park) – “waste” as far as human economics goes, but a grand place to be if you are a teasel or a thistle, a poppy, comfrey, or coltsfoot, or any of the seed-eating birds like goldfinches that particularly relish the thistles and teasels.  The commonest plants in this environment are fat hen, common sorrel, various docks (curled, clustered, broad-leaved and wood), hairy bitter-cress, creeping cinquefoil, common mallow, willowherbs (broad-leaved, great, American and rosebay) ground elder, hogweed, hemlock, wild carrot, plantains (greater & ribwort), great mullein, lesser burdock, thistles (creeping and spear), sow-thistles (perennial, smooth and prickly), common ragwort, feverfew, mugwort, teasel, meadow-grasses and barren brome.  They are accompanied by a vast array of garden escapes, and other plants that are generally uncommon in the area, like weld, goat’s-rue, bristly ox-tongue, silverweed, tufted vetch, prickly lettuce, tansy, horse-radish, hoary cress, dewberry, hawkweed ox-tongue, and Canadian fleabane.  The variety is immense and so is the wealth of nectar-sources provided by thistles, umbellifers and garden escapes like mint, fennel and marjoram.  What it lacks as a “natural community” it makes up for in exuberance and diversity.  It can therefore be among the most valuable wildlife habitats in the parish, especially when nectar-producing flowers are becoming increasingly rare in the rest of the countryside (Marren 2001).  Unfortunately, man tends to tidy up such wild urban areas - as happened at Brickfields, although a little of the same vegetation survives beside the sports centre car-park.  It is not human disturbance that is the problem, it is the tendency to control everything to boring uniformity like a flowerless green lawn, as close to a desert as are concrete walkways as far as wildlife is concerned.

Many insects, including butterflies find these expanses of wildflowers to their liking, and are followed in by the insect-eating birds.  The yellow-and-black banded caterpillars of the cinnabar moth crowd on the ragwort, their colours signifying their distastefulness to the predatory birds.  Common and rare insects congregate for nectar on the umbels of wild carrot and hogweed or on the blossoms of bramble.  Many parts of our rural countryside are less bio-diverse than these buzzing wastelands, where among swathes of common plants can be found much rarer species like grass vetchling, pyramidal orchid, common centaury and marjoram.  “Waste”, in fact, is an unsuitable term, as it is far from wasted as a wildlife site – “wildland” would be a more appropriate description.

 

Cinnabar caterpillars with nowhere left to go.  Another ragwort plant, in its demise, contributes to wider biodiversity.

Bramble with white-tailed bumble-bee and a longhorn beetle Rutpela maculata

 

Bare stony places comprise a rare habitat in the region and here lichens and mosses find a multitude of sites according to their different preferences of light and shade, dry and wet.  The shadier walls are also the only habitat in the parish for a number of ferns.  There may be hart’s-tongue, wall-rue and black spleenwort, each with only a few sites in the parish.  The shadiest, dampest side of Holy Trinity church is the only site in the parish where the tiny green spreading plant, mind-your-own-business, grows.  There are a few other walls supporting plant species in the parish, most commonly yellow corydalis, but the most notable is the little wall outside Stonygreen Farm, the only site in the parish for two different species – intermediate polypody and ivy-leaved toadflax – both of which have survived for at least 40 years, despite the limited space and competition from ivy.)  Species as diverse as bank voles, moss chrysalis snails, and the green ground beetle Pterostichus cupreus find safe hiding-places among lichen-covered churchyard grave-stones; the ant Formica lemani nests beneath them; while introduced rock- and white-stonecrops spread well among the loose chippings of the graves.  The ecological patchwork of trees, shrubbery, grass (long and short), disturbed soil and stone that churchyards provide is both valuable as a last resort for much of our wildlife and a habitat that is relatively unthreatened, given good management with one eye to the needs of non-human users (Rose 2001).

 

Wall-rue on Holy Trinity church

Hart's-tongue fern

 

Another habitat created by man and now often the last refuge of native plants is the roadside.  We have already mentioned the green hellebore and moschatel still flourishing under hedges besides one road.  Meadow crane's-bill has grown for a long time beside part of Hampden Road, and lesser swine-cress has survived for many years close to the Wycombe Road beside the parish church. Grass vetchling grows in long grass beside Bryants Bottom Road south of The Gate where sufficient verge has been left.  The only two sites for the native lady’s-mantle Alchemilla xanthochlora are also beside roads.  “Aliens” (usually garden escapes) may also find a niche here – winter heliotrope, garden lady’s mantle, and red bistort, for instance.  The latter can be seen by Wycombe Road opposite the King’s Head.  (There is also a thriving clump planted beside the parish church and this buzzes with bees in summer.)  Garden grape-hyacinth has spread under garden hedges along a good length of Wycombe Road.  Since at least 1999, a patch of thrift has flowered and multiplied beside Lodge Lane, sustained by road-salting that emulates its natural seaside habitat.  By hugging the kerb it has been fortunate enough to escape the mowers, unlike the rare corky-fruited water-dropwort and great burnet that are cut down every year before they can finish flowering (this being the only place in the parish, or much further afield in the case of the great burnet).  These verges, if left un-mown in spring, can also produce abundant lady’s-smock among the daisies, buttercups and clover, so much more attractive than scalped grass that turns brown over a dry summer.

As fast as we try to eliminate or keep control over the wild things, they adapt, and we find ourselves back where we started.  Or so it was for most of our history – current chemicals threaten to create such fast change that nothing can adapt, and we risk eliminating those creatures we actually value (or should do so), like the ladybird or hoverfly, each of whose larvae demolishes thousands of aphids in its short lifetime.  It is perhaps wiser in the longer term to try to live with the wild things, and, in so far as some prove a nuisance, to remember that there is a whole lot more that is beautiful and wonderful and useful.  If the price of preserving an attractive and lively countryside is that the cost of food production is a little higher, then maybe we should be prepared to pay the price, knowing that we are buying an environment that we can enjoy for the rest of our lives, and one that we can proudly hand down to later generations.  Let us leave living monuments as well as those of stone.
Losses and Gains: Changes in Wildlife over Time

 

For marmots and voles and everything else on the earth that is threatened and terrorized by the human race.

Arundhati Roy “The End of Imagination”

 

The stinging nettle only

Will still be found to stand:

The numberless, the lonely,

The thronger of the land,

The leaf that hurts the hand.

AE Housman

 

Nature is not static.  The balance of species is continually in flux as they compete for space and sustenance and new ones spread into a region.  These natural changes, however, have long been overshadowed by the presence of mankind.  As predatory animals control the numbers of prey species (and influence, in the very long term, their evolution) people as predators, as hunters, influenced wildlife around them from earliest times, including the extinction of several indigenous species like the wild boar (for food), the wolf (as a competitor for food), and the red kite (a species subject to the prejudices of gamekeepers who saw all predators as threats).  Even greater, however, was the impact of later cultivation, because this affected not just selected creatures but whole habitats – felling trees, draining swamps, tilling ground and fertilising it.  For the great part of our history, however, while this impact was widespread (so widespread that in our part of the country no habitat can any longer be considered to be truly wild), it occurred at such a pace that most plants and wildlife were able to survive by moving on, finding alternative niches or adapting to the new opportunities (such as buildings as nest-sites).

The last century has been different – for the first time in history the influence of human activity has proceeded at such a pace and with such intensity that species have become extinct, or almost so, at an alarming rate.  We are now in a position where we are in real danger of losing a third of all mammal species across the world in the next fifty years.  This has been all the more serious because at the same time we have moved from being a largely rural population to a largely urban one, with the accompanying change in philosophy from an understanding of our dependence on nature to a view of it as antagonistic.  In this mind-set anything not planted is a weed, anything not pruned is overgrown, and anything non-human that moves should be kept behind bars or shot (large) or stepped on (small).  Whether we could survive (and be happy) in a totally controlled and artificial sci-fi environment (metallic protective armour-suits and goldfish bowls as permanent head-gear) without the forest-generated atmosphere and the screening ozone layer, is a moot point; that the rest of the natural world could not is certain.

It is difficult to study changes in wildlife because we lack systematic information from the past.  The histories of a few prominent creatures (mostly mammals) are fairly well-known, but other evidence is partial.  We are lucky in our area to have a few records, especially of the plants, from various periods in the past.  These include a few records from the beginning of the C20^th in Druce’s (1926) Flora, Winifred Peedle’s observations from the 1930s (including quite a full list for the Picnic Site), and various botanical surveys and incidental records from the 1960s onwards (by various people including Ted Byrne (1967), Mike Collard (2003), Helen Marcan, Alan Showler and Roy Maycock, BBOWT volunteers in the 1980s, county wildlife officers surveying potential Local Wildlife Sites, Tim Harrison, myself and other Prestwood Nature members).  If a plant was not recorded earlier, that does not mean it was not there, because the parish was not scoured exhaustively (or at least no such records remain); similarly, even today, we cannot be sure that we know every plant around (especially as there are private lands to which botanists less often gain access).  Nevertheless, the sum of the information we do possess is sufficient to draw some conclusions.

Of 1182 wild plants recorded in the parish and surrounding districts (as far as Hampden, Great Missenden and Hughenden) up to 2014, nearly a third (357) are non-naturalised garden escapes or deliberately planted, whose casual occurrence is only of trivial interest.  I have therefore excluded these and examined the remaining 825, which are native or introductions of long standing (like green alkanet and honesty).  [Full details of this analysis can be found in the introductory chapter of Marshall (2019).]

Leaving aside 162 recent introductions (mostly temporary garden escapes), plant species recorded at some time in the parish up until 2001 comprise 467 indigenous or long-established plants, of which 45 (10%) are now extinct in the parish.  Others have probably disappeared, but they were not recorded earlier, as systematic surveys did not occur before the 1960s.  It is likely, therefore, that twice that number have vanished over the last century, a rate of about one a year.  It can be argued that there is a net gain in biodiversity, because 162 new species are recorded, outnumbering the extinct ones, but many of these new species are casuals and will not survive for very long.  Moreover, they are not part of our native flora and do not play such a significant part in the general ecology of the area, although some do act as nectar sources for butterflies and insects (of which the buddleia is the most obvious example).

Apart from the 45 species that were gone by 2001, there were an additional 72 growing at a single site, generally in very small numbers and most in imminent danger of disappearance.  Another fifty were locally rare, growing in only two places in the parish.  A new road, the change of use of a single field or woodland, could involve the local extinction of several species in one go.  Several have disappeared in this way in the last decade.  Of the 629 species ever recorded, just 234 (37%) occur frequently or commonly and can therefore be considered to be safe for some considerable time.  While the rate of extinction in the last century may be of some concern but not apparently disastrous, we could, if our countryside is not managed properly, be facing a mass extinction of the flora in the next fifty years.  Moreover, what these figures disguise is any decrease in the frequency of different plants, which from anecdotal evidence has been quite dramatic for many species.

The most dramatic loss has been among heathland plants.  Only five species normally associated with heathland are recorded, and three of them are extinct (e.g. heath violet).  Of the other two, one exists at two known sites, the other (heather) exists as just one small patch.  When the commons existed (before the dates of our first records, which only go back to the beginning of the C20^th there were scores of plants associated with such heaths, and heather would have been common.  The heath violet was common enough locally for a hybrid with common dog violet to occur.  Most of these common heathland plants were not specifically recorded for Prestwood and so we cannot document their loss.  If there were any argument for habitat restoration, then the recreation of heathland would have to be a local priority, for that habitat has itself, for all intents and purposes, become extinct.  The only remnant of heathland in the parish is the churchyard of Holy Trinity.

 

Heath violet - one we have lost

Heather, which once grew with heath violet, survives at one site in Holy Trinity churchyard

 

Wetlands comprise another habitat that has been much reduced.  Drainage for agriculture destroyed most of the swamps on the plateau centuries ago.  Ponds survived into the C20^th, until the time of piped water, but many have now gone.  Of the sixty wetland species recorded, seven are extinct, including the now nationally rare star-fruit that grew by Hatches Pond before it was filled in during the 1960s.  Only twelve occur frequently or commonly in the parish today.  Fifteen are restricted to one site and can be considered as locally endangered, while another twelve are little better off with just two sites each.  These sites are distributed across a number of different ponds and marshy areas.  Restoration is difficult because ponds need almost annual maintenance if they are not to become overgrown or silt up.

On the other hand, species of dry conditions appear to be doing better.  As a naturally damp and shady area, very few specifically dry-land plants are recorded for the parish, but over two-thirds of them are frequent or common (as against half of all recorded plants generally).  This may be associated not only with the diminution in the area of wetland but also with a more general drying out of the environment in association with global warming.  (Such drying out reduces the water-holding capacity of the land and increases the likelihood of floods and water run-off, hence causing even further loss of water.)

Natural unimproved grasslands have also declined in extent over the last century, either by becoming arable land, being fertilised, or, neglected, reverting to scrub.  Nine primarily grassland species, out of 84 recorded, are known to have become extinct (including several orchids), while sixteen survive at just one site (predominantly Prestwood Nature Reserve).  Extension of the area of semi-natural grasslands would be of great benefit to secure the future of the species that survive.  This would include chalk turf, longer grass meadows, wet meadows and hay meadows.

Of all the recorded plants that are associated with specific habitats, the largest group (102) is of those inhabiting disturbed ground.  One might have thought these would be doing well as population and consequent human disturbance have grown, but this is not so.  Fewer are frequent or common (43%) than of recorded native species generally (51%), while ten have become extinct and nineteen hang on at a single site.  The situation becomes clearer if we distinguish plants of any disturbed ground (doing relatively well) from those growing in more defined circumstances, mostly in arable land or open bare places (which are doing much less well).  Of the nineteen in this latter group, five are extinct (26%), five grow in one place only (26%), and only one is frequent or common (5%).  Of the more general plants of disturbed land (83), just 6% are extinct, 17% confined to single sites, and 51% are frequent or common.  This indicates that the main losses in habitat terms have been arable land where herbicides are not applied, and open sunny places with little other vegetation, such as may exist along paths.  The latter loss may be due to more extensive exploitation of available space in agriculture, combined with neglect of other areas, where rank vegetation is allowed to invade, similar to the loss of grasslands to scrub.  Rank vegetation has increased remarkably because of nutrients absorbed by the soil from air pollution and, in the case of hedgerows, from excessive fertiliser spray in neighbouring fields.

Walls, although a non-natural habitat, are the main habitat for seven local species that normally grow on rocks (particularly certain ferns).  While no such mural species are known to have become extinct in the last century in Prestwood, only one of them occurs frequently and the rest are all uncommon, including three at just one site each (two of them on the one little wall at Stony Green).  Mural vegetation takes a long time to become established, so that there is little prospect in the short term of increasing the number of habitats.  The main threats to their survival is the tendency for people to "clean up" their walls for the sake of a tidy appearance, and an overgrowth of ivy.

Plants of shady places, such as woods and under hedgerows, are doing relatively well, over two-thirds being frequent or common.  This is not surprising, as this is one habitat that has declined little over the last century in the parish and may even have increased as grasslands are invaded by woody species.  Nevertheless, even of these 89 woodland plants, 12 have become extinct (13%), most notably the stag's-horn club-moss in Lodge Wood.  Many of these are probably explained by the general drying out referred to above, coupled with the increasing use during the C20^th of clear-felling whole sections of woodland.

As well as looking at habitat preferences, we can also look at the soil types that certain species prefer.  Seventy-one of the recorded species are associated with chalk soils, of which only 30% are frequent or common today, and 15% extinct.  Twenty-seven are associated with acid soils, of which 26% are frequent or common and 15% extinct.  We therefore have the surprising conclusion that plants with both calcicolous and calcifugous tendencies have suffered equally badly.  This indicates a gradual neutralisation of the local soils, partly due to agricultural improvement and partly to air-borne and man-introduced pollution.  Associated with both is an increase in the nitrogen and nutrient content of our soils (eutrophication), which favours a few particular species (such as nettle and cow parsley), but discriminates against those that prefer the more specialist niches that are associated with lower fertility.

 

Stinging nettle and ...

Cow parsley - both doing very well

 

A final group of plants is the “generalists” – those that are not fussy about the circumstances where they grow.  Not only are they the largest group of recorded plants (excepting the recent introductions and garden escapes), comprising 115 species, but over two-thirds are frequent or common and only four (3%) have become extinct.  Prominent among these plants are those that thrive in high-nitrogen, high phosphate environments and eutrophic soils (high fertility), such as nine of the ten commonest species in Plantlife’s Common Plants Survey 2000: common nettle, cleavers, ribwort and great plantains, cow parsley, red and white clovers, herb-Robert, yarrow, and common chickweed, all of which are abundant throughout the Prestwood parish.  The preliminary report on this survey states: “ Results …reinforce our worst fears – that habitats are degrading due to widespread nitrogen-rich pollution from agricultural fertilisers, car exhausts and industrial sources, producing conditions that allow nettles to thrive at the expense of our wild flowers. ” (Harper 2001.)  So prescient has Housman proved to be (see the quote beginning this section).

These common plants should not be undervalued.  They are often the base of important food-chains supporting other species.  Most of our trees and grasses support a wide range of wildlife.  The common nettle is a particular host to 70 different species of fauna in the local records lists, while about 100 species regularly occurring on nettles are identified in Davis (1991).  Hawthorn and bramble are also of great importance.

Nevertheless, it is time to worry when a few species start to crowd out the less common ones and the overall diversity of species is reduced.  As far as its native plants are concerned, Prestwood has become less diverse and more uniform in the last century.  The increasing prevalence of garden escapes does little to maintain the overall ecosystem, not nearly as much as the native species, so that the diversity we have today is a less healthy one than in the past.  In this respect Prestwood is a microcosm of the country as a whole, following the trends recently noted in the Plantlife Survey (above) and the analysis associated with the publication of the Millennium Atlas of the British flora (Preston et al, 2002).

Apart from plants we have less extensive records, on the whole, on which to base estimates of change.  Among the mammals, the one really obvious change is the total extinction of the red squirrel (common in the early years of the last century) and its replacement by the introduced American grey squirrel, which is abundant all across the parish.  While this might appear to be the substitution of like for like, the change has actually been one from a species in balance with the eco-system to a species that causes considerable damage and is capable, on its own, of preventing the regeneration of beechwoods throughout the area.  The disappearance of a number of passerine birds as breeding species in local woods may also owe something to the depredation of grey squirrels on their eggs and young.  The common birds survive through the sheer weight of numbers (although they may be less frequent) and the larger ones are able to protect their nests (so that magpies, jays and jackdaws may actually have increased in prevalence and, given the reduced frequency of smaller birds’ broods on which to prey, are forced more regularly into gardens to survive on hand-outs or the small birds nesting there).  So the arrival of one alien species may have sent the whole environment out of kilter.

Many have also observed how two species of deer have become very common in the same period - muntjac and roe, both escapes from private deer parks.  Muntjac is an alien species and eats almost anything, including plants that are poisonous to most animals.  The roe was once a native of prehistoric woodlands, but had been exterminated centuries ago.  Both cause browsing damage to trees, although the roe deer is fond of bramble and helps to control its spread in woodlands.  Other alien introductions include the fat dormouse Glis glis, which causes much local annoyance when it invades people's lofts, but has so far had a relatively small effect on natural ecology.  The polecat, eradicated by gamekeepers centuries ago, has slowly returned naturally from its strongholds in Wales and is now once again established in low numbers.

The re-introduction of the red kite to the Chilterns in 1989 has brought back an iconic species to the area that had not been seen for centuries.  The birds' sweeping displays in flight, often quite low, and over residential areas as much as the open countryside, have become a routine sight and for most people a very welcome one.  The first one was seen in Prestwood in 1995.  Another large raptor, the buzzard, had been first seen in Prestwood a decade earlier, after a similarly long absence, and that has colonised naturally to become another familiar sight, usually soaring higher in the sky, although more common over open fields than inhabited places.  Similarly the raven, first seen in Prestwood in 2001, has become an established nesting species, although much less common.  These are exceptions, however, to the general trend, with populations of farmland songbirds crashing after the chemical-based revolution in agriculture from the 1960s onwards.  The lapwing has gone as a breeding species, and skylarks seemed to disappear for some time before coming back to certain more favourable fields in the parish, particularly on Denner Hill, although their numbers are still much reduced.  Garden bird-feeding, which has become increasingly popular, with more than half of local households participating, has made some of our local birds more familiar to, and appreciated by, a lot of people, but it has doubtfully done much to increase their numbers, which depend ultimately on the extent of natural nesting-sites and food-sources.

Among the insects, past records are harder to come by and our knowledge of change much less, but we have lost the chalkhill blue butterfly, along with its host plant the horseshoe vetch, from the short chalk-turf habitats that have become radically reduced.  The Duke of Burgundy butterfly has also disappeared, although its foodplant cowslip is still abundant in places.  Fritillary butterflies have much decreased, although the silver-washed has recently returned and appears to be doing well.  The decrease in elm trees with Dutch elm disease also led to a crash in numbers of the white-letter hairstreak, although it hangs on in a few hedgerows and wood-edges where young elms survive.  The glow-worm certainly remained common until a decade or so ago, although its current status is in doubt.  It depends on good chalk grassland and has been affected by the growth of housing and the consequent light pollution, which can disrupt its mating.

We have a large list of beetles collected mainly in the 1920s-40s by Horace Quilter.  Just over half of these have been recorded since, but most of those not seen again are small species that have a low probability of being recorded.  Those that have mostly been genuinely lost are ground beetles, those feeding on plants that have become very uncommon or extinct, those inhabiting wetlands and house pests (hit by central heating as well as more scrupulous cleanliness).  While we may have lost relatively few species, however, it is evident that almost all insects, not just beetles, have declined in frequency.  This is particularly obvious with the ladybirds, hoverflies, bees and butterflies.

Because of a warming climate there have in the last few decades many new insects added to our local fauna, some formerly rare species from the south coast and other warmer parts of Britain, such as Roessell's bush-cricket (which has become quite common), the box bug, and the long-winged conehead.  Others have immigrated from the continent and some of these have become very common indeed.  The effect of the horse-chestnut leaf-miner is seen by the early browning on leaves on all our horse-chestnut trees (except for the red-flowered species).  The harlequin ladybird has become one of our commonest ladybirds, although early huge populations have since declined as predators such as parasitic wasps have latched on to the new food source.  The tree bumble-bee has also become common and is one of our prettiest species.  The latest invader has been the ivy bee, which has established a major colony at Prestwood Picnic Site.  Few of these new invaders have become a problem locally, although the fungus that causes ash dieback could soon have a major impact, like Dutch elm disease before it.

The main result of such comparisons as we can make, therefore, is that Prestwood has suffered over the last century, in common with the rest of the country, a drop in diversity of flora and fauna, associated with habitat loss, and soil neutralisation, desiccation and eutrophication.  The negative effect of climate change (seen in increased desiccation) has, however, been somewhat ameliorated by making our area favourable for a wider range of insects, as warmer temperatures favour greater biodiversity in invertebrates.  Against this, the decline in plant diversity and density will limit the numbers of invertebrates that can be supported.  In turn, the number of invertebrates, at the bottom of the food-chain, affects populations of all higher predatory species, including many of our birds.

These we have gained

Tree bumble-bee

Roessel's bush-cricket