PURPOSES AND METHODS OF ECOLOGICAL HISTORY

1 1000 YEARS OF NATURAL HISTORY

Trans. Suffolk Nat. Soc. 36 (2000)

PURPOSES AND METHODS OF ECOLOGICAL HISTORY

OLIVER RACKHAM

Objectives and Uses of historical Ecology Both the rhetoric and the practice of modern ecological conservation are inseparable from the history of ecosystems. Conservationists can hardly open their mouths without making what are, in effect, historical judgements. They pronounce some sites to be irreplaceable, and by implication the rest of the landscape to be replaceable. This implies that they know by what processes a site reached its present state and whether or not they can be repeated.

Ecologists usually have some historical standard, often unspoken, by which they judge the present state of a feature or a site. For example, from time to time there is a public debate on the health of trees, especially oaks. The ‘stag-headed’ state of many oaks, with dead branches sticking out of the present leafage (Plate 1), is supposed to be abnormal, and plausible or fanciful theories are proposed to explain it. This may be true, or it may be that free-standing oaks, like Australian eucalypts, habitually go through phases of dieback and recovery. This can only be verified by studying the historical behaviour of oaks. The hidden premise, that the normal state of an oak-tree is what the writer considers to be perfect health, needs to be tested.

It is commonplace in southern Europe for landscapes to be pronounced ‘degraded’: in the past they were covered with ‘magnificent forests’, and their present semi-arid state results from human mismanagement by tree-felling, burning, and grazing livestock. Indeed, in the 1980s, interest in ‘desertification’ and its control grew into a worldwide industry. Questions about when and how degradation took place, and indeed that the original forests ever existed, tend to be answered, at best, in vague and theoretical terms (Grove & Rackham, 2000).

Identifying sites for conservation The first problem in conservation is recognising the conservable. ‘Hedges came in with the Enclosure Acts after 1750’: we used to be told this by Ministers of Agriculture, and also by a very eminent and learned conservationist, as a reason for not conserving hedges. It is a perfectly good argument: if hedges are so recent, they have little permanent value and can be made or unmade at will. But it is based on a factoid: a belief – that all hedges are modern – which looked like a fact, was respected as if it were a fact, and had all the properties of a fact except that it was not true. It can be disproved by anyone spending an hour among the early maps in the Suffolk Record Office.

Woodland conservation begins with recognising which are the ancient woods, and which features of a wood are replaceable and which not. One sometimes meets at public inquiries a developer asking to be allowed to destroy an ancient wood on the plea of making a replica. ‘Eurotunnel Moves Ancient Wood’, as a popular conservation journal put it. Can this be done? A feature can be irreplaceable, either because it would take longer than the life expectancy of a development company, or because it results from a particular


Suffolk Natural History, Vol. 36 2

sequence of historical events which cannot now be reproduced. Considered as an experiment, the attempt to make a replica may be of the greatest value in understanding how ancient woods work, but it is unlikely to be a substitute for conservation.

Historical research can challenge scientific views on the nature of ecosystems. Savanna – grassland with scattered trees – is traditionally thought to be confined to the tropics. Similar ecosystems in southern Europe are called ‘degraded forest’, meaning, presumably, forest from which some trees have been subtracted. The importance of wood-pasture in northern Europe, especially as the habitat of ancient trees and the creatures that specialise in ancient trees, has only recently come to be recognised. Staverton Park and Aspal Close, Mildenhall, are among Suffolk examples (Rackham, 1998a). This leads to questions about the nature of the boundaries between woodland and non-woodland. Was prehistoric wildwood just trees and trees and nothing but trees, or did it have a savanna-like component?

Management Historical knowledge establishes the genius loci of a site; what is special about it, how it differs from other sites, how it got into its present state, and within what limits it can be expected to change. This lays the foundation for maintaining it into the future.

If a site has been managed in a particular way for centuries, the obvious way to maintain its special features is to continue that management. Very good and specific arguments, at least, need to be produced before deciding to do something else. It is on this basis that conservationists maintaining coppicing, reject tree-planting, and uphold the difference between meadow (mown grassland) and pasture (grazed grassland).

Conservationists should not resort to drastic measures to remedy what they think is a deteriorating situation without understanding how it arose. A wood not full of young trees is supposed to be ‘not regenerating’, and some conservationists would go to any lengths to secure regeneration; in reality regeneration may normally be episodic, not happening all the time. In some other countries a conservationist’s first reaction is to suppress grazing in woodland, even if grazing is long-standing and an essential part of its ecology.

A corrective to changes of fashion Conservation, like any long-term human activity, is subject to the vagaries of fashion. In nature reserves, management plans are supposed to guard against unnecessary abandonment of long-standing practices, but they are easily circumvented or ignored by anyone wishing to introduce an innovation.

Historical ecology should provide an authentic reference against which to assess innovations. For example, replanting of woods in the 1950s and 1960s did vast, if often temporary, damage to ancient woodland. It was not sufficiently objected to by conservationists, because they accepted the foresters’ assurances that replanting was a normal woodland procedure. Little did either party realise that woods have a life of their own, and one day would defeat the foresters’ machinations (as happened with Reydon Wood among Suffolk Wildlife Trust reserves).



Almost any long-standing nature reserve or foreign National Park illustrates fashions in conservation. The history of the Yellowstone in America is a catalogue of human follies, from suppressing fires, to exterminating carnivores to introducing exotic fish (Chase, 1987). An example close to Suffolk is Hatfield Forest, which the National Trust acquired in 1924. Had it been a historic building, they would have done the most meticulous historical research to ensure that they maintained it authentically. But because it was land, they were unaware of what they had got, and did not investigate. It is a very well documented site, and even in the 1930s they could have discovered that the last surviving nearly complete royal Forest of medieval England had fallen intact into their hands (Rackham, 1989).

For many years the management of this complex wood-pasture site was regarded as a mere matter of taste. Pollarding was promptly stopped, but browsing (rightly) was kept up. The Trust continued coppicing, but failed to fence the coppices, so that cattle got in and ate the young shoots. They then let coppicing lapse on the plea of not enough money. The Trust’s historical knowledge extended back as far as 1923, when the Forest had been in the hands of timber-merchants who felled many of the big trees. Lacking the knowledge to set this felling in a historical context, the Trust regarded it as a tragedy and a disaster, which needed deliberate and drastic action to reverse it. This led to a period of bulldozing, tree-planting, and deals with the Forestry Commission, which were a greater breach of the traditions of Hatfield Forest and did much more damage than the felling.

Far be it from me to imply that the National Trust did particularly badly. Most other conservation bodies would have done worse. But only in recent years has Hatfield Forest been appreciated as one of the most historically significant of all the Trust’s properties, and received the care and research that would have been lavished on a building of equal significance.

One hears the argument that there is too much coppicing, to the extent that it threatens plants and animals sensitive to tree-felling (Hambler & Speight, 1995). It is the task of the historical ecologist to point out that almost all ancient woods have been coppiced for centuries, so that any such creatures will have died out centuries ago; and also to recognise sites that have not been coppiced before and that could still have them.

Restoration Restoration ecology, already a great industry in the United States, is beginning to take effect in this country, with many heathland and grassland restoration projects. This demands knowledge of what was there before and what is being re-created. It is easy to get money to set up a restoration project: it is much more difficult to do the decades of recording needed to find out how far it has been successful.

We all know the recent craze for planting trees. Over the past 30 years a tree-planting industry has grown up in the name of conservation. Very few have stopped to ask what exactly are the values attributed to existing trees, and whether the trees now planted will replicate those values in future. The values depend on the genetics of the tree and also on its treatment down the centuries.



In Moccas Park, Herefordshire, are the famous Beetle and Woolhope Oaks: both Quercus robur, but utterly different in appearance and in the habitats they provide. One is a medieval pollard, the other a giant upstanding tree of the 17th century. Is it possible, by planting oaks now, to ensure that these trees shall have adequate successors? How does one determine which oakling shall be a future Beetle Oak and which a future Woolhope Oak? (The rules of ‘local provenance’ for planted trees are supposed to deal with this problem, but so far have been of little use: the areas within which provenance is deemed to be local are far too large, and the rules are difficult to enforce.)

Restoration is not conservation, and easily degenerates into pastiche. The ‘restoration’ of the Great Caledonian Wood - the vast forest supposed to have covered much of the Scottish Highlands well into historic times - is dear to the hearts of Scottish nationalist politicians. They pursue this objective regardless of the protests of Scottish woodland historians, who point out that there never was a Great Caledonian Wood (Breeze, 1997). Is it possible to restore something that never existed?

Relation between biological conservation and conservation in general Biological conservation is a branch of conservation in general; others include that of historic buildings, archaeological sites, and manuscripts. Each branch ought to learn from the others, both in practical matters and in presenting its activities to the public. Archaeological sites tend to be good for wildlife, and wildlife sites tend to be good for archaeology.

There is some sign that archaeologists and ecologists are beginning to listen to each other (Macinnes & Wickham-Jones, 1992). Archaeologists are coming to realise that woods are not blank areas on the map. However, there are still periodic disasters when one branch of conservation forgets about the others. A tragic example that has just come to light is the repair of the Roman walls of Colchester. As well as being repaired (which was necessary), the walls were also cleaned with reckless rigour, doing great damage to a first-class lichen site (Earland-Bennett, 1999). Whoever organised the cleaning was apparently; ignorant of the lichens, which are just as much part of the archaeology as the stones and mortar themselves. It is shocking that this should have happened as recently as 1997; let it be the last time.

Kinds of Evidence

Pollen analysis Pollen analysis has been little used in Suffolk, though just over the border is Diss Mere, one of the richest sites in Europe. Pollen is the main source of evidence for prehistoric wildwood, but is less useful for the last 1000 years, partly because the craze for drainage has destroyed the top layers of many deposits.

There is a great potential record of recent centuries in the silt of ponds and moats. This in turn is now at risk because of the fashion for dredging out the silt of ponds, rather than digging new ones. In an ideal world one should investigate the silt before destroying it. Unfortunately this is a specialist task; pollen analysts have many calls on their time; and (as with other



archaeological deposits) it is better to leave the material undisturbed for future, more advanced investigation than to do a rescue study now.

Documents (Rackham 1998b) I have described written sources in The History of the Countryside. The earliest are place-names, many of which date back well over 1000 years, and often refer to woods, fens, heaths, trees, etc. Almost as early are the Anglo-Saxon perambulations, descriptions of the boundaries of estates, which mention specific roads, hedges, downs, trees, wood boundaries, etc. (A Welsh charter of c. 600 AD mentions a wood on the west side of Mount Skirrid near Abergavenny, probably the earliest record of an identifiable wood in Britain; it is still there.) Anglo-Saxon charters are the earliest written record of woodmanship and other kinds of land management. They are patchy in their geographical distribution; there are few for Suffolk.

Domesday Book is a description of landed estates throughout most of England, dating from 1086. The record for Suffolk is unusually full, including the woodland and meadow of each manor.

Detailed surveys of estates, with acreages, names of fields and woods, coppice rotations, etc., begin with the Ely Coucher Book of 1251. This enumerates the properties of the Bishopric of Ely, including Hitcham and Barking in Suffolk. In Barking the five woods which it mentions are still there (Rackham, 1990). Estate accounts begin in the late thirteenth century. Those for Staverton, for example, record money received for grazing in the park, sales of broom and holly (still a famous feature of Staverton Park), and surprisingly large amounts from sales of peat.

Large-scale maps begin c. 1580: an excellent example for Suffolk is that of Risby on the edge of the Breckland, which differentiates woodland from ‘pins’, fields full of pollard trees (Plate 2). Some accurate maps, such as that of Lawshall in 1612, are sources for the history of individual hedges (Rackham, 1985); often they show lines of trees across a field from an earlier hedge which had been grubbed out. Smaller-scale maps are unreliable and must not be accepted without being verified. The Ordnance Survey began in the 1790s, but inch-to-the-mile maps did not become wholly reliable until after 1820. The first edition six-inch and 25-inch of the 1870s and 1880s, however, are the most detailed and accurate maps ever produced.

Views and landscape pictures - both artistic and topographical are another source to be treated with caution. Artists vary in their ability to draw trees and scenery: Benninck, the fifteenth-century Belgian (Plate 3), did it much better than Gainsborough. Artists in general dislike depicting certain things, like open-field strip-cultivation and multi-stemmed trees.

Suffolk is well represented in early air photographs. In August 1940 Hitler photographed almost the whole county: the results are in the United States National Archives (Rackham, 1992a).

Botanical records for Suffolk begin with that of the Sea Pea (Lathyrus japonicus) by John Caius in 1555 at Orford Ness, still its chief stronghold in Britain (Halliday, 1999). Systematic recording for Suffolk begins rather late, in the late eighteenth century (Simpson, 1982).



Field archaeology Almost every wildlife site has at least some archaeology. The woodbanks that surround and sometimes subdivide woods are an essential source of historical evidence, complementing that of documents.

One needs also to recognise and map earthworks that reveal the previous land-use history of a site, such as moats, flint-mines, ridge-and-furrow (outside Suffolk), hillforts, and barrows.

Present flora and vegetation Historical evidence resides in long-lived trees and other plants (Rackham, 1990). Obvious examples are the giant coppice stools of the Bradfield Woods and the pollards of Staverton Park, some of which living trees go back to the middle ages. Less obvious are clonal plants, such as areas of elm or cherry within woods, which originated from a single, long-deceased tree and spread slowly outwards by root suckering. Herbs such as bracken, and fungi such as Armillaria, can form circular patches in the same way.

Plants can be characteristic of vegetation with particular kinds of history. To take a Suffolk example, the oxlip (Primula elatior) is characteristic of ancient woods; it spreads very slowly into new woodland, even adjacent to an ancient wood (Rackham, 1975). Small-leaved Lime (Tilia cordata) is very abundant in certain ancient woods near Sudbury, but rare in hedges - except in a hedge which represents the edge of a wood that has been grubbed out.

The historical ecologist looks out for discrepancies between old trees and their present environment. For example, where pollard trees occur in present woodland, other than on boundaries, they probably indicate that the wood grew up around what were originally free-standing trees: an example of the recent tendency of the world’s forests to get denser and savannas to turn into forest.

Historic buildings Some ancient buildings are related to the land-use history of a site. For example, Thetford Warren Lodge (in the Suffolk part of Thetford) is a massive building, almost a castle, and speaks of the importance of rabbit culture in the late-medieval Breckland.

Historic buildings also preserve samples of material. Timber-framed buildings tell of the species, sizes, growth-rates, etc. of the trees that went into them, and thus about medieval management of woodland and hedges. Wattle-and-daub gives similar information about underwood. A few thatched houses still preserve their original under-thatch, blackened with soot from the open hearth beneath; this contains actual specimens of medieval cereals and weeds (Letts, 1999).

Fallacies in interpreting historical information Ecological history is peculiarly productive of canards and factoids (Rackham, 1987). (Another factoid is the unsubstantiated belief that churchyard yews can be older than Christianity and inherited from previous heathen shrines.)

Historical ecology is history and ecology and both disciplines need to be treated with equal respect. Historians who are not informed about the



behaviour of plants and animals write pseudo-ecology. It is no good writing about woods being destroyed by people cutting them down or setting fire to them, without studying the local woods and finding out what happens after they are cut down, whether the trees will burn, and how they react to burning. Likewise, ecologists who fail to evaluate historical data write pseudo-history. Too often the historical side of the argument is reduced to a bald claim that ‘Ancient authors say that …..’, without specifying which ancient authors, what exactly they say, what the Latin words really mean and what are the grounds for believing them. In general ecologists have to make do with archives written for some other purpose than telling posterity what grew where.

It might seem obvious that an argument based on only historical or only botanical data is weaker than one that combines information from independent sources. But many historians still refuse to do fieldwork. and many ecologists refuse to study documents. I rarely encounter a site, even such an exceptionally well documented one as Gamlingay Wood, in which fieldwork does not reveal undocumented activities Rackham, 1992b). Historians who confine themselves to written arguments never learn what was happening at times when people were not writing. At the other extreme, ecologists like the authors of the National Vegetation Classification confine themselves rigorously to floristic data and pay little attention to structural, let alone historical, information. The result is a flat picture lacking all historical depth. as though there were no difference between the Bradfield Woods and a collection of Bradfield Woods’ plants.

The history of the countryside has to be built up from the individual histories of thousands of woods, fens, and hedges. The most useful documents are workaday ones that record specific actions like woodcutting or selling bracken. Contemporary generalisations, like the writings of John Evelyn, need to be verified and must not be taken at face value.

Although historical ecology as yet lacks a grand theory, like evolution, to which observations have to be made to fit, students should be on their guard against bending historical data to fit preconceived explanations. Palynologists usually assume that trees imply forests; protesting shouts from associated pollen-grains of non-forest plants are ignored. This is a preconception originating with the 18th-century Enlightenment, that the normal state of trees is growing close together in dense forests of tall straight trees, suitable for modern ideas of timber quality. In Europe there are three other possibilities: coppice-woods, savanna and maquis: there need to be criteria for discriminating between them (Grove & Rackham, 2000).

Some Conclusions

The fallacy of wholly-natural eocosystems Nearly all natural vegetation is part of a cultural landscape. in which human activities have interacted with wild plants and animals for thousands of years. Conservation involves understanding and paying attention to those activities. Some naturalists still talk of natural ecosvstems in the sense of ecosystems undisturbed by people. Even in other countries this is becoming an empty category as the extent and pervasiveness of the activities of what we used to



think of as primitive people becomes better known. Natural ecosystems are shrinking down to the categories of ‘ecosystems where the influence of human actions has not yet been investigated’.

Nor is it true. as a very recent writer put it, that ‘the countryside is an artefact, as man-made as a suburban garden’. There is a fundamental distinction between vegetation that has been planted or sown, as in forestry plantations and ryegrass leys, and that which has arisen spontaneously, as in woodland and old grassland. However, artificial ecosystems gradually lose their wholly artificial character as the years pass and wild plants and animals invade, as happens with plantations, ruined buildings and railway land. Even a suburban garden acquires some natural features with time.

One meets the argument that the duty of conservationists is to drop everything else they are doing and turn all their efforts to the preservation of wholly natural ecosystems. If one replies that this cannot be done in Suffolk or even Britain, where there are no wholly natural ecosystems, one is told that the proper object of conservation is restoring prehistoric wildwood. As a general objective this is unrealistic: we do not know enough about what the original wildwood was like (even the matter of forest versus savanna is debatable), still less do we know what it would have become by now if people had not interfered with it. It is clear that woodland does not turn back into wildwood merely if nothing is done with it: the commonest wildwood tree, small-leaved lime, does not recover lost ground. Non-intervention is a perfectly respectable object of conservation management, and even in Suffolk, where much effort has been put into restoring coppicing, non-intervention still covers a much larger fraction of ancient woodland than coppicing. However, it would be a great mistake to allow restored coppicing, the product of decades of research and investigation (Buckley, 1992), to lapse every time the wheel of conservationist fashion revolves round to non-intervention.

Recognising new and abnormal situations An essential basis of conservation is understanding the normal dynamics of ecosystems: distinguishing normal, but rare, events from events which fall outside normal dynamics. Is stag-head a normal feature of eucalypts? Or of oaks? Is Elm Disease an abnormality? Or is it something which happens to elms at long intervals, and to which their suckering behaviour is an adaptation (Rackham, 1986)?

Floods have been much in the news in recent years. Has there been a real increase? Or are floods better reported than they were? Or are people less cautious than they used to be in putting themselves and their property on flood-plains?. Do attempts to control floods aggravate the problem?

In America and Australia, it has long been recognised that fires are not a misfortune, but a normal part of the behaviour of vegetation; indeed. many plants are adapted to fire and will not reproduce without it. Is this true also of Mediterranean countries? Or are fires there a consequence of recent abandonment of farmland, which is then invaded by trees and plants, many of which (such as pines) happen to be fire-promoting? Is it reasonable of Spanish foresters to plant pines and then complain when they are consumed by fire before reaching timber size?



Stag-head, Elm Disease, floods, and fires are arguably part of the normal dynamics of landscapes, albeit sometimes aggravated by human activities. One modern feature which is definitely outside normal dynamics is artificially large numbers of deer. From the eleventh to the nineteenth centuries deer in Suffolk were confined to a few dozen parks. For reasons still unclear, this century has been particularly favourable to deer. The native red and roe deer and long introduced fallow now roam the landscape at large, and have been joined in eastern England by four species from the Fat East. This happens in other countries too: the United States are troubled by unprecedented numbers of white-tailed deer, Sweden by elk, Japan by sika deer. The landscapes of these countries, as they have developed over the last few hundred years, are being impoverished by numbers of deer beyond what the are adapted to.

Many conservationists, faced by proliferating deer, have urged ‘Bring back the wolf’. However, it is not clear that predation by wolves would indeed keep deer damage to a reasonable level. One of the most difficult tasks for the historical ecologist is to find out the level of browsing by wild beasts in prehistoric wildwood.

References Breeze, D. J. (1997). ‘The Great Myth of Caledon’ in Smout, C. (ed.) Scottish

Woodland History p. 47-51. Scottish Cultural Press, Edinburgh. Buckley, G. P. (ed.) (1992). Ecology and management of coppice woodlands.

Chapman & Hall. Chase, A. (1987). Playing God in Yellowstone: the Destruction of America’s

National Park, 2nd ed. Jovanovich, San Diego. Earland-Bennett P. (1999). ‘Colchester Walls’ Bulletin of the British Lichen

Society 851-854. Grove, A. T. & Rackham, O. (2000). The Nature of Southern Europe: the

question of desertification. Yale University Press. Halliday, R. (1999). A Suffolk miracle: the Sea Pea harvest of 1555. Suffolk

Review (New Series) 33: 37–46. Hambler, C. & Speight, M. R. (1995). Biodiversity conservation in Britain:

science replacing tradition. British Wildlife 6: 137-147. [See replies in British Wildlife 6: 337-338, 405, and by 0. Rackham in Tree News 1996]

Letts, J. B. (1999). Smoke Blackened thatch: a unique source of late medieval plant remains from southern England. University of reading.

Macinnes, L. & Wickham-Jones, C. R. (1992). All Natural Things: archaeology and the green debate. Oxbow Monograph 21, Oxford.

Rackham, O. (1975). Hayley Wood, its history and ecology. Cambs. & Isle of Ely Naturalists’ Trust, Cambridge.

Rackham, O. (1985). Ancient woodland and hedges in England in Woodell, S. R. J. (ed.) The English Landscape - past present, and future p. 48-67. Oxford.

Rackham, O. (1986). The History of the Countryside. Dent, London. Rackham, O. (1987). The countryside: history and pseudo-history. The

Historian 1413-1417. Rackham, O. (1989). The Last Forest: the story of Hatfield Forest. Dent,

London.



Rackham, O. (1990). Trees and woodland in the British landscape 2nd ed. Dent, London.

Rackham, O. (1992a) Woodland ecology in recent and historic aerial photographs. Photogrammetric Record 14: 227-390.

Rackham, O. (1992b). Gamlingay Wood. Nature in Cambridgeshire 34: 3-14. Rackham, O. (1998a). Savanna in Europe in Kirby, K. J. & Watkins C. (eds.)

The Ecological History of European Forests p. 1-24. CAB International, Wallingford.

Rackham, O. (1998b). Implications of historical ecology for conservation in Sutherland, W. (ed.) Conservation Science and Action p. 152-175. Blackwell, Oxford.

Simpson, F. W. (1982). Simpson’s Flora of Suffolk. Suffolk Naturalists’ Society, Ipswich.

O. Rackham Corpus Christi College Cambridge

Plate 2: Risby Pin, May 1980. A field full of pollard oaks (p. 5).

Plate 1: Polstead Park, August 1993. Stag-headed oaks. Is this condition due to

disease? Or damage? Or is it part of the normal behaviour of oaks? (p. 1).

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Plate 3: A scene attributed to Simon Benninck, the 15th-century Flemish artist. It

depicts a coppice wood with areas of one, two, and about twenty seasons’ growth

since last cutting, with underwood and standard trees of recognisable species (oak,

elm, aspen, and especially small-leaved lime. The surrounding country is of small

fields, thick hedges and scattered farmsteads. It looks very like Chalkney Wood,

Essex, and its surroundings today (p. 5).

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PURPOSES AND METHODS OF ECOLOGICAL HISTORY

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Transcript of PURPOSES AND METHODS OF ECOLOGICAL HISTORY