MODERN FORESTRY: ITS LEGACY
Plantations as Ecosystems
About 40 per cent of the vascular plant species in ancient woods have been unable to colonise new woodland even after 400 years, and there is no sign that they will do so eventually. While renewed attempts to plant more woodland on farmland are welcome because they create additional wildlife habitat, most of the characteristic and attractive plants of ancient woodland will not colonise without help.
G.F. PETERKEN
Plantations can have many different fates through design, accident or neglect. Weasenham Woods (west Norfolk), first appearing on Bryant’s 1824 map, have been nurtured by generations of the Coke family in the estate tradition, and are now famous among dendrologists for their magnificent conifers. Some of the conifers have become naturalised and grow from seed.1
Hafod passed to the commercial branch and became a Paradise Lost. The larches (or their successors) were felled in the 1940s in the ordinary course of business; the mansion was blown up as ‘unsafe’ in 1958; the Pensile Garden disappeared in Douglas fir plantations. By the 1990s only some beeches and the occasional cedar remained as stranded relics of the Johneses and Uvedale Price, plus one great pollard oak from a yet earlier period. The Hafod Trust was beginning the superhuman task of returning it to a Paradise Regained.
PLANTATIONS AND CONSERVATION
Objections to plantations are nearly two centuries old. Wordsworth the poet expressed a common sentiment:
Whole acres of artificial shrubbery and exotic trees among rocks and dashing torrents … the whole contents of the nurseryman’s catalogue jumbled together … But this deformity, bad as it is, is not so obtrusive as the small patches and large tracts of larch-plantations that are overrunning the hill-sides.
A GUIDE THROUGH THE DISTRICT OF THE LAKES, 1835
Taste is fickle: why did the relatively inoffensive larch incur such eloquent disdain?
In the third quarter of the twentieth century the Forestry Commission was scolded for spoiling mountain landscapes by ‘blanket afforestation’, for obscuring the detail of rock and bog with monotonous spruce and larch (or, worse, ‘pyjama-stripes’ of alternate spruce and larch), and for making incongruous sharp edges at property boundaries. They responded by hiring Dame Sylvia Crowe, landscape architect, to advise them on a more naturalistic layout of plantations. Besides these usually minor concessions to appearance, they altered their design in practical ways, such as by not planting the banks of streams to reduce the harmful effects on fish.
Forty years on, was it wise to object so strongly to blanket afforestation? Ought plantations to be scattered over the country, rather than concentrated in a few areas? Blanket afforestation intrudes on fewer views than pepperpot afforestation; it affords economies of scale for the foresters; and it allows plantation ecosystems – whatever they might be – to develop on a large scale and with a wider range of habitats and of possible sources of animals and plants. (Do similar considerations apply to wind farms, now being objected to on similar grounds to plantations?)
In its early years the Commission was blamed for destroying antiquities. This has been rectified; constraint maps of plantations include antiquities among the features that limit operations.
Despite the huge increase in woods and plantations in the past 150 years, tree-planting is more popular than ever, as all conservation organisations know. Creating new woodland by letting ‘scrub’ take over abandoned land has been forgotten, although it happens daily before the eyes of millions of commuters on trains.
Motives (other than pleasure or profit) for plantations
In other countries, plantations have been made or forests preserved for environmental reasons. It has been widely believed that trees attract rainfall, prevent floods and prevent erosion. Thus Richard St Barbe Baker, founder of Men of the Trees (now the International Tree Foundation), encouraged tree-planting all over the world, beginning in Africa.
The belief that trees increase rainfall had a scientific basis: John Woodward in the 1690s and Stephen Hales in the 1720s observed that trees transpire water vapour into the atmosphere, which returns in the form of rain. Well into he twentieth century savants claimed that deserts were created by people destroying trees. Baker in his early career was sceptical on this point, but later claimed to have demonstrated the increase of rainfall by measurement.2 The effect is real, but probably so small as to be lost among the ordinary fluctuations of rainfall.
The beliefs that forests prevent floods and prevent erosion are still alive. In Japan, where there may be some truth in them, they apparently originated independently of European influence. Baker made deserts his mortal enemy; his Men of the Trees hoped to ‘conquer’ the Sahara.3 (What happened to their trees? Did they conquer the Sahara? Have the vast tree-planting schemes in China held back the deserts?) These arguments are at their weakest in Britain, where it is difficult to argue that floods and erosion have much to do with lack of trees.
At the time of writing an oft-cited motive for tree-planting is to lock up carbon dioxide and thus reduce global warming. This, too, is a matter of scale: Britain is too small to make an appreciable difference.
PLANTATIONS ON NON-WOODLAND SITES
Are plantations really woodland?
At least nine factors may influence secondary woods:
A full study would involve all these in different combinations. Published studies seldom deal with more than two factors at a time, or with plantations more than 50 years old.
Most plantations, especially small ones, pass through a period of neglect. Neglect is part of the essential anthropology of plantations, and should be provided for, not dismissed as an unfortunate lapse that will never happen again. Any plantation, especially a neglected one, is subject to natural succession as is a neglected field or heath and, if left long enough, will acquire some of the characteristics of a wood. The Sandlings pine plantations in Suffolk, when blown down in 1987, turned out to be full of young oaks. Even moorland plantations can be invaded by birch and rowan.
A highland example: Burrator
Burrator Reservoir, on the edge of Dartmoor, is surrounded by plantations created by Plymouth Corporation on moorland-edge farm grassland, mainly from 1925 to 1965. The plantations were very piecemeal, mostly of a variety of conifers. They fluctuated between management and neglect until much of them was harvested after the great storm of 1990.
The ground vegetation developed with the age and species of the canopy. Most conifers (even the deciduous larch) went through a thicket stage with no herbaceous plants; as they got older and let through more light they were colonised by grasses, bracken and heath bedstraw (Galium saxatile). What resulted was, in effect, a weak grassland with trees. Only a few woodland plants appeared: wood-sorrel, occasional bluebell, and foxglove (a buried-seed plant in felled areas).4
This supports my own impression that highland plantations preserve an impoverished fraction of the preceding flora, rather than developing much woodland vegetation of their own. (Oak plantations may preserve more of the preceding flora than conifers.) They can be colonised by wood-sorrel or Luzula sylvatica, less often by Dryopteris ferns or raspberry, and sometimes develop a bryophyte flora different from moorland; however, they resemble moorland-with-trees rather than woodland.
Plantations on heathland: fungi
Much of the Forestry Commission’s activity in the 1930s was on heath or poor arable land, especially in the Breckland, east Suffolk and Dorset. They continued the heath plantations of past centuries.
At first sight heath plantations seem to lack a distinctive flora. Remnants of heathland survive precariously on rides, and if the canopy is not too dark a few moderately shade-tolerant plants such as the sedge Carex arenaria spread under the trees. Even old-established, coppiced plantations such as Emily’s Wood in the Breckland have not much of a woodland flora.
There are a few exceptions. There was a sensation in the nineteenth century when Goodyera repens, a rare orchid of Caledonian pinewoods, turned up in pine plantations in north Norfolk. It still persists, and has also spread into pine plantations in Scotland: maybe it shares mycorrhiza with the pines. In the 1960s the big pinewood mosses Rhytidiadelphus loreus and Ptilium crista-castrensis turned up in 40-year-old pine plantations in Breckland. These remain a mystery: although spores could have come on the wind they are rarely produced. (Will the mosses survive the felling of the plantations?)
Fungi colonise more easily. John Rishbeth found in the 1950s that Breckland pine plantations on ex-farmland were menaced by honey-fungus (Armillaria mellea in the strict sense). It came either from spores germinating on stumps after thinning or by clonal spread from existing mycelia in the hedges.
Brandon Park in the Suffolk Breckland is a country-house park, founded c.1805 on treeless heath or strip-cultivation. Its nineteenth-century plantations were partly infilled by the Forestry Commission with Scots and Corsican pines c.1935. There are fine middle-aged beeches, Scots (not Caledonian) pines and larches. Flowering plants comprise considerable remnants of Breckland heath and grassland, but no characteristic woodland species.
I have recorded visible fungi there nearly every autumn since 1959. The list is still growing; at 469 species it is comparable in numbers with the ancient woodland of the Bradfield Woods (where, however, there has been less recording effort).
Over 200 years Brandon Park has acquired a respectable list of fungi, many of them specialised to particular trees (Table 23). (For details of the mycorrhizals see Table 5.) Grassland and heather fungi could have survived from the previous vegetation – although much of the grassland has probably undergone a period of fertilising. Beech, which could be native to Breckland but not here, is the predominant host of mycorrhizals and litter-decomposers, although it is not the commonest tree. Pines have acquired many ground fungi and predominate among the wood-rotters. Even larch and cedar, natives of distant lands, have acquired some specific fungi. Oak, however, has rather few as yet. The fungus flora is probably still incomplete: in its native Alps larch has a wide range of mycorrhizals comparable with pine.
There have been some changes. Fly agaric (Amanita muscaria), mycorrhizal with birch and pine, used to be common, but I have only once seen it since 1992. (The absence of fruit-bodies does not prove that it is not there.) A. rubescens, common in the 1960s, last turned up in 1995. Collybia peronata and Helvella crispa, on beech litter, have become commoner since 1975. Many litter fungi and mycorrhizals used to be abundant in pine plantations up to 60 years old, but where these have been invaded by the sedge Carex arenaria very few agarics are now visible. I am reminded of the Japanese work on Tricholoma matsutake and its relation to the vegetation in pinewoods.
Have Sitka spruce, Douglas fir and western hemlock brought any mycorrhizal fungi from the eastern Pacific? If so, would this be an ecological gain, or a mere stage in mixing up all the world’s fungi? Should the conservation of such fungi, if needed, happen in Scotland or in Sitka?
As far as can be told, modern forestry has a bad effect on lichens. It destroys or weakens rock- or soil-growing lichens. By dealing in young trees, it favours quick colonisers that are already common.
Plantations and animals
Plantations are claimed to benefit birds and mammals. Much of what has been said is either vague and general or based on analogies with ‘similar’ natural forests in other countries. Many of the beneficiaries are species that are already common (in the case of deer, too common): for example rook and pheasant make use of plantations as well as all their other habitats.
It is plausibly claimed that the survival of the red squirrel depends on conifer plantations: the grey squirrel is a species of deciduous woods whereas the red is adapted to pinewoods.5 If so, how did red squirrels flourish in the long centuries when there were no pinewoods south of Perth? Or did they? Could the native red squirrel be extinct, replaced by a Continental lookalike imported in the eighteenth century when numbers were low?
Many birds require trees, often a particular structure of trees, but have little preference for species. Plantations benefit these through an increase of trees in general. A few such birds have increased dramatically: the goshawk is well established in plantations in Wales, south Scotland and Breckland. Among conifer specialists, crossbill (Loxia curvirostra) is now widespread in big plantations all over Britain and Ireland. However, the Scots endemic species of crossbill (L. scotica) has not correspondingly increased: it appears to require old pines, which forestry does not provide.6 Capercaillie, another conifer bird, is faring badly; blackcock is encouraged by young plantations, but then disappears. Goldcrest and firecrest are less strongly associated with conifers than they once were. Poplar plantations on Lakenheath Fen, Suffolk (the only big plantations in the Fens) were colonised by the golden oriole, a fabled songster, a summer migrant spreading northwards into Europe. However, many woodland species require old, rotten or dead trees, which forestry provides only through neglect.
Forestry disfavours birds limited to open ground; but the bustard disappeared from heaths long before plantations encroached on them, and the stone-curlew depends more on Breckland cultivation than on heathland. Another heath bird, Dartford warbler, is deterred by any trees, whether forestry or wild.
Moorland birds
The Flows of Caithness and Sutherland are the nearest that Britain has to wilderness, a vast peaty tundra beyond the present natural limit of forest. They were the scene in the 1980s of a curious perversion of commercial forestry. As forestry terrain they are comically worse even than Rannoch Moor. Speculators brought out all the resources of technology to get trees to grow where nature did not mean them to, the trees being not veneer-quality oak or even Sitka spruce, but mere lodgepole pine, nearly useless and very liable to insect attack. The motive was not to grow cellulose, but to exploit a temporary tax loophole.
This affair attracted the wrath of the European Union because the Flows were the chief stronghold of greenshank in the Union (before Sweden joined!). There was plenty of theory on what moorland afforestation ought to do to birds, but little evidence. From what there was, C. Lavers & R. Haines-Young identified a dozen other species likely to be affected. Not all were equally at risk: some, such as golden eagle and buzzard, flourish elsewhere.7
Whether birds are displaced and what happens to them – whether they vanish or crowd in somewhere else – varies from species to species. Effects may not be limited to the mere subtraction of area: birds like dunlin avoid not only plantations themselves, but moorland in their vicinity.
Conclusions
Aquatic birds increased dramatically in England in the last hundred years, partly because of new gravel-pits and reservoirs. The increase in plantations has had less effect. It has reduced the habitat of some heath and moorland species, has brought back the goshawk, and has probably made some common species a little commoner. As with plants, neglect – deliberate or accidental – would improve the habitat. Blanket rather than pepperpot afforestation might have reduced the adverse effects and possibly increased the benefits.
For other animals there is less evidence. Conifer woods have a complex ecosystem of insects and spiders in the canopy, which conifer plantations to some extent reproduce. Broadleaved trees have similar creatures if there are shrubby lichens in which they can feed and hide. C.M.P. Ozanne and others have found strong edge effects in spruce and pine plantations. Thrips, for example, are largely confined to within 70 feet (20 metres) of the edge of a plantation, whereas some sensitive species avoid this zone.8 Too little is yet known to put this observation into a wider context. Compared with tropical forests, these studies have been relatively neglected in Europe.
PLANTATIONS REPLACING EXISTING WOODLAND
Nineteenth-century plantings
The effects vary according to whether the planted trees lived, whether they were harvested, and what happened after the harvesting. At one extreme, after two cycles of replanting, a wood may be unrecognisable as an ancient wood, even the stumps having disappeared.
There are four possible fates for Victorian conifers. Some are still going strong, for example the ragged Abies grandis towering over an ancient wood close to a mansion, or yew as a specimen tree at a junction of rides. Some have died out or been felled and their stumps rotted away, but often a few survivors or mouldering logs remain: in Madingley Wood (Cambridge) a dwindling band of spruces remains from a planting of c.1870. Some have disappeared without trace, as in Gosling’s Corner, a fragment of the ancient Langton Wood east of Lincoln, where scattered conifers shown on the 1886 Ordnance Survey have vanished and native woodland has closed up the gaps. Some have turned into birch (Fig. 206). The spread of birch in the twentieth century was helped by plantings in the previous century, which when they died made openings for the birch. In the Bradfield Woods (Suffolk) a patch of conifers is now a patch of birchwood with a few oaks; by 1973 a few stumps were still visible, but any specific larch or spruce mycorrhizal fungi were defunct.
Replacing wild with planted oaks
The most widespread legacy of nineteenth-century forestry is the substitution of foresters’ for wild-type oaks. This was part of a process that increased during the twentieth century (Chapter 13). Replacement partly overlapped with the (Oak Change), the loss of oak’s ability to regenerate in woodland, for which foresters were not responsible. Did the loss of wild oaks (from a large minority of ancient woodland) matter?
Wild-type oaks are part of a wood’s integrity, appearance and value as a habitat. It is part of the meaning of oak that oaks should not all be the same. It is irregularities that make oak such an excellent habitat for other wildlife. The accumulation of epiphytic ferns and bryophytes in western oakwoods, the nearest that Britain has to the massive ‘fern gardens’ high in the canopy of tropical forests, calls for trees with stout horizontal branches. Replacing wild-type oaks with uniform oaks of good timber quality (as a past century defined timber quality) was part of the homogenisation of woodland and the loss of local variation – within woods and from one wood to another – that conservationists would now resist.
Oak-replacement woods, however, include some nature reserves and Sites of Special Scientific Interest. Scientists and the public persuaded the early Forestry Commission to retain much of the oak plantations of Dean and Alice Holt in the belief that these were the historic state of these Forests. Oak-for-oak replacement was not an ecological catastrophe, nor are wild-type oaks essential for a wood to be a nature reserve. But this is a factor that conservationists should routinely include in assessing the qualities of woods proposed as nature reserves, and in preparing management plans.
Twentieth-century replanting
Successful replantings: Borley Wood, south-east of Cambridge, is a big ancient wood (128 acres/52 ha). It is one of the drier boulder-clay woods, with patches of gravel. Two round barrows in the wood show that its prehistory was not simple. It had been mainly maple-wood, with ash and hazel and patches of elm, last coppiced in the 1920s. In c.1966 nearly the whole wood was felled and much of it grubbed out, leaving grasses and rosebay willowherb. The Forestry Commission then planted Corsican pine, Norway spruce and beech.
This had the makings of a successful replanting, favoured by a well-drained site, the use of Corsican pine, and the trouble taken to eliminate existing trees. By 1997 the growth of the planted trees had seen off most competition: of native trees, little remained except for a scatter of elm and maple and a few surviving ash stools. Dog’s-mercury carpeted much of the ground; bracken and bluebell had probably somewhat increased. The flora was comparatively rich, but mostly on rides, and contained few distinctive species. Primrose persisted, but oxlip (never abundant) was not found. Distinctive species included deadly nightshade, a characteristic plant of woodland disturbance.
This is one of the few coniferisations with data on fungi. A fungus foray in 1999 found roughly equal numbers of residual species from the original wood and newcomers associated with the conifers. Residuals include a number of wood-rotters on elm, the tree of which there are most survivors. Mycorrhizal fungi were lacking, either of native trees or conifers; this in a season when Russula, Lactarius, Laccaria and Boletus were fruiting moderately well elsewhere. To judge by this one year’s observations, Borley had lost the mycorrhizal agarics from the original wood without gaining those of the planted trees.
Nearby is Ditton Park Wood (185 acres/75 ha), a former ash–hazel-wood with some maple, a wet wood with extensive oxlip and meadowsweet as well as dog’s-mercury and a small bracken area. Apart from the name it has little to show for its medieval history as a park. It was long reputed the wood with the richest flora in east Cambridgeshire, and in the 1950s was declared a Site of Special Scientific Interest. Notwithstanding, it was replanted in 1957–8; some original trees were left standing, to be poisoned later. Many different conifers were planted, besides oak and beech. The county Naturalists’ Trust, in its report on SSSIS in 1965, made the best of a bad job: ‘It is hoped that the retention of a wide diversity of habitats will enable future generations of botanists to grasp something of the whole range of habitats which occurred in the past.’ This was not to be: the conifers grew only too well, and by 1976 I recorded fewer than half the plants known in the past – most of them on rides.
Much of the plantation was plucked out in the great storm of 1990, and the remainder, approaching commercial maturity, was drastically thinned, leaving planted oak and self-sown ash. Another threat to the flora emerged as Carex pendula, the aggressive sedge which suppresses most other plants and is encouraged by deer, took over thinned areas. In shade, dog’s-mercury and meadowsweet persisted in an attenuated form, but under dense Norway spruce little survived. Oxlip was much reduced.
Simon Leatherdale discovered two lime stools, the only native lime on the Cambridgeshire–Suffolk border, overlooked by all previous botanists. Lime is very resistant to replanting, and this was probably all that there had been.
Stanstead Great Wood, near Long Melford, was one of the biggest ancient woods in Suffolk: a hazel–ashwood on acidic sands and gravels as well as boulder-clay. It was planted in 1960–4 with Corsican pine, Douglas fir and western red cedar. In 1967 it was sprayed Vietnam-style with 2, 4, 5-T from a helicopter: apparently a unique event, for this notorious ‘Agent Orange’ poison was banned shortly after.9 This either killed the underwood or, more likely, gave the planted trees (which were relatively resistant) a competitive edge. By 1981 some stools survived, but most of the native trees were self-sown birch and sallow. The flora, though quite rich (again including deadly nightshade), was largely confined to rides.
Donald Pigott investigated a wood at Leith Hill, Surrey, an apparently ancient wood partly of oak–holly with bracken and bramble on acid soils, and partly of less acidic hazel–ashwood with dog’s-mercury and bluebell. Part of both types had been replanted by the National Trust [!] in 1957–8 with rows of sessile oak and Norway spruce or Douglas fir, the latter intended as a nurse crop. It was recorded in 1986, just before the great storm plucked out most of the conifers. Compared with intact parts of the wood, common woodland plants without long-lived seed, such as bluebell, anemone and bracken, disappeared from under the conifers, patches of oak acting as refuges. This Pigott interpreted as mainly an effect of the dark shade of spruce and fir, rather than of alteration to the soil. Only wood-sorrel benefited from replanting (as I have found elsewhere). After the storm, buried-seed plants, such as rushes, foxglove, woodrush and wood-sage emerged, as if after a coppicing.10
Partly successful replantings: Gamlingay Wood was recorded before planting (Chapter 21). Several methods of replanting were used, and parts were left unplanted. Many of the planted trees survived and produced a little timber. The effects, both on trees and on the ground vegetation, were complex and not altogether expected.
In the first 40–50 years, planting was good for birch (though birch was not planted) and bad for aspen. It was bad for oxlip (which additionally declined through increasing deer damage) and good for bluebell and dog’s-mercury, as well as creating its own plant communities of relatively fertile and well-drained soil. It bore out the theory that replanting a wood damages its individuality and promotes commonplace plant communities at the expense of rare ones. However, the survival of so much of the original wood is due to this being, in forestry terms, an unsuccessful replanting.
Reydon-by-Southwold Wood (40 acres/16 ha) is one-half of an ancient wood in the northeast Suffolk hornbeam area. It was apparently a hornbeam–ashwood with patches of hazel. In 1960 a forestry company severely replanted it with conifers, especially the darkly shading Lawson cypress. Being a small and remote plantation it was neglected. Native trees reasserted themselves: some were surviving coppice stools, but predominantly they were self-sown ash and sallow. For a time the ground vegetation was very attenuated. In 1985 Suffolk Wildlife Trust bought the wood and began coppicing and removing conifers. This brought back much of the original flora, which had probably survived as buried seed.
Failed replantings: Shrawley Wood, Worcestershire, is probably the biggest limewood in England (340 acres/137 ha). Most of it is nearly solid lime (including one of the tallest native trees in the kingdom). It is such a remarkable place that before limewoods were well known it was supposed to be a plantation.11 (The ‘evidence’ cited, that the lime stools are in rows, and that there is no lime in the surrounding country, was erroneous.) Some of the lime grows in huge rings. In the 1530s it had been a wood with common-rights of woodcutting, divided into ten named coppices.12 Later, the lime poles were used for the curious metallurgical practice of poling copper: stirring the molten metal with green wood, which as it chars reacts with impurities.
Shrawley Wood fell into the hands of the Forestry Commission and was given the usual treatment. But Agent Orange here met its match. By 1985 Shrawley was back to being a magnificent limewood, and one had to look carefully for miserable remains of conifers.
The most evocative of limewoods is Lynwode Wood, Lincolnshire, by the lonely church and deserted village of Lynwode, named after the wood; John Lyndewode’s funeral brass of 1421 bears his arms, ‘a chevron between three lime-leaves proper’. This received the usual treatment from the unreformed Commission: George Peterken told me ‘the air was acrid with herbicides’. But here too the lime-trees won. In 1993 they were alive and flourishing and beginning to overtop the drought-bitten Norway spruce. By 2005 most of the conifers had gone, revealing huge rings of multi-stemmed lime. They still bear the scars: each stem is hollowed into a kind of dugout canoe, the result of an assault on one side with a jimjam, a kind of poisoned axe.
Oak, beech and birch were easy to kill, followed by chestnut; hazel, maple, ash and hornbeam were intermediate; lime was apparently impossible. However, before poisons the order may have been different. In some of the Markshall Woods (Essex) the original limewood was replaced in Victorian times by chestnut, leaving strips of lime round the edges. The woods were later coniferised; they now have small dead stools of chestnut in the interior, lime round the edges, and occasional lime stools in the interior that survived both replantings. The nineteenth century had more success in getting rid of lime than the twentieth.
Conclusions
Effects of replanting vary from trivial to catastrophic. Whether the planted trees survive and whether they become dominant depends on the species previously existing, the species planted (Table 24), the site, and the degree of maintenance or neglect. To generalise from copious but unsystematic information, in eastern England the only planted trees likely to grow into timber on the site of an ancient wood were Corsican pine and oak. (Corsican pine, a Mediterranean mountain tree, resists both cold and drought.) In the West Country conifers from the eastern Pacific could be successful. Success was most likely on well-drained slopes or on the site of oakwoods; on flat clay sites or with limewoods the work swallowed up endless labour and was abandoned unfinished. The unreformed Commission put all the resources of science into destroying lime, and (as far as can now be told) had a success rate of zero.
Effects on ground vegetation depend on shade and leaf litter. At Gamlingay, poplars, inserted in rows among existing underwood, had little discernible effect. But Thuja occidentalis, almost as shady as a photographer’s darkroom, eliminates all herbaceous plants. Spruces are nearly as bad. Corsican pine allows an attenuated set of herbs to survive. However, well-grown beech and oak plantations attenuate the ground vegetation by their long-lasting leaf litter. Beech can be almost as destructive as the more densely shading conifers. In Great Gransden Wood (Huntingdonshire) a dense oak plantation allowed oxlip and bluebell to survive, but eliminated most of the rest of the oxlip–bluebell guild.
A successful plantation is homogeneous and eliminates the patchiness that is an essential characteristic of ancient woodland. Even small areas of failure – surviving coppice stools or birch or ash invasion – break up the monotony and retain woodland plants. (Do they retain woodland animals? This would be an interesting study in island biogeography and the survival of small populations.)
Replanted ancient woods may retain woodland grassland on rides. An extreme example is Bernwood Forest (Oxfordshire), a sad remnant of what was once a compartmental Forest like Hatfield, but a famous butterfly site and a National Nature Reserve on the strength of its grasslands.
RESTORATION
And I [the LORD] will restore to you the years that the locust hath eaten.
JOEL 2: 25
As in ancient Israel, the Locust Years were not to last for ever. Many commercial forestry plantations have come up to saleable size. The trees will die on felling; the economics of replacing them are dubious. Why not try to regain wild vegetation?
Heathland is now internationally rare; the fragments of it in England are an appreciable part of all the heath in the world. Conservationists have long been interested in preserving the remaining heath, and now in recovering recently lost heath. Much heathland restoration starts from farmland or recent natural woodland, but some replaces plantations.
‘Brandon Park Heath’ (Suffolk Breckland) is on the site of about 150 acres (60 ha) of Corsican pine on blown sand. The pines were planted by the Forestry Commission c.1950; some blew down in 1987 and others were felled later. The area was fenced to allow sheep-grazing, to prevent it from turning into a natural wood as birch and pine seedlings colonise. By 2004 heather was reasserting itself, some from survivors on rides, some from buried seed dormant for 50 years. Carex arenaria, becoming dominant under the plantations, has declined, replaced by the grass Deschampsia flexuosa. Earth-lichen communities, a special feature of Breckland, have become prominent again.
Moorland is still so widespread that its restoration from plantation is not yet high on the agenda, with one notable exception: the Royal Society for the Protection of Birds has begun the huge task of getting rid of the ill-fated conifers from the Flow Country.
Unreplanting or deconiferisation
In the Locust Years, ecologists like myself wrote off about 40 per cent by area of ancient woodland as irretrievably lost to replanting: we accepted the foresters’ claims to have killed off the trees, and shook our heads at the decline of plant life as the planted trees closed in. As time went on, we grew less pessimistic. Many woods were not so easily destroyed; the planted trees declined and native trees returned. Maintenance failed; rabbits devoured and squirrels crippled the beeches; the great summers of 1975–6, 1989–90 and 1995 took their toll of Pacific conifers and Norway spruce; even Corsican pine suffered from bark beetles.
In the 1980s the Commission, under a political cloud, sold many of its freehold woods. This was using the funds of one public body to pay the debts of another, for some of the woods were bought by county wildlife trusts with grants from the Department of the Environment.13
This opened opportunities for deconiferisation. Worcestershire Wildlife Trust bought Tiddesley Wood, a 230-acre (93 ha) wood near Pershore. This had been replanted with varying degrees of success. In places there was enough timber in the planted trees to be worth selling or growing on; in other places the conifers were alive but worthless, and in others there were only traces of the planting.
Chalkney Wood (Earl’s Colne, Essex): This brings up to date a story that I have told elsewhere.14 Chalkney (184 acres/74 ha) is one of the great limewoods of England, but includes areas of hornbeam, ash–hazel, and four steep little ravines with alder on flushed boggy slopes. It is one of the few woods to have records of its underwood composition going back 400 years. It had been the manorial wood of the Earls of Oxford, who liked to be thought of as swine: they imagined their family name, De Vere, to come from the Latin verres, a wild boar, which they bore as their crest and badge. In the later Middle Ages they made the wood into a park for wild swine.
In 1955 it was made a Site of Special Scientific Interest. (Why this one, out of about 30 limewoods in north Essex? Possibly because Sir Harry Godwin, the great ecologist, happened to know it; but one cannot disagree with the choice.) The Forestry Commission acquired two-thirds of it and applied the usual treatment. Limes and hornbeams were jimjammed; beech and a surprising variety of conifers were planted. Colin Ranson, the Nature Conservancy’s man in Essex, and I watched with weary dismay as the wood seemed to decline into just another tree-farm.
The remaining one-third of the wood belonged to three sisters, two of whom continued to coppice the underwood. In 1973 it was acquired by Essex County Council as a public open space. They have continued coppicing, making this a classic wood for buried-seed plants.
The years rolled on. Chalkney, an outlying Commission property, fell into neglect. The planted trees, except Corsican pine, suffered setbacks and lost to the native trees; in some parts self-sown ash replaced the planted trees. The attitude of the Commission was changing: I found myself arguing on their behalf to retain the wood as an SSSI, on the grounds that they had failed to destroy its scientific interest. In 1989 their staff were planning the restoration of the wood. I argued that there was no great urgency to remove the conifers: most of the damage that they were likely to do had already been done.
Markets were found for the conifers, and as I write only a few Corsican pine remain. The wood changed, as if by magic, from a poorly grown plantation back to a magnificent limewood. Virtually all the limes have survived, many with jimjam scars as at Lynwode (Fig. 151). Surprisingly many surviving hornbeams and other trees have emerged. Buried-seed plants reappeared: the rare sedge Carex strigosa was, for a time, one of the most abundant. I sense a degree of friendly rivalry between the two owners in showing off Chalkney Wood to the public as an example of their styles of management.
Woodland restoration as Forestry Commission policy
Chalkney was a good place to start. The planted trees would have had to go while there was a market for them, and the native trees had put up a stout resistance. It was soon taken up all over eastern England, often with woods in a much more difficult state than Chalkney.
Unreplanting is not always straightforward. At Rowney Wood, near Saffron Walden, subtraction of conifers reveals a monotonous stand of oak, planted with them, but little surviving underwood. The ground has been taken over by Carex pendula. The wood is distressingly uniform, without the diversity that it must once have had.
Deconiferisation was put in hand in most of the Commission’s ancient woods in the Midlands. Potton Wood in Bedfordshire (209 acres/84 ha) was where the replanting movement finally ran itself into the ground. Like Hayley, it is on a boulder-clay plateau that floods every wet spring. By the 1980s nearly half the area was abandoned as unplantable. Norway spruce grew for a time and then succumbed to droughts. After the great summer of 2003 there were more dead than alive; and as I write I hear that they have all gone (as have those in Ditton Park Wood). There is a population of oxlip that has increased – the only one in the county – despite fallow deer.15
I used to be told that successful plantations, even on Sites of Special Scientific Interest, ought not to be sacrificed to conservation interests. To this I would reply that a plantation, if successful, is likely to have been deleted as an SSSI. But even successful plantations rarely perpetuate themselves: the planted trees will be felled in the normal course of business, and the economics of planting another generation on an ancient woodland site are weak.
Estate forestry
This is the branch of modern forestry that appeals to the public. The Commission’s most popular sites tend towards the estate tradition or inherit the estate forestry of previous owners. Should there be more of it? If so, should it take over ancient woodland or former farmland?
There are four main objectives: timber production (usually ‘quality’ timber); wildlife conservation; amenity; and gamekeeping. Estates combine these in various ways. Some set an example: they employ excellent ecologists, scrupulously distinguish between plantations and ancient woods, and invite the public to see what they are doing. Others are secretive and carry gamekeeping to excess.
The values of ‘conserving wildlife in woodlands’, mainly within the estate-forestry tradition, are set out by Esmond & Jeanette Harris (1991). Estate foresters can be vague about what they are conserving and why it needs to be conserved; it may mean little more than making a few common birds even commoner. Many of them fail to appreciate the conservation of ancient woods themselves: that some woods are wildlife and that each one is different. Ground vegetation and archaeological features survive, or not, by chance. As I have remarked elsewhere,16 well-run estate forestry can very effectively drain out the meaning from an ancient wood, turning it into a grandiose tree-farm, with some trees of magnificent size, but leaving nothing older than one generation of planted trees.
Gamekeeping has its place: it promotes coppicing and woodland grassland, and produces excellent meat. Gamekeepers used to treat buzzards and polecats as deadly enemies, and a few still have brushes with the law over hen harriers. They created one peculiar ecosystem, gibbeted strings of sun-dried crows, stoats and grey squirrels and the special insects that inhabit them. Unfortunately there is a perversion of gamekeeping that breeds pheasants like battery chickens, in numbers such that even the shakiest marksman can hardly miss, and pays little attention to their eating quality. With this goes ‘cutting back the undergrowth’ by machinery, reducing a wood to a scatter of timber trees over tussocky, strongly competitive grasses and sedges, which is then particularly attractive to deer. This method of destroying a wood is legal as long as none of the trees cut is big enough to come within the scope of a felling licence.
If all estate forestry were up to the standards set by the best estates, I would not hesitate to recommend it as a model. My enthusiasm is tempered by the thought that of the few examples of degradation of ancient woodland by human agency I have seen in the twenty-first century, all but one have been within the estate tradition.
RESEARCH
Unless the original vegetation was recorded, it is virtually impossible to predict what had been lost.
C.D. PIGOTT, 1990
Plantations now cover about one-tenth of Great Britain, about one-third of the area of arable crops. This huge change to a new ecosystem in 120 years has attracted controversy, but remarkably little relevant research. Not that research on plantations is lacking, but it is mostly related to the planted trees and mostly to well-managed plantations. The examples that I have drawn on for this chapter could be multiplied, but would not amount to a systematic collection of data. Most plantations were not recorded before planting, so the consequences are not fully known.
Wildlife is not something homogeneous that can be discussed or provided for as a whole. Flowering plants respond differently from fungi, and one bird responds differently from another bird. The subject is far too complex to be resolved by a mere appeal to superficially similar forests in other parts of the world.
Do planted trees wage chemical warfare against their competitors? Pigott quotes a German study to show that the leaf litter of larch contains growth inhibitors, which may explain why little grows under larch although it is deciduous.17
A rudimentary scientific study would involve dividing a site, part to be planted and part not, studying each part before planting and after the plantation was fully developed, and comparing the effects of planting with those of not planting. Gamlingay Wood (p.405f) is probably the nearest there has been to such an investigation, involving several kinds of planting. Even it left much to be desired, especially in that two different people did the observations, and methods of recording had progressed in the interval. Would that I had had Adamson’s original field notes from 1911 instead of having to make do with the selection of his observations that he published!
The constraints are anthropological (Chapter 22). Who, as a student, will record an area about to be planted and follow through its ecology over the next 60 years? But amateurs may succeed where professionals fail. Young readers are urged to begin recording sites or to continue records kept by parents and teachers. Nothing complex is needed; lists and photographs – with notes sufficient for the exact spots to be found again in the future – are far better than nothing.
Plantations are clearly not adequate substitutes for ancient woodland even if they consist of native trees. Farmers should give priority to conserving ancient woodland if they are lucky enough to own some, and developers should not pretend that plantations are adequate substitutes for ancient woodlands which they propose to destroy.
All this does not mean that plantations have no value for conservation. They are enormously better for wildlife than arable fields or grass leys.
N.W. MOORE, 2002