- Deforesting the Earth: From Prehistory to Global Crisis by Michael Williams
Chicago, 689 pp, £49.00, January 2003, ISBN 0 226 89926 8
A new wave of forest clearance is now spreading across eastern Amazonia, driven partly by the European preference for non-GM soya. Siberian forests, meanwhile, are being released from Russian state control into private ownership, raising the prospect of unregulated clear-felling for timber. Forests in the American west, Australia and Mediterranean Europe have burned extensively in summer fires, leaving smoke and ashes, damage and distress. In parts of Indonesia, poorly enforced logging legislation, drought induced by abnormal climatic fluctuations and uncontrolled burning have reduced once continuous forests to patches too small to sustain either wildlife or the indigenous human population. Recent reports suggest that Burmese forests, one of the last repositories of wild teak, are being felled at a faster rate than any others in South-East Asia. Forest-loss has knock-on effects too, particularly the loss of topsoil and the flooding and silting of river-beds, deltas and estuaries (the last often hundreds of miles from the deforested land). Gonaives, in Haiti, where more than a thousand people died in the floods following Hurricane Jeanne, was inundated because every tree in the surrounding territories had long since been felled for charcoal.
Trees provide the three-dimensional structure that defines the space in which other species exist, above and below ground. The diversity of air-dwelling creatures reaches its peak in tropical rainforests, partly because of the spatial complexity and dynamism of the forest canopy. The removal of trees is an assertion of power over the environment and its inhabitants, eliminating the competition and sequestering its resources at a stroke. In classical times it was thought that forested land tended to offer the most fertile agricultural soil. As Michael Williams carefully describes, for diverse cultures in diverse periods in history, deforestation has been intimately bound up with agricultural aspirations. But because trees impart a unique physical structure to the environment – only corals, arguably, provide anything comparable – deforestation was probably the first form of human exploitation of the environment to have potentially permanent effects, setting ecosystems on new trajectories and not allowing them to settle back into established patterns.
Deforestation, in the strict sense, is the permanent removal of trees for the pursuit of some other goal, generally agriculture. In practice it means more than this: selective logging, for instance, can cause such damage to some forest soils that a new canopy of trees cannot develop; and ‘forest’ means not only a continuous cover of trees, but all that is supported within and beneath that canopy – plant, animal and microbial life. On the other hand, huge damage can be done to a forest, yet the tree cover can return when the disturbance ceases, as happened after the clearance of much of the eastern United States in the 19th century. In such ‘secondary’ forests, the three-dimensional structure of the forest, the relative proportions of different tree species, and the relative ages of individual trees all tend to be very different from how they were originally. Because its effects are so various, deforestation defies easy definition; Williams doesn’t get to definitions until page 452, by which time the question seems superfluous.
Media reports of deforestation often include arresting statistics: in the time it takes you to read the article, an area of Amazonia the size of Hyde Park or Hampshire or Wales will have been felled, and so on. Williams isn’t alarmist in any sense – as a historical geographer, rather than an ecologist or environmentalist, his tone is curiously detached – but can still numb with numbers. A Neolithic settlement of six households in Europe would have required a 52.8-hectare woodlot (8.8 hectares per family), 18.18 hectares of pasture, 19.66 km2 of natural meadow, and 2.56 hectares of forest browse. The Roman baths at Welwyn might have required 114 tons of wood a year (‘We cannot be more precise than that’); up to 123,636 km2 of woodland in Britain would have been required to heat the households of pre-industrial France; ‘approximately’ 11,135 hectares of woodland would have been affected by iron production at the beginning of the 16th century. This excessive precision detracts from Williams’s great achievement in this book, which is to show that humans’ use of wood has always been pervasive, and that logging and clearing have been integral to the development of society in all parts of the globe. He adds to the growing view that few of the world’s ecosystems – the oceans included – could be regarded as pristine and unaffected by human influence over the past several millennia. The forest might have been the first feature of the natural world on which humans made a permanent, detectable mark: for the past 10,000 years, and probably much longer, human settlement has been governed by the presence or availability of wood. Estimates vary as to the date of the earliest use of fire, but charcoal deposits suggest somewhere around 750,000 years ago. From that point on, the human story has been increasingly lignicentric.
Humans have affected the world’s forests, roughly speaking, in three great waves and for two main reasons. The three waves coincide with three pivotal events in human history: the discovery of fire, the settlement of land and the European colonial expansion that led to the Industrial Revolution. The two reasons have been to clear trees out of the way and to use their timber for fuel and building. This has meant, in one way or another, that only a tiny fraction of the forest still standing at the beginning of the 21st century can be regarded as untouched by people at any stage of their history, a fraction that dwindles to zero if the global effects of increased levels of atmospheric carbon dioxide are taken into account. While some of the most dramatic and damaging assaults have taken place over the past half-century, especially in the tropics, Williams reveals just how deep into our history deforestation stretches. He is contemptuous of those ‘modern-day ecologists, anthropologists, biogeographers and “wilderness” enthusiasts’ who cling to the notion of a pre-Columbian paradise of indigenous peoples living wisely and harmoniously with nature, though he does have to acknowledge that ‘the relative peace and harmonious relationship between the inhabitants and their environment in the peripheral parts of the world was shattered as Europe extracted the unused and stored-up potential of land and its vegetation for its own use.’ While any society is and was capable of self-defeating deforestation, European expansion changed the rules: local or regional economies became increasingly connected, with clear consequences for forests as the European (and later North American) demand grew for the resources of the newly discovered world.
The possibility of using fire to flush game out of forest and woodland was probably recognised early in prehistory. Williams proposes that such burning was the eventual cause of the extinction of species of large animal – the Pleistocene megafauna – from many parts of the world, most dramatically on islands such as New Zealand and Madagascar. Small numbers of people could have an impact on large areas: a population of just a few thousand was responsible for the deforestation of millions of hectares of New Zealand, and for the extinction there of every species of moa – relatives of the ostrich, some of which stood five metres tall – within a couple of hundred years of humans arriving in 900 AD. A world tour in Neolithic times, which Williams provides, reveals evidence of burning, clearing and the increasing use of wood, at scales sufficient to effect the long-term transformation of forest into open woodland and grassland.
The history of human influence on trees and forests, especially in what is now the north temperate zone – the band that stretches westward from Japan through Eurasia and North America – is made all the more complex by the dynamic nature of climates and vegetation. The series of great glaciations that took place during the early history of humanity enforced movements of vegetation on a grand scale. Ice sheets advanced and vegetation retreated; ice sheets retreated and vegetation advanced. Deposits of fossil pollen, which can be used to track and date such movements with remarkable accuracy, show further layers of complexity within the migrations of forest and grasslands: different plant species colonised and moved about the landscape at different rates in different places. To disentangle the effects of shifting climate and soil conditions, not to mention herbivores, from those of a gradually increasing (and increasingly skilled and versatile) human population is a task of forensic fascination.
The earliest detailed accounts of the impact of civilisation on trees come to us from the classical world. Forest and woodland around the Mediterranean basin was exploited for fuel, construction, shipbuilding, metal-smelting and brickmaking, all of which – together with clearing for grazing lands – established a pattern that persisted until the industrial era, when coal and, later, oil and gas began to take the pressure off wood as a source of fuel. Theophrastus was the first to attempt a formal description of Mediterranean forests and woodlands, and moreover wrote about saws – Williams notes that they were ‘up to 5.6 inches long’ – and the advantages of arranging the teeth to point alternately left and right, the better to expel sawdust and prevent clogging. As ships grew bigger and naval demand for them increased, it became important to understand the different properties of timber from different tree species. Theophrastus noted the propensity of Cypriot rulers to manage trees for their naval potential. These early tendencies towards management and conservation of forests and woodlands didn’t go far. Where ham was prized, woodlands were reprieved – acorns from oak forests sustained herds of swine – but, as Williams notes, there is little evidence of any attempt to plant trees in the classical world except to grow olives, or of much awareness of the consequences of forest clearance for soil erosion. On the other hand, there is evidence that coppicing was used in parts of the Roman Empire as a means of sustaining the output from woodlands. Otherwise, there was general satisfaction, remarked by Cicero among others, at the subjugation of nature to human needs. This subjugation had deforestation at its core.
Europe’s population doubled between 600 and 1000, and with this doubling went further deforestation, especially in the west of the continent. During this period came the heavy, horse-drawn plough and the ridge-and-furrow system, which together led to marked increases in agricultural efficiency. It is the paradox of all labour-saving devices that they lead to an expansion of activity, and in this case more land was brought into cultivation, and more trees were cut down. All of which was energetically encouraged by orders of monks all over Europe, whose unflagging work ethic and horror of wild nature drew them to the frontiers of the continent in order to tame them, clearing the way for population expansion and further deforestation. As in earlier times, forest clearance was accompanied by modest efforts at conservation, in particular by nobles anxious to preserve the quality of hunting; pollarding and coppicing became more widespread. But the Black Death and the wars of the 14th and 15th centuries took such a toll on the population that the forest returned with a vengeance across much of mainland Europe, as had already happened in the Yucatán lowlands following the collapse of the Mayan civilisation, and would later in the north-east US following the abandonment of agricultural land in the 19th century.
In China, a parallel and probably more extensive forest clearance was taking place. The written evidence is meagre, but we do know that while forests on the north-eastern fringes of the country remained largely intact because of their defensive value, across most of northern China they were cleared by the 12th century, for agriculture and to meet the fuel and material demands of its growing cities, several of which had more than a million inhabitants by that time. Williams suggests that the scarcity of wood led to an energy crisis in China that lasted from 1400 to the mid-19th century. And even before this, the most dramatic of early deforestations happened in the South Pacific, as Easter Island was stripped of all its trees soon after it was colonised by humans in 400 AD, forcing the new arrivals to cast off for woodier climes.
The third great phase of deforestation had its roots in the expansion of British, Dutch, French, Portuguese and Spanish colonial and trading adventures from the 16th century onwards, driven not least by a need for more ships’ timbers. The bulk of Williams’s book deals with this last phase, which saw a major shift as fossil fuels replaced wood as the principal source of power in the industrial world. In turn, this shift opened the door for mechanisation and versatile and abundant means of transport, eventually making possible the clearing of forests in ever more remote and rugged regions. Far from taking the pressure off wood, its redundancy as a fuel (except among the rural poor) paved the way for new depredations, documented in frightening detail in Williams’s final chapters.
There are few signs that the onslaught on the world’s remaining unmanaged forests will abate in the 21st century: economic growth entails greater demand on the earth’s resources, wood not least. Global consumption of wood products might be expected to rise by 20 to 30 per cent in the next decade. Forests and their inhabitants continue to be threatened by logging, pollution and climate change. On the other hand, the future for some parts of the managed world is probably increasingly woody. There are places where the numbers of trees have increased: not only in plantation forests, but also in second-growth forests where the trees have come back following earlier bouts of felling. There is likely to be more planting in the temperate world, to trap some of the excess carbon in the atmosphere – though the benefits for the mitigation of global warming may be limited and temporary. This strategy might help to buy, at best and other things being equal, a few decades to institute viable alternatives to fossil fuels, before the carbon re-enters the atmosphere through the natural death and decay of the trees in which it was locked up. But other things may not be equal. In a warmer climate, more carbon dioxide will be released by respiring plant roots, offsetting the benefits of carbon sequestration. Other strategies can help. Growing arable crops in lanes between rows of trees, for example, can enhance the productivity of both arable and woody crops, and techniques such as these would tend to increase landscape and biological diversity.
But there is no quick ecological fix for anthropogenic climate change: the only course is sustainable energy consumption. Legislation to protect trees and forests, and to regulate the international timber trade, helps to put a brake on the discounting of the future that characterises our post-industrial treatment of forests and other natural resources. But violations are routine, blind eyes are turned, and conservation legislation is hotly contested, as in the continuing case of the old-growth forests of the Pacific North-West of America, where loggers and conservationists have been fighting for decades over the fate of the northern spotted owl.
Can we manage without wild forest? Possibly, if we are prepared to live in a world stripped of a large part of its biological splendour and evolutionary future, and to tolerate the dispossession of forest-dwelling peoples. You might argue that that is where we are already. But can we manage without trees and wood? On the evidence of Williams, certainly not.