- 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.