Thursday, December 22, 2005

"Get planting"

Read Peter Campbell's full review of The Secret Life of Trees: How They Live and Why They Matter by Colin Tudge in the London Review of Books. (Subscription required.)


"Despite the variety of introduced species, if you confine yourself to England’s managed, temperate landscape the picture you get is very limited. Alan Mitchell’s Trees of Britain and Northern Europe, a field guide which reckons to include ‘every species and large-growing cultivar to be seen in the countryside, parks and gardens of Europe north of the Mediterranean littoral’, is a book of modest proportions. The rainforest is a different matter, as is the foggy, rain-free Californian coast, as is the Cerrado of Brazil or the eucalyptus forests in Australia; and the central theme of Colin Tudge’s The Secret Life of Trees is variety and the evolution of variety: variety in form, in adaptation, in kinds of dependence – most trees need to cohabit with soil fungi, some need insects, birds or fruit bats to pollinate them and spread their seed, some are parasitic on other trees.

"Tudge makes the British experience seem truly insular. He writes, for example, about ‘the wondrous Reserva Florestal Adolfo Ducke’, which covers a hundred square kilometres of Amazon rainforest. Two thousand times smaller than Britain, it has forty times as many native trees – 1300 species. That in itself raises a question: why are there so many more species in the tropics than in higher latitudes? Tudge goes through the theories (not all of them – there are in print, he says, about 120 recognisably distinct attempts at an explanation). He finds no clear winner but thinks two ideas are particularly cogent. First, that away from the tropics ice ages wiped the slate clean again and again, leaving tough terrain in tough climates where only the adept survive. Second, that in the tropics the pressures are biological rather than physical, and that pressure from parasites, which a species of fewer, widely spaced individuals is better able to counter, is a major reason for diversity."

"Knowledge about the ways in which growth, morphogenesis and reproduction are regulated has been advanced through studies of a few species. One, Arabidopsis thaliana, has become a model organism because it has a short life-cycle, produces abundant seed and is easy to manipulate genetically. The insight into plant life which has come from such single-species studies has begun to make sense of plant form and function at the level of the cell. This science is, to borrow the old terminology, ‘natural philosophy’. The term ‘natural history’ better fits descriptions and analyses which emphasise the variety of species, their adaptations and their interdependence in communities. The work of the ecologists, foresters, field botanists and taxonomists that Tudge draws on is of that kind."

"Tudge ends his book with a secular sermon. The modern world, he says, is governed by the idea – call it a principle – that the only measure of right policy is an increase in the volume and money-value of goods and services; that this destroys the possibility of a sustainable relationship between us and our planet; that fertile land is taken over by mechanised agriculture, to the benefit of the few; that the many, forced off the land, gather in the slums of cities which already contain half the world’s population; that burning fossil fuel to drive our industries is leading to deleterious climate change; and that our only hope lies in a new kind of politics, a democracy in which people realise where their true advantage lies and are able to prevent governments and businesses standing in the way of its achievement."

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