Root and branch

Oak by William Bryant Logan
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Oak: The Frame of Civilization
by William Bryant Logan
320pp, WW Norton and Co, £16.99

During the 18th century's melee of post-Commonwealth patriotism, naval nervousness and landscape make-overs, the oak tree became rather more than the backbone of our "wooden walls". In something close to sympathetic magic, it began to be seen as the stout "heart" of the nation, reflecting and energising the character of its people. The naval historian John Charnock, in an audacious melding of the practical and the symbolic, wrote that "the oak of other countries, though lying under precisely the same latitude with Britain, has been invariably found less serviceable than that of the latter, as though Nature herself had forbad that the national character of a British ship should be suffered to undergo a species of degradation by being built of materials not indigenous to it."

This is not quite "the frame of civilisation" that the American writer William Bryant Logan has in mind in the subtitle to his quirky eulogy to Quercus. His oaks are not so much numinous or emblematic or immemorial as literal bits of scaffolding. They have spread themselves so lavishly across the planet that they've provided most of the products humans needed for the development of technological cultures. The list is awesome: handles for stone axes to fell the first trees, frames for houses and boats, wine barrels and wine corks, bark for tanning leather, galls for making ink, charcoal to fuel iron-furnaces.

Further, he believes that it was, quite specifically, this huge family of beneficent trees that enabled humans to make the transition between hunter-gathering and settled cultivation. Archaeologists conventionally allot this role to the wild grasses of the Middle East, which slipped into cultivation maybe 10,000 years ago and made possible the development of agriculture, bread, permanent villages and the division of labour - a way of living that was exported, for better or worse, across the planet.

Logan's alternative is nimbly and seductively argued. He shows a map in which the distribution of early settled societies throughout the temperate zone appears exactly to coincide with the geographical spread of the 400-odd species of oak. He cites many cultures - in north America, ancient Mesopotamia, the highlands of Mexico - where a style of living midway between nomadic gathering and rooted agriculture was evident long before the advent of cereal farming. You could, I suppose, call it fixed foraging, the communal exploitation of a long-lived local resource. The resource was the oak tree, always there in one form or another - just above the waterline, if you were fisher-people, just below the uplands if you were hunters. And its first and most fundamental gift was the acorn, prolific, nutritious (you just needed to leach out the tannin with water), storable, cookable. Acorns, Logan argues, were the world's first staple. Even today the sweet fruit of evergreen oaks are nibbled as savouries in Spanish dehesas and the meal of southeast Asian acorns is made into a kind of tofu.

Then came the incomparable gift of oak-wood: tough, durable, cleavable. Oak planks made possible that crucial stepping stone to civil society, the fence; then they enabled migration, be it on wooden walkways across the marshes or in waterproof boats across the seas. Oak was doubtless the material of that obelisk at the start of Kubrick's 2001: A Space Odyssey, always there with its protean versatility to suggest the next step forward.

It's a beguiling thesis, and a more pleasing image of the natural transactions that gave birth to early civilisations than the bludgeoning march of agriculture. But like all grand theories, it rounds off the details that don't fit. The start of the bronze age slips back in time, maples are denied their evergreen species, neolithic trackways acquire rather more than their true percentage of oak planks. More seriously, the uniqueness of oak as a cultural root and branch is overstated. In Kyrgyzstan, there are ancient semi-nomadic communities based around walnut and wild apple trees. Sweet chestnut - as a source of nut-flour, building timber and fuel-wood - framed a whole civilisation in the Italian Appenines. The early Turks built very serviceable ships from pine, elm and mulberry. Even in oak-proud southern England, it was beech, not oak, that provided most of the fuel for London and for the iron- and glassworks of the Weald. Maybe there had to be some kind of symbiosis between trees in general and an ascendant humankind, but even this isn't a knot-free argument. In the author's own country, the Paiute Indians of the Nevada plains had a viable culture - boats and clothing from the leaves, flour from the pollen - based to a large extent on what we call bullrushes. Plants are multifarious, and human ingenuity has usually been able to make something out of whatever happened to be at hand. Oaks were pretty well always at hand. Like the human species the Quercus tribe is adaptable, pushy, colonial (look at the wild oaklings in set-aside fields next to woods), apt to throw up all kinds of promising organic templates. Put the two organisms together, by coincidence or choice, and life was bound to move on a notch.

It's the story of this engagement that Logan tells so well. He's best when he gets away from generalisations and on to detail, the grain of things. His account of the building of the timber-framed roof of Westminster Cathedral - 600 tons of wood spanning 68 feet without central support - has an epic reverence: "Each member of a roof truss - the triangular or spire assembly of rafters and tie beams - is a force made visible. Gravity flows down the roof rafters and pushes at the walls on which the roof sits. The tie beam resists, holding the two pieces in tension. Above the tie beam, the carpenter places a collar - a smaller and higher version of the tie beam - to siphon off some of gravity's pull." There's a touch of Whitman in his relishing of the way the carpenter cleaves to the wood: the sighting of the beam in the growing tree, the sensing of its weathering and tensions, the laying on of the saw, the smell of its age, the long mellowing in the barns, the first dip of the adze, the dowsing of the strength lines, the angle in the wood meeting the angle in the mind, the mortise joint, the tenon, the manufactured branch.

What Logan judges to be "the End of the Age" of oak was a rather less glorious meeting between man and wood. In a long and over-dramatised chapter he plots the victories of US wood-built frigates against the English, and how they met their nemesis, blown apart by iron-clad, steam-driven Confederate warships during the civil war. It's a demeaning arena in which to end such a basically creative celebration.

But if it was a kind of end, it was only to one aspect of the tree's human story. The book quite properly ends with the "Oak Itself", with its teeming narrative of attendant insects and epiphytic plants and subterranean fungi. Despite his relish for naval skirmishes, Logan is a gentle ecologist, and paints an enthralling picture of the cooperative business going on below ground, as the oaks' rootlets support one another, feed their ailing siblings and make the soil right for other organisms. This is the shape of the oak's game: making the best of things, avoiding conflict wherever possible, revelling in maximum diversity. The most intriguing oak of all is light-years away from the magisterial pillars worshipped by the 18th-century aristocracy. Quercus coccifera, the Mediterranean prickly-oak, is a tree-chameleon. Burnt to the ground or scrunched up by goats, it can prosper as a "ground-oak", never reaching more than few inches in height. Left to itself it can reach 60 feet tall and 10 feet across. Passing between the two states, it can grow flat or as a column or as series of plateaux, with goats grazing along the horizontal branches. It's deft, opportunist, un-tragic, a parable, perhaps, of the conditions for the mutual survival of all organisms, ourselves - oak-partners and oak-destroyers - included.

· Richard Mabey's Fencing Paradise: Reflections on the Myths of Eden is published by Transworld/Eden Books. To order Oak for £15.99 with free UK p&p call Guardian book service on 0870 836 0875.