The Tree (51 page)

Finally, trees can help ameliorate global warming if grown as a prime source of energy (and help us solve our energy problems as fossil fuels run out). Of course, when wood is burned it is oxidized to carbon dioxide—the very stuff that is causing global warming. But the carbon it releases is only what the tree itself has stored through a life of photosynthesis, and so, overall, trees grown for fuel are carbon neutral. Fossil fuels, by contrast, were created by plants (and other creatures, in the case of oil) that lived hundreds of millions of years in the past; and within a few decades, as we burn them, we release all the carbon that those ancient organisms took many millions of years to fix. Exactly how much energy we could and should derive from trees and other biomass (as opposed to other renewables—wind power, solar panels, tidal power) has yet to be determined, but it must be a great deal more than now.

A WORLD BUILT ON TREES

Great architecture (and great ships) began with timber. Yet in our frenetic search for new wonders, we have spent the past two hundred years developing alternatives, like steel and plastics. They have their place, of course, but an economy rooted in such high tech uses far too much energy. More broadly, economies rooted in industrial chemistry (the kind that produces steel and plastic) can now be seen to be old-fashioned. Future economies must be rooted in biology. In construction, especially but not exclusively of buildings, we must reverse the trend away from timber.

Timber cities would lock up a great deal of carbon. Even more to the point: although it requires energy to turn a tree trunk into a finished beam (sawing, planing, transport), it takes roughly twelve times as much to make a steel girder that is functionally equivalent. So it surely would pay us to use timber as much as possible instead of steel. By no means would timber necessarily be inferior. Timber burns, of course. But steel, when overheated, buckles. When timber is suitably coated and treated with fire retardants, it can take longer to collapse than steel would, giving people more time rather than less to escape from burning buildings.

Of course, the world already has many fine timber buildings: the meeting halls of the Maoris, with their carved gables and pillars of totara; the lovely colonial churches of New Zealand and the United States; their stunning modern counterparts in Scandinavia; many beautiful houses all over the world—and commercial buildings too: I recall a wondrous winery in California with a roof as broad as an aircraft hangar, built like a barrel. Britain is now acquiring some serious timber buildings, but on the whole we seem to retain folk memories of September 1666, when, in the Great Fire, street after street of London’s timber-framed houses were reduced to ash within five days. Other people—notably in New Zealand, so I’m told—harbor morbid fears of dry rot. But again, life doesn’t have to be like that. Even in Britain many an ancient beam has held up many a cathedral roof for the better part of a thousand years, and with good technique and modern technology fire and rot can largely be avoided. Many a concrete building, by contrast, has run its course in thirty years, and iron buildings burn too (as London’s Crystal Palace so spectacularly did in November 1936).

The world needs “green” architecture as a matter of urgency. We should be building as much as possible from materials that require as little energy as possible to prepare. There is no shortage of candidates. Surprisingly fine houses can be made even from straw bales. Some truly stunning haciendas in the southern United States and Central and South America are made from adobe: mud, dried gratis by the sun. Timber also falls into the low-energy category. Ideally, too, the materials should be endlessly renewable. Here, biological materials—straw and timber—score even over mud. There is no shortage of mud—but when you dig it out you leave a hole. When you harvest timber you make no holes.

The finished building should need very little energy to keep it warm or to keep it cool—as little air-conditioning as possible. The shape of the building makes an enormous difference: for instance, the traditional villages of Malaysia, built on stilts, make wondrously efficient use of the local breezes, which tend to blow several meters above the ground. But the materials are vitally important too. Straw and timber are wonderful insulators. Many peoples of northern Europe, not least in Iceland, made (and to some extent still make) roofs from turf: thick earth overhead with growing grass, often grazed by goats. The site of the building is also critical. It is far, far easier to keep a building cool, or to keep it cozy, if it is surrounded by trees than if it is on some bleak promontory. Woodland creates equable microclimates.

Yet since the start of the twentieth century, the architects’ favorite materials—especially for the most expensive and prestigious buildings—have been concrete and steel, with liberal quantities of bricks that have not been dried in the sun but fired in high-temperature, energy-guzzling kilns. Typically, too, they have been built in open spaces, apparently to show them off, or because trees have been considered inconvenient. So modern buildings are generally exposed to winds and merciless sun. They are made habitable only by constant infusions of energy to heat them and cool them down again. Twentieth-century architecture, in short, has for the most part been a prolonged exercise in profligacy.

But “greener” materials, sustainable and economical, have often seemed a little too rustic for modern tastes. Turf roofs do not seem appropriate for city centers (although there is a vogue these days for gardens and even for mini–wildlife reserves on the flat roofs of tower blocks and skyscrapers). The timber buildings of the west for the most part are merely cabins or even shacks. The green movement in general has a bucolic air. In Britain, green activists have nicknames such as “Swampy” and “Owl.” But rapprochement is needed between the dyed-in-the-wool rustics and the city slickers. We need architecture that is green—low maintenance, and made from low-energy and easily renewable materials—yet is also worthy of the most refined sensibilities.

It is already clear that this is achievable. In modern commercial Beijing, while there are more and more skyscrapers of concrete and steel, exposed to all that city’s extremes of climate, from crippling cold to blistering heat, the diplomatic quarter remains as serene as an orchard: the low, colonial buildings are all but concealed by sheltering evergreen trees. I can attest (having stayed there) that the environment within remains as equable as it looks even on days when people on the main streets are baked alive by the radiant heat from concrete and tarmac.

The world needs prestige buildings of timber, too. There are many already, including magnificent ancient temples and palaces all over southeast Asia—Burma, China, Thailand. Many modern architects worldwide are rising to the challenge, creating timber buildings as free in form as any sculpture (with modern techniques, wood can be molded this way and that) yet wonderfully comfortable. They are naturally warm in winter and cool in summer. Thus they contrast absolutely with the concrete and glass creations of the twentieth century which, without constant input of fossil fuel, are colder inside than out in winter, and hotter than the great outdoors in summer—the reverse of what a shelter should be. Truly prestigious buildings of timber should attract major prizes. How wonderful it would be if, say, the Sydney Opera House or the new Guggenheim Museum in Bilbao, in northern Spain, or any of the exciting commercial buildings of Chicago or San Francisco or Boston were made primarily of timber—renewable timber, that is: grown specifically for the task or sustainably harvested. Of course, the timber should not be cheap: we must, while we are about it, put an end to the centuries-old exploitation of wild places and human labor. This is just one of many ways in which the twenty-first century needs to be very different from the twentieth. If timber architecture truly came of age, and the necessary forestry was well managed, and the people who make it happen were properly treated, all humanity and the world at large would surely benefit beyond measure.

Building and civil engineering are among the world’s biggest industries. Biggest of all, though, and the most important, is farming. Farmers and foresters have all too often been at loggerheads. But when farming and forestry are judiciously combined, they can complement each other beautifully.

FORESTS AND FARMING IN TANDEM: THE PROMISE OF AGROFORESTRY

Forests provide us with a great deal more than timber; all the rest are collectively known as “nontimber forest products.” The total inventory of resins, fibers, and chemically potent agents would require several fat books of its own and, indeed, is the subject of many a library and not a few research centers. Suffice to say that a high percentage of all modern drugs are derived from plants, a large proportion of which are trees. Crops grown for spices, perfumes, and medicines provide high value from a small area and are easy to transport: a tremendous bonus, in principle, for small farmers—including agroforesters.

However, the world has yet to sort out the practicalities of such production—technical, legal, ethical. Many valuable, recondite materials from plants need serious pharmacological development, and this, in practice, is carried out by specialist university departments and commercial companies.

Some of the necessary high tech is to be found in the countries where the valued trees grow, but much of it is not. Not even the richest countries harbor every kind of expertise that’s needed. So partnerships are needed, typically between tropical (usually impoverished) countries that grow the relevant plants and rich countries with the necessary high tech—with as much work as possible carried out in the countries where the crops originate. Some such partnerships exist that are beneficial to all parties. But greed and opportunism have too often reared their horrible heads. Henry Wickham’s expropriation of rubber tree seeds from Brazil in 1876 might charitably be seen as a somewhat equivocal case, but many others have been just plain theft, of the kind known as biopiracy. Battalions of lawyers are now employed to give biopiracy the veneer of legality, and this surely is to plumb the venal depths, for when the law itself is on the side of palpable injustice there is nowhere else for humanity to run. The fear of biopiracy is such that many countries refuse to consider even legitimate partnerships that could do them good; and nongovernment organizations, which in general rank among the world’s most valuable institutions, have sometimes prevented very good deals from going through. Thus because of frank (if sometimes legalized) banditry on the one side and suspicion on the other (sometimes justified and sometimes not), the riches of wild plants in general are far less exploited than they might be. This is all very sad. There is little trust, and little basis for trust, and legal nicety (nice work for lawyers) prevails where simple respect and honesty should be enough.

Food from trees is significant already—but, again, we ain’t seen nothing yet. It’s obvious that human beings could not have become anything like so numerous as we are unless we had learned to grow our own food. The archaeological record suggests that large-scale, settled farming began around ten thousand years ago in the Middle East. By then, our species was already ancient and had spread out of Africa and Eurasia to Australia and the Americas—and yet the world population at that time is estimated at only around 10 million. By the time of Christ, after eight thousand years of settled farming, there were somewhere between 100 and 300 million of us. Now we number around 6 billion. Historians typically suggest that the kind of farming that could generate such numbers depended on cereals and pulses; that is, the farming that really counted was arable. In the Middle East, wheat and barley prevailed; in the Far East, it was rice; in North America, maize. Grains have obvious advantages and have long dominated world agriculture—indeed, rice, wheat, and maize currently provide humanity with half our total energy and two-thirds of our protein. All other crops (even soybeans, beef, and potatoes) are also-rans by comparison. The seeds and fruits of trees are reduced to footnotes.

But it’s a mistake to read history by extrapolating backward from the status quo. Even in the modern Mediterranean the olive is a significant source of calories, as well as of delectation. I find it entirely plausible that people of ten thousand years ago—and, indeed, well before—would have regarded olives as a staple. Dead goat and herbs have a lot to commend them nutritionally—protein, vitamins, minerals—but they are low in calories. Baste them in olive oil and they become substantial. Today, the coconut of India and the Pacific, the macadamia of Australia, and the mongongo nuts of the Kalahari are serious staples for local people. People of the Mediterranean and eastward into Asia would between them have leaned heavily on pistachio, walnut, cashew, and almond—all of which still feature strongly in Middle Eastern cooking. People farther north had hazelnuts and chestnuts: hazelnut flour is a significant presence in traditional German cooking, and the chestnut stuffings that now eke out the traditional goose might once have been the centerpiece, with the goose as the garnish. North Americans had walnuts and hickories, including pecans. The seeds of many pines are good, too. Nuts in general are rich both in fat (calories) and in protein. As a bonus, maple and birch and others give us syrups. The flesh of fruit, too, is not just for delectation and vitamins. Many are significant sources of fat, the richest of all sources of energy, including the coconut, olive, and avocado. Some fruits contain significant protein.

In short, it seems too cavalier by half to give all the credit to grains for the rise of farming, and hence for the expansion of the human species. Obviously grains played a huge part. They are also very convenient, lending themselves to simple technologies for mass production and processing—notably the plow and the millstone. They have short generation times too, giving plenty of scope for genetic improvement—which traditional farmers achieve simply by selecting the best, without formal knowledge of Mendelian genetics. But, I suggest, if there had been no grains at all—no wheat, no barley, no oats, no maize, no rice, no rye, and indeed no sorghum, millet, teff, quinoa, or amaranth—the human species might well have flourished just the same, with an “agriculture” built on trees. After all, if the same effort had been put into the walnut as has been put into wheat, walnut trees by now would be taking hundreds of forms—some mighty trees, some dwarfed, some grown like grapes as vines, some like peaches in espaliers, clinging to the wall; and there would be walnuts of all shapes, sizes, and flavors, and a range of liquors (walnut beer and walnut whiskey) fermented and distilled from them.