The Secret Life of Trees

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The Secret Life of Trees Page 43

by Colin Tudge


  FORESTS AND FARMING IN TANDEM: THE PROMISE OF AGROFORESTRY

  Forests provide us with a great deal more than timber – and all the rest are collectively known as ‘non-timber forest products’. The total inventory of resins, fibres and chemically-potent agents requires several fat books of its own, and indeed is the subject of many a library and not a few research centres. 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 harbour 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 ‘bio-piracy’. Battalions of lawyers are now employed to give bio-piracy 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 bio-piracy 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 (lovely jubbly 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 10,000 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 8,000 years of settled farming, there were somewhere between 100 and 300 million of us. Now we number around 6,000 million. 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 soya, 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 backwards 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 10,000 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 mac-adamia of Australia, and the mongongo nuts of the Kalahari are serious staples for local people. People of the Mediterranean and eastwards 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 further north had hazel and chestnuts: hazel 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 centrepiece, 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 plough 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 – then 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, then 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 flavours, and a range of liquors (walnut beer and walnut whisky) fermented and distilled from them.

  I am floating these ideas partly through whimsy but mainly to emphasize that although food from trees at present plays only a small part in human affairs (at least if you judge from global statistics), this is largely an historical and economic accident. Grains clearly do have advantages, but they have become as dominant as they have largely through their own momentum. In particular, once the plough was developed (at least 5,000 years ago) arable farming became the norm, and everything else became secondary. But if trees had only been taken more seriously, they could have become an enormous food resource – and might be now, if only the coin of history had flipped differently. Indeed, trees have many advantages over grains – they keep the soil in place, they help to keep the climate equable – and we should be growing as many as possible. So it is important to change our mindset – move away from the idée fixe which says that grains must be central and everything else is marginal. At present, much of Brazil, both rainforest and Cerrado, is being cleared to make way for vast estates of soya, which is now Brazil’s biggest agricultural export (and is destined not to feed people, but to fatten European cattle –and not because we need the cattle or because the cattle need feeding, but because Brazilian soya is, for the present, cheap). But modern research is showing that the Cerrado could yield far more, and do its society much more good, if its people were encouraged and helped to develop and exploit its native plants. In Frutas do Cerrado (2001) EMBRAPA lists fifty-seven native species of fruit, with recipes. The trees among them range from four kinds of araticum (various species of Annona, custard-apple relatives) through banha-de-galinha (Swart-zia langsdorfii) to pitomba-do-cerrado (Talisia esculenta) and puca (Mouriri pusa). But Frutas do Cerrado is only a brief brochure: there are scores of other species. Professor Carolyn Proenca of the University of Brasilia lists 120 – but stresses that this, too, is just a sample.


  Trees provide a great deal of food by indirect routes, too – and again could give us much more. In traditional agrarian economies the leaves, twigs, branches and seeds – including many that human beings find fairly unpalatable, such as acorns – support significant herds of livestock. In India you commonly see long files of women and girls carrying huge bundles of branches from the forest to feed their cattle. The technology could surely be improved – the work seems mighty hard – but the general idea, that cattle (and sheep, and indeed goats) can be raised on trees is at least salutary to westerners who think that only grass will do – and is hugely important, since woodland is often preferable to grassland. Pigs and poultry will eat seeds of the kind that humans generally prefer to leave alone, such as acorns. At present, half the world’s cereals (and 90 per cent of the soya) are used to feed livestock. Since people can live perfectly well on cereals (plus a few extra vitamins), the animals thus become our rivals: and indeed the United Nations calculates that by 2050, when the human population seems likely to reach around 9 billion, livestock will be consuming an amount equivalent to another 4 billion – increasing the world’s food burden by nearly 50 per cent. But if animals are fed on grass – or on bits of trees – then they add to our food supply, since we cannot usefully eat grass or trees. Research is in progress to provide better trees for fodder (more nutritious, less toxic), but nothing like the amount that is being done to add another fraction of a per cent to the yield of soya (which makes more money, though only for a few people).

  In various ways production of trees for all purposes – timber, food, resins, whatever – can be combined with production of livestock or of conventional food crops in systems known as ‘agroforestry’. Agroforesty is in all ways tremendously intriguing. It is ancient in principle – much of the economy of medieval Europe was based on ‘forestry’, and marauding herds of pigs (in particular) were very much a part of it. But it is also one of the great hopes for the future – and is now at least beginning to attract the kind of research funding that it deserves.

  There is a spectrum of agroforestry. In England, traditionally, farmers often left some trees (notably elms) to grow tall in hedgerows, to provide a useful source of timber in decades to come. Copses in field corners served the same purpose. In northern France, the rows of poplars along the field edges define the character of the entire landscape. They have cash value and in the short term serve as windbreaks – and, odd though it may seem, they form better windbreaks when there are gaps between them than they would if they formed a solid barrier, for solid fences create turbulence. In southern Europe you commonly see broad beans and other crops grown among olive trees. In Andalusia and Portugal cork oaks, valuable in their own right, become even more valuable as black pigs wax fat on their acorns. At the Food Animals Initiative in Oxfordshire, chickens are being raised under young trees – birches, beeches, hazels. Chickens prefer woodland: they are descended from Indian jungle fowl. Allegedly free-range chickens are often reluctant to take to the great outdoors precisely because they feel threatened if there is no shelter – and rightly, because even in Britain the main threat comes not from foxes on the ground but from above, notably from crows but also from herring gulls (and to a far lesser extent, from birds of prey). But the aerial invaders prefer a clear run. A cover of trees deters them.

  Yet the tropics surely have most to gain from agroforestry. The best coffee and tea is grown under shade. Some spices and medicinal plants grow in woods, including cardamoms, an important local industry in Kerala. Leguminous trees are commonly grown for shade: as nitrogen-fixers they also help to fertilize the crops around them, and their nitrogen-rich leaves make particularly fine fodder. Enormous herds of cattle, pigs and poultry could be raised in plantations to the benefit both of the trees (which would thereby be manured) and of the animals, which would find food (largely cut for them from the trees) and much-needed shade. The value of shade for livestock can hardly be overestimated. Of the common domestic livestock, all except sheep are descended from forest animals. Of all wild cattle, only the yak and the North American bison take naturally to the great open spaces – and America’s bison is descended, and only in relatively recent years, from the European bison, which is a forest animal and still roams in the forests of Poland. These broad biological observations translate into hard-nosed commerce. Research in Costa Rica has shown that the milk yield of tropical dairy cattle can increase by 30 per cent if they are shaded. Contrast this with the parched and desperate herds that traditionally run on the unprotected prairies, pampas and savannahs. We all like cowboys, driving their dogies across the plains of Texas and Wyoming. But as a way of raising cattle, this is both wasteful and cruel.

  Indeed, agroforestry benefits everybody, in all ways. Traditional foresters must typically wait around thirty years before seeing any return on their investment. But if they use the space between the trees to raise other crops (including valuable spice and medicinal crops), they can gain a short-term income too – while all the time the trees grow steadily, to provide a bonanza in the future. Again, I have come across this in Kerala. Again, one wonders why it is not the norm. In most of the world, in most circumstances, agroforestry makes obvious sense. Contrariwise, the present separation of forest and farming that is customary, with the farms more and more monocultural, often makes very little sense at all, except in the short term to a few entrepreneurs. But get-rich-quick is not what farming is supposed to be about. Yet there is still a case for growing trees in dedicated plantations –and for harvesting them judiciously from wild forest.

  HOW TO GROW TREES

  We can grow and manage trees specifically for our own use, and/or we can help them to grow just because they have a right to live, and are good for other species. Of course, too, by managing the climate and soil, trees are likely to bring us benefit even if we are not specifically growing them just for ourselves.

  Trees for our own use can be raised in plantations, and it makes sense to identify the kinds that produce the timber we need and grow quickest in the land available. This was the thrust of the colonial approach to tropical forestry, of the nineteenth and most of the twentieth century. Often the favoured trees were exotics, planted in lands not their own: and thus the world at large now has many thousands of hectares of eucalypts, originally transplanted from Australia, while Australia has estates of Indian sandalwood; South and Central America have acquired teak from India and Burma; huge estates of America’s Monterey pine can be found everywhere; there are plenty of European poplars in India; there’s a great forest of Caribbean pine on the outskirts of Brasilia; Britain’s Forestry Commission planted vast areas of uplands (and sometimes lowlands) with American Sitka spruce after the First World War; and so on.

  Such exotic planting has many advantages. Eucalypts judiciously planted in Africa and Asia commonly produce ten times as much timber per year as native species – and this in theory should take an enormous burden from the native forests. Commonly, too, species brought from abroad leave their usual pests behind them, so that teak grown in Amazonia, for instance, seems free of the defoliator moths that cause such havoc in India. But there are many drawbacks too. Britons have objected on aesthetic grounds to the military ranks of Sitka spruce. Exotic trees do provide shelter for local creatures and often supply some food, but in general they are far less hospitable to local wildlife than native species. Sometimes they are positively hostile: conifers on Scottish hillsides increased the acidity of the soil and compromised local flora, and eucalypts on dry soils can rob their neighbouring plants of water. Exotic timber trees have often escaped to become weeds – like many a eucalypt and acacia. Parasitic sandal-woods from India grown in Australia have sometimes escaped to attack the local eucalypts, while native sandalwoods in India have sometimes attacked eucalypt plantations. Human beings may choose to manipulate nature this way and that, but the natural battles of ecology continue.

  Finally, although exotics often grow supremely well in ideal land, they often fare
no better than the natives when planted on poor land: but forest is commonly relegated to poor land, since the best is reserved for agriculture. Then, native species would often be preferable because of their general friendliness to local people and wildlife – although they have often in practice been ousted by forestry plantations effectively as a matter of routine. In Harare, Zimbabwe, Gus Le Breton runs Phytotrade Africa, devoted to the development of native species, not least of the wonderfully versatile local baobab, Adansonia digitata. In 2004, at the Forestry Research Institute at Dehra Dun, the then director Dr Padam Bhojvaid was seeking to reinstate as many as possible of the 400 or so native Indian species that have been used commercially in the past, many of which have been sidelined through the emphasis on teak (native to India to be sure, but still grown in colonial style in huge monocultural plantations). In truth, there is and always will be a place for plantations of exotics, and the world has good cause to be grateful to the traditional ‘colonial’ foresters who laid the groundwork in science and technique and nowadays tend often to be under-appreciated. But it’s a mistake to apply even the best ideas slavishly and under all conditions – as the old-style foresters would certainly have agreed.

  Wild forest ideally should surely be kept pristine because pristine forest is, as serious actors say of live theatre, what it’s all about. Even so, in a crowded world we are obliged to make use of the natural forest as much as possible without destroying it. Besides, many people worldwide, particularly in Africa, tropical America and Asia, but also in much of Europe, make their living in the forest. Some traditional forest people are true foresters – producers of charcoal, for instance. Others specialize in wild foods or medicines. Nowadays tourism can be a huge source of income – it is the biggest earner by far in Kenya, for example, although it is easier to take tourists around the savannah than through, say, the forests of South-East Asia (although a ride I took in a cable car at canopy height in the subtropical forest of Yunnan in central China is one of the great memories of my life, the bamboos stretching endlessly below and endlessly above, the air awash with dragonflies, smoky pink and iridescent blue). But it is important that the cash that tourism generates should benefit local communities, and the habitats themselves, and this is often far from the case.

 

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