The Tree (54 page)

It follows that the most important initiatives are those that are called “grassroots.” Indeed they always have been, when you take a cool view of history: the suffragette movement, the trade unions, organic farming. Things start to work well when people at large take matters into their own hands. All these principles are exemplified by the Green Belt Movement in Kenya. Appropriately, it was begun by a woman from rural Kenya, Wangari Maathai; and it is built around trees.

WANGARI MAATHAI AND THE GREEN BELT MOVEMENT

Wangari Maathai was awarded the Nobel Peace Prize in 2004. She is not the first African to win it—others in recent years include Nelson Mandela, Archbishop Desmond Tutu, and Kofi Annan—but she is the first African woman. She began the Green Belt Movement in 1977—partly, she said in her Nobel acceptance speech, “responding to needs identified by rural women, namely lack of firewood, clean drinking water, balanced diets, shelter and income.” The people in this world whose opinions really count are those who are closest to the action, and in Africa, as Professor Maathai pointed out, “Women are the primary caretakers” and so “they are often the first to become aware of environmental damage as resources become scarce.”

From the outset the movement focused on planting trees, to supply the things that once were taken for granted but within the past half century, in Wangari Maathai’s lifetime, have gone missing. But the psychology is vital too, as all managers everywhere recognize, for, as she said, “tree planting is simple and guarantees successful results within a reasonable amount of time. This sustains interest and commitment.”

Since 1977 the women (primarily) of Kenya’s Green Belt Movement have planted no fewer than thirty million trees. The trees do indeed “provide fuel, food, shelter and income to support their children’s education and household needs”: everything that was hoped of them. More that that, though, as Professor Maathai told a meeting in London early in 2005, they have made the whole environment more agreeable. Kenyan people, women in particular, must still walk many miles carrying water and provisions. Whether you walk in burning sun or in shade makes all the difference—not only to the individual’s comfort but to social life. The women in treeless places had to some extent lost the habit of standing and talking. It was just too hard. Now they do it again. The temper of the whole society is improved. In the same way, Plato and Aristotle both taught their pupils in groves of trees around Athens. Ambience is everything.

The political implications are momentous—and for those who care about humanity, as opposed to those concerned only with personal wealth and power, they are all to the good. The women, by palpably improving the whole environment, have also vastly improved “their social and economic position and relevance in the family.” More broadly, when the Green Belt Movement first began, the Kenyan people “were conditioned to believe that solutions to their problems must come from ‘outside,’” and they were “unaware of the injustices of international economic arrangements.” But “through the Green Belt Movement, thousands of ordinary citizens were mobilized and empowered to take action and effect change. They learned to overcome fear and a sense of helplessness and moved to defend their democratic rights.” In short, the Green Belt Movement has relaid the foundations of autonomy and promoted democracy. If “development” means anything worthwhile at all, surely this is it.

Indeed, as Wangari Maathai said, “The tree became a symbol for the democratic struggle. In Nairobi’s Uhuru Park at Freedom Corner, and in many parts of the country, trees of peace were planted to demand the release of prisoners and a peaceful transition to democracy. In time, too, the tree became a symbol for peace and conflict resolution, especially during ethnic conflicts in Kenya. The Green Belt Movement used peace trees to reconcile disputing communities. The elders of the Kikuyu carried a staff from a thigi tree that, when placed between two disputing sides, caused them to stop fighting and seek reconciliation.” This tradition is widespread in Africa. Other societies worldwide, including North America, mediate discussions through “talking sticks.” Only those with the stick in hand may talk, and when they do, everyone else must listen.

Eventually, in 2002, Kenya elected a new government, more deliberately committed to the ideals of democracy and autonomy. Wangari Maathai serves in the Ministry of Environment and Natural Resources. In 2004 she established the Wangari Maathai Foundation to continue the work on a global scale. It has an office in London, at the Gaia Foundation, as well as in Nairobi.

Kenya’s Green Belt Movement is not alone. There have been and are comparable initiatives elsewhere in the world, not least in India. But it encapsulates everything that seems to matter most. It is a people’s movement. It deals with realities—“real” realities, those of day-to-day life, of human beings and of other living creatures. All the abstractions—the need to create agrarian economies, rooted in biological reality and a true concern for human well-being—are put into practice. The abstractions can then be put where they belong, far in the background. Reality is far more interesting. What is happening in Kenya could be reenacted, in a thousand different forms, all over the world: people themselves creating a world that is good to live in. The contrast with the grand schemes that are now imposed de haut en bas, in the name of “progress,” is absolute.

Trees are, of course, at the heart of things. How could it be otherwise? The human lineage began in trees. We have left our first ancestors far behind, but we are creatures of the forest still.

NOTES AND FURTHER READING

First, a short list of books that I refer to constantly (I have noted titles specific to chapters below).

Jeffery Burley, Julian Evans, and John A. Youngquist, eds.
Encyclopedia of Forest Sciences.
4 vols. Oxford: Elsevier, 2004. As comprehensive as can reasonably be imagined, with many fine essays. There is promise of constant updating.

D. V. Cowen.
Flowering Trees and Shrubs in India.
6th ed. Bombay: Thacker and Co., 1984. A lovely piece of publishing.

V. H. Heywood, ed.
Flowering Plants of the World.
Oxford: Oxford University Press, 1978. A classic, found on the shelves of a high proportion of the botanists I have visited. I refer to it as “Heywood.”

Hugh Johnson.
The International Book of Trees.
London: Mitchell Beazley, 1978.

Walter S. Judd, Christopher S. Campbell, Elizabeth A. Kellogg, Peter F. Stevens, and Michael J. Donoghue, eds.
Plant Systematics.
2nd ed. Sunderland, Mass.: Sinauer Associates, 2002. This book has become an instant classic. This is the book I call “Judd.”

William T. Stearne.
Botanical Latin.
Portland, Oreg.: Timber Press, 2004. A luxury, but a pleasure for those who like words.

1. TREES IN MIND

1. Biologists contrive to estimate the number of trees in the tropics by applying a few statistical tricks from the few areas of certainty. One approach is to look at the number of species discovered in a single family since records began and see whether the curve is leveling out. Within the Sapotaceae (the big tropical family that includes chicle, the chewing-gum tree), effectively no species at all were known to European science by 1700. But as naturalists and then modern scientists got involved, the numbers of known types rose logarithmically, which in effect means ever more rapidly, so that by 1990 three hundred species of Sapotaceae had been recorded in the neotropics. If in the last decade of that period the number of new discoveries had leveled off, we could conclude that nearly all the neotropical Sapotaceae must by then have been known. But there was no leveling off. In 1990 the number of newly recorded types was increasing more rapidly than ever. So there is no obvious top end on the number of Sapotaceae species that might be out there. Judd suggests that the present inventory stands at eleven hundred (in fifty-three genera). But there could be many thousands.

Another approach is to look in the world’s herbaria. For obvious reasons, common species tend to appear in many different herbaria, while rarer ones turn up only in a few. The very rare species are represented in no herbaria at all—meaning that they are as yet unknown. Again, it’s reasonable to suppose that a great many are unknown—precisely because they are rare (and/or extremely inaccessible). In fact, there is good reason to suppose that
most
of the species in any one genus are rare. Since the rarest are the least likely to be found, this in turn implies that within any one genus, only a minority of species (the commonest ones) have so far been identified (even after three hundred years of exploration, which in some areas has been fairly intense).

Dr. Mike Hopkins and his colleagues at the Brazilian EMBRAPA research center applied comparable chains of reasoning to the known distribution of various species of trees from several families and genera. As with all plants, a few species of Amazonian trees are fairly common over quite a wide area; some are common in one place but rare elsewhere; some are rare all over but widely scattered; and some are rare and seem to occur in only one or a few places. Any one area is liable to contain various species of any one genus, some common and some rare, some belonging to widespread species and some very local. From the limited data available—good studies of a few places, such as the Ducke Reserve, and scattered observations from elsewhere—and by making a few assumptions that are largely commonsensical, the botanists are able at least roughly to work out what the distribution of each species is liable to be. Thus if specimens of one particular species are known only from areas six hundred miles apart, it is obvious that there must be others in between, even though the others are not known. Either that, or the two specimens that are known are the last of their species and are simply waiting to go extinct. By such cogitations (reinforced by computer models), botanists are able at least roughly to estimate the distribution of the trees they have identified, as well as how densely they are liable to occur even in places that no botanist has yet visited.

By putting all such data and estimates together, and applying a series of mathematical projections whose details I won’t try to convey, the botanists can then work out, at least to a first approximation, how many species of plants (or trees) there are likely to be in any one place, and how greatly the list of species is liable to differ between any two places. They are able to do this (approximately) even though they have not visited most of the places they are making guesses about, let alone studied them. They are also able to estimate how many species in any one place are still unknown. Finally, and important, they are able to guess where the “hot spots” are liable to be: the places where there are liable to be most species. All this may sound too rarefied for words—guesswork running miles ahead of data, pulling itself along by its own bootlaces. Indeed, such ways of thinking are known generically as “bootstrapping.” In fact, the method is more robust than it may seem from this necessarily rough description. More important, the estimate arrived at is not just a guess, left hovering in space. It offers testable hypotheses, which are the stuff of real science. That is, if today’s botanists guess that such-and-such an area ought to contain a high number of species, with a high proportion of a particular genus, then, in the fullness of time, when more grant money is available, future botanists will be able to go out and see if the projections are true. The more the predictions do prove to be true, the more the calculations on which they are based are vindicated; and if they prove untrue, that is instructive too. In the short term, such estimates could have great significance for conservation—not least because it’s the hot spots, so far identified only on theoretical grounds, that seem most worthy of protection. In short: even if the estimates are wrong, they are definitely better than nothing.

2. KEEPING TRACK

Jose Eduardo L. da S. Ribeiro, ed.
Flora da Reserva Ducke.
Manaus: INPADFID, 1999.

1. At least a dozen different species of trees are marketed as “angelim.” All are from the family Fabaceae—but they do come from two different subfamilies. Thus from the subfamily Papilionoideae come at least half a dozen different species of
Hymenolobium;
at least another three from the genus
Vatairea;
plus a
Vataireopsis
and an
Andira.
From the subfamily Mimosoideae come
Zygia racemosa, Dinizia excelsa,
and the magnificent
Parkia pendula.
Similarly, the valued taurai tree commonly includes at least five species (and probably many more) from the Brazil nut family, Lecythidaceae. At least two of the alleged taurais are from the genus
Cariniana,
and another three (probably more) from
Couratari.

3. HOW TREES BECAME

1. Martin Ingrouille.
Diversity and Evolution of Land Plants
(London: Chapman & Hall, 1992). An excellent general outline of plant evolution.

4. WOOD

Aiden Walker, ed.
The Encyclopedia of Wood.
London: Quantum Publishing, 2001.

5. TREES WITHOUT FLOWERS

Aljos Farjon.
World Checklist and Bibliography of Conifers.
2nd ed. Kew: Royal Botanic Gardens, 2001.

6. TREES WITH FLOWERS

1. In particular I have in mind Heywood’s
Flowering Plants.

7. FROM PALMS AND SCREW PINES TO YUCCAS AND BAMBOOS

E. J. H. Corner.
The Natural History of Palms.
London: Weidenfeld & Nicolson, 1966. A classic by one of the twentieth century’s most original botanic thinkers. In the text I call it “Corner.”

9. FROM OAKS TO MANGOES

Thomas Pakenham.
The Remarkable Baobab.
London: Weidenfeld & Nicolson, 2004.

1. Thus while in the 1970s Heywood placed both the currants and the hydrangeas within the Saxifragaceae family, Judd (writing in 2002) separates the currants into the Grossulariaceae family and gives the hydrangeas their own family, the Hydrangeaceae—which, for good measure, he transfers to a quite different rosid order, the Cornales. Then again, while Heywood groups the American sweet gum (
Liquidambar
) in with the witch hazels (
Hamamelis
) within the Hamameliaceae family, Judd puts the sweet gums together with the ramara tree (
Altingia
), within the Altingiaceae family. At this stage of taxonomic history, with molecular studies and computer-assisted cladistics rapidly coming on board, life can be very confusing.

2.
Cercidiphyllum
is often traditionally classified alongside
Trochodendron
in the Trochodendraceae.

3. Rosaceae is such a big and various family that it has often been divided into tribes: Judd recognizes the Rosoideae (the group with roses) and Maloideae (the group with apples) and several smaller groupings that don’t seem to fit in either. The Maloideae in particular have a remarkable tendency to hybridize not only within species but even between genera.
Crataegus
demonstrates this in spades: Judd speaks of 265 species worldwide, but others estimate nearer 400; in any case, it is extremely hard to see which is a true species and which a hybrid, and which true species have arisen as hybrids of others. The same is true to a lesser extent of
Amelanchier
(with about thirty-three recognized species); for good measure,
Crataegus
and
Amelanchier
seem at times to have hybridized with each other.

4. Botanists have struggled ever since the time of Linnaeus to bring some order to the prodigious variety of oaks. There are more than twenty different classifications in the literature. But there are big problems. Some individual species of
Quercus
are enormously variable.
Quercus,
too, is among those many genera of trees that are prone to hybridize, so it can be hard to see where one species ends and the next begins. As we saw in Chapter 1, the concept of “species” seems to be far more flexible among trees (and, indeed, plants in general) than among animals—although even animals hybridize far more than was traditionally supposed. To cap it all, taxonomists cannot agree on which features reveal true evolutionary relationships and which are incidental. As things stand, many taxonomists at present split the genus into three “series”: the red oaks, restricted to North America; the white oaks; and a mixed bag of intermediates. Some kinds, however, including the holm oak,
Q. ilex,
do not seem to fit comfortably into any of these groupings. It seems best to treat this genus splitting as work in progress, and hope that in time the new molecular studies will throw more light.

5. From their origins in Southeast Asia oaks spread in all directions, and by the Eocene, around 55 million years ago, the fossils show they were common in China, Europe, and North America. This was a warm period: there were cycads, primarily trees of the tropics, as far north as Alaska. The world has been cooling fairly steadily ever since (although there have been a few warm spells). The pending greenhouse effect is returning us (roughly) to the climate of forty to fifty million years ago. Oaks diversified rapidly between thirty-five and five million years ago, a cooler and drier period that gave rise to the vast expanse of modern grasslands. Most of the several hundred modern species of oak were probably extant by fourteen million years ago.

11. HOW TREES LIVE

M. R. Macnair. “The Hyperaccumulation of Metals by Plants.” In
Advances in Botanical Research,
vol. 40, pp. vi–105. Amsterdam: Elsevier, 2003. On plants that tolerate nickel and other metals.

Peter H. Raven, Ray F. Evert, and Susan E. Eichhorn.
Biology of Plants.
5th ed. New York: Worth Publishers, 1992. A good general introduction to plant physiology.

1. The evolution of photosynthesis, somewhere around two billion years ago, changed the course of life on earth. The evolution of all creatures changed direction. The cyanobacteria (or their ancestors) that first evolved photosynthesis clearly lived at first in the absence of free oxygen—since before they developed photosynthesis, there wasn’t any. As those first photosynthesizers put more and more oxygen into the atmosphere, so they and all other creatures had to adapt to it (or stay out of its way, as some microbes still do, living in the depths of airless marshes). The adaptation of ancient creatures to the constant presence of oxygen gas was a huge physiological leap, of enormous evolutionary importance. Oxygen is very lively stuff, very reactive, and for creatures that can make use of it, it is extremely useful. In particular, creatures like us use it to break down sugars to provide energy by the method known as “aerobic respiration”; and aerobic respiration is fast and efficient. But for creatures that are not adapted to it, oxygen is highly toxic, one of the quickest and surest killers there is. (Creatures like us, who do make use of oxygen, still need to pack our bodies with “antioxidants,” such as vitamin C, to protect our flesh against its corrosiveness.)

As described in Chapter 3, the chloroplasts, which contain the chlorophyll within green leaves, have evolved from cyanobacteria that, in the deep past, lodged in the host cell.

2. The two forms are known as Pr and Pfr. Pr absorbs red light and Pfr absorbs “far-red” (which effectively means infrared) light. Pfr is biologically active, and causes things to happen. Pr is inactive, its presence leaving the plant unmoved. Light flips the pigment between its two forms, and thus provides an on-off switch. Red light shone on (inactive) Pr converts it to (active) Pfr; and far-red light shone on (active) Pfr converts it to (inactive) Pr. Sunlight contains both red and far-red, so Pr and Pfr are normally in equilibrium. At noon, with the sun at its brightest, about 60 percent of the phytochrome is in the form of Pfr. But in the dark of night, as the hours pass, Pfr steadily spontaneously degrades to become Pr: the active form decays into inactivity. Yet one brief flash will reconvert the accumulating Pr back into the active Pfr. In a long-day (short-night) plant, the burst of Pfr induces flowering. In a short-day (long-night) plant, it suppresses flowering.