How Peter Raven transformed what we know about plants

Well before dawn Peter Raven walks out the back door of his house in St. Louis and up a path to a low, modern building faced in glass that in daylight reflects the surrounding grounds of the oldest institution of its kind in the United States. For the past 19 years Raven has been director of the Missouri Botanical Garden, which he has transformed into a landscape of exceptional beauty. His alarm at what is happening to tropical rain forests, however, has caused the garden to transcend aesthetics and become one of the world's leading centers for tropical botanical research. 

At least two-thirds of all species live in the profuse rain forests of the tropics. Yet, as Raven points out, these forests are being rapidly cleared and burned, extinguishing species and the genes of evolution. This also accelerates climatic warming by loading more carbon dioxide into the atmosphere through burning and by removing trees, which, by photosynthesis, absorb carbon dioxide. In something less than geologic time, the corn belt may become the dust bowl. 

Raven leans forward in a loping gait, a tall, somewhat jowly man of 54 in a blue pin-striped suit. He unlocks the entrance door and heads for his office, on occasion startling the bejesus out of some poor graduate student working overnight in the herbarium. 

The herbarium, below Raven's office, is a repository of nearly four million specimens of pressed, dried plants, which have been carefully mounted on acid-free paper, labeled, and stored on open shelves in movable orange bins. Among them are collections from Captain James Cook and Charles Darwin. Each year the collection expands by 120,000 more specimens shipped in from around the world. Smelling faintly of dead grass, the herbarium is the botanists' encyclopedia—a palpable record of what grows where on earth and what is rapidly disappearing. 

"Think of it," Raven said to me. "All this deforestation is destroying each year an area roughly the size of Illinois. About one quarter of all biological diversity in the world—more than a million species—will likely vanish in the next quarter century. No extinction episode of this magnitude has occurred during the past 65 million years. The great majority of these species—and their potential for humanity—will disappear unknown. That's one reason we are dedicated to the collection and identification of plants."

One needn't have a lifelong affection for plants to appreciate how our survival depends on photosynthesis, and how much of what we eat is plants, or burgers or chops derived from grass, and that the aspirin we take for headaches originated with willow bark. Roughly 25 percent of all prescription medicines in the United States are derived from plants, including alkaloids from the rosy periwinkle of Madagascar that have arrested childhood leukemia and Hodgkin's disease. As the garden's botanists document what is still growing in the tropics, they are, by no stretch of metaphor, in a profound race against the clock. 

David Neill and Cal Dodson are among ten of the garden's 39 Ph.D. botanists spread across the tropics, living where they collect specimens. In the brilliant light and thin air of the high Andes the two men leave their apartments in Quito, Ecuador. Cal, a world expert on orchids, heads toward the Andean cloud forests. David drives east toward the Oriente, the Ecuadorian portion of the Amazon basin. He studies tropical trees. 

David, 37, lanky, russet-bearded, steers down the east face of the Andes in a dilapidated Chevy Suburban, passing torrents of Amazon drainage and cows perched on slopes that would alarm a goat. Six hours later in the humid lowlands, the darkness accented by beeping frogs, we pull up to a small sign reading ESTACION BIOLOGICA JATUN SACHA.

Jatun Sacha—"big forest"—in Quechua consists of a few hundred acres of virgin rainforest that David has helped preserve with his own savings. His research shows that more species of trees may exist in a few dozen acres at Jatun Sacha than in all the United States east of the Mississippi. Here in the Oriente, where oil drilling since the early 1970s has brought roads and settlers, about a third of the rain forest has fallen to the chain saw.

To get into parts of the Oriente he can't reach by canoe or Suburban, David hitches rides in oil-company helicopters. Stuffing his cuttings into plastic bags, he moves on, eventually kneeling in the forest to fold each specimen in a page of newspaper, recording the species, if he knows it, and where and when he collected it. A cluster of grape red flowers goes into the comics of Quito's El Comercio. 

When the stack is precipitously tipping, David puts it in his plant press—two latticed frames of hardwood cinched with nylon straps. Back at camp he places the cuttings in a tublike plant dryer, lights the kerosene, and dries them for 24 hours. Shipped to St. Louis, they will be labeled and checked by other taxonomists and mounted for storage. 

David unloads his gear from the Suburban, heaves a coiled rope and sections of a 42-foot aluminum pruning pole onto his shoulder, and hikes up a forest trail to the station. In a clearing stand four bunkhouses, a kitchen/field office, a caretaker's house, and an out house for four (with view). In equatorial Ecuador, days and nights are almost the same length, and the sun goes down early. We eat and go to bed. 

The next day we walk into the rain forest—uniformly green, dim, quite passable, the air emphatically still. In the distance a chain saw is groaning. Tripping over a fallen limb, I fall flat on my face, confirming that tropical soils have all the organic cushion of macadam. With no winters to kill insects and with ample heat and humidity to encourage them, organic matter decomposes so quickly that only a thin layer of fallen leaves and twigs covers the soil. The luxuriant forest feeds on itself through fungi, which draw nutrients from this detritus into the roots—a closed system of nutrition that virtually bypasses the heavily leached soils.

Clear a temperate forest and it comes back quickly. Log a rain forest and the sterile soil becomes hot pavement. Centuries may pass before there is rain forest again. Many species will have vanished forever. 

To identify a species, botanists prefer to collect when the plant is in fruit or flower. David assumes the working pose of a tropical botanist: head tilted back, binoculars to his eyes, looking straight up. Flowers and fruit 50 to 100 feet overhead seek light above a canopy of trees. Many tropical plants are epiphytic, meaning they grow on supporting trees, often far out of reach of his pruning pole. 

"We'll find flowers littering the ground," he says. "Then we have to find out where they came from and climb the tree. It can be difficult and scary. Some botanists are really gung ho about climbing trees. Not me."

Ants are profuse in tropical forests and often live in trees. So do wasps. Tom Croat, a garden botanist whose large, scarred hands are proof that botany is no delicate calling, was once climbing a tree in Panama when his nose reached a wasp nest. He kicked his leg spikes free of the bole, intending to rappel down the tree with his safety belt. But his rope snapped, and he fell 75 feet like a stone, crashing against a root buttress. He was able to wiggle his toes. That day he climbed again. 

David and his Ecuadorian colleagues are seeking Minquartia guianensis, a tree used throughout the Amazon region because it resists rot. Medicine men use its bark to fight intestinal parasites, bronchial disorders, and tuberculosis. Despite the tree's importance, foresters know almost nothing of its natural regeneration and population dynamics. They can't do tree-ring analysis for dating because trees in the tropical rain forest grow year round and lack rings. 

For hours we bushwhack through a study section of Jatun Sacha in search of Minquartia, sliding down muddy draws. David turns up only ten. "That's a pretty good average," he says.

In any temperate forest, such as a grove of oaks and hickories in Missouri, you find numerous trees but only a few species. Tropical forests are just the reverse: Individual populations are small and scattered, but the number of different species is enormous. A single tree in Peru harbors as many species of ants as exist in all the British Isles. Within walking distance of their camp, David and his colleagues have identified 1,500 plant species. He believes they are probably only half of what is here. 

On the other side of the Andes, in Ecuador’s coastal lowlands, Cal Dodson checks the orchid pots at his farm at Río Palenque. The entire U.S. has no more than 200 species of orchids. Ecuador boasts 2,670 known species, and Cal has collected more than 2,000 of them. He brings specimens to his farm and grows them until they flower, so he can identify the species. 

When Cal arrived here in the late 1950s, there was forest everywhere. Since then the population of Ecuador has almost tripled, forcing open the western lowlands to roads and banana and palm-oil plantations.

"It took only about 20 years for western Ecuador to evolve from primeval forest to farmland," he says. "Only 6 percent of the coastal lowland forest is left, and that is rapidly going." 

Cal points to a tree behind a storage building. "Río Palenque mahogany—the most prized wood in all western Ecuador, because bugs don't destroy it. And here everything decomposes quickly. It used to be common. Now there are only 12 mature trees left in the world, and they're all on this property."

The Missouri Botanical Garden is one of three institutions collecting tropical plants for the National Cancer Institute in hopes of finding new drugs for treatment. But that's not Cal's motive for being in the tropics. He wants to know what's growing here and how it survives, how it is that the male tachinid fly will mistake a particular orchid flower for a female fly, hop on to mate, and inadvertently pollinate an orchid. 

"I suspect that we know a good deal more about the universe than we do about tropical forests. People ask, 'What are you doing down here?' We say, 'We're looking for the cure for cancer.' They say, 'Oh, yeah, that's important.' But the real reason we're here is to learn more about the tropical world." 

The Missouri Botanical Garden is a few minutes from downtown St. Louis, its 79 acres surrounded by brick houses owned mainly by descendants of the city's German and Irish immigrants. Italians had settled just west of the garden to mine the clay for this brick that so dominates St. Louis architecture.

Natives are inclined to refer to it as Shaw's Garden. Henry Shaw, who founded it, came to St. Louis in 1819. The 18-year-old English man saw in the nearby frontier a market for cutlery and hardware he could ship in from his native Sheffield. Amassing a fortune, he invested in St. Louis real estate. In the 1850s, while visiting the gardens at Chatsworth in England, Shaw was inspired to put his landed wealth to public purpose. 

Planning a public botanical garden—the first in the U.S.—on his country estate, he was guided by the eminent botanists Sir William Jackson Hooker of the Royal Botanic Gardens at Kew, England, and Asa Gray of Harvard. But it was the St. Louis physician and botanist George Engelmann who persuaded Shaw to make his garden not just a display but a scientific institution as well. 

Shaw endowed the Henry Shaw School of Botany at nearby Washington University, donated land adjacent to the garden to St. Louis for a park, willed the garden to a trust and the bulk of his estate to its maintenance. It wasn't enough. The garden for a time got into the business of selling orchids. By the 1920s, coal smoke from the city became so oppressive that the gardeners couldn't see from one end of the greenhouses to the other. To save the huge orchid collection, they removed it to the arboretum, a large farm purchased farther west. 

For years the garden slid into neglect. By the 1950s, as glass was falling out of the greenhouses, a consultant recommended that the garden give up botanical research and turn over its herbarium and fine botanical library to Washington University, steps that would have reduced the garden to a historical relic. John Lehmann, a wealthy lawyer, took over the board of trustees, donated $10,000, and began to open up the wallets of St. Louis. 

In 1960 the garden finally came out of the doldrums with completion of the Climatron. This geodesic-domed greenhouse displayed some 1,500 species of tropical plants under plexiglass panels suspended from a frame work of aluminum tubing. The Climatron was conceived by former director Frits Went, a plant physiologist who had expected its unusual circulation system to create four different climatic zones. The plants themselves defeated the engineering. 

"Went had hoped for sharper gradients," Peter Raven told me. "But the Climatron essentially created two zones: warm on the lower end and cooler at the upper end." The plexiglass became so pitted that it reduced the sunlight, and it was eventually replaced with glass. After a multimillion-dollar restoration, the Climatron reopened in March 1990. 

On a warm April day Raven walked me around the garden. Redbud trees were in flower, and dogwood, cherry, tulips, pansies, and the aromatic Judd viburnum. A garden volunteer led a group of schoolchildren past us, their noses dusted yellow and black with pollen. "We're pretending we're bees." 

We strolled by Shaw's Italianate summer villa, pausing on a bridge over the pond. Raven looked down at the carp assembling in open-mouthed anticipation of bread crumbs and sighed. "Ah, to be a carp in April." 

Coming to St. Louis in 1971, Peter Raven expanded the garden and gave it a dramatic face-lift-the English Woodland Garden and the Japanese Garden, a visitors center, sculptures and fountains, and myriad details of taste. His vigorous style of leadership is admired in St. Louis: "Raven has turned a sleepy little botanical garden into a world-class institution. He's got charm, humor—as tight as money is in this city, he can peel thousands of dollars off people." 

When one of the garden's fundraisers expressed his frustration at being stonewalled by a donor, Raven smiled, his mouth a straight line turned up at the corners. "There's no such thing as a permanent no." 

A respected scientist on the governing boards of national scientific societies and honored internationally, Raven published the first of more than 300 papers when only 14—on collecting plants in the High Sierra. "I knew that writing scientific papers was important. I began to find my identity by doing that," he said. 

Raven was only two when his father took him for the first of many visits to the California Academy of Sciences' Natural History Museum, near his home in San Francisco. "I had the idea of writing very early," he told me. "I spent a lot of time copying things about beetles out of books. By seven or eight I was writing about butterflies and birds." He carted caterpillars around in his red wagon and thought about how they would become butterflies. Then he collected the butterflies. 

Soon his interests widened to plants. He would find a plant in flower, fasten it to a piece of notepaper with Scotch tape, and press it between the pages of the telephone directory. His first herbarium was his bureau drawer. "As a boy I went all over by Greyhound bus, collecting plants."

Raven's curiosity continued to widen. His college studies and collecting took him to the Natural History Museum in London, the Royal Botanic Gardens at Kew, Costa Rica, and New Zealand. In Colombia he got his first taste of the tropics and of human misery. 

"I saw a lot of poverty—not the stereotypical smiling children. Teaching at Stanford, I became friends with Paul Ehrlich—my office was next to his." Ehrlich and Raven developed the theory of coevolution, how animals, by what they choose to eat, and plants, by the chemicals they produce, influence the other's evolution. "I got very interested in population and in the overuse of world resources." 

When Raven came to St. Louis, the garden's research program consisted of only three Ph.D.'s, and its tropical effort was Tom Croat collecting in Panama. Raven hired Al Gentry to go into the Chocó of Colombia, Peter Goldblatt for Africa, and Gerrit Davidse for Central America. He put two botanists in Madagascar, directed by Pete Lowry in Paris, where the National Museum of Natural History has the largest herbarium of Madagascar plants. 

The garden now has botanists in the Field Museum of Natural History in Chicago, London's Natural History Museum, and many countries in South America and Africa. "A lot of institutions would have insisted that they be here," Raven said. "But I have always wanted to put people where their work is." 

I was in Raven's office one day as his staff tried to make order out of his hectic schedule. He would be speaking the next day at the University of Massachusetts and had scribbled a note to his wife: "Going to Mass. tomorrow." His handwriting admits of interpretation. She telephoned him: "I have this note that says you are going to Mars tomorrow."

In China botanists have been patiently cataloging their 28,000 known plant species in 120 volumes. Concerned that this would be useful only to those who read Chinese, Peter Raven encouraged the Chinese to collaborate in publishing an abbreviated English version of the Flora of China. (The garden is also involved in producing floras of North and Central America, Madagascar, and various countries in South America and Africa.) He brought in a delegation of Chinese botanists and other experts on Asian plants to work out details, the agreement being signed in 1988 in a public ceremony among the garden's lacy trees. 

At the ceremony Raven pointed out that 20 percent of China's plants are used in medicine. He held up a chunk of shale containing a 62-million-year-old fossil of a coniferous tree—Metasequoia, or dawn redwood—long thought extinct until a forester in the 1940s found some growing near a mountain village in China. Seeds arrived in 1947 at the garden. In the filigreed shade of Metasequoia, Raven's voice rose: "We're in an environmental crisis. In the next 25 years one-fourth of the 250,000 plant species of the world will be in danger of extinction."

Raven stirs audiences on the consequences of rain forest destruction. He reminds them that we survive by the ability of plants, algae, and some bacteria to photosynthesize energy from the sun. "We are consuming, diverting, or wasting 40 percent of that production—in large part by deforesting the tropics—and will face enormous difficulties in the future, as world population is expected to double by the middle of the next century." 

When Raven speaks, his body swivels from side to side. "The 1.1 billion people who inhabited the tropics and semitropics in 1950 will grow to about five billion people by 2020—more than quadrupling in just 70 years. One billion live in absolute poverty. Each year some 13 million people—mainly children—starve to death in the tropics. It's morally indefensible." 

He says that the poor are pressed into clearing forest for firewood and food just to stay alive, while the developed world demands hardwoods, beef, bananas, and other products that tropical countries, deep in a trillion-dollar debt, provide by clearing more forest. 

"Rice, wheat, and corn supply more than half of all human energy requirements," he continues. "However, there are maybe tens of thousands of additional plants that could provide human food if their properties were fully explored and they were brought into cultivation. Many of them come to us from the tropics. Oral contraceptives for years were produced from Mexican yams; muscle relaxants come from an Amazonian vine traditionally used to poison darts."

Raven believes that the U. S. and other countries, for charity and self-interest, should help the world's poor to farm cutover lands, replant trees, and save what rain forest is left. He hopes this will happen on Madagascar, which holds about 5 percent of the world's species, some 75 percent found nowhere else. "Unfortunately," he says, "much of the island is now degraded pasture." 

With support from the U. S. Agency for International Development, garden botanists are helping the Madagascar government establish a huge national park in what is left of the rain forests in the northeast. They are encouraging neighboring villages to develop plans to reduce pressure on the forests. 

Raven wants to show that there are positive alternatives to the ax. As he says, "People won't want to do anything if all you say is, 'Oh, isn't it awful about what's happening to the rain forests?'"