February 18, 1999
University Gazette


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Saving Plants that May Save Us

By Alvin Powell

Contributing Writer

Carlos Gomez, a member of the Baré group from the upper Rio Negro, is covering an empty bottle with a strip of "mamure" (Heteropsis spruceana), that will be used as a handle.

The compound stopped AIDS dead in its tracks, but they nearly lost it.

It was an extract of a small tree in the Bornean forest called Calophyllum, but when researchers rushed back to the site where it had been collected, the tree had already been cut down. They took samples from Calophyllum trees nearby, but extracts made from those trees proved ineffective against the AIDS virus.

It was a bit of a mystery. To solve it, they called on the Harvard Herbaria, which had a preserved sample from the original tree, collected in 1987 by Harvard researcher John Burley on a mission for the National Cancer Institute.

The sample was examined by Peter Stevens, a Harvard biology professor and a Calophyllum expert. He identified the original tree as a variety normally rare in the forests where the specimen was taken.

Once they knew what they were looking for, scientists found living specimens of the right Calophyllum variety in the Singapore Botanic Garden. Sure enough, an extract proved effective against the AIDS virus.

That discovery has not only led to an anti-AIDS drug that is in human testing, it also highlights the importance of facilities like the Harvard Herbaria and Arnold Arboretum in storing and preserving the important information found in plants.

In the Herbaria's case, scientists routinely send dried specimens of different plants they've collected for cataloging and storage. This not only gives the Herbaria an enormous collection -- it recently preserved its 5 millionth specimen -- it also creates a well of information that scientists can dip into, examining or testing a specimen firsthand rather than reading about it in a textbook.

"Whenever you want a piece of knowledge, you go to the library. If you want to see what a plant looks like, you go to the herbarium," said Otto Solbrig, Bussey Professor of Biology. "It's a tremendous repository of knowledge. And it's fairly cheap. To take out all that knowledge, publish it and put it in a library would be very expensive."

The Arboretum provides a similar repository, but for living woody plants. In recent years, the Arboretum has repatriated specimens to China that had become rare in the years since the Arboretum samples were collected. And one of today's common ornamental plants, Metasequoia, once thought extinct, owes its distribution to the Arboretum, where the plant was propagated and seeds collected.

The Arboretum has 5,000 specimens spread out over 265 acres in Boston and contains one of the largest collections of Chinese plants outside of China.

The furniture, baskets, and brooms made from the aerial roots of "mamure" are sold on a street corner at the Puerto Ayacucho public market.

Peter James Del Tredici, director of living collections at the Arboretum, said the Arboretum tries to obtain specimens from the wild as much as possible, to preserve the bloodlines -- or "saplines" as the case may be -- of the wild plants.

"The real strength of our collection is we know where everything was collected, what mountain, what road," said Del Tredici. "It allows people to do research with our collection."

Preserving Plant Uses

Harvard researchers in the field are preserving not just plants, but the knowledge of how they're used.

In the Venezuelan Amazon, local craftsmen make and sell furniture made of the roots of particular epiphytic plants, or "trees on trees" as Harvard researcher Gustavo Romero likes to call them. Epiphytic plants are those that grow above the ground, on other plants, with roots that get nourishment from the air. The furniture production makes up about 10 percent of the local economy, directly and indirectly employing 500 to 1,000 people.

As important as its economic benefit is the fact that the industry makes the forest valuable in its natural state, rather than as pasture or farmland, at a time when forests are rapidly disappearing around the world.

A problem arose in 1996, however, when more of these "trees on trees" were being cut to meet growing demand for the wicker-like furniture. United Nations development officials realized they didn't even know what the plant was, never mind whether it was being over-harvested. So they sent in Romero, an orchidologist and ethnobotanist at the Harvard Herbaria, to observe the local people and assess the situation.

"We go in and interview people. We go out with them into the field and they show us what plants they harvest and how they collect them," said Romero, who is the keeper of the Orchid Herbarium of Oakes Ames. "It was being locally over- harvested."

After investigating, Romero found that the locals were using the aerial roots of the vine and that these roots would re-grow from a clean cut, but not if they were hacked, twisted, and torn off.

Armed with this knowledge, the local people adopted new techniques for harvesting that would ensure an adequate supply of the "trees on trees."

The work of Romero and other ethnobotanists aims to preserve plants in their home environments. He continues to travel to the Amazon twice a year, spending weeks at remote field sites or small towns, hiking or traveling by boat from there to collecting spots.

Romero said he enjoys his time in the field despite the sometimes oppressive heat. He doesn't worry much about snakes or large animals when in the field, but insects are a constant nuisance.

Black flies and mosquitoes are omnipresent and complemented by a variety of ticks and chiggers, not to mention ants that will clean out any food stored improperly and termites that can transform an ordinary backpack into a cozy nest in an amazingly short time.

In the field, the day usually begins at 7 a.m. with a trip, sometimes several hours long, to the collecting site. On site, Romero will observe the local plant life and the people collecting it. He pays particular attention to orchids, which are his specialty, collecting samples for drying before starting the trip back.

Romero is concentrating his efforts on finding economically valuable uses for the forest. Though the preservation of medicinal plants has gotten a lot of attention recently, Romero believes medicinal plants alone can't stop development.

"I don't believe under the current system that you can preserve a chunk of land just because of a medicinal plant. You have to have a multiple usage base so you can argue that it must be saved," Romero said.

To do that, Romero is turning to the local people, who have been using the forest for centuries. He believes it's important to preserve their intimate knowledge of the forest and the plants in it, before that knowledge is lost.

"People are working on ways to save the forests. The questions that need to be asked are, 'What plants are the local people going to cut? How often? How much?' " Romero said. "The techniques they use, that's the part we're losing. How to weave, how to harvest, that's just as important as medicinal uses."


Copyright 1999 President and Fellows of Harvard College