National Geographic : 1990 Oct
WORKING AND SLEEPING aboard a raft where the treetops interlock reminded me of sailing. When the wind came up, the raft undulated on the ocean of green that is the tropical rain forest canopy. With my eyes closed I could imagine myself at sea, except for the sounds: monkeys, insects, birds, frogs, their separate voices becoming a single chorus. True to its name, the rain forest is wet. Our study area received about four meters (155 inches) of rain during the year of our visit. The transpiration of water vapor was so intense that at night it seemed to rain up. By morning everything RENCH GUIANA was soaked. (FRANCE) By day, seen from a bird's-eye EQTO view, the canopy is the true face of the forest- BRAZIL bright and abounding with life. Most of the SOUTHAMERICA forest's biological diversity is found at the top. Yet relatively little is known about this canopy. Much of our ignorance is due to logistical problems. In trying to solve them, my colleagues and I had used a number of approaches but found all of them wanting. Relying solely on climbing ropes is uncomfortable and dangerous. Towers per mit some proximity, but to only a few trees in a vertical column. Elevated walkways don't always touch the canopy, and they restrict the area of study. Our solution was to build a raft light enough to settle safely on the treetops for prolonged access and employ a dirigible to move it about. The part of the French Guiana rain forest where we deployed the raft is uninhabited by humans. Elsewhere in South America and on other continents, the tropical forests are disappearing at an alarming rate, as vast swaths are harvested by loggers and burned to clear land for agriculture. If the destruction isn't stopped, the virgin forests could be gone in 25 years. The resulting environmental damage would be incalculable, and mankind would lose an irreplaceable resource: the gene pool inherent in tropical plants. A researcher seeking to develop a disease-resistant banana, for example, would have no place to search for hardy, wild plants of the same family to cross with commercially grown varieties. Pineapples, coffee, cacao, oranges, avocados, cassava-all warm-climate plants-could be improved by properly using the genetic resources of the tropical forest. But to me, all this is secondary to the fundamental reason for saving the rain forest: It was here before man arrived. We have no right to destroy it. FRANCIS HALLE, a professor of tropical botany at the University of Montpellier, France, has studied rain forests in 20 countries. Free-lance photographer RAPHAEL GAILLARDE lives in Paris. This is his first NATIONAL GEOGRAPHIC article.