Air Date: Week of April 18, 1997

One of the least explored environments on earth is the canopy of rainforests high above the forest floor among the branches of tall trees is a living web of thousands of plants and animals. It is home for hundreds of birds and reptile, tens of thousands of insects and countless numbers of microbes. Recently, scientists have begun a systematic study of the rainforest canopy, and one of their favorite sites is in Panama where the Smithsonian Tropical Research Institutes operates a crane that gives scientists unprecedented access to this natural world. Living on Earth contributor Bob Carty went up and along for the ride, and sent us this profile of the people who work at the top of the trees.

Transcript

CURWOOD: It's Living on Earth. I'm Steve Curwood. One of the least explored environments on Earth is the canopy of rainforests. High above the forest floor the branches of tall trees create a living web of thousands of other plants and animals. It is home for hundreds of birds and reptiles, tens of thousands of insects, and countless microbes. Recently, scientists have begun a systematic study of the rainforest canopy. One of their favorite sites is in Panama. Here the Smithsonian Tropical Research Institute operates a crane that gives scientists unprecedented access to this natural world. Living on Earth contributor Bob Carty went up and along for the ride, and sent us this profile of the people who work at the top of the trees.

(Music up and under: Aaron Copland's "Appalachian Spring." Fade to and blend with rainforest sounds: bird calls and other animal calls)

CARTY: Six o'clock in the morning on the edge of Panama City. The sun has been up for half an hour, but here in the Metropolitan Park rainforest, a roof of branches and leaves 10 stories above makes the trail below seem like a darkened tunnel.

(Calls continue)

CARTY: At the end of the trail, the square metal leg of a construction crane sits on a cement base and disappears up into the trees. A few yards away, a cable hangs back down through the branches and a young woman works to clamp it to a steel cage.

(Metal clamping sounds)

LOVELOW: My name's Catherine Lovelow, and I'm a postdoctoral fellow from Australia. This little cage that we're in is called a gondola -- well, that's what we call it. Fits about 3 or 4 people. We've just hooked it up and we're heading up to the canopy.

(Metal sounds continue; fade to bird calls)

WRIGHT: My name is Joe Wright. I'm a research biologist with the Smithsonian Tropical Research Institute. Opening the canopy with these cranes has been a tremendous breakthrough. The canopy is one of the final frontiers for biologists on the planet; just the force of gravity has kept us out of there. It would be like a marine biologist who was stuck at the surface and could just look down at the coral reef. We were in the same situation. We were stuck on the ground and we could only look up. And something like 90% of the leaves in the forests are up there in the canopy.

(Metal sounds continue)

LOVELOW: So you'll notice as we're coming up here, the light change. It was very dark down at the bottom and now, as we're coming to the top we're getting into low humidity, a bit more breeze, and lots of light.

(Bird calls)

LOVELOW: So we've got this amazing view of the Bay of Panama and Panama City. But if you look back across the isthmus we've got lots of forest.

(Bird calls)

LOVELOW: We're about -- oh, 40 meters above the ground, just hanging here, swaying a little bit. And now I'm going to get Jose, the crane driver, to take us for a little bit of a tour.

(Metal sounds)

LOVELOW: So now he's taking us out to the very end of the -- the crane's arm. Actually, I'm not that comfortable with heights but up here -- I mean, I've just been up here enough that it doesn't bother me any more. I'm happy.

(Metal sounds)

LOVELOW: You feel that nice breeze as we're going along? Nothing better than when the sun's out and you're baking up here, like you're in a little oven. And then he whisks you somewhere and you get a nice breeze.

CARTY: The canopy crane gives researchers access to 8,000 square yards of jungle top. But the roof of the rainforest is not flat. It is a rolling topography of peaks and valleys. It is so densely matted that in places only 1% of the sunlight reaches the ground. A large tree supports up to 20 tons of other life. Vines, mosses, ferns, epiphytes, animals, and insects. One acre of canopy supports a population of 2 million insects.

WRIGHT: We've had a Norwegian graduate student studying just 2 families of beetles, the weevils and the leaf beetles. And after about 600 cumulative hours of work on the crane, he'd identified a total of about 1,100 totally new species. One big question in biology today is how many species are there out there? Fifteen years ago they might have said 5 million species total on the planet. But there's now good reason to believe that there are actually tens of millions of species of insects in the canopies of tropical forests.

LOVELOW: Ah -- let's go down. (Shouts in Spanish.) Oh, there are the ti-ti monkeys; they're beautiful. They look like they've got little Mohawk haircuts to me. The animals that we see most here are ti-ti monkeys, which are these little tiny monkeys with strange little hair cuts; sloths; and iguanas. They're the most obvious animals. And then there are lots of birds.

(Music up and under; fade to and overlap with bird calls)

WRIGHT: Traditionally, biologists have gotten into the canopy by climbing ropes. Once up there they've connected walkways between trees, like the movie Medicine Man. Our canopy crane represents a qualitative breakthrough in that we aren't supported by the trees. It allows us to get to them without disturbing them.

LOVELOW: Jose --
I'm telling him now to go down to one of my experimental trees. I'm working on the influence of elevated carbon dioxide levels. The carbon dioxide level in the atmosphere has been slowly increasing because of burning fossil fuel. We have to find out whether the trees will soak up the extra CO2. I mean, because plants need and use carbon to grow. We're coming up to the side of a tree where I have CO2 enrichment chambers around branches.

CARTY: And what have you found?

LOVELOW: You think when you add more carbon that they're going to grow more, but that doesn't appear to be the case. The forests may not act as a big sponge for the extra CO2. That means high CO2 levels, warmer planet.

(Bird calls)

LOVELOW: All right. I've just asked the crane driver to take us up and over this big anacardium tree and back down to the ground.

(Metal sounds)

CARTY: The rainforest canopy may not be a sink for the world's greenhouse problem. Still, it may become the top shelf of the drugstore, a warehouse of new pharmaceutical compounds. Canopy cranes are now exploring forests in Washington State and Venezuela. Another crane is coming to Panama. Scientists are just getting to know the canopy. At the same time, each year human activity destroys at least 23,000 square miles of rainforest: an area the size of Vermont, New Hampshire, and Massachusetts.

(Metal clanking sounds)

CARTY: For Living on Earth, I'm Bob Carty in Panama.