ALEX COHEN, host:
This is DAY TO DAY. I'm Alex Cohen.
ALEX CHADWICK, host:
I'm Alex Chadwick.
New Yorker writer Richard Preston is best known for his science books - "The Hot Zone," "The Demon in the Freezer" - true tales of lethal viruses and bioterror. Now he goes overhead in his latest book. "The Wild Trees" describes a world hundreds of feet above Northern California in the canopy of coastal redwood forests.
Redwood trees are some of the tallest and biggest living organisms in the world. A small group of scientists is studying them with unusual devotion, a story that Richard Preston found, even though he wasn't exactly looking for it.
Mr. RICHARD PRESTON (Author, "The Wild Trees"): I was surfing the Internet and I came across a school in Atlanta where you could learn how to climb trees with ropes the way the pros do. It sounded terrific, and so I went down there and I began to learn these kind of rarified techniques for how you get up and down trees while using special ropes and gear.
Then I began hearing about these people who climb super tall trees - redwoods on the West Coast. And it occurred to me that this really would make a terrific piece of writing. So I proposed it to the New Yorker magazine and they sent me out there. And I got to know Steve Sillett and Marie Antoine, redwood forest canopy scientists - also husband and wife - who are climbing in the world's tallest forests. These trees are so huge that people who are climbing them can't communicate with the ground or with each other except with handheld radios.
CHADWICK: Because you climb out of sight in these trees, way out of sight.
Mr. PRESTON: You climb utterly out of sight. Try to picture this. These coast redwood trees which grow in these little rainforest valleys on the North Coast of California can be up to 30 feet across at the base. And then the big ones - that is, the massive ones - can rise 32 stories into the air. The tall ones are up to nearly 40 stories tall and they're proportioned more like a knitting needle; they're narrow, thins spears that go up into space.
When you get up into the crown of a redwood tree, you lose sight of the ground entirely. You also lose sight of the sky. And you're in a lost world. You're in an undiscovered, unexplored ecosystem, somewhere between heaven and earth, filled with forms of life, not all of which have been given names by scientists yet.
Everything from hanging gardens of ferns, to caves carved into the trees by forest fires, layers of soil sitting on the limbs - layers that can be up to a meter deep, filled with organisms, and then small trees growing on the branches of redwood trees. Trees of many different species - these are bonsai of the canopy.
CHADWICK: These are trees growing out of the limbs of redwoods, so these trees have trees growing on them?
Mr. PRESTON: Yes. Thickets of huckleberry bushes, with ripe berries hanging in them if it happens to be in the fall. You can stop and rest and eat the berries. Flowering Rhododendrons, Laurel trees, Hemlocks, Spruce trees, all growing in little places in nooks and crannies on the giant redwoods. It's an ecosystem in the air.
CHADWICK: Again and again, you tell stories in this of people in the trees. I have a fear of heights. It turns out that Steve has a fear of heights, but what happens up there?
Mr. PRESTON: Well, I'm afraid of heights too. And that's a very interesting question. I believe we're probably the only primate species that is afraid of heights. All other primates that I know of, when they're scared, they run up into a tree where they feel safe. But for some reason natural selection has programmed us to be very afraid of heights.
So yes, and when I'm up on a rope in a redwood tree, try to picture what this is like. You're hanging on a rope, like a thread. They're using military tactical ropes that are as thin as your pinky, and they extend 30 to 35 stories up into space, so you can't see the rope. It just disappears somewhere up there.
At times you get a profound sense of vertigo. And there have been times when I just had to stop what I was doing and just try to relax and remember that my equipment is good and that these are strong branches, and as long as I do everything correctly, I'm going to be all right.
CHADWICK: You follow Steve Sillett and Marie Antoine. In the course of climbing, in the course of falling in love with these redwoods and with each other, they actually become the top botanists in their field. I mean they know more about these redwoods and what happens to them than anyone else.
Mr. PRESTON: They do. And it is a rainforest. I think one of the things that I was amazed at myself was that California has rainforests in it. These are temperate rainforests where it doesn't get too cold in the winter or too hot in the summer. Forest canopy scientists - the people who study the great green ocean over our heads - have largely focused on the tropical regions of the Earth - the rainforests of the Amazon, for example, and Central America, because it was always thought that that was where the greatest biodiversity was and also because the tropical rainforests are so threatened by logging and burning and agricultural.
Nobody really had paid any attention to the fact that North America also has rainforests that are also very threatened and are filled with biodiversity and biomass. Redwood rainforest has five to 10 times the biomass; that's the sheer weight of living material, of, say, deep tropical rainforest in the Amazon basin.
Redwood rainforest is also anywhere from two to three times taller than tropical rainforest, but very little research has been done into them. We know precious little about what really exists in the air above California.
CHADWICK: But how is it that these growths could remain undiscovered. After all, these forests have been logged, many of them, and they're on public land. How is it that people don't get to them?
Mr. PRESTON: It's so incredible. I can almost not answer that question because I don't know myself, but the truth of the matter is that Redwood rainforest is exceedingly difficult to move through physically.
You get out in there and it takes a physically fit person up to 12 hours to move two miles; you're belly-crawling, you're crawling through thorns, your skin gets all bloody, you can't see anything, it's absolutely thick, and then you come across these piles of redwood trunks that have fallen down like pick-up sticks.
These are trunks that are anywhere from eight to 12 feet in diameter piled up, and as you climb over them...
CHADWICK: And they weren't logged. They're lost in storms or...
Mr. PRESTON: These are natural wind-falls, dead-falls that accumulate one after the other until you get a wall of wood that may be 30 feet tall, and as you climb over it, if you slip down into a crack, you can fall into the pile, fall 30 feet and break your leg and never be heard from again.
CHADWICK: Well, that would explain why people don't go back into these forests. Even so, the idea that at the end of your book they actually do find what they think is the world's tallest tree, and indeed no one had ever seen it before.
Mr. PRESTON: I had actually finished the manuscript of "The Wild Trees" and turned it in to Random House when all of a sudden word came. Michael Taylor and his colleague, Chris Atkins, another explorer, have just knocked one out of the park. They found the world's tallest tree.
The tree is named Hyperion, 379.1 feet tall. It grows in a small, hidden valley inside the borders of Redwood National Park. I informally call it Hyperion Valley. The valley itself may not have had visitors in it in about 30 years. Probably timber cruisers went through the valley about 30 years ago when there was a lot of logging going on near the park.
So we were completely stunned, and it ended up being an expedition. There were four climbers - I was one of them - and we made the first climb of Hyperion. I interviewed Michael Taylor; he came along to watch the show. Michael Taylor is desperately afraid of heights. He may or may not ever climb a redwood tree. He certainly hasn't done it so far. And I asked him, you know, how in the world did you ever find this tree? And he said the secret of success is just don't ever stop, just don't give up, and when somebody tells you something is impossible, do it first and then keep going.
CHADWICK: Richard Preston is the author of "The Wild Trees: A Story of Passion and Daring" about redwoods and the people who climb them. Richard, thank you for speaking with us on DAY TO DAY.
Mr. PRESTON: It's been lovely to be with you.