The ascent offered everything Cornell's climbing wall lacks: red-eyed tree frogs and in-your-face howler monkeys, monster-movie spiders and cartoon-colored toucans, pink bromeliads filled with water and animal life, and a toucan's eye view of the Costa Rican rain forest that "seemed like it went on forever."

Safely back in Ithaca, the 12 students from BioES 400 (Canopy Biology and Canopy Access in the Neotropics) are glad they learned climbing fundamentals on indoor rock before heading up the Virola trees. "The only moment I've thought about my death came and went in the tree while taking measurements with strong winds swinging me in all directions," recalled Erin Lindquist, a junior in Cornell's College of Agriculture and Life Sciences (ALS). She was measuring relative humidity by twirling a sling psychrometer in the Cerro de la Muerte region of Costa Rica, where solid ground is already 10,000 feet above sea level and trees have nowhere to go but up.

"I saw my life flash before me," Lindquist said. "My adrenaline was at its max."

Not to worry, dear parents of students who spent Dec. 31 to Jan. 16 in a rare experience of "higher" education. Lindquist, like her fellow students and instructors, knew what to do next. She maneuvered herself into a stable crotch of the gyrating tree, reconfigured her climbing gear and rappelled 60 feet to the ground. Or rather, the "understory," as they say in the rain forest.

Besides the montane oak forest of Cerro de la Muerte, the two-week, one-credit field course, run jointly by Cornell's Ecology and Systematics and Outdoor Education departments, took the biology undergraduates to the lowland rain forest of La Selva and the dry forest of Santa Rosa in western Costa Rica. They will earn another two course credits by writing up their research findings this semester.

And the neotropical flora and fauna they found could fill an encyclopedia. The list of birds alone runs to six typed pages, from Tinamus major (the great tinamou) and Selasphorus flammula (volcano hummingbird) to Cacrduelis xanthogastra (yellow-bellied siskin).

"After hearing about the fer-de-lance vipers, bullet ants and killer bees, I was a little nervous," Audrey Taylor admitted. But the Ag College junior knew the four Cornell instructors were not run-of-the-mill tour guides.

Deedra McClearn, assistant professor of ecology and systematics who organized the field course, has been conducting canopy research in Panama since 1990. She led a 1994 canopy research course in Costa Rica for the Organization for Tropical Studies (OTS), the organization that provided many of the arrangements for the January Cornell course.

Dan Tillemans, director of the Cornell Outdoor Education Program and another leader of the 1994 OTS canopy course, has 20 years of experience in wilderness expeditions. Like Tillemans, biology graduate student and teaching assistant David Able also is a certified rock-climbing instructor.

Kevin McGowan, curator of the university's ornithology and mammalogy collections, is a senior research associate who goes where the birds are, climbing into temperate forest canopies since 1989. Generations of crows in Ithaca wear coded wing tags because McGowan ascended to their nests.

What impressed students most was the incredible biodiversity of Costa Rica. Emily Hudson remembers crossing a suspension bridge from La Selva's base camp "into another world. It was like a wildlife mecca," the Ag College senior said, "as if this were the favorite place on the whole planet for most organisms."

And she was still on the ground at that point. One hundred and five feet up in the rain forest canopy is where the action really is, according to Luis Raul Padilla, an ALS senior who was testing a nightime photography device he designed to "shoot" marsupials. "Not many professional biologists have this kind of access to the trees," Padilla said. "A few graduate students are beginning to get into the canopies, but for undergraduates, this is practically unheard of. This was my greatest learning experience." Immersion in the rain forest "was sensory overload," said an initially overwhelmed Amy Heuskinveld, but learning names for all the plants and animals helped. Watching the howler monkeys of Santa Rosa made the Ag College senior wonder "how much they see that we don't because we're usually stuck on the ground. What I'll remember most is looking out over the canopy and feeling like it went on forever." "Everything I saw piqued my curiosity and made me realize how valuable and intricate this neotropical rain forest is to all life," said Brian Kurzel, a senior in the Agriculture College. "Our access into the canopy was an amazing way to experience this forest."

Running a field course like this is a costly venture, said Peter Bruns, director of Cornell's Division of Biological Sciences, which helped make up the difference between the $350 course fee and the actual expense of nearly $2,000 per student. Financial support was provided by the Cornell Center for the Environment, Section of Ecology and Systematics, and the colleges of

Agriculture and Life Sciences and Arts and Sciences. Cornell Outdoor Education provided technical climbing equipment and outdoor expedition support.

"Not many universities can put together a course led by faculty members who know about the rain forests and how to climb into them," Bruns said.

"Canopy access is about three-quarters rock-climbing and the rest special techniques," Tillemans said, describing the giant slingshot students used to shoot a weighted fishing line -- and then the climbing ropes -- into the tree tops. "A lot of biologists learn to climb on their own and frankly, they climb dangerously."

The Cornell canopy-climbers learned on the Lindseth Climbing Wall, the largest indoor natural-rock wall in North America, and in the trees of Cornell Plantations.

"I was nervous but excited and confident," Emily Hudson said of her first rain forest ascent to collect plant samples, "and I was determined to stay up there. I think that day in the tree for seven hours was one of the strongest of my life."

"One of the goals of outdoor education at Cornell," Tillemans said, "is to teach skills that can be applied in an academic setting -- and in the real world."

The canopy course's "two Audreys" agree with that. Audrey Taylor will work, climbing trees in McGowan's crow study, this spring.

And Audrey Washburn, who graduated in December from the Ag College, credits the canopy experience for helping her get a job with the U.S. Fish and Wildlife Service. She'll be in Florida, climbing for kites -- the swallow-tailed kind.