The cloud forest is seductive.

Across a canyon, the canopy roils in the wind under blurring pulses of mist. In foggy vales, scarlet flowers glint like channel lights. Strangler figs embrace their host tree like entwining snakes while ferns curl with the delicacy of a doily. A young howler monkey dangles from his tail, peeling a twig like a prize. Hummingbirds fly sorties to nectar -- a flash of blue-purple gone as soon as it is glimpsed - and an orange butterfly hurries across a hole of sunlight.

In the stillness of dusk, the "tink" of a frog.

Entrancing. Spiritual. Yet how much, economically, is the cloud forest worth?

Ecologist J. Boone Kauffman of Oregon State University is weighing it to find out.

Kauffman, a vigorous Texan from George W. Bush's hometown and who covers ground like a loping horse, briskly leads our One World Journeys team to his covey of seven students combing a .75 hectare (1.9 acre) section of trees in the Monteverde Cloud Forest Preserve. He's put them to work weighing the carbon that the wood, leaves, and soil store.

Half the weight of a log, for example, is carbon the tree captured from our atmosphere. The top meter of soil is also heavy with stored carbon in the guise of downed logs, leaves, and forest duff. Carbon dioxide is a greenhouse gas. Plants take the carbon from that molecule to build their cells, releasing oxygen as a byproduct. The bigger a tree grows, the more it combats global warming.

Re-grow forests in tropic pastures, and each hectare would remove 12 to 15 tons of carbon each year for decades, 45-year-old Kauffman estimates.

At Monteverde, trees grow to mature height in two decades, though it may take more than a century to duplicate a cloud forest's climactic complexity.

Weighing the forest is beautiful, wet, and dirty work, repeated by Kauffman's team at sites all over Costa Rica. "We've hit killer bee nests, hornets nests, and snakes," he cheerfully recounts. His students compete by counting their bug bites. The day the group arrived a division of army ants invaded their intended rustic housing, flushing out the tarantulas and carrying off scorpions to devour.

The students have also seen three species of monkey in a single day.

"I love it," says Susie Kovacs, who the day before hiked several miles in the rain. "This forest has more diversity than any place I've been."

Adam Kahler and Jennifer Orlowski apply giant calipers to trees. By measuring tree width they can estimate height and thus weight, using formulas derived from careful measurement of over 4,000 trees. Amanda Rogers marks off distances with a range finder to help calculate shrub and litter volume. Dana Nagy and Jaimie Williams take soil samples that will be burned in Oregon, their carbon measured.

Because cloud forest debris rots slowly in the coolness of the high mountains, soil carbon is twice that stored in the trees: a surprise for scientists. Grow more of this jungle and we can literally bury some of our pollution.

"Carbon pools are one of the least studied things," explains student Francine Nogash.

These students like the significance of their hard labor, which could influence global warming treaties to trade carbon credits. This complex scheme of carbon trading, which global negotiators are proposing, could help less developed countries reforest. Car emissions would be balanced by growing tropical trees.

The problem is, how many trees do you need to counter a dirty car? That's where Kauffman's team, funded by the National Science Foundation and advised by Costa Rica's Tropical Science Center, comes in. He sends data to the International Panel on Climate Control, which advises global leaders.

Leading the One World Journeys team out from his study site and past a waterfall, he takes us to a nearby pasture. It is noticeably hotter. While we could sink our fingers easily into the forest soil, the field is so compacted by hooves that it feels like hard rubber. The forest holds water like a sponge, but the pasture sheds it like concrete.

The forest may also hold 30 times as much carbon as the pasture.

"We're discovering a whole new value for these forests," said Kauffman. "We already knew they were important for water quality, soil conservation, biodiversity, and aesthetics. Now they're important for carbon storage as well."

He started his career in the Amazon but chose Costa Rica for this study because it represents most tropical climate zones in a small area. Its diversity makes it perfect.

That's why the National Geographic Society recently funded Monteverde ecologist Bill Haber to see if plants are migrating upward in elevation as animals are. With more than 700 species of trees in the cloud forest, this is a complex issue to answer. Haber has already looked at 80 sites, and "each is different."

But if he can successfully map the cloud forest's complexity, future scientists can tell if its plant species are disappearing as the mercury rises.

Haber has worked in Monteverde for 30 years, collecting 20,000 plant samples and discovering botany new to science. With his wife, conservationist Willow Zuchowski, he's been a leader in preservation efforts. Yet his talk quickly turns to how much more needs to be done.

There is limited coordination of Monteverde's determinedly independent scientists and little grant money. "Biologists like to go off and work by themselves," he observes. "It would make sense for us to get together and seek real support." There's no network of stations to track weather and climate change. No baseline information for hundreds of species.

Yet Monteverde is better studied that most places in the tropics, largely because a small group of dedicated researchers fell in love with the place. Accordingly, warnings of the consequences of tropic warming are showing up here first.

Do we leave the cloud forest as pessimists? No, too much good work is being done here. One can stand in the wind of La Ventana, look down at the velvet bowl of the Penas Blanca valley, and marvel that donations - many from the world's schoolchildren - have saved its lushness so the world can learn from it.

At the nearby Santa Elena Cloud Forest Reserve, a children's trail winds up to a wooden platform that looks out across the canopy, shrouded in fog and murmuring with bird and insect song.

Someone has used a pocketknife to carve a single word into the railing.

I finger the lettering. "Hope."