Cloud Forests Fading in the Mist, Their Treasures Little Known

John Roach
for National Geographic News
August 13, 2001
They are nature's "water towers," providing billions of gallons of
fresh, clean, filtered water. They are home to thousands of indigenous
peoples, and storehouses of biodiversity, at least 80 percent of which
has not yet been catalogued.

Yet in as little as ten years' time, biologists warn, the world's cloud forests—evergreen mountain forests that are almost permanently shrouded in mist and clouds—may be all but gone.

They are being cleared for cattle grazing and coca plantations. Logged to provide fuel for heating and cooking. Paved over and developed to make way for transportation and telecommunications networks. They are being damaged and dried out by air pollutants and global warming.

Now, cloud forests are rising to the top of the world's scientific and conservation agenda. But will scientists learn enough about these important ecosystems to be able to convince the world to conserve them before they are gone forever?

Percy Nuñez, a research biologist in Cuzco, Peru, who studies cloud forests, estimates they are disappearing at a such a rate that the "the cloud forest will all be gone in the next ten years."

"We don't know about our resources—80 to 90 percent of the cloud forests are a mystery to us all," Nuñez said.

Yet scientists have barely begun assessing the wide range of species that clod forests harbor, he noted. "We don't have biologists working in cloud forests. We are not training young scientists to do the work," he said.

Now, he added, "we are working with NASA, using satellite images to get some idea of what's there before it is gone. There aren't any field guides available."

Essential Irrigation

Cloud forests are broadly defined as forests that are frequently covered in clouds or mist. They are found in tropical and subtropical mountainous regions of the world, where cooler temperatures on mountain slopes cause clouds to form.

In Central and South America, cloud forest stretches from Panama to northern Argentina. "It's the belt between the jungle and the highlands and, as such, is narrow and delicate. It is also known as the 'eyebrow of the jungle,' " Nuñez explained.

On continental landscapes, cloud forests are found at 5,000 to 10,000 feet (1,500 and 3,000 meters) above sea level. They often occur at much lower heights—as low as 1,600 feet (500 meters)—on oceanic islands, such as in the Caribbean and Hawaii. The trees in cloud forests are generally 50 to 65 feet tall (15.2 to 18.3 meters) at lower elevations, much shorter and mossier at higher elevations.

The trees perform a crucial hydrological function. They strip water from windblown fog and clouds, aiding the healthy functioning of surrounding ecosystems.

"One of the key things is they are important for capturing water from clouds, which provides water downstream to industry, towns, and regions," said Phillip Bubb, director of the Tropical Montane Cloud Forest Initiative.

Based in the United Kingdom, the program was launched in 1999 by a host of conservation organizations that include the United Nations Environment Program, the World Conservation Union, and the World Wide Fund for Nature. The groups are working collectively to raise awareness and promote conservation of cloud forests.

The importance of cloud forests to the year-round provision of fresh water cannot be overestimated, said Bubb. Many mountainside trees filter the water that feeds the headwaters of river systems. Cloud forests, however, capture water that would otherwise never fall to the ground as rain.

The extra water from this cloud-stripping effect amounts to 20 percent of ordinary rainfall. In mossy forests that are particularly exposed to the elements, the extra water-trapping capacity can be as much as 60 percent.

The cloud forest in La Tigra National Park in Honduras, for example, supplies 40 percent of the water consumed by the 850,000 residents of Tegucigalpa. In Tanzania, the cloud forests of the Udzungwa mountains provide water needed to operate the hydroelectric dams that supply power to Dar es Salaam.

Storehouses of Diverse Species

The provision of abundant, fresh water ought to be reason enough to conserve cloud forests. But these forests are also important because they are rich in biological diversity.

Nuñez, an ethnobiologist specializing in the plants of southern Peru, estimates that he has collected 30,000 to 40,000 plants, most of which have gone to museums for closer examination.

That amount only begins to scratch the surface. "In a small area the size of Machu Picchu, we can find the same plant diversity as on the whole continent of Europe," he said.

"So far we have described only 20 percent of the species—plants and animals—that live in this almost vertical landscape," he added.

Much of the biodiversity found in cloud forests is endemic—it can be found nowhere else. For example, most of the shrubs, orchids, and insect-eating plants found on the Cerro de la Neblina in Venezuela are unique to the mountain's summit.

"Cloud forests are habitat pockets," said Bubb. "There are different species found on each [mountain] range."

Scientists say a cloud forest's water-tapping ability can be restored by measures such as replanting.

"But restoration of the intricate mix of life-forms—of the authenticity, and of the complexity of the ecological interactions that maintain a healthy ecosystem—is simply beyond our capability," the scientific coalition notes in its publication titled Decision Time For Cloud Forests.

Bubb said the group has stepped-up efforts to raise public awareness of the need to conserve cloud forests and obtain funding for conservation strategies, such as establishing private reserves and national parks.

Meanwhile, scientists such as Nuñez are dedicated to documenting the diverse life of cloud forests and the traditional way of life of people who inhabit them, before the forests are gone.

He is aware that time is running out: "It is so easy doing research, but we have just 3 percent of the forest left."

© 1996-2008 National Geographic Society. All rights reserved.