Cloud Forests

A cloud forest is a generally tropical or subtropical evergreen montane forest characterized by a high incidence of low-level cloud cover, usually at the canopy level.

Typically, there is a relatively small band of altitude in which the atmospheric environment is suitable for rain forest development. This is characterized by persistent mist or clouds at the vegetation level, resulting in the reduction of direct sunlight and thus of evapotranspiration.

Trees in these regions are generally shorter and more heavily stemmed than in lower altitude forests in the same regions, and the moisture promotes the development of an abundance of vascular epiphytes.

This results in abundant moss and fern covering, and frequently flowers such as orchids may be found. Soils are rich but boggy, with a preponderance of peats and humus. Within cloud forests, much of the precipitation is in the form of fog drip, where fog collects on tree leaves and then drips onto the ground below.

The definition of cloud forest can be ambiguous, with many countries not using the term (preferring such terms as Afromontane forest and upper montane rain forest, or more localized terms such as the Peruvian yungas, and the laurisilva of the Atlantic Islands), and occasionally subtropical and even temperate forests in which similar meteorological conditions occur are considered to be cloud forests.

Temperate cloud forests

Although far from universally accepted as being true cloud forests, several forests in temperate regions have strong similarities with tropical cloud forests. The term is further confused by occasional reference to cloud forests in tropical countries as "temperate", due to the cooler climate associated with these misty forests.

Distribution of cloud forests

UNEP World Conservation Monitoring Centre

In the News ...

Mummies of 'cloud warriors' tribe found in Peruvian cave Independent - October 9, 2006

Archaeologists in Peru have discovered an underground burial vault that could unlock the mystery of a pre-Colombian tribe known as the "warriors of the clouds".

The Chachapoyas commanded a vast kingdom stretching across the Andes to the fringe of Peru's northern Amazon jungle until they were conquered by the Incas in the 15th century. The Incan empire was itself overrun soon after by the Spanish, and details of the Chachapoyas and their way of life were lost or destroyed in the widespread pillaging that followed. Now a team of archaeologists, working on a tip-off from a local farmer, have uncovered a burial site in a 820ft-deep cave. The researchers have so far found five mummies, two of which are intact with skin and hair, as well as ceramics, textiles and wall paintings, the expedition's leader, Herman Corbera, told Reuters. "This is a discovery of transcendental importance. We have found these five mummies but there could be many more," Mr Corbera said. "We think this is the first time any kind of underground burial site this size has been found belonging to Chachapoyas or other cultures in the region."

The tribe's own name is unknown. The word Chachapoyas is thought to come from the Quechua for "cloud people", and is the name by which they were known to the Incas, because of the cloud forests they inhabited in what is now northern Peru. A white-skinned people who were famed as ferocious fighters, the Chachapoyas held out against the Incans, who ruled an empire stretching from southern Chile to northern Ecuador until their conquest by the Spanish.

Today, the Cloud People are best known for their stone citadel, Kuelap, with more than 400 buildings and massive exterior stone walls, which is often referred to as the Machu Picchu of the north. Mr Corbera said the walls in the limestone cave near the mummies were covered with paintings of faces and warrior-like figures which may have been drawn to ward off intruders and evil spirits. "The remote site for this cemetery tells us that the Chachapoyas had enormous respect for their ancestors because they hid them away for protection," Mr Corbera said. "Locals call the cave Iyacyecuj, or Enchanted Water in Quechua, because of its spiritual importance and its underground rivers. "The idea now is to turn this cave into a museum, but we've got a huge amount of research to do first and protecting the site is a big issue."

Earth's cloud forests threatened

February 9, 2004 - BBC

Pressures are mounting on one of the Earth's rarest and most distinctive types of forest, scientists have found. The alert comes from the UK-based World Conservation Monitoring Centre, now a part of the UN Environment Programme. It says the threats to the world's cloud forests, which shelter thousands of rare species and provide water for millions of people, are increasing. The centre says the extent of the cloud forests is about one-fifth smaller than scientists had previously believed. The forests are found in tropical mountains, and at some point virtually every day they are enveloped in cloud. They sometimes grow as low as 500m (1,650 feet) in coastal regions, but are typically found at 2-3,000m (6,550-9,850 feet).

Unep-WCMC has produced its report, Cloud Forest Agenda, with IUCN-The World Conservation Union and Unesco. It is being launched at a meeting in Kuala Lumpur, Malaysia, of the Convention on Biological Diversity, which runs from 9 to 20 February. The authors relied on satellite data to establish that cloud forests cover just under 400,000 sq km (98,840,000 acres) worldwide, less than 2.5% of the Earth's tropical rain forests. Mark Collins of Unep-WCMC said of the report: "A key finding is that cloud forests are rarer than thought, with the true area 20% less than the previous estimate of half a million square kilometres." The researchers found about 60% of cloud forests are in Asia, not in Latin America as had been thought. About 25% of the share is there, with the remaining 15% in Africa.

The report says: "The ability of cloud forests to strip and retain moisture from cloud and fogs is key to abundant, clean and predictable water supplies in many areas, especially during dry seasons. "The cloud forests of La Tigra National Park in Honduras provide over 40% of the water for the 850,000 people living in the capital, Tegucigalpa.

Genetic treasury

Apart from their utility, cloud forests are home to many species found nowehere else on Earth, including the mountain gorilla of Africa, the spectacled bear, and the resplendent quetzal, Guatemala's national symbol. The report says wild relatives of key food crops often grow in the forests, making them important gene pools. Threats include farming, poaching, fires, logging, road-building and the introduction of alien species. But the authors think climate change could be the biggest danger. Philip Bubb of Unep-WCMC, one of the authors, said: "A unique feature of these forests is that they can capture moisture through condensation from the clouds. "If temperatures rise one degree in the lowland this equates to two degrees in the mountains and can result in the clouds lifting and the cloud forest drying out."

Antediluvian memories

Mr Bubb told BBC News Online: "Often the forests are growing at the top of the mountains, and have nowhere to retreat to from the rising temperature. And the increasing heat make the clouds rise anyway. "My chief memory of the forests is of their stunning beauty. They're like something out of The Lord of the Rings, great tall trees covered in ferns and orchids. The birdsong echoes through the cool moist air, and they feel very ancient places."