Cloud forest
Encyclopedia
Montane
In biogeography, montane is the highland area located below the subalpine zone. Montane regions generally have cooler temperatures and often have higher rainfall than the adjacent lowland regions, and are frequently home to distinct communities of plants and animals.The term "montane" means "of the...
moist forest
Tropical and subtropical moist broadleaf forests
Tropical and subtropical moist broadleaf forests , also known as tropical moist forests, are a tropical and subtropical forest biome....
characterized by a persistent, frequent or seasonal low-level cloud
Cloud
A cloud is a visible mass of liquid droplets or frozen crystals made of water and/or various chemicals suspended in the atmosphere above the surface of a planetary body. They are also known as aerosols. Clouds in Earth's atmosphere are studied in the cloud physics branch of meteorology...
cover, usually at the canopy level. Cloud forests often exhibit an abundance of moss
Moss
Mosses are small, soft plants that are typically 1–10 cm tall, though some species are much larger. They commonly grow close together in clumps or mats in damp or shady locations. They do not have flowers or seeds, and their simple leaves cover the thin wiry stems...
es covering the ground and vegetation, in which case they are also referred to as mossy forests. Mossy forests usually develop on the saddles of mountains, where moisture introduced by settling clouds is more effectively retained.
Distribution and climate
Evapotranspiration
Evapotranspiration is a term used to describe the sum of evaporation and plant transpiration from the Earth's land surface to atmosphere. Evaporation accounts for the movement of water to the air from sources such as the soil, canopy interception, and waterbodies...
. Within cloud forests, much of the precipitation
Precipitation (meteorology)
In meteorology, precipitation In meteorology, precipitation In meteorology, precipitation (also known as one of the classes of hydrometeors, which are atmospheric water phenomena is any product of the condensation of atmospheric water vapor that falls under gravity. The main forms of precipitation...
is in the form of fog drip
Fog drip
Fog drip is a type of precipitation that forms when fog droplets condense on the needles or leaves of trees or other objects, and drips to the ground....
, where fog
Fog
Fog is a collection of water droplets or ice crystals suspended in the air at or near the Earth's surface. While fog is a type of stratus cloud, the term "fog" is typically distinguished from the more generic term "cloud" in that fog is low-lying, and the moisture in the fog is often generated...
condenses
Condensation
Condensation is the change of the physical state of matter from gaseous phase into liquid phase, and is the reverse of vaporization. When the transition happens from the gaseous phase into the solid phase directly, the change is called deposition....
on tree leaves and then drips onto the ground below.
Tropical cloud forests extend from 23°N to 25°S latitudes and occur in a relatively narrow altitudinal zone with a special atmospheric environment which is characterized by at the vegetation level.
Annual rainfall can range from 500 to 10,000 mm/year and mean temperature between 8 to 20 °C.
While cloud forest today is the most widely used term, in some regions these ecosystems or special types of cloud forests are called mossy forest, elfin forest, montane thicket, dwarf cloud forest, nuboselva, bosque montano nebuloso, selva de neblina, bosque nuboso, bosque de ceja, selva sublada, nebelwald, wolkenwald, forêt néphéliphile, forêt de nuage, unmu-rin, bosque anao, foresta nebular, mata nebular, matinha nebular, floresta fe neblina, floresta nuvigena, mata de neblina, matinha de altitude, floresta nublada, and floresta pluvial montana e/ou alto montana.
The definition of cloud forest can be ambiguous, with many countries not using the term (preferring such terms as Afromontane
Afromontane
Afromontane is a term used to describe the Afrotropic subregion and its plant and animal species common to the mountains of Africa and the southern Arabian Peninsula...
forest and upper montane rain forest, montane laurel forest
Laurel forest
Laurel forest is a subtropical or mild temperate forest, found in areas with high humidity and relatively stable and mild temperatures. They are characterized by tree species with evergreen, glossy, enlongated leaves, known as laurophyll or lauroide...
, or more localised terms such as the Bolivian yungas
Yungas
The Yungas is a stretch of forest along the eastern slope of the Andes Mountains from southeastern Peru through central Bolivia. It is a transitional zone between the Andean highlands and the eastern forests. Like the surrounding areas, it has characteristics of the Neotropic ecozone...
, and the laurisilva
Laurisilva
Laurisilva or laurissilva is a subtropical forest, found in areas with high humidity and relatively stable and mild temperatures. They are characterised by evergreen, glossy-leaved tree species that look alike with leaves of lauroide type...
of the Atlantic Islands), and occasionally subtropical and even temperate forests in which similar meteorological conditions occur are considered to be cloud forests.
Only 1% of the global woodland is covered by cloud forests.
Important areas of cloud forest are in Central- and South America, East- and Central Africa, Indonesia, Malaysia, at the Philippines, Papua-New Guinea and in the Caribbean. (see following list and http://www.unep-wcmc.org/forest/cloudforest/)
Temperate cloud forests
Although far from being universally accepted as 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 temperate cloud forests
- ArgentinaArgentinaArgentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...
- CatamarcaCatamarca ProvinceCatamarca is a province of Argentina, located in the northwest of the country. The province has a population of 334,568 as per the , and covers an area of 102,602 km². Its literacy rate is 95.5%. Neighbouring provinces are : Salta, Tucumán, Santiago del Estero, Córdoba, and La Rioja...
and TucumánTucumán ProvinceTucumán is the most densely populated, and the smallest by land area, of the provinces of Argentina. Located in the northwest of the country, the capital is San Miguel de Tucumán, often shortened to Tucumán. Neighboring provinces are, clockwise from the north: Salta, Santiago del Estero and... - AustraliaAustraliaAustralia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
- Lamington National ParkLamington National ParkLamington is a national park in Queensland, Australia, lying on the Lamington Plateau of the McPherson Range on the Queensland/New South Wales border...
(QueenslandQueenslandQueensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
) - ChileChileChile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...
(Bosque de Fray Jorge National ParkBosque de Fray Jorge National ParkBosque de Fray Jorge national park or Bosque Fray Jorge national park lies in the Limarí Province, Coquimbo Region, Chile. It is a UNESCO Biosphere reserve.- Geography :...
) - People's Republic of ChinaPeople's Republic of ChinaChina , officially the People's Republic of China , is the most populous country in the world, with over 1.3 billion citizens. Located in East Asia, the country covers approximately 9.6 million square kilometres...
- Yunnan Plateau, mountains of southern and eastern China - JapanJapanJapan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
- parts of Yakushima IslandYakushima, one of the Ōsumi Islands, is an island of about 500 km² and roughly 15,000 islanders to the south of Kyūshū in Kagoshima Prefecture, Japan. The Vincennes Strait separates it from Tanegashima. The highest point on the island is Miyanoura-dake at 1,935 metres... - New ZealandNew ZealandNew Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
- parts of FiordlandFiordlandFiordland is a geographic region of New Zealand that is situated on the south-western corner of the South Island, comprising the western-most third of Southland. Most of Fiordland is dominated by the steep sides of the snow-capped Southern Alps, deep lakes and its ocean-flooded, steep western valleys...
, Mount TaranakiMount TaranakiMount Taranaki, or Mount Egmont, is an active but quiescent stratovolcano in the Taranaki region on the west coast of New Zealand's North Island. Although the mountain is more commonly referred to as Taranaki, it has two official names under the alternative names policy of the New Zealand...
and Mount CargillMount CargillMount Cargill is a 680 metre high volcanic outcrop which dominates the skyline of northern Dunedin, New Zealand. It is situated some 15 kilometres north of the city centre....
, near DunedinDunedinDunedin is the second-largest city in the South Island of New Zealand, and the principal city of the Otago Region. It is considered to be one of the four main urban centres of New Zealand for historic, cultural, and geographic reasons. Dunedin was the largest city by territorial land area until...
. - PortugalPortugalPortugal , officially the Portuguese Republic is a country situated in southwestern Europe on the Iberian Peninsula. Portugal is the westernmost country of Europe, and is bordered by the Atlantic Ocean to the West and South and by Spain to the North and East. The Atlantic archipelagos of the...
- AzoresAzoresThe Archipelago of the Azores is composed of nine volcanic islands situated in the middle of the North Atlantic Ocean, and is located about west from Lisbon and about east from the east coast of North America. The islands, and their economic exclusion zone, form the Autonomous Region of the...
and Madeira - South AfricaSouth AfricaThe Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
- SpainSpainSpain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...
- Canary Islands (laurisilvaLaurisilvaLaurisilva or laurissilva is a subtropical forest, found in areas with high humidity and relatively stable and mild temperatures. They are characterised by evergreen, glossy-leaved tree species that look alike with leaves of lauroide type...
) - TaiwanTaiwanTaiwan , also known, especially in the past, as Formosa , is the largest island of the same-named island group of East Asia in the western Pacific Ocean and located off the southeastern coast of mainland China. The island forms over 99% of the current territory of the Republic of China following...
- Chiantianshan Nature Reserve, Yuanyang Lake Nature Reserve - United StatesUnited StatesThe United States of America is a federal constitutional republic comprising fifty states and a federal district...
- Redwood Coast
Characteristics
In comparison with lower tropical moist forests, cloud forests show a reduced tree stature combined with increased stem density and generally the lower diversity of woody plants. Trees in these regions are generally shorter and more heavily stemmed than in lower altitude forests in the same regions, often with gnarled trunks and branches, forming dense, compact crowns. Their leaves become smaller, thicker and harder with increasing altitude. The high moisture promotes the development of a high biomassBiomass
Biomass, as a renewable energy source, is biological material from living, or recently living organisms. As an energy source, biomass can either be used directly, or converted into other energy products such as biofuel....
and biodiversity
Biodiversity
Biodiversity is the degree of variation of life forms within a given ecosystem, biome, or an entire planet. Biodiversity is a measure of the health of ecosystems. Biodiversity is in part a function of climate. In terrestrial habitats, tropical regions are typically rich whereas polar regions...
of epiphyte
Epiphyte
An epiphyte is a plant that grows upon another plant non-parasitically or sometimes upon some other object , derives its moisture and nutrients from the air and rain and sometimes from debris accumulating around it, and is found in the temperate zone and in the...
, particularly bryophytes, lichens, fern
Fern
A fern is any one of a group of about 12,000 species of plants belonging to the botanical group known as Pteridophyta. Unlike mosses, they have xylem and phloem . They have stems, leaves, and roots like other vascular plants...
s (including filmy ferns), bromeliads and orchids. The number of endemic plants can be very high.
An important feature of cloud forests is that the tree crowns can intercept the wind-driven cloud moisture, part of which drips to the ground. This water stripped from the clouds is termed horizontal or occult (because it is not recorded with normal rainfall measurement) precipitation, and can be an important contribution to the hydrologic cycle.
Due to the high water content of the soil, the reduced solar radiation and the low rates of decomposition
Decomposition
Decomposition is the process by which organic material is broken down into simpler forms of matter. The process is essential for recycling the finite matter that occupies physical space in the biome. Bodies of living organisms begin to decompose shortly after death...
and mineralization
Mineralization (soil)
Mineralization in soil science, is when the chemical compounds in organic matter decompose or are oxidized into plant-accessible forms,. Mineralization is the opposite of immobilization....
, the soil acidity is very high, with more humus and peat
Peat
Peat is an accumulation of partially decayed vegetation matter or histosol. Peat forms in wetland bogs, moors, muskegs, pocosins, mires, and peat swamp forests. Peat is harvested as an important source of fuel in certain parts of the world...
often forming the upper soil layer.
Stadtmüller (1987) distinguishes two general types of tropical montane cloud forests:
- Areas with a high annual precipitation due to a frequent cloud cover in combination with heavy and sometimes persistent orographic rainfall; such forests have a perceptible canopy strata, a high number of epiphytes and a thick peat layer which has a high storage capacity for water and control the runoff;
- In drier areas with mainly seasonal rainfall cloud stripping can amount to a large proportion of the annual precipitation.
Importance of cloud forests
- Watershed function. Because of the cloud stripping strategy the effective rainfall can be doubled in dry seasons and increase the wet season rainfall by about 10 percent. Experiments of Costin and Wimbush (1961) showed that the tree canopies of non-cloud forests intercept and evaporate 20 percent more of the precipitation than cloud forests, which means a loss to the land component of the hydrological cycle.
- Vegetation. Tropical montane cloud forests are not as species-rich as tropical lowland forests but they provide the habitats for many species that are found nowhere else. For example, the Cerro de la Neblina, a cloud covered mountain in the south of VenezuelaVenezuelaVenezuela , officially called the Bolivarian Republic of Venezuela , is a tropical country on the northern coast of South America. It borders Colombia to the west, Guyana to the east, and Brazil to the south...
accommodates many shrubs, orchids and insectivorous plants which are restricted to this mountain only. - Fauna. The endemism in animals is also very high. In PeruPeruPeru , officially the Republic of Peru , is a country in western South America. It is bordered on the north by Ecuador and Colombia, on the east by Brazil, on the southeast by Bolivia, on the south by Chile, and on the west by the Pacific Ocean....
, more than one third of the 270 endemic birds, mammals and frogs are found in cloud forests. One of the best known cloud forest mammal is the Mountain GorillaMountain GorillaThe Mountain Gorilla is one of the two subspecies of the Eastern Gorilla. There are two populations. One is found in the Virunga volcanic mountains of Central Africa, within three National Parks: Mgahinga, in south-west Uganda; Volcanoes, in north-west Rwanda; and Virunga in the eastern Democratic...
(Gorilla b. beringei). Many of those endemic animals have important functions such as seed dispersal and forest dynamics in this ecosystems.
Current situation
In 1970, the original extent of cloud forests was around 50 million hectareHectare
The hectare is a metric unit of area defined as 10,000 square metres , and primarily used in the measurement of land. In 1795, when the metric system was introduced, the are was defined as being 100 square metres and the hectare was thus 100 ares or 1/100 km2...
s. Population growth
Population growth
Population growth is the change in a population over time, and can be quantified as the change in the number of individuals of any species in a population using "per unit time" for measurement....
, poverty
Poverty
Poverty is the lack of a certain amount of material possessions or money. Absolute poverty or destitution is inability to afford basic human needs, which commonly includes clean and fresh water, nutrition, health care, education, clothing and shelter. About 1.7 billion people are estimated to live...
and uncontrolled land use have contributed to the loss of cloud forests. The 1990 Global Forest Survey found that 1.1% of tropical mountain and highland forests were lost each year, which was higher than in any other tropical forests. In Colombia, one of the countries with the largest area of cloud forests, only 10-20% of the initial cloud forest cover remains. Significant areas have been converted to plantation
Plantation
A plantation is a long artificially established forest, farm or estate, where crops are grown for sale, often in distant markets rather than for local on-site consumption...
s, or for use in agriculture
Agriculture
Agriculture is the cultivation of animals, plants, fungi and other life forms for food, fiber, and other products used to sustain life. Agriculture was the key implement in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that nurtured the...
and pasture
Pasture
Pasture is land used for grazing. Pasture lands in the narrow sense are enclosed tracts of farmland, grazed by domesticated livestock, such as horses, cattle, sheep or swine. The vegetation of tended pasture, forage, consists mainly of grasses, with an interspersion of legumes and other forbs...
. Important crops in montane forest zones are tea
Tea
Tea is an aromatic beverage prepared by adding cured leaves of the Camellia sinensis plant to hot water. The term also refers to the plant itself. After water, tea is the most widely consumed beverage in the world...
and coffee
Coffee
Coffee is a brewed beverage with a dark,init brooo acidic flavor prepared from the roasted seeds of the coffee plant, colloquially called coffee beans. The beans are found in coffee cherries, which grow on trees cultivated in over 70 countries, primarily in equatorial Latin America, Southeast Asia,...
, but also logging
Logging
Logging is the cutting, skidding, on-site processing, and loading of trees or logs onto trucks.In forestry, the term logging is sometimes used in a narrow sense concerning the logistics of moving wood from the stump to somewhere outside the forest, usually a sawmill or a lumber yard...
special species such as Podocarpus
Podocarpus
Podocarpus is a genus of conifers, the most numerous and widely distributed of the podocarp family Podocarpaceae. The 105 species of Podocarpus are evergreen shrubs or trees from 1-25 m in height...
causes changes to forest structure.
Currently, one third of all cloud forests are protected.
Impact of climate change on cloud forests
Because of their delicate dependency on local climate, cloud forests will be strongly affected by global climate changeClimate change
Climate change is a significant and lasting change in the statistical distribution of weather patterns over periods ranging from decades to millions of years. It may be a change in average weather conditions or the distribution of events around that average...
. A number of climate models suggest that the low-altitude cloudiness will be reduced, which means that the optimum climate for many cloud forest habitats will increase in altitude. Linked to the reduction of cloud moisture immersion and increasing temperature, the hydrological cycle will change with the consequence that the system will dry out. This can result in the wilting and the death of epiphytes, which rely on high humidity. Frogs and lizards are expected to suffer from increased drought. In addition, climate changes can result in a higher amount of hurricanes, which may increase damage to tropical montane cloud forests. All in all the results of the climate change will be a loss in biodiversity, altitude shifts in species ranges and community reshuffling and, in some areas, complete loss of cloud forests.
External links
- Laurisilva Montane Cloud Forest in the National Park of Garajonay, Canary Islands
- Monteverde Costa Rica Cloud Forest
- Tropical Montane Cloud Forest Initiative
- National GeographicNational Geographic MagazineNational Geographic, formerly the National Geographic Magazine, is the official journal of the National Geographic Society. It published its first issue in 1888, just nine months after the Society itself was founded...
(2001), "Cloud Forests Fading in the Mist, Their Treasures Little Known" - An Ecological Reserve in the Cloud Forest of Mindo Ecuador
- St. Elena and Rara Avis, Costa Rica - Video
- Tropical hydrology and cloud forests project
- Hydrology of tropical cloud forests project
- Cloud Forest Video - Rara Avis CR
- Tropical Montane Cloud Forests – Science for Conservation and Management (L.A. Bruijnzeel, F.N. Scatena and L.S. Hamilton, 2011)