A cloud forest, also called a water forest, primas forest, or tropical montane cloud forest, is a generally tropical or subtropical, evergreen, montane, moist forest characterized by a persistent, frequent or seasonal low-level cloud cover, usually at the canopy level, formally described in the International Cloud Atlas (2017) as silvagenitus.[1][2] Cloud forests often exhibit an abundance of mosses 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.
Cloud forests are among the most biodiversity-rich ecosystems in the world, with a large number of species directly or indirectly depending on them.[3]
The presence of cloud forests is dependent on local climate (which is affected by the distance to the sea), the exposition and the latitude (from 23°N to 25°S), and the elevation (which varies from 500 m to 4000 m above sea level). Typically, there is a relatively small band of elevation in which the atmospheric environment is suitable for cloud forest development. This is characterized by persistent fog at the vegetation level, resulting in the reduction of direct sunlight and thus of evapotranspiration.[7][8] Within cloud forests, much of the moisture available to plants arrives in the form of fog drip, where fogcondenses on tree leaves and then drips onto the ground below.
Annual rainfall can range from 500 to 10,000mm/year and mean temperature between 8 and 20 °C (46.4 and 68°F).[7][8]
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, and dwarf cloud forest.[8]
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, montane laurel forest, or more localised terms such as the Bolivian yungas, and the laurisilva of the Atlantic Islands),[9][10] and occasionally subtropical and even temperate forests in which similar meteorological conditions occur are considered to be cloud forests.
In comparison with lower-altitude tropical moist forests, cloud forests show a reduced tree stature combined with increased stem density and generally, a lower diversity of woody plants.[7][8] 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.[11] The high moisture promotes the development of a high biomass and biodiversity of epiphyte, particularly bryophytes, lichens, ferns (including filmy ferns), bromeliads and orchids.[7][8] The number of endemic plants can be very high.[7]
An important feature of cloud forests is the tree crowns that intercept the wind-driven cloud moisture, part of which drips to the ground. This fog drip occurs when water droplets from the fog adhere to the needles or leaves of trees or other objects, coalesce into larger drops and then drop to the ground.[12] It can be an important contribution to the hydrologic cycle.[8]
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 controls the runoff;
In drier areas with mainly seasonal rainfall, cloud stripping can amount to a large proportion of the moisture available to plants.
Distribution of tropical montane cloud forests
Distribution of tropical montane cloud forests in 2016 .
The 1997 version of the World Conservation Monitoring Centre's database of cloud forests found a total of 605 tropical montane cloud forest sites in 41 countries. 280 sites, or 46% of the total, were located in Latin America, known in biogeography as the Neotropical realm. Twelve countries had tropical montane cloud forest sites, with the majority in Venezuela (64 sites), Mexico (64), Ecuador (35) and Colombia (28). Southeast Asia and Australasia had 228 sites in 14 countries – 66 in Indonesia, 54 in Malaysia, 33 in Sri Lanka, 32 in the Philippines, and 28 in Papua New Guinea. 97 sites were recorded in 21 African countries, mostly scattered on isolated mountains. Of the 605 sites, 264 were in protected areas.[16]
Conservation status
Cloud forests occupied 0.4% of the global land surface in 2001 and harboured ~3,700 species of birds, mammal, amphibians and tree ferns (~15% of the global diversity of those groups), with half of those species entirely restricted to cloud forests.[3] Worldwide, ~2.4% of cloud forests (in some regions, more than 8%) were lost between 2001 and 2018, especially in readily accessible places. While protected areas have slowed this decline, a large proportion of loss in TCF cover is still occurring despite formal protection.[3]
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.
Costa Rica – Monteverde Cloud Forest Reserve. 10,500 Hectares of Cloud Forest. There are 2500 plant species (most species of orchids in a single place on earth), 100 species of mammals, 400 species of birds, 120 species of reptiles, and thousands of insects.
Fiji Islands - Tropical Montane cloud forests of Taveuni [Ash, J., 1987. Stunted cloud-forest in Taveuni, Fiji.], Gau Island [Keppel, G. and Thomas, N.T., 2009. Composition and structure of the cloud forest on Mt Delaco, Gau, Fiji. The South Pacific Journal of Natural and Applied Sciences, 27(1), pp.28-34.]
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%.[24][10][25] Experiments of Costin and Wimbush (1961)[non-primary source needed] 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.[citation needed]
Vegetation: Tropical montane cloud forests are not as species-rich as tropical lowland forests, but they provide the habitats for many species found nowhere else.[26][10] For example, the Cerro de la Neblina, a cloud-covered mountain in the south of Venezuela, accommodates many shrubs, orchids, and insectivorous plants which are restricted to this mountain only.[26]
Fauna: The endemism in animals is also very high. In Peru, more than one-third of the 270 endemic birds, mammals, and frogs are found in cloud forests.[26] One of the best-known cloud forest mammals is the spectacled bear (Tremarctos ornatus). Many of those endemic animals have important functions, such as seed dispersal and forest dynamics in these ecosystems.[8]
Current situation
Seaborne moisture is vital to the cloud forest of Fray Jorge that is surrounded by the arid southern reaches of the Atacama Desert.
In 1970, the original extent of cloud forests on the Earth was around 50 million hectares. Population growth, poverty 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.[26] In Colombia, one of the countries with the largest area of cloud forests, only 10–20% of the initial cloud forest cover remains.[7] Significant areas have been converted to plantations, or for use in agriculture and pasture. Significant crops in montane forest zones include tea and coffee, and the logging of unique species causes changes to the forest structure.[8]
In 2004, an estimated one-third of all cloud forests on the planet were protected at that time.[27]
Impact of climate change
Because of their delicate dependency on local climates, cloud forests will be strongly affected by global climate change. Results show that the extent of environmentally suitable areas for cloud forest in Mexico will sharply decline in the next 70 years.[28] A number of climate models suggest low-altitude cloudiness will be reduced, which means the optimum climate for many cloud forest habitats will increase in altitude.[29][30] Linked to the reduction of cloud moisture immersion and increasing temperature, the hydrological cycle will change, so the system will dry out.[30] This would lead to the wilting and the death of epiphytes, which rely on high humidity.[29] Frogs and lizards are expected to suffer from increased drought.[30] Calculations suggest the loss of cloud forest in Mexico would lead to extinction of up to 37 vertebrates specific to that region.[31] In addition, climate changes can result in a higher number of hurricanes, which may increase damage to tropical montane cloud forests. All in all, the results of 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.[29]
In botanical gardens
Cloud-forest conditions are hard and expensive to replicate in a glasshouse because it is necessary to maintain very high humidity. Day temperatures have to be between 70-75F while night temperatures have to be maintained between 55-60F. In most cases, sophisticated refrigeration equipment has to be used to provide night temperatures below 60F. Such displays are usually quite small, but there are some notable exceptions. In the United States, The Atlanta Botanical Garden has a large tropical cloud forest greenhouse with a large collection of cloud forest epiphytes from around the world. It implements a refrigeration system to decrease the temperature at night. For many years, the Singapore Botanic Gardens had a so-called coolhouse. The Gardens by the Bay features a 0.8 hectares (2.0 acres) coolhouse that is simply named "Cloud Forest". The latter features a 35-metre (115ft)-high artificial mountain clad in epiphytes such as orchids, ferns, clubmosses, bromeliads and others.[32] Due to a relatively mild climate and summer fog, the San Francisco Botanical Garden has three outdoor cloud forest collections, including a 2-acre Mesoamerican Cloud Forest established in 1985.[33] The Buffalo and Erie County Botanical Gardens contains a "Panama Cloud Forest" garden in House 11.[34]
↑ Mark Aldrich, Clare Billington, Mary Edwards and Ruth Laidlaw (1997) "Tropical Montane Cloud Forests: An Urgent Priority for Conservation" WCMC Biodiversity Bulletin No. 2, World Conservation Monitoring Centre.
↑ Köhler, Lars; Tobón, Conrado; Frumau, K. F. Arnoud; Bruijnzeel, L. A. (Sampurno) (1 December 2007). "Biomass and water storage dynamics of epiphytes in old-growth and secondary montane cloud forest stands in Costa Rica". Plant Ecology. 193 (2): 171–184. doi:10.1007/s11258-006-9256-7. ISSN1573-5052. S2CID1032485.
Temperate rainforests are rainforests with coniferous or broadleaf forests that occur in the temperate zone and receive heavy rain.
Laurel forest, also called laurisilva or laurissilva, is a type of subtropical forest found in areas with high humidity and relatively stable, mild temperatures. The forest is characterized by broadleaf tree species with evergreen, glossy and elongated leaves, known as "laurophyll" or "lauroid". Plants from the laurel family (Lauraceae) may or may not be present, depending on the location.
The Ethiopian Highlands is a rugged mass of mountains in Ethiopia in Northeast Africa. It forms the largest continuous area of its elevation in the continent, with little of its surface falling below 1,500 m (4,900 ft), while the summits reach heights of up to 4,550 m (14,930 ft). It is sometimes called the "Roof of Northeastern Africa" due to its height and large area. It is the only country in the region with such a high elevated surface. This elevated surface is bisected diagonally by the Great East African Rift System which extends from Syria to Mozambique across the East African Lakes. Most of the Ethiopian Highlands are part of central and northern Ethiopia, and its northernmost portion reaches into Eritrea.
In biology, the canopy is the aboveground portion of a plant cropping or crop, formed by the collection of individual plant crowns. In forest ecology, canopy refers to the upper layer or habitat zone, formed by mature tree crowns and including other biological organisms. The communities that inhabit the canopy layer are thought to be involved in maintaining forest diversity, resilience, and functioning. Shade trees normally have a dense canopy that blocks light from lower growing plants.
Mount Tambuyukon or Tamboyukon is a mountain located at the West Coast and Kudat divisions of Sabah, Malaysia. It is considered the third-highest mountain in the country with height at 2,579 metres (8,461 ft), lying north of the highest Mount Kinabalu.
The Serra do Mar coastal forests is an ecoregion of the tropical moist forests biome. It is part of the Atlantic Forest of eastern South America. This ecoregion has an outstanding biodiversity consisting of flora, mammals, birds, and herpetofauna.
Hagenia is a monotypic genus of flowering plant with the sole species Hagenia abyssinica, native to the high-elevation Afromontane regions of central and eastern Africa. It also has a disjunct distribution in the high mountains of East Africa from Sudan and Ethiopia in the north, through Kenya, Uganda, Rwanda, Burundi, Democratic Republic of Congo, and Tanzania, to Malawi and Zambia in the south. A member of the rose family, its closest relative is the Afromontane genus Leucosidea.
Dwarf forest, elfin forest, or pygmy forest is an uncommon ecosystem featuring miniature trees, inhabited by small species of fauna such as rodents and lizards. They are usually located at high elevations, under conditions of sufficient air humidity but poor soil. There are two main dwarf forest ecosystem types, involving different species and environmental characteristics: coastal temperate and montane tropical regions. Temperate coastal dwarf forest is common for parts of Southern California. Montane tropical forests are found across tropical highlands of Central America, northern South America and Southeast Asia. There are also other isolated examples of dwarf forests scattered across the world, while the largest dwarf forest is found in the Philippines.
Farallones de Cali is a cluster of mountains in the West Andes of Colombia. It is located west of the city of Cali and gives rise to many of the rivers that provide water and electricity to Cali. The PNN Farallones de Cali encompasses 150,000 ha (580 sq mi) in the mountains as well as much of the Pacific slope and is an area of very high biodiversity. The average temperature ranges from 25 °C (77 °F) in the tropical foothills to 5 °C (41 °F) in the páramo. In this territory are located the district of Pichinde, Andes and Leonera, and two villages Penas Blancas and Lomas de la Cajita.
Fog drip is water dripping to the ground during fog. It occurs when water droplets from the fog adhere to the needles or leaves of trees or other objects, coalesce into larger drops and then drop to the ground.
The Jama-Coaque Ecological Reserve is a 2,100-acre protected area of Pacific Equatorial Forest in coastal Ecuador. It is one of the last significant remnants of tropical moist forest and premontane cloud forest in the region between the Andes mountains and the Pacific Ocean in Ecuador. It is estimated that only 2% of the native forest still remains in coastal Ecuador. The Jama-Coaque Ecological Reserve is owned and managed by Third Millennium Alliance (TMA), a non-profit conservation foundation. It is part of the Tumbes-Chocó-Magdalena biodiversity hotspot as designated by Conservation International.
Cinnadenia is a flowering plant genus belonging to the family Lauraceae. They are present in low and mountain cloud forest in Southeast Asia.
The Itombwe Mountains are a range of mountains in the South Kivu province of the Democratic Republic of the Congo (DRC). They run along the west shore of the northern part of Lake Tanganyika. They contain a vast area of contiguous montane forest and are home to a rich diversity of wildlife.
Montane ecosystems are found on the slopes of mountains. The alpine climate in these regions strongly affects the ecosystem because temperatures fall as elevation increases, causing the ecosystem to stratify. This stratification is a crucial factor in shaping plant community, biodiversity, metabolic processes and ecosystem dynamics for montane ecosystems. Dense montane forests are common at moderate elevations, due to moderate temperatures and high rainfall. At higher elevations, the climate is harsher, with lower temperatures and higher winds, preventing the growth of trees and causing the plant community to transition to montane grasslands and shrublands or alpine tundra. Due to the unique climate conditions of montane ecosystems, they contain increased numbers of endemic species. Montane ecosystems also exhibit variation in ecosystem services, which include carbon storage and water supply.
Desarrollo Forestal Montreal S.A. is a nature reserve and cloud forest adjacent to Braulio Carrillo National Park in the central area of Costa Rica, about 30 miles (48 km) north of San José. The area is located between 1600–1800 meters (5,249–5,905 ft.) above sea level and extends throughout the mountain range.
Sambucus palmensis is a species of shrub or small tree in the family Adoxaceae. It is endemic to the Canary Islands and is present in the laurel forest. It can reach 6 m tall and yields blackish berries.
Álvaro José Negret was a Colombian scientist and author specializing in ornithology and conservation. Negret as a boy collected birds for the Natural History Museum of the University of Cauca in Popayán. As an undergraduate Negret co-founded the Natural History Museum at the University of Caldas before completing a Master's degree in Ecology and Management of Natural Resources at the University of Brasília in Brazil. Upon his return to Colombia Negret became a professor at the University of Cauca and Director of its Natural History Museum from 1987–98. He was married to geologist Patricia Torres.
The Southern Annamites montane rain forests ecoregion covers a region of high biodiversity in the central and southern mountains of the Annamite Range in Vietnam. Terrain ranges from wet lowland forest to evergreen hardwood and conifer montane rain forest. There is a short dry season centered on January–February, but fog and dew are common throughout the year and support a lush forest character.
The Sierra Madre de Chiapas moist forests is a tropical moist broadleaf forest ecoregion in southern Mexico and southern Guatemala, extending into the northwestern corner of El Salvador.
Drimys brasiliensis is a broadleaf evergreen tree of family Winteraceae. it is native to Atlantic Forest of eastern Brazil, western Paraguay, and northwestern Argentina, and to Bolivia.
Bruijnzeel, L. A; Proctor, J (1995). "Hydrology and Biogeochemistry of Tropical Montane Cloud Forests: What Do We Really Know?". In Hamilton, Lawrence S.; Juvik, James O.; Scatena, F. N. (eds.). Tropical Montane Cloud Forests. Ecological Studies. Vol.110. pp.38–78. doi:10.1007/978-1-4612-2500-3_3. ISBN978-1-4612-7564-0.
García-Santos, G. (2007). An ecohydrological and soils study in a montane cloud forest in the National Park of Garajonay, La Gomera (Canary Islands, Spain) (PhD Thesis). hdl:1871/12697.
García-Santos, G; Bruijnzeel, L.A; Dolman, A.J (2009). "Modelling canopy conductance under wet and dry conditions in a subtropical cloud forest". Agricultural and Forest Meteorology. 149 (10): 1565–72. Bibcode:2009AgFM..149.1565G. doi:10.1016/j.agrformet.2009.03.008.
Häger, Achim (2006). Einfluss von Klima und Topographie auf Struktur, Zusammensetzung und Dynamik eines tropischen Wolkenwaldes in Monteverde, Costa Rica[Influence of climate and topography on the structure, composition and dynamics of a tropical cloud forest in Monteverde, Costa Rica] (Dissertation) (in German). doi:10.53846/goediss-2265. hdl:11858/00-1735-0000-0006-B0EE-1. S2CID247019823.
Hamilton, Lawrence S; Juvik, James O; Scatena, F. N (1995). "The Puerto Rico Tropical Cloud Forest Symposium: Introduction and Workshop Synthesis". In Hamilton, Lawrence S.; Juvik, James O.; Scatena, F. N. (eds.). Tropical Montane Cloud Forests. Ecological Studies. Vol.110. pp.1–18. doi:10.1007/978-1-4612-2500-3_1. ISBN978-1-4612-7564-0.
Costin, A.B.; Wimbush, D.J. (1961). Studies in catchment hydrology in the Australian Alps. IV, Interception by trees of rain, cloud, and fog. OCLC822214607.
Stadtmüller, Thomas (1987). Cloud Forests in the Humid Tropics: A Bibliographic Review. ISBN978-92-808-0670-0.
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