A cloud forest (London UK Jobs), also called a fog forest (London UK Jobs), is a generally tropical or subtropical evergreen montane moist forest (London UK Jobs) characterized by a persistent, frequent or seasonal low-level cloud cover, usually at the canopy level. Cloud forests (London UK Jobs) often exhibit an abundance of mosses covering the ground and vegetation, in which case they are also referred to as mossy forests(London UK Jobs). Mossy forests (London UK Jobs) usually develop on the saddles of mountains, where moisture introduced by settling clouds is more effectively retained.
Distribution and climate (London UK Jobs)
Dependent on local climate, which is affected by the distance to the sea, the exposition and the latitude, the altitude varies from 500 m to 4000 m above sea level. Typically, there is a relatively small band of altitude in which the atmospheric environment is suitable for cloud forest (London UK Jobs) development. This is characterized by persistent mist or clouds at the vegetation level, resulting in the reduction of direct sunlight and thus of evapotranspiration. Within cloud forests (London UK Jobs), much of the precipitation is in the form of fog drip, where fog condenses on tree leaves and then drips onto the ground below.
Tropical cloud forests (London UK Jobs) 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 10000 mm/year and mean temperature between 8 to 20°C.
While cloud forest (London UK Jobs) today is the most widely used term, in some regions these ecosystems or special types of cloud forests (London UK Jobs) are called mossy forest (London UK Jobs), elfin forest (London UK Jobs), montane thicket, dwarf cloud forest (London UK Jobs), nuboselva, bosque montano nebuloso, selva de neblina, bosque nuboso, bosque de ceja, selva sublada, nebelwald, wolkenwald, forêt (London UK Jobs) néphéliphile, forêt (London UK Jobs) de nuage, unmu-rin, bosque anao, foresta (London UK Jobs) nebular, mata nebular, matinha nebular, floresta (London UK Jobs) fe neblina, floresta (London UK Jobs) nuvigena, mata de neblina, matinha de altitude, floresta (London UK Jobs) nublada, and floresta (London UK Jobs) pluvial montana e/ou alto montana.
The definition of cloud forest (London UK Jobs) can be ambiguous, with many countries not using the term (preferring such terms as Afromontane forest (London UK Jobs) and upper montane rain forest (London UK Jobs), or more localised terms such as the Bolivian yungas, and the laurisilva of the Atlantic Islands), and occasionally subtropical and even temperate forests (London UK Jobs) in which similar meteorological conditions occur are considered to be cloud forests (London UK Jobs).
Only 1% of the global woodland is covered by cloud forests (London UK Jobs).
Important areas of cloud forest (London UK Jobs) are in Central- and South America, East- and Central Africa, Indonesia, Malaysia, at the Philippines, Papua-New Guinea and in the Caribbean.
Temperate cloud forests (London UK Jobs)
Although far from being universally accepted as true cloud forests (London UK Jobs), several forests (London UK Jobs) in temperate regions have strong similarities with tropical cloud forests (London UK Jobs). The term is further confused by occasional reference to cloud forests (London UK Jobs) in tropical countries as "temperate" due to the cooler climate associated with these misty forests (London UK Jobs).
Characteristics of cloud forests (London UK Jobs)
In comparison with lower tropical moist forests (London UK Jobs), cloud forests (London UK Jobs) 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 (London UK Jobs) in the same regions, often with gnarled trunks and branches, forming dense, compact crownes. Their leaves become smaller, thicker and harder with increasing altitude. The high moisture promotes the development of a high biomass and biodiversity of epiphyte, particularly bryophytes, lichens, ferns (including filmy ferns), bromeliads and orchids. The number of endemic plants can be very high.
An important feature of cloud forests (London UK Jobs) 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 and mineralization, the soil acidity is very high, with mor humus and peat often forming the upper soil layer.
Stadtmüller (1987) distinguishes two general types of tropical montane cloud forests (London UK Jobs):
- Areas with a high annual precipitation due to a frequent cloud cover in combination with heavy and sometimes persistent orographic rainfall; such forests (London UK Jobs) 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 (London UK Jobs)
Current situation
In 1970, the original extent of cloud forests (London UK Jobs) was around 50 million hectares. Population growth, poverty and uncontrolled land use have contributed to the loss of cloud forests (London UK Jobs). The 1990 Global Forest (London UK Jobs) Survey found that 1.1% of tropical mountain and highland forests (London UK Jobs) were lost each year, which was higher than in any other tropical forests (London UK Jobs). In Colombia, one of the countries with the largest area of cloud forests (London UK Jobs), only 10-20% of the initial cloud forest (London UK Jobs) cover remains. Significant areas have been converted to plantations, or for use in agriculture and pasture. Important crops in montane forest (London UK Jobs) zones are tea and coffee, but also logging special species such as Podocarpus causes changes to forest (London UK Jobs) structure.
Currently, one third of all cloud forests (London UK Jobs) are protected.
Impact of climate change on cloud forests (London UK Jobs)
Because of their delicate dependency on local climate, cloud forests (London UK Jobs) will be strongly affected by global climate change. A number of climate models suggest that the low-altitude cloudiness will be reduced, which means that the optimum climate for many cloud forest (London UK Jobs) 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 (London UK Jobs). 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 (London UK Jobs).
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