Tropical Montane Cloud Forest
What are cloud forests? 
Cloud forests are a type of evergreen mountain forest found in tropical
areas, where local conditions cause cloud and mist to be frequently in
contact with the forest vegetation. One of their most obvious features
is an abundance of mosses, ferns, orchids and other epiphytic plants on
every tree and rock surface.
The definition of a cloud forest is not straightforward. For the purposes
of the Mountain Cloud Forest Initiative and the production of cloud forest
maps, the definition produced by the 1993 International Tropical Mountain
Cloud Forest (TMCF) Symposium has been used.
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"The tropical montane cloud forest is composed of forest ecosystems
of distinctive floristic and structural form. It typically occurs
as a relatively narrow altitudinal zone where the atmospheric
environment is characterised by persistent, frequent or seasonal
cloud cover at the vegetation level. Enveloping clouds or wind-driven
clouds influence the atmospheric interaction through reduced solar
radiation and vapour deficit, canopy wetting, and general suppression
of evapotranspiration. The net precipitation (throughfall) in
such forests is significantly enhanced (beyond rainfall contribution)
through direct canopy interception of cloud water (horizontal
precipitation or cloud stripping) and low water use by the vegetation.
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In comparison with lower latitude tropical moist forest, the
stand characteristics generally include reduced tree stature and
increased stem density. Canopy trees usually exhibit gnarled trunks
and branches; dense compact crowns; and small, thick and hard
(sclerophyll) leaves. TMCF is also characterised by having a high
proportion of biomass as epiphytes (bryophytes, lichens and filmy
ferns) and a corresponding reduction in woody climbers. Soils
are wet and frequently waterlogged and highly organic in the form
of humus and peat (histosol). Biodiversity in terms of tree species
of herbs, shrubs and epiphytes can be relatively high (considering
the small areal extent) when compared with tree species-rich lowland
rain forest. Endemism is often very high.
TMCF occurs on a global scale within a wide range of annual
and seasonal rainfall regimes (ie 500-10,000 mm/year). There is
also significant variation in the altitudinal position of this
mountain vegetation belt. For large, inland mountain systems,
TMCF may typically be found between 2000-3500m (Andes, Rwenzoris),
whereas in coastal and insular mountains this zone may descend
to 1000m (Hawai,'i). Under exceptionally humid, marine, equatorial
conditions, a TMCF zone may develop on steep, small island mountains
at elevations as low as 500m or even lower (Kosrae in Micronesia
and Gau in Fiji)."
Hamilton, Juvik, and Scatena (1993).
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Cloud forests have been subdivided into lower montane, upper montane and
subalpine cloud forest. Further information on these definitions can be
found in 'Decision Time for Cloud Forests' on the Resources
page.
 Cloud
Forest Terminology
A wide range of terminology is used to describe cloud forests. The term
"cloud forest" or its Spanish equivalents are commonly used in association
with montane forests in South and Central America, but is rarely used
in Asia, Africa, Caribbean Islands or in the Oceania/Pacific region. In
Asia the term 'cloud forest' is best equated to the more commonly described
upper montane rainforests, although the terms elfin forest and mossy forest
are also used. In Africa Afromontane forest is most commonly used, as
well 'Upper montane forest'.
Spanish Terminology
The term 'bosque nublado' is the most frequent denomination in Latin America
to describe forest under the strong influence of clouds. 'Bosque de niebla'
and 'selva nublada' are also used. In Mexico cloud forests are often called
'Bosque mesófilo de montaña'. In the Andean region the belt
of cloud forest on the mountainside is sometimes called 'ceja andina'.
In Peru, Bolivia and Argentina the mountain forest zone containing cloud
forests is often called 'Yungas'.
German Terminology
The most frequently used term in German literature to describe cloud forest
is the term 'Nebelwald', signifying fog forest. The term 'Wolkenwald'
is also used as a more direct translation of "cloud forest". Another German
term is 'Gebirgs-Nebelwald', which means mountain cloud forest.
1993 International TMCF Symposium List of TMCF Accepted Terms
These included: mossy forest, elfin forest, montane thicket, dwarf cloud
forest, nuboselva, bosque montano nebuloso, selva neblina, bosque nuboso,
bosque de ceja, selva nublada, 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 ombrófila densa montana e/ou alto-montana,
floresta de altitude, floresta nublada, and floresta pluvial montana e/ou
alto montana.
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