Seasonal tropical forest

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Tropical seasonal climate sub-types:
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Am--Tropical monsoon climate.
Aw/As--Tropical savanna climate.
(note: Af in light green is Tropical rainforest) Koppen World Map Af Am Aw.png
Tropical seasonal climate sub-types: (note: Af in light green is Tropical rainforest)

Seasonal tropical forest, also known as moist deciduous, semi-evergreen seasonal, tropical mixed or monsoon [1] forest, typically contains a range of tree species: only some of which drop some or all of their leaves during the dry season. This tropical forest is classified under the Walter system as (i) tropical climate with high overall rainfall (typically in the 1000–2500 mm range; 39–98 inches) and (ii) having a very distinct wet season with (an often cooler “winter”) dry season. These forests represent a range of habitats influenced by monsoon (Am) or tropical wet savanna (Aw/As) climates (as in the Köppen climate classification). Drier forests in the Aw/As climate zone are typically deciduous and placed in the Tropical dry forest biome: with further transitional zones (ecotones) of savannah woodland then tropical and subtropical grasslands, savannas, and shrublands.

Contents

Distribution

Bhawal National Park.jpg
Into the green, Bhawal National Park.jpg
Extreme differences are very much evident between the wet and dry seasons in a tropical seasonal forest. The image to the left shows Bhawal National Park in central Bangladesh during the dry season, while the image to the right depicts the same area during monsoon season.
Trees at Cat Tien National Park: showing seasonal forest structure in the early dry season (December) BenCu forest structure 23Dec08.jpg
Trees at Cat Tien National Park: showing seasonal forest structure in the early dry season (December)
Seasonal forest in Northern Thailand Subtropical semi-evergreen seasonal forest in Northern Thailand.JPG
Seasonal forest in Northern Thailand

Seasonal (mixed) tropical forests can be found in many parts of the tropical zone, with examples found in:

Emergent tree rising above the main canopy in Khao Yai National Park forest Fut emergeant.jpg
Emergent tree rising above the main canopy in Khao Yai National Park forest

Climate

The climate of seasonal forests is typically controlled by a system called the Intertropical Convergence Zone (ITCZ), located near the equator and created by the convergence of the trade winds from the Northern and Southern Hemispheres. The position of these bands vary seasonally, moving north in the northern summer and south in the northern winter, and ultimately controlling the wet and dry seasons in the tropics. [7] These regions appear to have experienced strong warming, at a mean rate of 0.26 degrees Celsius per decade, which coincides with a global rise in temperature resulting from the anthropocentric inputs of greenhouse gases into the atmosphere. Studies have also found that precipitation has declined and tropical Asia has experienced an increase in dry season intensity whereas Amazonian has no significant pattern change in precipitation or dry season. [8] Additionally, El Niño-Southern Oscillation (ENSO) events drive the inter-annual climatic variability in temperature and precipitation and result in drought and increased intensity of the dry season. As anthropogenic warming increases the intensity and frequency of ENSO will increase, rendering tropical rainforest regions susceptible to stress and increased mortality of trees and other plants. [8]

Onset dates and prevailing wind currents of the southwest summer monsoon. India southwest summer monsoon onset map en.svg
Onset dates and prevailing wind currents of the southwest summer monsoon.

Structure

As with tropical rainforests there are different canopy layers, but these may be less pronounced in mixed forests, which are often characterised by numerous lianas due to their growth advantage during the dry season. [9] The colloquial term jungle , derived from the Sanskrit word for "forest", has no specific ecological meaning but originally referred to this type of primary and especially secondary forest in the Indian subcontinent. Determining which strands of mixed forest are primary and secondary can also be problematic, since the species mixture is influenced by factors such as soil depth and climate, as well as human interference.

Characteristic biology

The fauna and flora of seasonal tropical mixed forest are usually distinctive. Examples of the biodiversity and habitat type are often well described for National Parks in:

Falling Waters in Korup National Park Falling Waters in KORUP National park.jpg
Falling Waters in Korup National Park

Related Research Articles

<span class="mw-page-title-main">Tropics</span> Region of Earth surrounding the Equator

The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at 23°26′10.1″ (or 23.43613°) N and the Tropic of Capricorn in the Southern Hemisphere at 23°26′10.1″ (or 23.43613°) S. The tropics are also referred to as the tropical zone and the torrid zone.

<span class="mw-page-title-main">Tropical and subtropical moist broadleaf forests</span> Habitat type defined by the World Wide Fund for Nature

Tropical and subtropical moist broadleaf forests (TSMF), also known as tropical moist forest, is a subtropical and tropical forest habitat type defined by the World Wide Fund for Nature.

<span class="mw-page-title-main">Precipitation</span> Product of the condensation of atmospheric water vapor that falls under gravity

In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls from clouds due to gravitational pull. The main forms of precipitation include drizzle, rain, sleet, snow, ice pellets, graupel and hail. Precipitation occurs when a portion of the atmosphere becomes saturated with water vapor, so that the water condenses and "precipitates" or falls. Thus, fog and mist are not precipitation but colloids, because the water vapor does not condense sufficiently to precipitate. Two processes, possibly acting together, can lead to air becoming saturated: cooling the air or adding water vapor to the air. Precipitation forms as smaller droplets coalesce via collision with other rain drops or ice crystals within a cloud. Short, intense periods of rain in scattered locations are called showers.

<span class="mw-page-title-main">Subtropics</span> Geographic and climate zone

The subtropical zones or subtropics are geographical and climate zones to the north and south of the tropics. Geographically part of the temperate zones of both hemispheres, they cover the middle latitudes from 23°26′10.1″ (or 23.43613°) to approximately 35° north and south. The horse latitudes lie within this range.

<span class="mw-page-title-main">Intertropical Convergence Zone</span> Meteorological phenomenon

The Intertropical Convergence Zone, known by sailors as the doldrums or the calms because of its monotonous windless weather, is the area where the northeast and the southeast trade winds converge. It encircles Earth near the thermal equator though its specific position varies seasonally. When it lies near the geographic Equator, it is called the near-equatorial trough. Where the ITCZ is drawn into and merges with a monsoonal circulation, it is sometimes referred to as a monsoon trough.

<span class="mw-page-title-main">Tropical climate</span> One of the five major climate groups in the Köppen climate classification

Tropical climate is the first of the five major climate groups in the Köppen climate classification identified with the letter A. Tropical climates are defined by a monthly average temperature of 18 °C (64.4 °F) or higher in the coolest month, and feature hot temperatures all year-round. Annual precipitation is often abundant in tropical climates, and shows a seasonal rhythm but may have seasonal dryness to varying degrees. There are normally only two seasons in tropical climates, a wet (rainy/monsoon) season and a dry season. The annual temperature range in tropical climates is normally very small. Sunlight is intense in these climates.

<span class="mw-page-title-main">Climate of India</span> Overview of climatic conditions in India

The climate of India consists of a wide range of weather conditions across a vast geographic scale and varied topography. Based on the Köppen system, India hosts six major climatic sub types, ranging from arid deserts in the west, alpine tundra and glaciers in the north, and humid tropical regions supporting rain forests in the southwest and the island territories. Many regions have starkly different microclimates, making it one of the most climatically diverse countries in the world. The country's meteorological department follows the international standard of four seasons with some local adjustments: winter, summer, monsoon or rainy season, and a post-monsoon period.

<span class="mw-page-title-main">Wet season</span> Yearly period of high rainfall

The wet season is the time of year when most of a region's average annual rainfall occurs. Generally, the season lasts at least one month. The term green season is also sometimes used as a euphemism by tourist authorities. Areas with wet seasons are dispersed across portions of the tropics and subtropics.

<span class="mw-page-title-main">Madden–Julian oscillation</span> Tropical atmosphere element of variability

The Madden–Julian oscillation (MJO) is the largest element of the intraseasonal variability in the tropical atmosphere. It was discovered in 1971 by Roland Madden and Paul Julian of the American National Center for Atmospheric Research (NCAR). It is a large-scale coupling between atmospheric circulation and tropical deep atmospheric convection. Unlike a standing pattern like the El Niño–Southern Oscillation (ENSO), the Madden–Julian oscillation is a traveling pattern that propagates eastward, at approximately 4 to 8 m/s, through the atmosphere above the warm parts of the Indian and Pacific oceans. This overall circulation pattern manifests itself most clearly as anomalous rainfall.

<span class="mw-page-title-main">Geography of South America</span> Overview of the geography of South America

The geography of South America contains many diverse regions and climates. Geographically, South America is generally considered a continent forming the southern portion of the landmass of the Americas, south and east of the Colombia–Panama border by most authorities, or south and east of the Panama Canal by some. South and North America are sometimes considered a single continent or supercontinent, while constituent regions are infrequently considered subcontinents.

<span class="mw-page-title-main">Tropical savanna climate</span> Climate subtype

Tropical savanna climate or tropical wet and dry climate is a tropical climate sub-type that corresponds to the Köppen climate classification categories Aw and As. The driest month has less than 60 mm (2.4 in) of precipitation and also less than mm of precipitation.

<span class="mw-page-title-main">Tropical rainforest climate</span> Type of tropical climate in which there is no dry season

A tropical rainforest climate or equatorial climate is a tropical climate sub-type usually found within 10 to 15 degrees latitude of the equator. There are some other areas at higher latitudes, such as the coast of southeast Florida, United States, and Okinawa, Japan that fall into the tropical rainforest climate category. They experience high mean annual temperatures, small temperature ranges, and rain that falls throughout the year. Regions with this climate are typically designated Af by the Köppen climate classification. A tropical rainforest climate is typically hot, very humid, and wet with no dry season.

<span class="mw-page-title-main">Rain</span> Precipitation in the form of water droplets

Rain is water droplets that have condensed from atmospheric water vapor and then fall under gravity. Rain is a major component of the water cycle and is responsible for depositing most of the fresh water on the Earth. It provides water for hydroelectric power plants, crop irrigation, and suitable conditions for many types of ecosystems.

<span class="mw-page-title-main">Humid subtropical climate</span> Transitional climatic zone

A humid subtropical climate is a temperate climate type characterized by hot and humid summers, and cool to mild winters. These climates normally lie on the southeast side of all continents, generally between latitudes 25° and 40° and are located poleward from adjacent tropical climates, and equatorward from either humid continental or oceanic climates. It is also known as warm temperate climate in some climate classifications.

<span class="mw-page-title-main">Tropical monsoon climate</span> Climate subtype in the Köppen climate classification system

An area of tropical monsoon climate is a tropical climate subtype that corresponds to the Köppen climate classification category Am. Tropical monsoon climates have monthly mean temperatures above 18 °C (64 °F) in every month of the year and a dry season. The tropical monsoon climate is the intermediate climate between the wet AF and the drier Aw.

<span class="mw-page-title-main">Earth rainfall climatology</span> Study of rainfall

Earth rainfall climatology Is the study of rainfall, a sub-field of meteorology. Formally, a wider study includes water falling as ice crystals, i.e. hail, sleet, snow. The aim of rainfall climatology is to measure, understand and predict rain distribution across different regions of planet Earth, a factor of air pressure, humidity, topography, cloud type and raindrop size, via direct measurement and remote sensing data acquisition. Current technologies accurately predict rainfall 3–4 days in advance using numerical weather prediction. Geostationary orbiting satellites gather IR and visual wavelength data to measure realtime localised rainfall by estimating cloud albedo, water content, and the corresponding probability of rain.

<span class="mw-page-title-main">Monsoon of South Asia</span> Monsoon in Indian subcontinent

The Monsoon of South Asia is among several geographically distributed global monsoons. It affects the Indian subcontinent, where it is one of the oldest and most anticipated weather phenomena and an economically important pattern every year from June through September, but it is only partly understood and notoriously difficult to predict. Several theories have been proposed to explain the origin, process, strength, variability, distribution, and general vagaries of the monsoon, but understanding and predictability are still evolving.

<span class="mw-page-title-main">Tropical vegetation</span> Vegetation in tropical latitude

Tropical vegetation is any vegetation in tropical latitudes. Plant life that occurs in climates that are warm year-round is in general more biologically diverse that in other latitudes. Some tropical areas may receive abundant rain the whole year round, but others have long dry seasons which last several months and may vary in length and intensity with geographic location. These seasonal droughts have great impact on the vegetation, such as in the Madagascar spiny forests.

<span class="mw-page-title-main">Costa Rican seasonal moist forests</span> Ecoregion in Costa Rica and Nicaragua

The Costa Rican seasonal moist forests ecoregion covers the Pacific Slope of the volcanic mountain range of northwestern Costa Rica and the extreme south of Nicaragua. The area has a distinct dry season during which the characteristic deciduous trees drop their leaves. The forests themselves have been highly degraded in the past by human conversion to agriculture and settlement. The Costa Rican capital city of San Jose is in the middle of this ecoregion.

<span class="mw-page-title-main">Rainforests and vine thickets</span>

Rainforests and vine thickets are a major vegetation group in Australia. It consists of temperate to tropical rainforests, monsoon forests, and vine thickets. Rainforests and vine thickets are generally found in small pockets across the eastern and northern portions of the continent, including western Tasmania, eastern New South Wales, eastern Queensland, the northern portion of the Northern Territory, and the Kimberley Region of northeastern Western Australia.

References

  1. Mongbay: Types of tropical forest (accessed 21 March 2017)
  2. Beard, J.S.; Keneally, K.F. (1987), 'Rainforests of Western Australia'. In 'The rainforest legacy: Australian national rainforests study'. Special Australian heritage publication series 7(1), pp. 289–304
  3. Webb, L. J. (Leonard James); Tracey, J. G. (John Geoffrey) (1982), An ecological survey of the monsoon forests of the north-western region of the Northern Territory, Australian National Parks and Wildlife Service
  4. Russell-Smith, Jeremy; Dunlop, Clyde (1987), The status of monsoon vine forests in the Northern Territory: a perspective. In 'The rainforest legacy: Australian national rainforests study. Special Australian heritage publication series 7(1)
  5. Stanton, J.P.; Fell, David. G. (2005). "The rainforests of Cape York Peninsula". Rainforest CRC via National Library of Australia.
  6. Leigh EG, Rand AS, Windsor DM (Eds. 1983) The ecology of a tropical forest. Seasonal rhythms and long-term changes. Oxford University Press 468 pp.
  7. NWS JetStream – Inter-Tropical Convergence Zone. Srh.noaa.gov (5 January 2010). Retrieved on 28 March 2013.
  8. 1 2 Malhi, Yadvinder & Wright, James (2004). "Spatial patterns and recent trends in the climate of tropical rainforest regions". Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences. 359 (1443): 311–329. doi:10.1098/rstb.2003.1433. PMC   1693325 . PMID   15212087.
  9. Ya-Jun Chen, Kun-Fang Cao, Stefan A. Schnitzer, Ze-Xin Fan, Jiao-Lin Zhang, Frans Bongers (2015) Water-use advantage of lianas over trees in seasonal tropical forests. New Phytologist, 205[1]: 128–136

See also