Tropical rainforest

Tropical rainforests are rainforests that occur in areas of tropical rainforest climate in which there is no dry season – all months have an average precipitation of at least 60 mm – and may also be referred to as lowland equatorial evergreen rainforest. True rainforests are typically found between 10 degrees north and south of the equator (see map); they are a sub-set of the tropical forest biome that occurs roughly within the 28 degree latitudes (in the equatorial zone between the Tropic of Cancer and Tropic of Capricorn). Within the World Wildlife Fund's biome classification, tropical rainforests are a type of tropical moist broadleaf forest (or tropical wet forest) that also includes the more extensive seasonal tropical forests.[3]

Aerial view of the Amazon Rainforest
An area of the Amazon rainforest in Brazil. The tropical rainforests of South America contain the largest diversity of species on Earth.[1][2]
Koppen-Geiger Map Af present
Tropical rainforest climate zones (Af).

Overview

Rio Madre de Dios, Peru
Amazon River rain forest in Peru

Tropical rainforests can be characterized in two words: hot and wet. Mean monthly temperatures exceed 18 °C (64 °F) during all months of the year.[4] Average annual rainfall is no less than 1,680 mm (66 in) and can exceed 10 m (390 in) although it typically lies between 1,750 mm (69 in) and 3,000 mm (120 in).[5] This high level of precipitation often results in poor soils due to leaching of soluble nutrients in the ground.

Tropical rainforests exhibit high levels of biodiversity. Around 40% to 75% of all biotic species are indigenous to the rainforests.[6] Rainforests are home to half of all the living animal and plant species on the planet.[7] Two-thirds of all flowering plants can be found in rainforests.[5] A single hectare of rainforest may contain 42,000 different species of insect, up to 807 trees of 313 species and 1,500 species of higher plants.[5] Tropical rainforests have been called the "world's largest pharmacy", because over one quarter of natural medicines have been discovered within them.[8][9] It is likely that there may be many millions of species of plants, insects and microorganisms still undiscovered in tropical rainforests.

Tropical rainforests are among the most threatened ecosystems globally due to large-scale fragmentation as a result of human activity. Habitat fragmentation caused by geological processes such as volcanism and climate change occurred in the past, and have been identified as important drivers of speciation.[10] However, fast human driven habitat destruction is suspected to be one of the major causes of species extinction. Tropical rain forests have been subjected to heavy logging and agricultural clearance throughout the 20th century, and the area covered by rainforests around the world is rapidly shrinking.[11][12]

History

Tropical rainforests have existed on earth for hundreds of millions of years. Most tropical rainforests today are on fragments of the Mesozoic era supercontinent of Gondwana.[13] The separation of the landmass resulted in a great loss of amphibian diversity while at the same time the drier climate spurred the diversification of reptiles.[10] The division left tropical rainforests located in five major regions of the world: tropical America, Africa, Southeast Asia, Madagascar, and New Guinea, with smaller outliers in Australia.[13] However, the specifics of the origin of rainforests remain uncertain due to an incomplete fossil record.

Other types of tropical forest

Several biomes may appear similar-to, or merge via ecotones with, tropical rainforest:

Moist seasonal tropical forest
Rain Forest Daintree Australia
Daintree "rainforest" in Queensland is actually a seasonal tropical forest.

Moist seasonal tropical forests receive high overall rainfall with a warm summer wet season and a cooler winter dry season. Some trees in these forests drop some or all of their leaves during the winter dry season, thus they are sometimes called "tropical mixed forest". They are found in parts of South America, in Central America and around the Caribbean, in coastal West Africa, parts of the Indian subcontinent, and across much of Indochina.

Montane rainforests

These are found in cooler-climate mountainous areas, becoming known as cloud forests at higher elevations. Depending on latitude, the lower limit of montane rainforests on large mountains is generally between 1500 and 2500 m while the upper limit is usually from 2400 to 3300 m.[14]

Flooded rainforests

Tropical freshwater swamp forests, or "flooded forests", are found in Amazon basin (the Várzea) and elsewhere.

Forest structure

Rainforests are divided into different strata, or layers, with vegetation organized into a vertical pattern from the top of the soil to the canopy.[15] Each layer is a unique biotic community containing different plants and animals adapted for life in that particular strata. Only the emergent layer is unique to tropical rainforests, while the others are also found in temperate rainforests.

Forest floor

Gorilla gorilla04
Western lowland gorilla

The forest floor, the bottom-most layer, receives only 2% of the sunlight. Only plants adapted to low light can grow in this region. Away from riverbanks, swamps and clearings, where dense undergrowth is found, the forest floor is relatively clear of vegetation because of the low sunlight penetration. This more open quality permits the easy movement of larger animals such as: ungulates like the okapi (Okapia johnstoni), tapir (Tapirus sp.), Sumatran rhinoceros (Dicerorhinus sumatrensis), and apes like the western lowland gorilla (Gorilla gorilla), as well as many species of reptiles, amphibians, and insects. The forest floor also contains decaying plant and animal matter, which disappears quickly, because the warm, humid conditions promote rapid decay. Many forms of fungi growing here help decay the animal and plant waste.

Understory layer

The understory layer lies between the canopy and the forest floor. The understory is home to a number of birds, small mammals, insects, reptiles, and predators. Examples include leopard (Panthera pardus), poison dart frogs (Dendrobates sp.), ring-tailed coati (Nasua nasua), boa constrictor (Boa constrictor), and many species of Coleoptera.[5] The vegetation at this layer generally consists of shade-tolerant shrubs, herbs, small trees, and large woody vines which climb into the trees to capture sunlight. Only about 5% of sunlight breaches the canopy to arrive at the understory causing true understory plants to seldom grow to 3 m (10 feet). As an adaptation to these low light levels, understory plants have often evolved much larger leaves. Many seedlings that will grow to the canopy level are in the understory.

Canopy layer

The canopy is the primary layer of the forest forming a roof over the two remaining layers. It contains the majority of the largest trees, typically 30–45 m in height. Tall, broad-leaved evergreen trees are the dominant plants. The densest areas of biodiversity are found in the forest canopy, as it often supports a rich flora of epiphytes, including orchids, bromeliads, mosses and lichens. These epiphytic plants attach to trunks and branches and obtain water and minerals from rain and debris that collects on the supporting plants. The fauna is similar to that found in the emergent layer, but more diverse. It is suggested that the total arthropod species richness of the tropical canopy might be as high as 20 million.[16] Other species habituating this layer include many avian species such as the yellow-casqued wattled hornbill (Ceratogymna elata), collared sunbird (Anthreptes collaris), grey parrot (Psitacus erithacus), keel-billed toucan (Ramphastos sulfuratus), scarlet macaw (Ara macao) as well as other animals like the spider monkey (Ateles sp.), African giant swallowtail (Papilio antimachus), three-toed sloth (Bradypus tridactylus), kinkajou (Potos flavus), and tamandua (Tamandua tetradactyla).[5]

Emergent layer

The emergent layer contains a small number of very large trees, called emergents, which grow above the general canopy, reaching heights of 45–55 m, although on occasion a few species will grow to 70–80 m tall.[15][17] Some examples of emergents include: Balizia elegans, Dipteryx panamensis, Hieronyma alchorneoides, Hymenolobium mesoamericanum, Lecythis ampla and Terminalia oblonga.[18] These trees need to be able to withstand the hot temperatures and strong winds that occur above the canopy in some areas. Several unique faunal species inhabit this layer such as the crowned eagle (Stephanoaetus coronatus), the king colobus (Colobus polykomos), and the large flying fox (Pteropus vampyrus).[5]

However, stratification is not always clear. Rainforests are dynamic and many changes affect the structure of the forest. Emergent or canopy trees collapse, for example, causing gaps to form. Openings in the forest canopy are widely recognized as important for the establishment and growth of rainforest trees. It’s estimated that perhaps 75% of the tree species at La Selva Biological Station, Costa Rica are dependent on canopy opening for seed germination or for growth beyond sapling size, for example.[19]

Ecology

Climate

El bosque inundado amazonico-cosmocaixa-2009 (2)
Artificial tropical rainforest in Barcelona

Tropical rainforests are located around and near the equator, therefore having what is called an equatorial climate characterized by three major climatic parameters: temperature, rainfall, and dry season intensity.[20] Other parameters that affect tropical rainforests are carbon dioxide concentrations, solar radiation, and nitrogen availability. In general, climatic patterns consist of warm temperatures and high annual rainfall. However, the abundance of rainfall changes throughout the year creating distinct moist and dry seasons. Tropical forests are classified by the amount of rainfall received each year, which has allowed ecologists to define differences in these forests that look so similar in structure. According to Holdridge’s classification of tropical ecosystems, true tropical rainforests have an annual rainfall greater than 2 m and annual temperature greater than 24 degrees Celsius, with a potential evapotranspiration ratio (PET) value of <0.25. However, most lowland tropical forests can be classified as tropical moist or wet forests, which differ in regards to rainfall. Tropical forest ecology- dynamics, composition, and function- are sensitive to changes in climate especially changes in rainfall.[20]

Soils

Soil types

Soil types are highly variable in the tropics and are the result of a combination of several variables such as climate, vegetation, topographic position, parent material, and soil age.[21] Most tropical soils are characterized by significant leaching and poor nutrients, however there are some areas that contain fertile soils. Soils throughout the tropical rainforests fall into two classifications which include the ultisols and oxisols. Ultisols are known as well weathered, acidic red clay soils, deficient in major nutrients such as calcium and potassium. Similarly, oxisols are acidic, old, typically reddish, highly weathered and leached, however are well drained compared to ultisols. The clay content of ultisols is high, making it difficult for water to penetrate and flow through. The reddish color of both soils is the result of heavy heat and moisture forming oxides of iron and aluminium, which are insoluble in water and not taken up readily by plants.

Soil chemical and physical characteristics are strongly related to above ground productivity and forest structure and dynamics. The physical properties of soil control the tree turnover rates whereas chemical properties such as available nitrogen and phosphorus control forest growth rates.[22] The soils of the eastern and central Amazon as well as the Southeast Asian Rainforest are old and mineral poor whereas the soils of the western Amazon (Ecuador and Peru) and volcanic areas of Costa Rica are young and mineral rich. Primary productivity or wood production is highest in western Amazon and lowest in eastern Amazon which contains heavily weathered soils classified as oxisols.[21] Additionally, Amazonian soils are greatly weathered, making them devoid of minerals like phosphorus, potassium, calcium, and magnesium, which come from rock sources. However, not all tropical rainforests occur on nutrient poor soils, but on nutrient rich floodplains and volcanic soils located in the Andean foothills, and volcanic areas of Southeast Asia, Africa, and Central America.[23]

Oxisols, infertile, deeply weathered and severely leached, have developed on the ancient Gondwanan shields. Rapid bacterial decay prevents the accumulation of humus. The concentration of iron and aluminium oxides by the laterization process gives the oxisols a bright red color and sometimes produces minable deposits (e.g., bauxite). On younger substrates, especially of volcanic origin, tropical soils may be quite fertile.

Nutrient recycling

This high rate of decomposition is the result of phosphorus levels in the soils, precipitation, high temperatures and the extensive microorganism communities.[24] In addition to the bacteria and other microorganisms, there are an abundance of other decomposers such as fungi and termites that aid in the process as well. Nutrient recycling is important because below ground resource availability controls the above ground biomass and community structure of tropical rainforests. These soils are typically phosphorus limited, which inhibits net primary productivity or the uptake of carbon.[21] The soil contains microbial organisms such as bacteria, which break down leaf litter and other organic matter into inorganic forms of carbon usable by plants through a process called decomposition. During the decomposition process the microbial community is respiring, taking up oxygen and releasing carbon dioxide. The decomposition rate can be evaluated by measuring the uptake of oxygen.[24] High temperatures and precipitation increase decomposition rate, which allows plant litter to rapidly decay in tropical regions, releasing nutrients that are immediately taken up by plants through surface or ground waters. The seasonal patterns in respiration are controlled by leaf litter fall and precipitation, the driving force moving the decomposable carbon from the litter to the soil. Respiration rates are highest early in the wet season because the recent dry season results in a large percentage of leaf litter and thus a higher percentage of organic matter being leached into the soil.[24]

Buttress roots

A common feature of many tropical rainforests is the distinct buttress roots of trees. Instead of penetrating to deeper soil layers, buttress roots create a widespread root network at the surface for more efficient uptake of nutrients in a very nutrient poor and competitive environment. Most of the nutrients within the soil of a tropical rainforest occur near the surface because of the rapid turnover time and decomposition of organisms and leaves.[25] Because of this, the buttress roots occur at the surface so the trees can maximize uptake and actively compete with the rapid uptake of other trees. These roots also aid in water uptake and storage, increase surface area for gas exchange, and collect leaf litter for added nutrition.[25] Additionally, these roots reduce soil erosion and maximize nutrient acquisition during heavy rains by diverting nutrient rich water flowing down the trunk into several smaller flows while also acting as a barrier to ground flow. Also, the large surface areas these roots create provide support and stability to rainforests trees, which commonly grow to significant heights. This added stability allows these trees to withstand the impacts of severe storms, thus reducing the occurrence of fallen trees.[25]

Forest succession

Succession is an ecological process that changes the biotic community structure over time towards a more stable, diverse community structure after an initial disturbance to the community. The initial disturbance is often a natural phenomenon or human caused event. Natural disturbances include hurricanes, volcanic eruptions, river movements or an event as small as a fallen tree that creates gaps in the forest. In tropical rainforests, these same natural disturbances have been well documented in the fossil record, and are credited with encouraging speciation and endemism.[10]

Biodiversity and speciation

Young orang utan
Young orangutan at Bukit Lawang, Sumatra

Tropical rainforests exhibit a vast diversity in plant and animal species. The root for this remarkable speciation has been a query of scientists and ecologists for years. A number of theories have been developed for why and how the tropics can be so diverse.

Interspecific competition

Interspecific competition results from a high density of species with similar niches in the tropics and limited resources available. Species which "lose" the competition may either become extinct or find a new niche. Direct competition will often lead to one species dominating another by some advantage, ultimately driving it to extinction. Niche partitioning is the other option for a species. This is the separation and rationing of necessary resources by utilizing different habitats, food sources, cover or general behavioral differences. A species with similar food items but different feeding times is an example of niche partitioning.[26]

Pleistocene refugia

The theory of Pleistocene refugia was developed by Jürgen Haffer in 1969 with his article Speciation of Amazonian Forest Birds. Haffer proposed the explanation for speciation was the product of rainforest patches being separated by stretches of non forest vegetation during the last glacial period. He called these patches of rainforest areas refuges and within these patches allopatric speciation occurred. With the end of the glacial period and increase in atmospheric humidity, rainforest began to expand and the refuges reconnected.[27] This theory has been the subject of debate. Scientists are still skeptical of whether or not this theory is legitimate. Genetic evidence suggests speciation had occurred in certain taxa 1–2 million years ago, preceding the Pleistocene.[28]

Human dimensions

Habitation

Tropical rainforests have harboured human life for many millennia, with many Indian tribes in South- and Central America, who belong to the Indigenous peoples of the Americas, the Congo Pygmies in Central Africa, and several tribes in South-East Asia, like the Dayak people and the Penan people in Borneo.[29] Food resources within the forest are extremely dispersed due to the high biological diversity and what food does exist is largely restricted to the canopy and requires considerable energy to obtain. Some groups of hunter-gatherers have exploited rainforest on a seasonal basis but dwelt primarily in adjacent savanna and open forest environments where food is much more abundant. Other people described as rainforest dwellers are hunter-gatherers who subsist in large part by trading high value forest products such as hides, feathers, and honey with agricultural people living outside the forest.[30]

Indigenous peoples

Índios isolados no Acre 7
Members of an uncontacted tribe encountered in the Brazilian state of Acre in 2009

A variety of indigenous people live within the rainforest as hunter-gatherers, or subsist as part-time small scale farmers supplemented in large part by trading high-value forest products such as hides, feathers, and honey with agricultural people living outside the forest.[29][30] Peoples have inhabited the rainforests for tens of thousands of years and have remained so elusive that only recently have some tribes been discovered.[29] These indigenous peoples are greatly threatened by loggers in search for old-growth tropical hardwoods like Ipe, Cumaru and Wenge, and by farmers who are looking to expand their land, for cattle(meat), and soybeans, which are used to feed cattle in Europe and China.[29][31][32][33] On 18 January 2007, FUNAI reported also that it had confirmed the presence of 67 different uncontacted tribes in Brazil, up from 40 in 2005. With this addition, Brazil has now overtaken the island of New Guinea as the country having the largest number of uncontacted tribes.[34] The province of Irian Jaya or West Papua in the island of New Guinea is home to an estimated 44 uncontacted tribal groups.[35]

Living on the rainforest
Pygmy hunter-gatherers in the Congo Basin in 2014

The pygmy peoples are hunter-gatherer groups living in equatorial rainforests characterized by their short height (below one and a half meters, or 59 inches, on average). Amongst this group are the Efe, Aka, Twa, Baka, and Mbuti people of Central Africa.[36] However, the term pygmy is considered pejorative so many tribes prefer not to be labeled as such.[37]

Some notable indigenous peoples of the Americas, or Amerindians, include the Huaorani, Ya̧nomamö, and Kayapo people of the Amazon. The traditional agricultural system practiced by tribes in the Amazon is based on swidden cultivation (also known as slash-and-burn or shifting cultivation) and is considered a relatively benign disturbance.[38][39] In fact, when looking at the level of individual swidden plots a number of traditional farming practices are considered beneficial. For example, the use of shade trees and fallowing all help preserve soil organic matter, which is a critical factor in the maintenance of soil fertility in the deeply weathered and leached soils common in the Amazon.[40]

There is a diversity of forest people in Asia, including the Lumad peoples of the Philippines and the Penan and Dayak people of Borneo. The Dayaks are a particularly interesting group as they are noted for their traditional headhunting culture. Fresh human heads were required to perform certain rituals such as the Iban "kenyalang" and the Kenyah "mamat".[41] Pygmies who live in Southeast Asia are, amongst others, referred to as "Negrito".

Resources

Cultivated foods and spices

Yam, coffee, chocolate, banana, mango, papaya, macadamia, avocado, and sugarcane all originally came from tropical rainforest and are still mostly grown on plantations in regions that were formerly primary forest. In the mid-1980s and 1990s, 40 million tons of bananas were consumed worldwide each year, along with 13 million tons of mango. Central American coffee exports were worth US$3 billion in 1970. Much of the genetic variation used in evading the damage caused by new pests is still derived from resistant wild stock. Tropical forests have supplied 250 cultivated kinds of fruit, compared to only 20 for temperate forests. Forests in New Guinea alone contain 251 tree species with edible fruits, of which only 43 had been established as cultivated crops by 1985.[42]

Ecosystem services

In addition to extractive human uses, rain forests also have non-extractive uses that are frequently summarized as ecosystem services. Rain forests play an important role in maintaining biological diversity, sequestering and storing carbon, global climate regulation, disease control, and pollination.[43] Half of the rainfall in the Amazon area is produced by the forests. The moisture from the forests is important to the rainfall in Brazil, Paraguay, Argentina[44] Deforestation in the Amazon rainforest region was one of the main reason that cause the severe Drought of 2014-2015 in Brazil[45][46]

Tourism

Monteverde puente
Canopy walkway for seeing the diverse tropical forest in Costa Rica

Despite the negative effects of tourism in the tropical rainforests, there are also several important positive effects.

  • In recent years ecotourism in the tropics has increased. While rainforests are becoming increasingly rare, people are travelling to nations that still have this diverse habitat. Locals are benefiting from the additional income brought in by visitors, as well areas deemed interesting for visitors are often conserved. Ecotourism can be an incentive for conservation, especially when it triggers positive economic change.[47] Ecotourism can include a variety of activities including animal viewing, scenic jungle tours and even viewing cultural sights and native villages. If these practices are performed appropriately this can be beneficial for both locals and the present flora and fauna.
  • An increase in tourism has increased economic support, allowing more revenue to go into the protection of the habitat. Tourism can contribute directly to the conservation of sensitive areas and habitat. Revenue from park-entrance fees and similar sources can be utilised specifically to pay for the protection and management of environmentally sensitive areas. Revenue from taxation and tourism provides an additional incentive for governments to contribute revenue to the protection of the forest.
  • Tourism also has the potential to increase public appreciation of the environment and to spread awareness of environmental problems when it brings people into closer contact with the environment. Such increased awareness can induce more environmentally conscious behavior. Tourism has had a positive effect on wildlife preservation and protection efforts, notably in Africa but also in South America, Asia, Australia, and the South Pacific.[48]

Conservation

Threats

Deforestation

OkTediMine
The Ok Tedi Mine in southwestern Papua New Guinea

Deposits of precious metals (gold, silver, coltan) and fossil fuels (oil and natural gas) occur underneath rainforests globally. These resources are important to developing nations and their extraction is often given priority to encourage economic growth. Mining and drilling can require large amounts of land development, directly causing deforestation. In Ghana, a West African nation, deforestation from decades of mining activity left about 12% of the country's original rainforest intact.[49]

With the invention of agriculture, humans were able to clear sections of rainforest to produce crops, converting it to open farmland. Such people, however, obtain their food primarily from farm plots cleared from the forest[30][50] and hunt and forage within the forest to supplement this. The issue arising is between the independent farmer providing for his family and the needs and wants of the globe as a whole. This issue has seen little improvement because no plan has been established for all parties to be aided.[51]

Agriculture on formerly forested land is not without difficulties. Rainforest soils are often thin and leached of many minerals, and the heavy rainfall can quickly leach nutrients from area cleared for cultivation. People such as the Yanomamo of the Amazon, utilize slash-and-burn agriculture to overcome these limitations and enable them to push deep into what were previously rainforest environments. However, these are not rainforest dwellers, rather they are dwellers in cleared farmland[30][50] that make forays into the rainforest. Up to 90% of the typical Yanamomo diet comes from farmed plants.[50]

Some action has been taken by suggesting fallow periods of the land allowing secondary forest to grow and replenish the soil.[52] Beneficial practices like soil restoration and conservation can benefit the small farmer and allow better production on smaller parcels of land.

Climate change

The tropics take a major role in reducing atmospheric carbon dioxide. The tropics (most notably the Amazon rainforest) are called carbon sinks. As major carbon reducers and carbon and soil methane storages, their destruction contributes to increasing global energy trapping, atmospheric gases. Climate change has been significantly contributed to by the destruction of the rainforests. A simulation was performed in which all rainforest in Africa were removed. The simulation showed an increase in atmospheric temperature by 2.5 to 5 degrees Celsius.[53]

Protection

Efforts to protect and conserve tropical rainforest habitats are diverse and widespread. Tropical rainforest conservation ranges from strict preservation of habitat to finding sustainable management techniques for people living in tropical rainforests. International policy has also introduced a market incentive program called Reducing Emissions from Deforestation and Forest Degradation (REDD) for companies and governments to outset their carbon emissions through financial investments into rainforest conservation.[54]

See also

References

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External links

Amazon natural region

Amazonía region in southern Colombia comprises the departments of Amazonas, Caquetá, Guainía, Guaviare, Putumayo and Vaupés, and covers an area of 403,000 km², 35% of Colombia's total territory. The region is mostly covered by tropical rainforest, or jungle, which is a part of the massive Amazon rainforest.

Amazon rainforest

The Amazon rainforest (Portuguese: Floresta Amazônica or Amazônia; Spanish: Selva Amazónica, Amazonía or usually Amazonia; French: Forêt amazonienne; Dutch: Amazoneregenwoud), also known in English as Amazonia or the Amazon Jungle, is a moist broadleaf forest in the Amazon biome that covers most of the Amazon basin of South America. This basin encompasses 7,000,000 km2 (2,700,000 sq mi), of which 5,500,000 km2 (2,100,000 sq mi) are covered by the rainforest. This region includes territory belonging to nine nations. The majority of the forest is contained within Brazil, with 60% of the rainforest, followed by Peru with 13%, Colombia with 10%, and with minor amounts in Venezuela, Ecuador, Bolivia, Guyana, Suriname and France (French Guiana). States or departments in four nations contain "Amazonas" in their names. The Amazon represents over half of the planet's remaining rainforests, and comprises the largest and most biodiverse tract of tropical rainforest in the world, with an estimated 390 billion individual trees divided into 16,000 species.

Bernard Hyland

Bernard Hyland (Bernard Patrick Matthew Hyland, born 1937), known as Bernie Hyland, has a long career as an Australian botanist.

He has contributed significantly to understanding of Australian plants especially rainforest plants. His contributions include many activities. He has collected eighteen thousand specimens. He has named and scientifically described hundreds of species, especially species of his home and workplace the Wet Tropics of Queensland. He has particular expertise in the Australian rainforests’ rich diversity of species of the plant families Lauraceae and Myrtaceae. For instance, his Lauraceae 1989 major revision of seven genera of one hundred and fifteen species, and his rainforest Myrtaceae 1983 major revision of seventy species of the genus Syzygium and allied genera.

Boorganna Nature Reserve

The Boorganna Nature Reserve is a protected nature reserve located northwest of Taree on the Comboyne Plateau in New South Wales, Australia. The 396-hectare (980-acre) reserve, managed by the NSW National Parks & Wildlife Service, was gazetted in 1904 and is the second oldest nature reserve in the state. The reserve features various forest types, including stands of sub tropical rainforest of which the large rosewood, yellow carabeen and small leaf fig are particularly noteworthy. The reserve is a remnant of the former extensive rainforest on the Comboyne Plateau. The plateau was cleared between 1900 and 1925. Australian red cedar was logged in the area in the nineteenth century. Originally proposed to be part of the world heritage rainforest group. The exploration, knowledge, uses and history of this area by Indigenous Australians is not well known in the present day.

Citrus inodora

Citrus inodora or Microcitrus inodora, commonly known as Russell River lime, is a tree native to the Bellenden-Ker Range in northern Queensland, Australia.

It grows in lowland tropical rainforest. Much of its native habitat has now been cleared for agricultural use, so the species is becoming quite rare. There has to date been no commercial use of the fruits.Citrus inodora is a shrub up to 4 m tall. Fruit is egg-shaped, yellowish-green. Leaves and flowers are essentially odourless, lacking the aromatic oils characteristic of the genus.

Comboyne, New South Wales

Comboyne is a village on the Mid North Coast region of New South Wales. It is situated on the Comboyne Plateau, some 60 km south-west of Port Macquarie, 35 km west of Kew and 54 km north-west of Taree. It is an attractive agricultural area with fertile soils and a high rainfall. The word "Comboyne" is a corruption of the local Biripi people's name for "a place of kangaroos" (Gambuyn). At the 2011 census, Comboyne had a population of 453.Previously, the area was covered in sub-tropical rainforest which has almost all been cleared by the early 20th century. The early explorers originally sought the valuable timber of the Australian Red Cedar. The second oldest natural reserve in the state is at nearby Boorganna Nature Reserve which preserves a remnant of sub-tropical rainforest. The Antarctic beech has been recorded at four sites in the Comboyne area.

Daintree Rainforest

The Daintree Rainforest is a region located on the north east coast of Queensland, Australia, north of Mossman and Cairns. At around 1,200 square kilometres (460 sq mi), the Daintree is a part of the largest continuous area of tropical rainforest on the Australian continent. The Daintree Rainforest is a part of the Wet Tropics Rainforest, that spans across the Cairns Region. The Wet Tropics Rainforest (that the Daintree is a part of) is the oldest continually surviving tropical rainforest in the world. Along the coastline north of the Daintree River, tropical forest grows right down to the edge of the sea.In 2009 as part of the Q150 celebrations, the Daintree Rainforest was announced as one of the Q150 Icons of Queensland for its role as a "Natural attraction".

El Yunque (Puerto Rico)

This article refers to the mountain. For information on the national forest, see El Yunque National Forest.Pico El Yunque or El Yunque Peak is a mountain that is located fully within the boundaries of the El Yunque National Forest, part of the U.S. Forest Service, which is the only tropical rainforest that belongs to the U.S. Forest Service. The peak itself is one of the highest in Puerto Rico, standing at 1,080 meters (3543 feet) above sea level. The peak is nearly always covered in thin mist and, due to its high humidity, a quick shower develops during some afternoon. " El Yunque" is the biggest rainforest in the Caribbean. As part of El Yunque there are a few rivers like El Espiritu Santo . It take almost 4 hours and a half walking to get from Minas Falls to " El Pico ".

Its name is Spanish for "The Anvil".

Jungle green

Jungle green is a color that is a rich tone of medium spring green.

The specific tone of the color jungle green called "jungle green" by Crayola, displayed at right, was formulated by Crayola in 1990.

The first recorded use of jungle green as a color name in English was in 1926.

Kakamega Forest

Kakamega Forest is a tropical rainforest situated in the Kakamega and Kisumu Counties of Kenya, northwest of the capital Nairobi, and near to the border with Uganda. It is Kenya's only tropical rainforest and is said to be Kenya's last remnant of the ancient Guineo-Congolian rainforest that once spanned the continent.

Miri Division

Miri Division is one of the twelve administrative divisions of Sarawak, Malaysia. It has a total area of 26,777.1 square kilometres, and is the second largest division after Kapit Division.

The population of Miri Division (year 2000 census) was 316,400. Ethnically, the population was Iban, Chinese, Malay (mostly Bruneian and Kedayan), Melanau, Kayan, Kenyah, Lun Bawang and Kelabit. Due to the petroleum industry, there is also a large foreign worker population.

Miri Division consists of two districts: Miri and Marudi.

The economy is largely based on petroleum and natural gas extraction from both onshore and offshore wells, and related petroleum refining, liquefied natural gas and chemical production. Another major industry is timber processing from Miri's huge tropical rainforest. Processed wood products, rather than log export has been given priority by the government. Agriculture is includes oil palm, rubber, and pepper as the main products. Tourism, particularly ecotourism, is a growing component of the economy.

Rainforest

Rainforests are forests characterized by high rainfall, with annual rainfall in the case of tropical rainforests between 250 and 450 centimetres (98 and 177 in), and definitions varying by region for temperate rainforests. The monsoon trough, alternatively known as the intertropical convergence zone, plays a significant role in creating the climatic conditions necessary for the Earth's tropical rainforests.

Around 40% to 75% of all biotic species are indigenous to the rainforests. There may be many millions of species of plants, insects and microorganisms still undiscovered in tropical rainforests. Tropical rainforests have been called the "jewels of the Earth" and the "world's largest pharmacy", because over one quarter of natural medicines have been discovered there. Rainforests are also responsible for 28% of the world's oxygen turnover, sometimes misnamed oxygen production, processing it through photosynthesis from carbon dioxide and consuming it through respiration.

The undergrowth in some areas of a rainforest can be restricted by poor penetration of sunlight to ground level. If the leaf canopy is destroyed or thinned, the ground beneath is soon colonized by a dense, tangled growth of vines, shrubs and small trees, called a jungle. The term jungle is also sometimes applied to tropical rainforests generally.

Rainforests as well as endemic rainforest species are rapidly disappearing due to deforestation, the resulting habitat loss and pollution of the atmosphere.

Sherwood Nature Reserve

Sherwood Nature Reserve is a protected nature reserve located near Woolgoolga in the north coast region of New South Wales, Australia.

92 tree species have been recorded in the sub tropical rainforest at Woolgoolga Creek. Significant tree species include blue quandong, white booyong, hoop pine, blush bloodwood, strangler fig, red carabeen, bangalow palm, sugarbark, grey myrtle, coachwood and maiden's blush.The rainforest at Woolgoolga Creek is a known habitat of the rare mottled tree snail.

Tijuca Forest

The Tijuca Forest (Portuguese: Floresta da Tijuca) is a tropical rainforest in the city of Rio de Janeiro, Brazil. It is claimed to be the world's largest urban forest, covering some 32 km² (12.4 mi²), although there are sources assigning this title to the urban forest of Johannesburg, South Africa, where between 6 and 9.5 million trees were planted. Similar to Rio de Janeiro's Tijuca Forest, the UNESCO World Heritage Site Singapore Botanic Gardens (established in 1859) is another renowned garden with a tropical rainforest within its city limits.

Tropical Rainforest Heritage of Sumatra

The Tropical Rainforest Heritage of Sumatra site was inscribed as a UNESCO World Heritage site in 2004. It comprises three Indonesian national parks on the island of Sumatra: Gunung Leuser National Park, Kerinci Seblat National Park and the Bukit Barisan Selatan National Park. The site is listed under Criteria vii - outstanding scenic beauty; ix- an outstanding example representing significant on-going ecological and biological processes; and x- contains the most important and significant natural habitats for in-situ conservation. The Tropical Rainforest Heritage of Sumatra has been placed on the Danger List since 2011 to help overcome threats posed by poaching, illegal logging, agricultural encroachment, and plans to build roads through the site.

Tropical climate

A tropical climate in the Köppen climate classification is a non-arid climate in which all twelve months have mean temperatures of warmer than 18 °C (64 °F). In tropical climates there are often only two seasons: a wet season and a dry season. Tropical climates are frost-free, and changes in the solar angle are small. In tropical climates temperature remains relatively constant (hot) throughout the year. Sunlight is intense.

Tropical monsoon climate

A area of tropical monsoon climate (occasionally known as a tropical wet climate or a tropical monsoon and trade-wind littoral climate) is a type of climate that corresponds to the Köppen climate classification category "Am". Tropical monsoon climates have monthly mean temperatures above 18 °C (64.4 °F) in every month of the year. Tropical monsoon climates is the intermediate climate between the wet Af (or tropical rainforest climate) and Aw (or tropical savanna climate).

A tropical monsoon climate, however, has its driest month seeing on average less than 60 mm, but more than 100 – [total annual precipitation {mm}/25] of average monthly precipitation. This latter fact is in direct contrast to a tropical savanna climate, whose driest month sees less than 60 mm of precipitation and also less than 100 – [total annual precipitation {mm}/25] of average monthly precipitation. In essence, a tropical monsoon climate tends to either see more rainfall than a tropical savanna climate or have less pronounced dry seasons. Additionally, a tropical monsoon climate tends to see less variance in temperatures during the course of the year than a tropical savanna climate. This climate has a driest month which nearly always occurs at or soon after the "winter" solstice for that side of the equator.

Tropical rainforest climate

A tropical rainforest climate is a tropical climate usually found within 10 to 15 degrees latitude of the equator, and has at least 60 mm (2.4 inches) of rainfall every month of the year. Regions with this climate are typically designated Af by the Köppen climate classification. A tropical rainforest climate is typically hot and wet.

Biomes
Biogeographic
realms
See also

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