Rainforest: Difference between revisions

Browse history interactively

← Previous edit Next edit →

Content deleted Content added

VisualWikitext

Inline

Revision as of 11:59, 3 June 2008

The canopy layer contains the majority of the largest trees, typically 30-45 m tall. The densest areas of biodiversity are found in the forest canopy, a more or less continuous cover of foliage formed by adjacent treetops. The canopy, by some estimates, is home to 50 percent of all plant species, suggesting that perhaps half of all life on Earth could be found there. The fauna is similar to that found in the emergent layer, but more diverse. A quarter of all insect species are believed to exist in the rainforest canopy. Scientists have long suspected the richness of the canopy as a habitat, but have only recently developed practical methods of exploring it. As long ago as 1917, naturalist William Beebe declared that "another continent of life remains to be discovered, not upon the Earth, but one to two hundred feet above it, extending over thousands of square miles." True exploration of this habitat only began in the 1980s, when scientists developed methods to reach the canopy, such as firing ropes into the trees using crossbows. Exploration of the canopy is still in its infancy, but other methods include the use of balloons and airships to float above the highest branches and the building of cranes and walkways planted on the forest floor. The science of accessing tropical forest canopy using airships, or similar aerial platforms, is called dendronautics.^[1]
The understory layer lies between the canopy and the forest floor. The understory (or understorey) is home to a number of birds, snakes, and lizards, as well as predators such as jaguars, boa constrictors, and leopards. The leaves are much larger at this level. Insect life is also abundant. Many seedlings that will grow to the canopy level are present in the understory. Only about 5 percent of the sunlight shining on the rainforest reaches the understory. This layer can also be called a shrub layer, although the shrub layer may also be considered a separate layer.
The forest floor layer receives only 2 percent of 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. It also contains decaying plant and animal matter, which disappears quickly due to the warm, humid conditions promoting rapid decay. Many forms of fungi grow here which help decay the animal and plant waste.

^ DENDRONAUTICS - Introduction

[1] DENDRONAUTICS - Introduction

[1]

@@ Line 1: / Line 1: @@
-{{dablink|For the novel, see [[Rainforest (novel)]].}}
-[[Image:Daintree Rainforest.JPG|280px|thumb|right|The [[Daintree Rainforest]] in [[Queensland]], [[Australia]].]]
-[[Image:800px-tropical wet forests.png|280px|thumb|right|General distribution of tropical rainforest]]
-[[Image:Temperate rainforest map.png|280px|thumb|right|General distribution of temperate rainforest.]]
-[[Image:DSC00686Cairns.JPG|280px|thumb|right|The [[Daintree Rainforest]] near Cairns, in [[Queensland]], [[Australia]].]]
-'''Rainforests''' are [[forest]]s characterized by high [[rain]]fall, with definitions setting minimum normal annual rainfall between 1750-2000 mm (68-78 inches).
-Rainforests are home to two-thirds of all the living [[animal]] and [[plant]] [[species]] on [[Earth]]. It has been estimated that many hundreds of millions of species of plants, insects and [[microorganism]]s are still undiscovered. Tropical rainforests have been called the "jewels of the Earth," and the "world's largest [[pharmacy]]," because of the large number of natural [[medicine]]s discovered there.
-The [[undergrowth]] in a rainforest is restricted in many areas by the lack of [[sunlight]] at ground level. This makes it possible to walk through the forest. If the [[leaf]] [[Canopy (forest)|canopy]] is destroyed or thinned, the ground beneath is soon colonized by a dense, tangled growth of [[vine]]s, [[shrub]]s and small [[tree]]s called a [[jungle]]. The two types of rainforest are:
-*'''[[Tropical rainforest]]s''' are rainforests in the [[tropics]], found near the [[Equator]] (between the [[Tropic of Cancer]] and [[Tropic of Capricorn]]) and present in [[southeast Asia]] ([[Myanmar]] to [[Indonesia]] and [[Papua New Guinea]], northern and eastern [[Australia]]), [[sub-Saharan Africa]] from [[Cameroon]] to the [[Democratic Republic of Congo|Congo]], ([[Congo River|Congo Rainforest]]), [[South America]] (the [[Amazon Rainforest]]) [[Central America]] ([[Bosawás Biosphere Reserve|Bosawás]],  southern [[Yucatán Peninsula]]-[[El Peten]]-[[Belize]]-[[Calakmul Biosphere Reserve|Calakmul]]), and on many of the [[Pacific Islands]](such as [[Hawaii tropical moist forests|Hawaii]]). Tropical rainforests have been called the "Earth's [[lung]]s," although it is now known that rainforests contribute little net [[oxygen]] additions to the [[Earth's atmosphere|atmosphere]] through [[photosynthesis]].<ref>Broeker, Wallace S. (2006). "Breathing easy: Et tu, O<sub>2</sub>." Columbia University http://www.columbia.edu/cu/21stC/issue-2.1/broecker.htm.</ref><ref>Moran, E.F., "Deforestation and Land Use in the Brazilian Amazon," Human Ecology, Vol 21, No. 1, 1993"</ref>
-*'''[[Temperate rainforest]]s''' are rainforest in [[temperate]] regions. They can be found in [[North America]] (in the [[Pacific Northwest]], the [[British Columbia Coast]], and in the [[inland rainforest]] of the [[Rocky Mountain Trench]] east of [[Prince George, British Columbia|Prince George]]), in [[Europe]] (in coastal areas of [[Ireland]], [[Scotland]] and southern [[Norway]], parts of the western [[Balkans]] along the [[Adriatic Sea|Adriatic]] coast, and coastal areas of the eastern [[Black Sea]], including [[Georgia (country)|Georgia]] and coastal [[Turkey]]), and in [[East Asia]] (in [[southern China]], [[Taiwan]], much of [[Japan]] and [[Korea]], and on [[Sakhalin Island]] and the adjacent [[Russian Far East]] coast), and also [[Australia]] and [[New Zealand]].
-==Soils==
-Despite the growth of [[vegetation]] in a rainforest, [[soil quality]] is often quite poor. Rapid [[bacteria]]l decay prevents the accumulation of [[humus]]. The concentration of [[iron]] and [[aluminium]] [[oxide]]s by the [[Laterite|laterization]] process gives the [[oxisol]]s a bright red color and sometimes produces [[Mine|minable]] [[deposit]]s such as [[bauxite]]). On younger substrates, especially of [[Volcano|volcanic]] origin, tropical soils may be quite fertile.
-==Effect on global climate==
-A natural rainforest emits and absorbs vast quantities of [[carbon dioxide]]. On a global scale, long-term fluxes are approximately in balance, so that an undisturbed rainforest would have a small net impact on atmospheric carbon dioxide levels [http://www.grida.no/CLIMATE/IPCC_TAR/wg1/pdf/TAR-03.PDF], though they may have other climatic effects (on [[cloud]] formation, for example, by recycling [[water vapour]]). No rainforest today can be considered to be undisturbed.<ref name = Lewis>Lewis, S.L. , Phillips, O.L., Baker, T.R., Lloyd, J. et al 2004 “Concerted changes in tropical forest structure and dynamics: evidence from 50 South American long-term plots”  Phil. Trans. R. Soc. Lond. 359</ref>  Human induced deforestation plays a significant role in causing rainforests to release carbon dioxide,<ref name = Malhi> Malhi, Y and Grace, J. 2000 " Tropical forests and atmospheric carbon dioxide”, Tree 15</ref> as do natural processes such as drought that result in tree death.<ref>[http://www.theage.com.au/articles/2004/03/06/1078464675256.html?from=storyrhs Drought may turn forests into carbon producers - Science - www.theage.com.au<!-- Bot generated title -->]</ref> These droughts themselves are believed{{Who|date=April 2008}} to be exacerbated by human induced climate change. Some climate models run with interactive vegetation predict a large loss of Amazonian rainforest around 2050 due to drought, leading to forest dieback and the subsequent feedback of releasing more carbon dioxide [http://www.metoffice.gov.uk/research/hadleycentre/pubs/HCTN/HCTN_42.pdf].
-==Rainforest layers==
-[[Image:Rainforest,bluemountainsNSW.jpg|thumb|Rainforest in the [[Blue Mountains]], [[Australia]]]]
-The rainforest is divided into four different parts, each with different plants and animals, adapted for life in that particular area:
-*The '''''emergent layer''''' contains a small number of very large [[tree]]s which grow above the general [[Canopy (forest)|canopy]], reaching heights of 45-55 m, although on occasion a few species will grow to 70-80 m tall.<ref>{{cite book |last= Bourgeron |first= Patrick S.|editor= Frank B. Golley |title=Tropical Rain Forest Ecosystems. Structure and Function |origyear= 1983 |edition= 14A|series= Ecosystems of the World |publisher= Elsevier Scientific |isbn= 0444419861 |pages= 29-47 |chapter= Spatial Aspects of Vegetation Structure}}</ref><ref>{{cite web | url = http://www.nativetreesociety.org/worldtrees/sea_ei/malaysia/sabah2005.htm | title = Sabah | publisher = Eastern Native Tree Society | accessdate= 2007-11-14}}</ref> They need to be able to withstand the hot temperatures and strong winds. [[Eagle]]s, [[Butterfly|butterflies]], [[bat]]s and certain [[monkey]]s inhabit this layer.
 *The '''''canopy layer''''' contains the majority of the largest trees, typically 30-45 m tall. The densest areas of biodiversity are found in the forest canopy, a more or less continuous cover of foliage formed by adjacent treetops. The canopy, by some estimates, is home to 50 percent of all plant species, suggesting that perhaps half of all life on Earth could be found there. The fauna is similar to that found in the emergent layer, but more diverse. A quarter of all insect species are believed to exist in the rainforest canopy. Scientists have long suspected the richness of the canopy as a habitat, but have only recently developed practical methods of exploring it. As long ago as 1917, [[Natural history|naturalist]] [[William Beebe]] declared that "another continent of life remains to be discovered, not upon the Earth, but one to two hundred feet above it, extending over thousands of square miles." True exploration of this habitat only began in the 1980s, when scientists developed methods to reach the canopy, such as firing ropes into the trees using [[crossbow]]s. Exploration of the canopy is still in its infancy, but other methods include the use of [[Balloon (aircraft)|balloons]] and [[airship]]s to float above the highest branches and the building of cranes and walkways planted on the forest floor. The science of accessing tropical forest canopy using airships, or similar aerial platforms, is called dendronautics.<ref>[http://www.dendronautics.org/ DENDRONAUTICS - Introduction<!-- Bot generated title -->]</ref>
 *The '''''understory layer''''' lies between the canopy and the forest floor. The [[understory]] (or understorey) is home to a number of [[bird]]s, [[snake]]s, and [[lizard]]s, as well as [[predator]]s such as [[jaguar]]s, [[boa (genus)|boa constrictors]], and [[leopard]]s. The leaves are much larger at this level. Insect life is also abundant. Many seedlings that will grow to the canopy level are present in the understory. Only about 5 percent of the sunlight shining on the rainforest reaches the understory. This layer can also be called a ''shrub layer'', although the shrub layer may also be considered a separate layer.
 *The '''''forest floor layer''''' receives only 2 percent of sunlight. Only plants [[Adaptation|adapted]] to low light can grow in this region. Away from [[river]]banks, [[swamp]]s, and clearings where dense undergrowth is found, the forest floor is relatively clear of vegetation because of the low sunlight penetration. It also contains [[decay]]ing plant and animal matter, which disappears quickly due to the warm, humid conditions promoting rapid decay. Many forms of [[Fungus|fungi]] grow here which help decay the animal and plant waste.
-==Flora and Fauna==
-[[Image:Shongololo Equatorial guinea.jpg|thumb|right|[[Millipede]] on the forest floor of Rio Muni, [[Equatorial Guinea]]]]
-More than half of the world's species of plants and animals are found in the rainforest.  Rainforests support a very broad array of [[fauna]] including [[mammal]]s, [[reptile]]s, [[bird]]s and [[invertebrate]]s.  Mammals may include [[primate]]s, [[felid]]s and other families.  Reptiles include [[snake]]s, [[turtle]]s, [[chameleon]]s and other families while birds include such families as [[vangidae]] and [[Cuculidae]]. Dozens of families of invertebrates are found in rainforests. [[Fungi]] are also very common in rainforest areas as they can feed on the decomposing remains of plant and animal life. As a result of all the decomposing matter on the forest floor, rainforests develop high levels of organic matter in the soil, making it very nutritious for plant and animal life. This [[humus]] is a major factor in allowing rainforests to be highly active ecosystems, with rainforests home to more than two-thirds of the Earth's species. This amounts to over 5 million species of plants and animals.
-==Human uses==
-{{main|Tropical rainforest#Human uses}}
-Tropical rainforests provide timber as well as animal products such as meat and hides. Rainforests also have value as tourism destinations and for the ecosystem services provided. Many foods originally came from tropical forests, and are still mostly grown on plantations in regions that were formerly primary forest.<ref>Myers, N. (1985). ''The primary source''. W. W. Norton and Co., New York, pp. 189-193.</ref> Tropical rainforests are also the source of medicinal drug components.
-Rainforests cover only six percent of the Earth, however, twenty-five percent of all drugs are derived from rainforest ingredients.<ref>[http://www.healthquesttravel.com/amazonmp2003.htm Health Quest 2002 Amazon – Pharmacy from the Rainforest April 2008]</ref>
-More than 1,430 varieties of tropical plants are thought to be potential cures for cancer. The National Cancer Institute claims that 70 percent of the plants identified as having anti-cancer properties are found in the rainforest. The rainforest has shown to hold many other types of medicines as well, from everyday pain killers like aspirin to important cardiac drugs. In fact, plant derived medicines are commonly used for fever, fungal infections, burns, gastrointestinal problems, pain, respiratory problems, and wound treatment.<ref>[http://jrscience.wcp.muohio.edu/fieldcourses03/PapersCostaRicaArticles/FinalPaper.TheMedicinalVa.html Final Paper: The Medicinal Value of the Rainforest May, 15 2003. Amanda Haidet April 2008]</ref>
-==Deforestation==
-{{main|Deforestation}}
-[[Image:Amazonie deforestation.jpg|thumb|right|200px|Deforestation in the Amazon Rainforest, as seen from a satellite]]
-[[Tropical rainforest|Tropical]] and [[temperate rain forest]]s 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. Biologists have estimated that large numbers of species are being driven to [[extinction]] (possibly more than 50,000 a year) due to the removal of habitat with destruction of the rainforests. Protection and regeneration of the rainforests is a key goal of many environmental charities and organizations. (It is doubtful that this rate will be sustained as the relative cost of logging rises with dwindling resources.{{Fact|date=April 2008}})
-Another factor causing the loss of rainforest is expanding urban areas. [[Littoral]] Rainforest growing along [[coastal]] areas of eastern [[Australia]] is now rare due to [[ribbon development]] to accommodate the demand for [[seachange (demography)|seachange]] lifestyles.
-About half of the mature [[tropical rainforests]], between 750 to 800 million hectares of the original 1.5 to 1.6 billion hectares that once graced the planet have already fallen. The devastation is already acute in [[South East Asia]], the second of the world's great biodiversity hot spots. Most of what remains is in the [[Amazon basin]], where the [[Amazon rainforest]] covered more than 600 million hectares, an area nearly two thirds the size of the United States. The forests are being destroyed at an ever-quickening pace. Unless significant measures are taken on a world-wide basis to preserve them, by 2030 there will only be 10% remaining with another 10% in a degraded condition. 80% will have been lost and with them the natural diversity they contain will become extinct.
-Many tropical countries, including [[Indonesia]], [[Thailand]], [[Malaysia]], [[Bangladesh]], [[China]], [[Sri Lanka]], [[Laos]], [[Nigeria]], [[Liberia]], [[Guinea]], [[Ghana]] and the [[Cote d'lvoire]] have already lost large areas of their rainforest. Eighty percent of the forests of the Philippine archipelago have already been cut down. In 1960 [[Central America]] still had four fifths of its original forest; now it is left with only two fifths of it. Half of the Brazilian state of [[Rondonia]]'s 24.3 million hectares have been destroyed or severely degraded in recent years. Several countries, notably the [[Philippines]], [[Thailand]] and [[India]] have declared their deforestation a national emergency.[http://www.rainforestweb.org/Rainforest_Destruction/][http://www.guardian.co.uk/brazil/story/0,,1488468,00.html]
-==See also==
-<div style="-moz-column-count:4; column-count:4;">
-*[[Centre National d’Appui au Développement et à la Participation populaire]]
-*[[Cloud forest]]
-*[[Coalition for Rainforest Nations]]
-*[[Deforestation]]
-*[[Endangered species]]
-*[[Holocene extinction event]]
-*[[Illegal logging]]
-*[[Inland rainforest]]
-*[[Jungle]]
-*[[Rubber tapping]]
-*[[Temperate rain forest]]
-*[[Tropical and subtropical moist broadleaf forests]]
-*[[Tropical rainforest]]
-</div>
-==References==
-{{Morefootnotes|date=February 2008}}
-===General references===
-* Richards, P. W. (1996). ''The tropical rain forest''. 2nd ed. Cambridge University Press ISBN 0-521-42194-2
-* Whitmore, T. C. (1998) ''An introduction to tropical rain forests''. 2nd ed. Oxford University Press. ISBN 0-19-850147-1
-* Butler, R. A. (2005) ''A Place Out of Time: Tropical Rainforests and the Perils They Face''. Published online: [http://rainforests.mongabay.com rainforests.mongabay.com]
-===Specific references===
-{{reflist}}
-Annual Rainforest Commitee of New York (ARCNY)
-==External links==
-{{Commons|Rainforest}}
-{{Wiktionary}}
-* [http://www.rainforestportal.org/ Rainforest Portal]
-* [http://www.ran.org Rainforest Action Network]
-* [http://www.un.org/esa/forests United Nations Forum on Forests]
-* [http://www.rainforestcoalition.org/eng/ The Coalition for Rainforest Nations]
-[[Category:Rainforests| ]]
-[[ay:Muntaña tuqi suyu]]
-[[zh-min-nan:Ú-lîm]]
-[[ca:Selva pluvial]]
-[[cy:Fforest law]]
-[[da:Regnskov]]
-[[de:Regenwald]]
-[[es:Selva]]
-[[eo:Pluvarbaro]]
-[[fo:Regnskógur]]
-[[fr:Forêt tropicale humide]]
-[[he:יער גשם]]
-[[hr:Kišna šuma]]
-[[id:Hutan hujan]]
-[[is:Regnskógur]]
-[[it:Foresta equatoriale]]
-[[jv:Alas tropis]]
-[[sw:Msitu wa mvua]]
-[[la:Silva Imbrica]]
-[[hu:Esőerdő]]
-[[mk:Дождовна шума]]
-[[ml:മഴക്കാട്]]
-[[nl:Regenwoud]]
-[[no:Regnskog]]
-[[nn:Regnskog]]
-[[pl:Wilgotny las równikowy]]
-[[ro:Selvă]]
-[[qu:Paray sach'a-sach'a]]
-[[ru:Сельва]]
-[[simple:Rainforest]]
-[[sk:Dažďový les]]
-[[sl:Deževni gozd]]
-[[fi:Sademetsä]]
-[[sv:Regnskog]]
-[[ta:மழைக்காடு]]
-[[th:ป่าดิบชื้น]]
-[[tr:Yağmur ormanları]]
-[[uk:Дощовий ліс]]
-[[zh-yue:雨林]]
-[[zh:雨林]]