Rainforest on the island of Borneo
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Section 1:
TROPICAL RAINFORESTS OF THE WORLD
Tropical rainforests are a world
like none other; and their importance to the global ecosystem and human
existence is paramount. Unparalleled in terms of their biological diversity,
tropical rainforests are a natural reservoir of genetic diversity which
offers a rich source of medicinal plants, high-yield foods,
and a myriad of other useful forest products. They are an important
habitat for migratory animals and sustain as much as 50 percent of the species on Earth, as well as a number of
diverse and unique indigenous cultures. Tropical rainforests play an
elemental role in regulating global weather in addition to maintaining
regular rainfall, while buffering against floods, droughts, and erosion.
They store vast quantities of carbon, while producing a significant
amount of the world's oxygen.
Despite their monumental role, tropical forests are restricted to the
small land area between the latitudes 23.5° North and 23.5° South
of the equator, or in other words between the Tropic of Capricorn
and the Tropic of Cancer. Since the majority of Earth's land is located
north of the tropics, rainforests are naturally limited to a relatively
small area.
Tropical rainforests, like so many other natural places, are a scarce
resource in the 21st century. The vast swaths of
forest, swamp, desert, and savanna that carpeted Earth's land surface
a mere five generations ago have been reduced to scattered fragments;
today, more than two-thirds of the world's tropical rainforests exist
as fragmented remnants. Just a few thousand years ago, tropical rainforests
covered as much as 12 percent of the Earth's land surface, or about 6 million square miles (15.5 million square km),
but today less than 5 percent of Earth's land is covered with
these forests (about 2.41 million square miles or 625 million hectares).
The largest unbroken stretch of rainforest is found in the Amazon river
basin of South America. Over half of this forest lies in Brazil, which
holds about one-third of the world's remaining tropical rainforests.
Another 20 percent of the world's remaining rainforest exists
in Indonesia and Congo Basin, while the balance of the world's rainforests
are scattered around the globe in tropical regions.
The global distribution of tropical rainforests can be broken up into
four biogeographical realms based roughly on four forested continental
regions: the Ethiopian or Afrotropical, the Australiasian or Australian,
the Oriental or Indomalayan/Asian, and the Neotropical.
Rainforest cover by biogeographical realm
| Realm | Percent share of
world rainforest cover | Million
square miles | Million
hectares |
| Ethiopian/Afrotropical | 30.0% | 0.72 | 187.5 |
| Australasian | 9.0% | 0.22 | 56.3 |
| Oriental or Indomalayan | 16.0% | 0.39 | 100.0 |
| Neotropical | 45.0% | 1.08 | 281.2 |
| Total | | 2.41 | 625.0 |
More on forest cover
charts & tables | primary forest | forest area
Review questions:
- Where are rainforests located?
- How much land area rainforests do cover?
- What percentage of Earth is covered by rainforests?
- How many rainforest biogeographical realms are there?
- What biogeographical realm has the most rainforest?
- True or false - less than 5% of Earth's land is covered with rainforests.
[print version | spanish | french | portuguese
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Continued: Biogeographical Forest Realms
This article was written by Rhett A. Butler [bibliographic citation for this page] and was last updated on the most recent date listed in the column on the right side.
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WEEKLY NEWSLETTER
INTERACT
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Recent news
Some toilet paper production destroys Indonesian rainforests, endangering tigers and elephants
(02/09/2012) American consumers are unwittingly contributing to the destruction of endangered rainforests in Sumatra by purchasing certain brands of toilet paper, asserts a new report published by the environmental group WWF. The report, Don't Flush Tiger Forests: Toilet Paper, U.S. Supermarkets, and the Destruction of Indonesia's Last Tiger Habitats, takes aim at two tissue brands that source fiber from Asia Pulp & Paper (APP), a paper products giant long criticized by environmentalists and scientists for its forestry practices on the Indonesian island of Sumatra. The brands — Paseo and Livi — are among the fastest growing, in terms of sales, in the United States.
Tropical ecologist: Australia must follow U.S. and EU in banning illegally logged wood
(02/09/2012) Australia should join the widening effort to stamp out illegal logging, according to testimony given this week by tropical ecologist William Laurance with James Cook University. Presenting before the Australian Senate's rural affairs committee, Laurance argued that the massive environmental and economic costs of illegal logging worldwide should press Australia to tighten regulations against importing illegally logged timber at home.
Humans drove rainforest into savannah in ancient Africa
(02/09/2012) Three thousand years ago (around 1000 BCE) several large sections of the Congo rainforest in central Africa suddenly vanished and became savannah. Scientists have long believed the loss of the forest was due to changes in the climate, however a new study in Science implicates an additional culprit: humans. The study argues that a migration of farmers into the region led to rapid land-use changes from agriculture and iron smelting, eventually causing the collapse of rainforest in places and a rise of grasslands. The study has implications for today as scientists warn that the potent combination of deforestation and climate change could flip parts of the Amazon rainforest as well into savannah.
Green groups: government moving too slowly on protecting Canada's Great Bear rainforest
(02/08/2012) Three environmental groups have submitted a letter to British Columbia Premier, Christy Clark, to ask the government to speed up the process of implementing the Great Bear Rainforest Agreement, which is meant to ensure 70 percent of old-growth forest is maintained.
Majority of protected tropical forests "empty" due to hunting
(02/08/2012) Protected areas in the world's tropical rainforests are absolutely essential, but one cannot simply set up a new refuge and believe the work is done, according to a new paper in Bioscience. Unsustainable hunting and poaching is decimating tropical forest species in the Amazon, the Congo, Southeast Asia, and Oceana, leaving behind "empty forests," places largely devoid of any mammal, bird, or reptile over a few pounds. The loss of such species impacts the whole ecosystems, as plants lose seed dispersers and the food chain is unraveled.
More rainforest news
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