SavannaSavanna is grassland
with scattered individual trees. Savannas of one sort or another cover almost
half the surface of Africa (about five million square miles, generally central
Africa) and large areas of Australia, South America, and India. Climate is the
most important factor in creating a savanna. Savannas are always found in warm
or hot climates where the annual rainfall is from about 50.8 to 127 cm (20-50
inches) per year. It is crucial that the rainfall is concentrated in six or
eight months of the year, followed by a long period of drought when fires can
occur. If the rain were well distributed throughout the year, many such areas
would become tropical forest. Savannas which result from climatic conditions are
called climatic savannas. Savannas that are caused by soil conditions and
that are not entirely maintained by fire are called edaphic savannas.
These can occur on hills or ridges where the soil is shallow, or in valleys
where clay soils become waterlogged in wet weather. A third type of savanna,
known as derived savanna, is the result of people clearing forest land
for cultivation. Farmers fell a tract of forest, burn the dead trees, and plant
crops in the ashes for as long as the soil remains fertile. Then, the field is
abandoned and, although forest trees may recolonize, grass takes over on the
bare ground (succession), becoming luxuriant enough to burn within a year or so.
In Africa, a heavy concentration of elephants in protected parkland have created
a savanna by eating leaves and twigs and breaking off the branches, smashing the
trunks and stripping the bark of trees. Elephants can convert a dense woodland
into an open grassland in a short period of time. Annual fires then maintain the
area as a savanna.
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Deforestation in the Amazon - 0 views
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Home What's New About Contribute Submissions Rainforests Mission Introduction Characteristics Biodiversity The Canopy Forest Floor Forest Waters Indigenous People Deforestation Consequences Saving Rainforests Amazon rainforest Borneo rainforest Congo rainforest Country Profiles Statistics Works Cited For Kids For Teachers Photos/Images Expert Interviews Rainforest News XML Feeds Chinese French Japanese Spanish Other Languages Pictures Books Links Newsletter Education Mongabay Sites Kids' site Travel Tips Tropical Fish Madagascar Contact About this site Providing tropical forest news, statistics, photos, and information, rainforests.mongabay.com is the world's most popular rainforest site. [more] Deforestation in the Amazon DEFORESTATION IN BRAZIL: 60-70 percent of deforestation in the Amazon results from cattle ranches while the rest mostly results from small-scale subsistence agriculture. Despite the widespread press attention, large-scale farming (i.e. soybeans) currently contributes relatively little to total deforestation in the Amazon. Most soybean cultivation takes place outside the rainforest in the neighboring cerrado grassland ecosystem and in areas that have already been cleared. Logging results in forest degradation but rarely direct deforestation. However, studies have showed a close correlation between logging and future clearing for settlement and farming. [Português | Español | Français] Deforestation by state Deforestation Figures for Brazil Year Deforestation [sq mi] Deforestation [sq km] Change [%] 1988 8,127 21,050 1989 6,861 17,770 -16% 1990 5,301 13,730 -23% 1991 4,259 11,030 -20% 1992 5,323 13,786 25% 1993 5,751 14,896 8% 1994 5,751 14,896 0% 1995 11,220 29,059 95% 1996 7,012 18,161 -38% 1997 5,107 13,227 -27% 1998 6,712 17,383 31% 1999 6,664 17,259 -1% 2000 7,037 18,226 6% 2001 7,014 18,165 0% 2002 8,260 2 -
TROPICAL RAINFORESTS: Deforestation in Brazil Click Here Home What's New About Contribute Submissions Rainforests Mission Introduction Characteristics Biodiversity The Canopy Forest Floor Forest Waters Indigenous People Deforestation Consequences Saving Rainforests Amazon rainforest Borneo rainforest Congo rainforest Country Profiles Statistics Works Cited For Kids For Teachers Photos/Images Expert Interviews Rainforest News XML Feeds Chinese French Japanese Spanish Other Languages Pictures Books Links Newsletter Education Mongabay Sites Kids' site Travel Tips Tropical Fish Madagascar Contact About this site Providing tropical forest news, statistics, photos, and information, rainforests.mongabay.com is the world's most popular rainforest site. [more] Deforestation in the Amazon DEFORESTATION IN BRAZIL: 60-70 percent of deforestation in the Amazon results from cattle ranches while the rest mostly results from small-scale subsistence agriculture. Despite the widespread press attention, large-scale farming (i.e. soybeans) currently contributes relatively little to total deforestation in the Amazon. Most soybean cultivation takes place outside the rainforest in the neighboring cerrado grassland ecosystem and in areas that have already been cleared. Logging results in forest degradation but rarely direct deforestation. However, studies have showed a close correlation between logging and future clearing for settlement and farming. [Português | Español | Français] Deforestation by state Deforestation Figures for Brazil Year Deforestation [sq mi] Deforestation [sq km] Change [%] 1988 8,127 21,050 1989 6,861 17,770 -16% 1990 5,301 13,730 -23% 1991 4,259 11,030 -20% 1992 5,323 13,786 25% 1993 5,751 14,896 8% 1994 5,751 14,896 0% 1995 11,220 29,059 95% 1996 7,012 18,161 -38% 1997 5,107 13,227 -27% 1998 6,712 17,383 31% 1999 6,664
The grassland biome - 0 views
HowStuffWorks "How Rainforests Work" - 0 views
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The World's Lungs? In the past, scientists often referred to tropical rainforests as the "lungs of the world" because of the large amount of oxygen they produce. More recent evidence shows that rainforests don't have much of an effect on the world's oxygen supply. The decomposition of dead plant matter consumes roughly the same amount of oxygen that the living plants produce. But rainforests do play a key role in the global ecosystem. Some experts are now calling them the "air conditioners to the world," because their dark depths absorb heat from the sun. Without the forest cover, these regions would reflect more heat into the atmosphere, warming the rest of the world. Losing the rainforests may also have a profound effect on global wind and rainfall patterns, potentially causing droughts throughout the United States and other areas
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sO THE RAINFOREST IS THE EARTHS LUNGS.
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UNICEF - Cambodia - For Cambodian girls, education is antidote to poverty and sexual ex... - 0 views
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OPTIONS scholarships enable girls at risk of dropping out to remain in primary and lower secondary school. In poor provinces like Prey Veng, where many families are forced to migrate to escape the impact of persistent floods and drought, the scholarships also help protect girls from being trafficked or sexually exploited.
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