I want to know what is the features of rainforest

1) Where are they?
A: In Central Africa (Congo Basin), South Asia and South America (Amazon basin)

2) Why are they there?
A: These areas are in the tropical zones and thus they are warm (sufficient sunlight) and humid (much rain), these are good for plants since they can keep their leaves evergreen* and easy to grow
*Plants shed their leaves in Winter because there is evapotranspiration on lef surface which takes water away from the plant, as there are not much water in Winter (less rain), plants shed their leaves to reduce the leaf area, thus reduce the amount of water been taken away. (and since TPF-- tropical rainforest is always humid, plants there have no need to shed their leaves)

3) What are Tropical Rainforests?
A: Tropical Rainforests are a place which is hot and humid. There are many species of plants and animals and some we still have not yet found. TRF is divided into 5 layers (from top to bottom): emergent layer, canopy layer, understorey, shrub layer and ground layer. (they have different characteristics which is too complicated to be explained here) The general characteristics of TRF is there are a lot of climbers, epiphytes and parasites (which live on other plants), some of the plants (mostly in bottom part) have broad leaves to absorb more sunlight (since the sunlight is blocked by top layers) and frip-tip leaves to shed rainwater away quickly. For the tall trees, they have buttress roots to support them.
However, since there are a lot of valuable woods in TRF, many logging companies go there and cut numerous trees. Besides cutting useful trees, they burn those soft wood which is not quite valuable to move away the useful ones (burning is cheapest). Also, there are many other factors which cause the reduction of TRF like building dams, mining, etc. These offends the natives and environmentalists, but the priviledged groups of people like merchants and logging companies have no plan to stop. *sigh*

Amazon Rainforest

The Amazon Rainforest is a moist broadleaf forest in the Amazon Basin of South America. It encompasses 7 million km² (1.2 billion acres), with parts located within nine nations: Brazil (with 60% of the rainforest), Colombia, Peru, Venezuela, Ecuador, Bolivia, Guyana, Suriname and French Guiana. This forest represents over half of the planet's remaining rainforests. States or departments in four nations bear the name Amazonas for the Amazon. Amazonian rainforests comprise the largest and most species rich tract of tropical rainforest that exists.


Biodiversity
Wet tropical forests are the most species-rich biome, and tropical forests in the Americas are consistently more species rich than the wet forests in Africa and Asia[1]. As the largest tract of tropical rainforest in the Americas, the Amazonian rainforests have unparalleled biodiversity.

The region is home to about 2.5 million insect species, tens of thousands of plants, and some 2000 birds and mammals. To date, at least 40,000 plant species, 3,000 fish, 1,294 birds, 427 mammals, 427 amphibians, and 378 reptiles have been scientifically classified in the region [2]. Scientists have described between 96,660 and 128,843 invertebrate species in Brazil alone [3].

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由於字數收到規限所以未能盡錄。Please refer to http://en.wikipedia. org/wiki/Amazon_rain forest for the complete article.

你仲可以參考下以下既網址﹕
http://www.eduweb.co m/amazon.html
http://www.rain-tree .com/
http://www.amazon-ra inforest.org/
http://rainforests.m ongabay.com/amazon/
www.rainforest-allia nce.org
www.ran.org

用point form 可能會好些...

- THEY LOCATE AROUND 5-10 N/S
- THE MEAN TEMPERATURE IS 25 DEGREE CELCIUS OR ABOVE
- THE ANNUAL PRECIPITATION IS OVER 2,000 mm
- THEY HAVE 5 LAYERS OF TROPHIC LEVEL, AND A LONG FOOD CHAIN
- THEY WILL FORM A MICRO-CLIMATE(微氣候) IN THE TRF.