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热带雨林介绍(英文)

来源:学生作业帮 编辑:作业帮 分类:英语作业 时间:2024/05/03 04:02:17
热带雨林介绍(英文)
A tropical rainforest is an ecosystem type that occurs roughly within the latitudes 28 degrees north or south of the equator (in the equatorial zone between the Tropic of Cancer and Tropic of Capricorn).This ecosystem experiences high average temperatures and a significant amount of rainfall.Rainforests can be found in Asia,Australia,Africa,South America,Central America,Mexico and on many of the Pacific,Caribbean,and Indian Ocean islands.Within the World Wildlife Fund's biome classification,tropical rainforests are thought to be a type of tropical wet forest (or tropical moist broadleaf forest) and may also be referred to as lowland equatorial evergreen rainforest.
History Tropical rainforests:
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.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.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.However,the specifics of the origin of rainforests remain uncertain due to an incomplete fossil record.
Types of tropical rainforest
Several types of forest comprise the general tropical rainforest biome:
Lowland equatorial evergreen rain forests are forests which receive high rainfall (more than 2000 mm,or 80 inches,annually) throughout the year.These forests occur in a belt around the equator,with the largest areas in the Amazon Basin of South America,the Congo Basin of Central Africa,Indonesia,and New Guinea.
Moist deciduous and semi-evergreen seasonal 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.These forests 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 rain forests,some of which are known as cloud forests,are found in cooler-climate mountain areas.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.
Flooded forests,seven types of flooded forest are recognized for Tambopata Reserve in Amazonian Peru:
Permanently waterlogged swamp forest--Former oxbow lakes still flooded but covered in forest.
Seasonally waterlogged swamp forest--Oxbow lakes in the process of filling in.
Lower floodplain forest--Lowest floodplain locations with a recognizable forest.
Middle floodplain forest--Tall forest,flooded occasionally.
Upper floodplain forest--Tall forest,rarely flooded.
Old floodplain forest--Subjected to flooding within the last two hundred years.
Previous floodplain--Now terra firme,but historically ancient floodplain of Tambopata River.
Due the human's excessive exploitation,tropical forests are now facing a great danger of disappear from the surface of the Earth.Urgent steps and actions required from all countries of the tropical area to protect them from further damages.