Unit 1 Tropical rainforests-- what and where are they? Unit 1 Tropical rainforests--what and where are they?

What are the characteristics of tropical rainforests? Unit 1 Tropical rainforests--what and where are they? What is an ecosystem? An ecosystem is a community in which all plants and animals live together and are interdependent on each other for survival.

What are the characteristics of tropical rainforests? Unit 1 Tropical rainforests--what and where are they? What is an ecosystem?  Click here

 The tropical rainforest is an old, rich and complex ecosystem.  Tropical rainforests have a great variety of plant and animal species.  The rich and dense vegetation provides abundant food for a large number of insects, birds and animals living in the forests. Unit 1 Tropical rainforests--what and where are they? What are the characteristics of tropical rainforests?

 The tropical rainforests have a great variety of plant and animal species. Unit 1 Tropical rainforests--what and where are they? What are the characteristics of tropical rainforests?  Click here

 Tropical rainforests are luxuriant and trees are evergreen.  Trees are tall and straight because they have to compete for sunlight.  Trees develop plank-like buttress roots for firm support. Unit 1 Tropical rainforests--what and where are they? What are the characteristics of tropical rainforests?

 Trees in tropical rainforests are tall and straight. They develop plank-like buttress roots for firm support. Unit 1 Tropical rainforests--what and where are they? What are the characteristics of tropical rainforests?  Click here

 Trees have waxy leaves with downward- dipping points or drip tips to shed rainwater.  There are a lot of climbing and creeping plants.  There are ferns, lichens and mosses. Unit 1 Tropical rainforests--what and where are they? What are the characteristics of tropical rainforests?

The structure of a tropical rainforest Top layer Main layer Lower layer Ground layer This is the highest layer with trees rising up to 40 m. The trees form a continuous canopy effectively cutting off the forest floor from sunlight. This is a layer of young, short trees about 5 m to 15 m high. This layer is covered with plant litter. It is dark and has little undergrowth as sunlight cannot reach it. m Unit 1 Tropical rainforests--what and where are they? What are the characteristics of tropical rainforests?

The structure of a tropical rainforest Unit 1 Tropical rainforests--what and where are they? What are the characteristics of tropical rainforests?  Click here

 Tropical rainforests are found between the Tropic of Cancer (23.5°N) and the Tropic of Capricorn (23.5°S). They form a broken green belt around the world.  Dense tropical rainforests are found in lower latitudes between 10  north and south of the equator.  There are three main tropical rainforest regions: Unit 1 Tropical rainforests--what and where are they? Where are the tropical rainforests? 1. The Amazon Basin in South America 2. Indonesia in Southeast Asia 3. The Congo Basin of Central Africa

The Amazon Basin  The Amazon basin covers 6.4 million km².  The Amazon spreads across much of South America, which includes Colombia, Ecuador, Peru, Bolivia, Brazil and Venezuela.  Mestizos is the indigenous people in the Amazon Basin. Their lifestyle was called subsistence because they hunted and grew only what they needed to subsist, or survive. They practiced a kind of agriculture called slash and burn.  They mainly grow coffee, maize and cacao. Unit 1 Tropical rainforests--what and where are they?

Indonesia  Indonesia has the third largest area of tropical rainforests in the world, which is 10% of the world total.  The richest areas are the primary lowland forests of Borneo, Sumatra, Java and Irian Jaya, with Borneo supporting the largest expanse of tropical rainforest in Southeast Asia.  Lumbering plays an important role in Indonesia. In 1993, forest products accounted for 7% of the country's GDP.  Many tropical rainforests are designated for non-forest uses such as agriculture, settlement and transmigration. Unit 1 Tropical rainforests--what and where are they?

The Congo Basin The Congo Basin is located i n West Africa. Nearly 90 % of the original moist forest is gone, and what remains is heavily fragmented and degraded. Most of the people in the Congo Basin are Bantus who live in tribal settlements. For their own use, the people grow cassavas, corn, yams, peanuts, and beans. The villagers may also raise bananas, rice millet, sugarcane, tobacco and cotton. Some villagers keep chickens and goats. Unit 1 Tropical rainforests--what and where are they?

Where are the tropical rainforests? Unit 1 Tropical rainforests--what and where are they? km Congo Basin Tropical rainforests S. E. Asia Amazon Basin N S  N Indonesia

Why are the rainforests there? High Temperature  Tropical regions are hot throughout the year. The annual range of temperature is only about 2°C.  During the day, the temperature may reach 35°C in the afternoon.  At night the temperature may fall to 18°C. Unit 1 Tropical rainforests--what and where are they?

Heavy rainfall  Tropical rainforests lie in the low pressure belt at the equator where warm, moist winds from the ocean meet.  The air rises upwards to form strong convection currents bringing heavy rain.  The monthly rainfall in most tropical rainforests is over 200 mm. The annual rainfall is between mm and mm a year.  The humidity is always high in these areas. The sky is often cloudy and rain comes in downpours. Unit 1 Tropical rainforests--what and where are they? Why are the rainforests there?

Unit 1 Tropical rainforests--what and where are they? Why are the rainforests there? Warm, wet air Clouds Low pressure Rain Strong convection current Air cooled to form clouds and rain Hot, wet air rises when heated Hot ground

Terms to learn  Ecosystem ( 生態系統 ) -- a community in which living things are interdependent on each other for their survival.  Buttress roots ( 板根 ) -- plank-like roots branching out from the trunk above the ground. Drip-tips  Drip-tips ( 滴水葉尖 ) -- the downward-dipping points of leaves for shedding rainwater. Unit 1 Tropical rainforests--what and where are they?

Terms to learn Lichens  Lichens ( 地衣 ) -- small plants growing like a crust on rocks, trunks and branches of trees. Mosses  Mosses ( 苔蘚 ) -- small plants with simple stems and leaves but no roots growing on the trunks and branches of trees like a green velvet layer. Canopy  Canopy ( 冠層 ) -- the dense mass of leaves and branches of a tree that covers the ground underneath. Unit 1 Tropical rainforests--what and where are they?

Terms to learn Plant litter  Plant litter ( 枯枝落葉 ) -- the fallen leaves and branches lying on the forest floor. Undergrowth  Undergrowth ( 樹林低層植物 ) -- the small trees and shrubs that grow beneath and among the taller trees. Convectional rain  Convectional rain ( 對流雨 ) -- rain which is formed when moist air heated by hot ground expands and rises upwards to form strong convection current. Unit 1 Tropical rainforests--what and where are they?