- Created by: sanjay cj
- Created on: 05-04-10 11:14
· Grow in places that have an equatorial climate.
· Tropical rainforests are the most luxuriant vegetation systems.
· Over 1/3 of the world’s trees grow in tropical rainforests.
· Rainforest has an evergreen appearance – continuous growing season allows trees to shed their leaves at any time.
· Vegetation grows in distinct layers. (Shrubs, under-canopy, main canopy, the emergent trees).
· Trees have to grow rapidly in order to reach the sunlight.
· Tree trunks are straight, and branchless in the lower part due to their efforts in growing tall.
· Large buttress roots stand above the ground to give support to the trees.
· Lianas, which are vine-like plants, use the large trees as a support in their efforts to reach the canopy and sunlight.
· There is very little undergrowth; only 1% of sunlight reaches the forest floor.
· Shrubs and smaller plants have adapted to the lack of sunlight.
· During the wetter months, large areas of land near to the main rivers are flooded.
· Leaves have drip-tips to shed heavy rainfall.
· Fallen leaves decay in the hot, wet climate. They make the humus layer.
· There is dense undergrowth near rivers and in forest clearings where sunlight is able to penetrate the canopy.
· Rainforest is a fragile environment, as it relies on the constant recycling of nutrients.
· Once the forest is cleared, then the nutrient cycle is broken. Humus is not replaced and the underlying soil soon becomes infertile and eroded. Not only is the rainforest unable to re-establish itself, but the land becomes too poor to be used for farming.
Found in 3 continents of South America, Africa and Asia. South America has the most of any continent, 55%, Brazil has the most as a single country, 35%.
Lies mainly just either side of the Equator 0º, but stretches north to Tropic of Cancer 22½ º and south to Tropic of Capricorn 22½º.
Very hot, always over 25ºC on average every month. Usually varies between 25ºC to 28ºC on average, so a very small range of temperature of 3ºC.
Very wet, almost 200mm annual total. Rain is heavy every month, but 4 to 5 months are usually heavier than the others. Months with less rain are called the dry season, and heavy rain, wet season.
Climate is generally hot and wet all year, humid.
Vegetation / Animals
Richest store of animals and plants in the world, 50% of all species. Many specially adapted plants and animals:
1. Emergents- tall trees growing through the canopy.
2. Canopy – coniferous layer of trees, which block most of the light and rain from the floor
3. Lower canopy – straggly layer beneath the canopy trying to reach the light.
4. Ground layer – quite sparse as little light.
5. Epiphytes – grow on trees and climb to the light.
6. Lianas – grow from ground but climb up the trees to the light.