Where is the tropical rainforest located
Facts about Tropical Rainforests
What are the features that are typical of all tropical rainforests. Tropical
rainforests cover about six to seven percent of the earth's land surface and are
mainly located in the tropics. That is the regions of the earth between
the Tropic of Cancer and the Tropic of Capricorn. The world's largest
rainforests are the Amazon rainforest of South America, the Congo River Basin in
West Africa and the rainforests of Southeast Asia. There are also smaller
rainforests in Central America, Madagascar, the Pacific Islands, Northern
Australia and India. The reason for this pattern is that on the equator sunlight
strikes the earth at a roughly a ninety degree angle. This results in intense
solar energy as there is a consistent length of day. That is twelve hours a day,
365 days a year. Regions close to the equator have warm
temperatures all year round. Tropical rainforests thrive in equatorial
regions since plants love this consistent light that powers
photosynthesis. The high temperatures of the tropical regions generates a water
cycle whereby the accelerated evaporation of water results in high
levels of rainfall. Tropical rainforests receive at least 2,000 millimetres of
rainfall per year. The climate of equatorial regions are
heavily influenced by the Intertropical Convergence zone or ITCZ. The ITCZ
is the region near the equator where the northeast trade winds and the southeast
trade winds converge, forcing air up into the atmosphere.
This is aided by the fact that the intense solar heating of the tropics
heats the ground, forcing warm air to rise through
convection. The air cools as it rises causing water vapor to condense into
clouds, which eventually leads to convectional precipitation. These storms
are often heavy but are over relatively quickly.
The position of the ITCZ changes seasonally. It moves north in the
Northern Hemisphere summer and South in the Northern Hemisphere winter. This is
what is responsible for wet and dry seasons in tropical regions. In the
northern hemisphere the wet season occurs from May to July. In the southern
hemisphere from November to February.
Rainforests have a high level of biodiversity. Although they cover less
than 7 percent of the Earth's surface, about half of the Earth's terrestrial
plants and animals live in rainforests. From the great to the small, tropical
rainforests hosts an enormous diversity of wildlife. To name a few from these
forests in Thailand one can find mammals such as the Asian elephant,
Gibbons and crab-eating macaques. There are
numerous bird species. There are an abundance of reptiles and amphibians.
Insects such as butterflies, dragonflies, ants
and termites all flourish here and the rivers of rainforests teeming with fish.
The main reason for this abundance of life is that since rainforests are
located of the tropics they receive a lot of sunlight. Plants convert the
sunlight to energy through photosynthesis. Thus there's a lot of
energy stored in the rainforest plants. These plants are in turn eaten by
animals. The canopy structure of rainforests provides a habitat for animals and
plants to shelter, hide and abundant food sources. Species in the rainforest often have
an interaction known as a symbiotic relationship. These relationships are
sometimes beneficial or others are harmful. For example, strangler fig trees
often dispersed by birds will germinate in the canopy of a host tree. As it grows
the roots develop and descend along the trunk of the host tree. Once they reach
the ground the roots enter the soil. Gradually the roots envelop the host
tree forming a lattice like structure which surrounds the hosts trunk. The fig
suffocates the host leaving behind a magnificent fig with a hollow core. The
dense vegetation of equatorial rainforests competes for sunlight
resulting in a stratified pattern and the rainforest.
Scientists consider rainforests to have five vertical layers. Emergent trees
consist of widely spaced trees with an umbrella shape. These are the tallest
trees ranging up to 30 to 40 metres whose tops protrude much higher than the
average canopy height. The canopy layer consists of overlapping branches and
leaves formed by tall rainforest trees around 30 metres with long slender
trucks. The tall trees of both the emergent and canopy layers have shallow
spreading root systems designed to collect nutrients, and wide buttress
roots to prevent them from toppling over. Most of the plants and
animals in the rain forest including monkeys frogs lizards and birds live in
the canopy. Parasitic plants such as orchids grow in cracks in the branches
high up at the canopy. The sub canopy is made up of shorter trees around 20
meters high. Trees often support epiphytes and lianas. This layer is also
the home of many birds and animals. The shrub or sapling
layer consists of bushes, small trees and ferns that are adapted to living in
low-light conditions. The sparse undergrowth is caused by the lack a light
penetrating the canopy, with only three percent penetration. Where the rainforests
meets the edge of an estuary, there may be mangroves. The rainforest floor is
often dark, humid and clear of dense vegetation due to the constant shade from
the canopies leaves. Here you will find large tree trunks, hanging vines,
seedlings and saplings and a relatively sparse number of ground
plants. It is here on the forest floor where decomposition takes place.
Decomposition is the process by which decomposes like fungi and microorganisms
break down leaf litter, dead plants and animals and recycle essential materials
and nutrients. Many of the largest rainforest animals such as the Asian
elephant are found on the forest floor.
Tropical rainforests typically have reddish brown soils known as laterites. The red
coloration comes from the oxides of iron and aluminium in the soil. The upper
horizons of the soil are thin and low in minerals due to a process called
leaching. This occurs when the frequent heavy rainfall in tropical regions
causes high volumes of water to wash away iron, silica and other minerals to
the lower horizons of the soil. As a result the top layer is often lighter in
color. Despite the infertile soil the
rainforest survives because of the rapid nutrient cycle that exists in the warm
humid environment. The hot and humid conditions of a tropical rainforest are
ideal for decomposers like insects, fungi and bacteria. They decompose dead plant and
animal matter quickly and convert it back to nutrients. Most of the nutrients
are taken up by the rapidly growing plants and trees immediately rather than
remaining in the soil.
