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Our Under Appreciated Rainforests
Earth's Ecological System
Rainforests are extremely important to Earth’s ecological system. The many variety of plant life growing in them produce much of our planets’ oxygen and many are used in manufacturing new drugs to treat disease and illness.
They are home to millions of insects, reptiles, amphibians, birds, and mammals. It has been estimated millions more species of plants, insects and microorganisms have yet to be discovered.
There are generally two types, tropical and temperate. Tropical rainforestsare found in a belt around the equator across South America, Central America, Africa, Southeast Asia and Australia. The temperate rainforests can be found along the U.S. Pacific coast and Canada, in New Zealand, Tasmania, Chile, Ireland, Scotland and Norway. The importance of rainforests can’t be over emphasized. They recycle and clean water and remove carbon dioxide from the atmosphere.
There are many tribes living in the tropical rainforests like the Yanomamo tribe of the Amazon rainforests of Brazil and southern Venezuela. However, their populations are declining. They are mostly hunter-gatherers. Many grow small gardens in cleared areas of the forest but the soil is poor. Therefore the gardens must be rotated often.
A tropical rainforest has four main layers, with different plants and animals adapted for each layer. The layers are emergent, canopy, understory, and forest floor.
The emergent layer contains a number of large trees called emergents. They grow above the general canopy and are home to certain monkeys, eagles, bats and butterflies. These trees reach heights of 45–55 meters however a few species can grow to 70–80 m tall. Since they reach such heights they must be able to withstand hot temperatures and strong winds.
The canopy layer contains the majority of the largest trees, typically 30–45 m tall. The canopy is more or less a continuous cover of foliage formed by treetops. A quarter of all insect species are thought to live in the canopy.
The understory layer lies below the canopy and is inhabited by birds, lizards and snakes. Predators such as jaguars, leopards and boa constrictors can usually be found there as well. The leaves are much larger at this level and insect life thrives there. Many seedlings grow in the understory. Only about 5% of sunlight ever reaches the understory.
The forest floor, receives only about 2% of sunlight and only certain plants accustomed to low light levels can survive in this environment. So, the forest floor is relatively clear of vegetation. It is made up of decaying plant and animal matter. However, it rapidly disappears due to warm, humid conditions prompting rapid decomposition. The many forms of fungi found there also help in this process.
Over half of the world's species of plants and animals are found in rainforests. But these species are disappearing at an unprecedented rate due to deforestation, loss of habitat, and biochemicals.
In spite of the vast array of vegetation growth, soil quality is quite poor. Bacterial decomposition inhibits the buildup of humus, necessary for richer soil. This causes tree roots to be near the surface due to lack of nutrients deeper down.
Tropical rainforests provide timber as well as animal products. Many foods around the world originally came from these forests and some are still grown on plantations that were previously forest area.
Rainforests around the world are rapidly shrinking because of heavy logging and agricultural clearing. Researchers have declared large numbers of species are becoming extinct due to habitat and rainforest destruction. Urban areas are rapidly encroaching upon prime rainforest acreage. Studies have shown almost 90% of West African rainforest has been destroyed. Madagascarhas lost two thirds. And at current rates, rainforests in Indonesia could be destroyed in 10 years. Some countries, like Brazil have declared this deforestation a national emergency.
However, promising news in a New York Times article of January 2009 stated, "By one estimate, for every acre of rain forest cut down each year, more than 50 acres of new forest are growing in the tropics..."
This combined with land management and logging slow down efforts makes the situation seem maybe not quite so bleak.