The world’s largest tropical rainforests are in South America, Africa, and Southeast Asia. Rainforests are characterized by high rainfall. Tropical rainforests receive from 60 to 160 inches of precipitation that is fairly evenly distributed throughout the year. The combination of constant warmth and abundant moisture makes the tropical rainforest a suitable environment for many plants and animals. The hot and humid conditions make tropical rainforests an ideal environment for bacteria and other microorganisms. Because these organisms remain active throughout the year, they quickly decompose matter on the forest floor. The decomposition of leaf litter adds nutrients to the soil. But in the tropical rainforest, plants grow so fast that they rapidly consume the nutrients from the decomposed leaf litter. As a result, most of the nutrients are contained in the trees and other plants rather than in the soil.
Rainforests are home to two-thirds of all the living animal and plant species on the planet. It has been estimated that many hundreds of millions of new species of plants, insects, and microorganisms are still undiscovered and as yet unnamed by science. Rainforests support a very broad array of mammals, reptiles, birds and invertebrates. Rainforests are also often called the “Earth’s lungs”. Tropical rain forests are called the world’s largest “pharmacy” because of the large amount of natural “medicines” discovered there. For example, rain forests contain the basic ingredients of hormonal contraception methods, cocaine, stimulants, and tranquilizing drugs. Rain forests play an important role in maintaining biological diversity, modulating precipitation infiltration and flooding, increasing scientific knowledge and in the spiritual well-being of humans. Such ecosystem services are of use to humans without the need for any modification or management of the forest itself.
