Science

Tropical Forests

The rainforests are home to more worldwide species than all other biomes added together. About 80 percent of the world's known biodiversity could be found in forests.[8] The leafytops of tall trees - extending from 50 to 85 metres above the forest floor - form the forest canopy. Shorter trees and tall shrubs form the understory. Organic matter that falls to the forest floorquickly decomposes, and the nutrients.
Rainforests are partly characterized by high rainfall. This often results in poor soils due to leaching of soluble nutrients. Generally the soils of rainforestsare classified as Oxisols, which are annually replenished with fertile silt.
Tropical rain forests have been subjected to heavy logging and agricultural clearance throughout the 20th century, and thearea covered by rainforests around the world is rapidly shrinking.[9][10]
Rainforests are also often called the "Earth's lungs"; however, there is no scientific basis for such a claim as tropicalrainforests are known to be essentially oxygen neutral.[11][12]
The rainforest is humid. Tall, broad-leaved evergreen trees are the dominant plants, forming a leafy canopy over the forest floor. Tallertrees, called emergents, may rise above the canopy. The upper portion of the canopy often supports a rich flora of epiphytes, including orchids, bromeliads, mosses, and lichens, who live attached tothe branches of trees. The undergrowth or understory in a rainforest is often restricted by the lack of sunlight at ground level, and generally consists of shade-tolerant shrubs, herbs, ferns, smalltrees, and large woody vines which climb into the trees to capture sunlight. The relatively sparse under story vegetation makes it possible for people and other animals to walk through the forest. Indeciduous and semi-deciduous forests, or forests where the canopy is disturbed for some reason, the ground beneath is soon colonized by a dense tangled growth of vines, shrubs and small trees called...