Earth Science - Other

Structure of a Rainforest

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"Structure of a Rainforest"
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Tropical rainforests exhibit the most profound layering or stratification. Temperate rainforests have strata, but some ecologists do not recognize the definitions of layers in a rainforest. The tropical rainforests are classified as existing between the Tropic of Cancer and the Tropic of Capricorn. They have annual rainfall of up to 6 feet per year. The variation in the temperature of the three warmest and the three coldest months is less than 5 degrees centigrade.

The canopy of tropical rainforests are populated by the canopies of the biggest trees, which can grow up to 150 feet tall. These trees hog much of the light, building their trunks and root systems until there is enough canopy to allow the photosynthesis that is needed for flowering and reproduction. Although these giants are the dominant life form, they only comprise an estimated 10 percent of the trees in a rainforest.

The next level of tropical rainforest is populated by shorter trees that compete mightily for light. These trees have thinner trunks and put their energy into pure growth until they get enough photothensis to support flowering and reproduction.  After this level, the woodier plants and shrubs attempt to grow in whatever light is left after the first two layers battle it out.

The rainforest floor is populated in a unique way. Where even a beam of light penetrates, a unique group of non woody plants has the opportunity to grow, depending on the available seeds, the soil quality, water and strength of light. The size and composition of the group is then unique in the forest, once it is established.

Light can come from tree fall, as filtered light or in beams that are fairly steady when holes or gaps form in the dense canopy.

Temperate rainforests will have different trees, climates, and other factors such as wide variations in annual temperature and long periods of drought. There are still canopies, areas where smaller trees fight for light, lower level shrubs and woody plants and plants that populate the forest floor when there is light available.

The major tropical rainforests of the world are in South to Southeast Asia, Central Africa and Central and Southern Latin America. Temperate rainforests are far more plentiful, with major forests in Canada, Russia and Europe.

The best way to observe the components and structure of a rainforest is to look at the various forms of available light, the groupings of non woody ground plants, the tallest trees, the smaller trees and the woody shrubs and plants and to see how they are growing.

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