Wednesday, May 21, 2008

Tropical Rainforests: Climate and Plants

In an average year the climate in a tropical rain forest is very humid because of all the rainfall. A tropical rainforest gets about 150 cm of rain per year. It gets lots of rain because it is very hot and wet in rain forests. The hotter the air, the more water vapor it can hold. It rains usually about 1/8 of an inch per day.
This climate is found near the equator. That means that there is more direct sunlight hitting the land and sea there than anywhere else. The sun warms the land and sea and the water evaporates into the air. The warm air can hold a lot of water vapor. As the air rises, it cools. That means it can hold less water vapor. Then as warm meets cold, condensation takes place and the vapor forms droplets and clouds form. The clouds then produce rain. It rains more than ninety days a year and the strong sun usually shines between the storms. The water cycle repeats often along the equator.
The main plants in this biome are trees. This is important because in the rain forest, some rain never gets past the trees and to the smaller plants and ground below. Trees in this climate reach a height of more than 164 feet. They form a canopy. The forest floor is called understory. The canopy also keeps sunlight from reaching the plants in the understory. Between the canopy and understory is a lower canopy made up of smaller trees. These plants do receive some filtered sunlight.
The tropical rain forest is classified under the Köppen Classification system as Af, meaning tropical forest. The A is given to tropical climates that are moist for all months and which have average temperatures above 18 degrees Celsius. The f stands for sufficient precipitation for all months. The latitude range for my climate is 15° to 25° North and South of the equator.
The annual precipitation of a rain forest is greater than 150 cm. In a rain forest there is a short dry season. In only a month the rainforest receives 4 inches of rain. The rain forest climate is different from a lot of other climates. In other climates, the evaporation is carried away to fall as rain in far off areas, but in the rain forests, 50 percent of the precipitation comes from its own evaporation. A lot of the rain that falls on the rain forest never reaches the ground, instead it stays on the trees because the leaves act as a shield.
The average temperature of a rain forest is about 77° Fahrenheit. The rain forest is about the same temperature year round. The temperature never drops below 64° Fahrenheit. Rain forests are so hot because they are found near the equator. The closer to the equator you are, the more solar radiation there is. The more solar radiation there is, the hotter it is. Rain forest are never found in climates which have temperatures 32° Fahrenheit and below because the plant life will not be able to live in the frost. All the plants will die out if the rain forest is cooler.
The plants that make up the understory of a rain forest have adapted to the small amount of sunlight that they receive. Ferns and mosses do well, along with epiphytes. These are plants that grow on other plants. They can be found growing on branches of tall trees. There are many different plant species found in the rain forest.

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