 The Open Door Web Site |
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The Canopy
The canopy of a forest is formed by the spreading branches of the trees as they meet each other above the ground. In the tropical rain forests of Costa Rica the canopy can be divided into three layers. In the lower canopy the trees are between 10 metres and 25 metres above the ground. The trees in the middle layer of the canopy are 35 metres above the ground and the tallest trees are over 50 metres in height. Because of the dense canopy vegetation, the forest field layer receives only 1% of the sunlight which falls on the canopy.
The plants in the canopy, such as the balsa tree, need to grow as tall as they can to receive the maximum amount of sunlight. What they gain in height, they lose in strength. The trunk and the branches of the balsa tree are light, thin and can be easily broken.
Every year about 210000km2 of tropical rainforest is chopped down to make way for farmland and pastureland. At this rate most of the tropical rain forests will have disappeared in the next 50 years. This means that half of the world's animal and plant species which exist will be extinct by the year 2100.
The Rocky Shore
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© Paul Billiet and Shirley Burchill 2009 |
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