Geography (Forest+Deforestation)

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Test topics:
* Tropical Rainforest
* Location:
* Characteristics:
* Very dense vegetation- Trees, ferns, palms, epiphytes and lianas grow in close proximity to each other. * Great diversity of plant species- In one hectare of forest, there could be as many as 400 species of trees. The dominant species family is the Dipterocarpaceae with common members such as the Seraya, Keruing and Meranti. The high and uniform temperature and rainfall throughout the year supports a large variety of plant species. In Manaus or Kisagani, the monthly temperature is uniformly high, between 25°C and 28°C. An average of 100 mm of rain falls ever month. These climatic characteristics allow plants to grow rapidly and in abundance. * Five layered structure- Different species of vegetation grow in the emergent, canopy, understory, shrub and ground layers. The high level of rainfall and abundance of sunlight ensure plants grow throughout the year. Different plant species have different growth cycles, giving rise to the many layers in the forest structure. The emergents are the tallest trees while the canopy shuts out much of the sunlight from the ground, causing undergrowth to be sparse. i. Emergent- The emergents are the tallest trees in the forest. They grow to a height of about 50 metres. They are scattered over the forest and grow above the canopy layer. ii. Canopy- The trees grow to height of about 40 metres. The crowns of the trees interlock to form a continuous canopy layer over the forest shuts out much sunlight from the forest floor. This makes the forest look dark. iii. Understory- Smaller trees in this layer grow to heights of between 10 and 30 metres. Lianas, which are woody epiphytes, can be found in this layer. iv. Shrub- Shrubs, sapling and young trees which are usually not taller than 10 metres can be found in this layer. v. Ground- This layer consists of the forest floor. Ferns, mosses, fungi and other small plants are found here. The vegetation is sparse as not much sunlight reaches the forest floor. * Evergreen- The abundance of rain and sunlight throughout the year means that plant growth is continuous throughout the year, giving the forest a permanently ‘green look’. The trees do not shed their leaves at the same time in a year but at different time, according to individual growth cycles. The uniform high temperatures and rainfall throughout the year provide the trees the opportunity to continuously grow throughout the year. Different trees shed their leaves at different times. * Tall straight trunks- In a bid to reach to reach the sunlight, some of the trees can grow to a height of 50 metres or more. Epiphytes and lianas attach themselves to other trees the reach the sunlight above the canopy. The trees in the forest grow rapidly and to great heights because of favourable climatic factors and also because they have to reach for the abundant sunlight above the canopy that cannot penetrate to the ground level. * Buttress roots- Buttress roots help to anchor the tall trees to the ground, though they tend to be shallow so as to access the nutrients on the soil surface. The temperatures of the tropical rainforest enable decomposition to take place rapidly. Tree roots are shallow so as to access the abundant nutrients found on the surface of the forest soil. As many of the tropical rainforest trees grow to great heights, their buttress toots, which can extend up to five metres above the ground, help to support their massive weight. * Broad and waxy leaves- The leaves on tropical rainforest vegetation are usually thick, broad and waxy with drip-tips. The leathery and thick leaves of the trees help to prevent excessive water loss through transpiration. The leaves also have waxy surfaces and drip tips so that excess water can drip off during heavy convectional rain common...
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