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Tropical Rainforests Climate Distribution of Rainforest Structure of the Forest Plant adaptations Threats to the forest Useful products.

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Presentation on theme: "Tropical Rainforests Climate Distribution of Rainforest Structure of the Forest Plant adaptations Threats to the forest Useful products."— Presentation transcript:


2 Tropical Rainforests Climate Distribution of Rainforest Structure of the Forest Plant adaptations Threats to the forest Useful products

3 Distribution of Rainforests

4 Climate The temperature averages 28- 30°C all year but gets warmer in March and September when the sun is not directly overhead and there is less cloud. 28- 30°C 28- 30°C There is a convectional storm almost every afternoon except in March and September when, because there is less sunshine, there is less evaporation so the atmosphere is not so full of moisture and there are fewer clouds. convectional stormconvectional storm The climate is described as humid humid


6 Structure of the Forest Structure of the Forest EEEE mmmm eeee rrrr gggg eeee nnnn tttt ssss CCCC aaaa nnnn oooo pppp yyyy UUUU nnnn dddd eeee rrrr c c c c aaaa nnnn oooo pppp yyyy SSSS hhhh rrrr uuuu bbbb l l l l aaaa yyyy eeee rrrr GGGG rrrr oooo uuuu nnnn dddd llll aaaa yyyy eeee rrrr There are 5 layers in the forest


8 Plant adaptations 1. Emergents and 2. the Canopy 1. Emergents and 2. the Canopy 1. Emergents and 2. the Canopy Many plants have waxy leaves and ‘drip tips’ to allow heavy rainfall to run off. The canopy and the emergents have buttress roots, to anchor the tree. buttress Large leaves and dark green foliage to maximise photosynthesis. photosynthesis These emergent trees grow to over 40m as they try to gather the maximum amount of sunlight. The canopy forms a closed layer which allows little light through. There is a huge amount of growth in all layers every year. The increase in the Biomass is balanced by the amount of decay. This is Nutrient cycling. This can be shown in a Gersmehl Diagram. (see slide 15) BiomassNutrient cyclingGersmehlsee slide 15BiomassNutrient cyclingGersmehlsee slide 15

9 3. The under canopy 3. The under canopy In this layer plants have to be shade tolerant; they have very big and very dark green leaves. There are often few branches on the tall, straight trunks. Flowers are very bright to attract insects; the air is too still for wind pollination. There are sometimes parasitic plants living on the trunks of trees: they get their food from the host tree. Many of the plants have valuable fruits such as Brazil nuts, bananas, mangoes, rubber

10 4. The shrub Layer 4. The shrub Layer In this layer the shrubs are bushy and have many stems Shrubs have dark green leaves at the top of the plant The plants are shade tolerant They often have bright flowers which are strongly scented Tea, coffee and cocoa are crops that grow naturally in this layer

11 5. Ground Layer 5. Ground Layer It is very dark on the forest floor Ferns and orchids are common plants at this level. Some of the plants are parasitic. parasitic There are many gaps between plants but it is very difficult to get around due to the tangle of vines and dead, fallen branches. The Litter layer is quite thick but Plant and animal material decays quickly in the hot, humid conditions. This is the Litter layer. Litter

12 Threats to the Forest An area of forest the size of Belgium is clear felled for timber every year Local people have growing populations and need farmland Timber from the tall, straight trees is much sought after for building and for furniture Big business wants to extract resources from under the forest Hydro-electric schemes flood the forest Accidental fires burn out of control Satellite image of deforestation in the Amazon region, taken from the Brazilian state of Para on July 15, 1986. The dark areas are forest, the white is deforested areas, and the gray is regrowth. The pattern of deforestation spreading along roads is obvious in the lower half of the image. Scattered larger clearings can be seen near the center of the image.

13 Glossary Biomass Biomass : Living and dead matter produced, including plants and animals. (Kg/m2/annum) Biomass Canopy Canopy : The highest layer of the rainforest, made up of the tops of trees. Animals such as howler monkeys, red-eyed tree frogs, sloths and parrots live here. Canopy Equator : An imaginary circle around the earth, equally distant at all points from the North and South poles. It divides the earth into two halves - the Northern and Southern Hemispheres. Emergent Emergent : The tops of the tallest trees in a rainforest. Emergent Evaporate : When moisture changes from liquid to gas in the air. Extraction : To remove something (for example, to take out Brazil nuts from the Amazon rainforest). Forest Floor Forest Floor : The ground layer, made up of tree roots, soil and decaying matter. Mushrooms, earthworms, and elephants all make their homes here. Forest Floor Greenhouse Effect : The warming of the planet caused by chemicals which trap heat in the air. This process is being sped up by humans who put too many heat-trapping chemicals into the air. Some causes include car exhaust, factory smoke, and burning rainforests. Interdependence : The concept that everything in nature is connected to each other, and cannot survive without the help of other plants, animals and abiotic factors (such as sun, soil, water and air) around it. Nutrients Nutrients : Food needed for growth by living things. Nutrients Species : A distinct kind of plant or animal that has many common characteristics or qualities. Sustainable : Using products of the forest in a way that does not permanently destroy them, so that people in the future can also use them. Tropic of Cancer : A circle around the earth, parallel and to the north of the equator. Tropic of Capricorn : Similar to the Tropic of Cancer, but to the south of the equator. Understorey Understorey : The second layer of rainforests, made up mostly of young trees and shrubs. Animals that live here include jaguars, tapirs, snakes, and woodpeckers. Understorey

14 Additional Glossary Buttress roots Buttress roots – wide spreading roots like scaffolding that support the very tall emergent and canopy trees. Buttress roots Climogram Climogram - a graph that shows temperature and rainfall on double axes. This is useful for describing climate and comparing the climate of two or more places. Climogram Convectional storm Convectional storm - rain that is the result of early evening cooling of moist air so that the vapour condenses and a short heavy storm happens Convectional storm Humid Humid - the air is almost saturated with moisture and cooling a small amount will result in rainfall Humid Nutrient Cycling Nutrient Cycling – the process of material dropping to the forest floor, decaying and the nutrients being added to the soil then being taken up by plants to make new growth. Nutrient Cycling Parasitic Parasitic - a plant or animal that lives on and gets its food from another species Parasitic Photosynthesis Photosynthesis - the biological process that uses sunlight, water and carbon dioxide to produce food for the plant and oxygen. The plants need to have Chlorophyll in their leaves for this to happen Photosynthesis

15 Useful Products It is difficult to know how many useful products come from the rainforest; many species of plant and animal have yet to be studied. However we do know of many food crops such as coffee, cocoa, tea, Brazil nuts, Oil palms, coconuts etc. that are found in tropical forests and can be farmed and harvested. Raw materials such as Copra, Sisal, Hemp, Mahogony, Teak, Rubber are all rainforest crops There are huge deposits of useful minerals under the forest e.g. Iron ore, Bauxite, Gold, Silver, Tin and Diamonds The high rainfall and fast flowing rivers make Hydro Electricity cheap once the dams and generators have been installed. Many medicines such as quinine for Malaria, Aspirin and several anti- cancer drugs have been extracted from Rainforest plants.

16 Gersmehl Diagram Gersmehl Diagram for the Rainforest Biomass Litter Soil Leaf fall Decay Nutrient Take up Sunlight Animal waste + Decay Water Weathered Rock Erosion Harvest Each circle represents a store of nutrients. Each arrow represents a flow of nutrients. The size of the circle is proportional to the volume of nutrients stored. The width of the arrow is proportional to the volume of nutrients flowing along that route. Back to Emergents slide

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