Tropical RainforestsTropical Rainforests

•Climate

•Distribution of Rainforest

•Structure of the Forest

•Plant adaptations

•Threats to the forest

•Useful products

Distribution of Rainforests

ClimateClimate

The temperature averages The temperature averages 28-30°C all year but gets warmer in all year but gets warmer in March and September when the March and September when the sun is not directly overhead and sun is not directly overhead and there is less cloud.there is less cloud.

There is a There is a convectional storm almost every afternoon except in almost every afternoon except in March and September when, March and September when, because there is less sunshine, because there is less sunshine, there is less evaporation so the there is less evaporation so the atmosphere is not so full of atmosphere is not so full of moisture and there are fewer moisture and there are fewer clouds.clouds.

The climate is described as The climate is described as humid

Climogram for Manaus,Brazil

0

50

100

150

200

250

jan feb mar apr may jun jul aug sep oct nov dec

Months

Pre

cip

itati

on

(m

m)

27

27.5

28

28.5

29

29.5

30

30.5

Tem

pera

ture

(C

)

Rainfall Temperature

Structure of the Forest

Emergents

Canopy

Under canopy

Shrub layer

Groundlayer

There are 5 layers in the forestThere are 5 layers in the forest

Structure of the RainforestStructure of the Rainforest

SHRUB LAYER

UNDER CANOPY

GROUND LAYER

EMERGENT TREE

CANOPY

Plant adaptationsPlant adaptations 1. Emergents and 2. the Canopy

Many plants have Many plants have waxy leaveswaxy leaves and and ‘drip tips’ ‘drip tips’ to to allow heavy rainfall to run off.allow heavy rainfall to run off.

The canopy and the emergents have The canopy and the emergents have buttress roots, roots, to anchor the tree.to anchor the tree.

Large leavesLarge leaves and dark green foliage to maximise and dark green foliage to maximise photosynthesis..

These emergent trees grow to These emergent trees grow to over 40mover 40m as they try as they try to gather the maximum amount of sunlight.to gather the maximum amount of sunlight.

The canopy forms a The canopy forms a closed layerclosed layer which allows little which allows little light through.light through.

There is a huge amount of growth in all layers every There is a huge amount of growth in all layers every year.year.

The increase in the The increase in the Biomass is balanced by the is balanced by the amount of decay. This is amount of decay. This is Nutrient cycling. This can . This can be shown in a be shown in a Gersmehl Diagram. ( Diagram. (see slide 15))

3. The under canopy

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

4. The shrub Layer

In this layer the shrubs are bushy In this layer the shrubs are bushy and have many stemsand have many stems

Shrubs have dark green leaves at Shrubs have dark green leaves at the top of the plantthe top of the plant

The plants are shade tolerant The plants are shade tolerant

They often have bright flowers They often have bright flowers which are strongly scentedwhich are strongly scented

Tea, coffee and cocoa are crops Tea, coffee and cocoa are crops that grow naturally in this layerthat grow naturally in this layer

5. Ground Layer

It is very dark on the forest floorIt is very dark on the forest floor

Ferns and orchids are common plants at this level. Some Ferns and orchids are common plants at this level. Some of the plants are of the plants are parasitic..

There are many gaps between plants but it is very There are many gaps between plants but it is very difficult to get around due to the tangle of vines and dead, difficult to get around due to the tangle of vines and dead, fallen branches. The Litter layer is quite thick butfallen branches. The Litter layer is quite thick but

Plant and animal material decays quickly in the hot, Plant and animal material decays quickly in the hot, humid conditions. This is the humid conditions. This is the Litter layer. layer.

Threats to the ForestThreats to the Forest

An area of forest the size of Belgium is clear felled for timber every yearLocal people have growing populations and need farmlandTimber from the tall, straight trees is much sought after for building and for furnitureBig business wants to extract resources from under the forestHydro-electric schemes flood the forestAccidental 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.

GlossaryGlossary Biomass: Living and dead matter produced, including plants and animals. (Kg/m2/annum): Living and dead matter produced, including plants and animals. (Kg/m2/annum)

Canopy: The highest layer of the rainforest, made up of the tops of trees. Animals such as : 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. howler monkeys, red-eyed tree frogs, sloths and parrots live here.

EquatorEquator: An imaginary circle around the earth, equally distant at all points from the North and : 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. South poles. It divides the earth into two halves - the Northern and Southern Hemispheres.

Emergent: The tops of the tallest trees in a rainforest. : The tops of the tallest trees in a rainforest.

EvaporateEvaporate: When moisture changes from liquid to gas in the air. : When moisture changes from liquid to gas in the air.

ExtractionExtraction: To remove something (for example, to take out Brazil nuts from the Amazon : To remove something (for example, to take out Brazil nuts from the Amazon rainforest). rainforest).

Forest Floor: The ground layer, made up of tree roots, soil and decaying matter. Mushrooms, : The ground layer, made up of tree roots, soil and decaying matter. Mushrooms, earthworms, and elephants all make their homes here. earthworms, and elephants all make their homes here.

Greenhouse EffectGreenhouse Effect: The warming of the planet caused by chemicals which trap heat in the : 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. 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. air. Some causes include car exhaust, factory smoke, and burning rainforests.

InterdependenceInterdependence: The concept that everything in nature is connected to each other, and : 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, cannot survive without the help of other plants, animals and abiotic factors (such as sun, soil, water and air) around it. water and air) around it.

Nutrients: Food needed for growth by living things. : Food needed for growth by living things.

SpeciesSpecies: A distinct kind of plant or animal that has many common characteristics or qualities. : A distinct kind of plant or animal that has many common characteristics or qualities.

SustainableSustainable: Using products of the forest in a way that does not permanently destroy them, : Using products of the forest in a way that does not permanently destroy them, so that people in the future can also use them. so that people in the future can also use them.

Tropic of CancerTropic of Cancer: A circle around the earth, parallel and to the north of the equator. : A circle around the earth, parallel and to the north of the equator.

Tropic of CapricornTropic of Capricorn: Similar to the Tropic of Cancer, but to the south of the equator. : Similar to the Tropic of Cancer, but to the south of the equator.

Understorey: The second layer of rainforests, made up mostly of young trees and shrubs. : The second layer of rainforests, made up mostly of young trees and shrubs. Animals that live here include jaguars, tapirs, snakes, and woodpeckers. Animals that live here include jaguars, tapirs, snakes, and woodpeckers.

Additional GlossaryAdditional Glossary Buttress rootsButtress roots – – wide spreading roots like scaffolding that support the very tall emergent and wide spreading roots like scaffolding that support the very tall emergent and canopy trees.canopy trees.

ClimogramClimogram- a graph that shows temperature and rainfall on double axes. This is useful for - 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.describing climate and comparing the climate of two or more places.

Convectional stormConvectional storm - rain that is the result of early evening cooling of moist air so that the - rain that is the result of early evening cooling of moist air so that the vapour condenses and a short heavy storm happensvapour condenses and a short heavy storm happens

HumidHumid- the air is almost saturated with moisture and cooling a small amount will result in rainfall- the air is almost saturated with moisture and cooling a small amount will result in rainfall

Nutrient CyclingNutrient Cycling – the process of material dropping to the forest floor, decaying and the – 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.nutrients being added to the soil then being taken up by plants to make new growth.

ParasiticParasitic- a plant or animal that lives on and gets its food from another species- a plant or animal that lives on and gets its food from another species

PhotosynthesisPhotosynthesis- the biological process that uses sunlight, water and carbon dioxide to - 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 produce food for the plant and oxygen. The plants need to have Chlorophyll in their leaves for this to happenthis to happen

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.

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.

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