Tropical rainforests have a humid climate with high temperatures year-round and heavy rainfall almost daily. They have a complex structure with five layers - emergent trees, canopy, understory, shrub layer, and forest floor. Plants in each layer have adaptations like buttress roots and waxy leaves to survive in the dense forest. Threats to the rainforest include deforestation for agriculture, timber, and development which can be seen increasing over time in satellite images. Rainforests provide many useful products like foods, materials, medicines and maintain nutrient and water cycles.

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

2. Distribution of Rainforests

3. ClimateClimate
The temperature averagesThe temperature averages 28-3028-30
°C°C all year but gets warmer inall year but gets warmer in
March and September when theMarch and September when the
sun is not directly overhead andsun is not directly overhead and
there is less cloud.there is less cloud.
There is aThere is a convectional stormconvectional storm
almost every afternoon except inalmost 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 thethere is less evaporation so the
atmosphere is not so full ofatmosphere is not so full of
moisture and there are fewermoisture and there are fewer
clouds.clouds.
The climate is described asThe climate is described as humidhumid

4. Climogram for Manaus,Brazil
0
50
100
150
200
250
jan feb mar apr may jun jul aug sep oct nov dec
Months
Precipitation(mm)
27
27.5
28
28.5
29
29.5
30
30.5
Temperature(C)
Rainfall Temperature

5. Structure of the ForestStructure of the Forest
EmergentsEmergents
CanopyCanopy
Under canopyUnder canopy
Shrub layerShrub layer
GroundlayerGroundlayer
There are 5 layers in the forestThere are 5 layers in the forest

6. Structure of the RainforestStructure of the Rainforest
SHRUB LAYER
UNDER CANOPY
GROUND LAYER
EMERGENT TREE
CANOPY

7. Plant adaptationsPlant adaptations
1. Emergents and 2. the Canopy1. Emergents and 2. the Canopy
Many plants haveMany plants have waxy leaveswaxy leaves andand ‘drip tips’‘drip tips’ toto
allow heavy rainfall to run off.allow heavy rainfall to run off.
The canopy and the emergents haveThe canopy and the emergents have buttressbuttress
roots, to anchor the tree.roots, to anchor the tree.
Large leavesLarge leaves and dark green foliage to maximiseand dark green foliage to maximise
photosynthesisphotosynthesis..
These emergent trees grow toThese emergent trees grow to over 40mover 40m as they tryas they try
to gather the maximum amount of sunlight.to gather the maximum amount of sunlight.
The canopy forms aThe canopy forms a closed layerclosed layer which allows littlewhich allows little
light through.light through.
There is a huge amount of growth in all layers everyThere is a huge amount of growth in all layers every
year.year.
The increase in theThe increase in the BiomassBiomass is balanced by theis balanced by the
amount of decay. This isamount of decay. This is Nutrient cyclingNutrient cycling. This can. This can
be shown in abe shown in a GersmehlGersmehl Diagram. (Diagram. (see slide 15see slide 15))

8. 3. The under canopy3. The under canopy
In this layer plants have to beIn this layer plants have to be
shade tolerant; they have very bigshade tolerant; they have very big
and very dark green leaves.and very dark green leaves.
There are often few branches onThere are often few branches on
the tall, straight trunks.the tall, straight trunks.
Flowers are very bright to attractFlowers are very bright to attract
insects; the air is too still for windinsects; the air is too still for wind
pollination.pollination.
There are sometimes parasiticThere are sometimes parasitic
plants living on the trunks of trees:plants living on the trunks of trees:
they get their food from the hostthey get their food from the host
tree.tree.
Many of the plants have valuableMany of the plants have valuable
fruits such as Brazil nuts,fruits such as Brazil nuts,
bananas, mangoes, rubberbananas, mangoes, rubber

9. 4. The shrub Layer4. The shrub Layer
In this layer the shrubs are bushyIn this layer the shrubs are bushy
and have many stemsand have many stems
Shrubs have dark green leaves atShrubs have dark green leaves at
the top of the plantthe top of the plant
The plants are shade tolerantThe plants are shade tolerant
They often have bright flowersThey often have bright flowers
which are strongly scentedwhich are strongly scented
Tea, coffee and cocoa are cropsTea, coffee and cocoa are crops
that grow naturally in this layerthat grow naturally in this layer

10. 5. Ground Layer5. 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. SomeFerns and orchids are common plants at this level. Some
of the plants areof the plants are parasiticparasitic..
There are many gaps between plants but it is veryThere 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 thehumid conditions. This is the LitterLitter layer.layer.

11. Threats to the ForestThreats 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.

12. GlossaryGlossary
BiomassBiomass: Living and dead matter produced, including plants and animals. (Kg/m2/annum): Living and dead matter produced, including plants and animals. (Kg/m2/annum)
CanopyCanopy: 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.
EmergentEmergent: 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 FloorForest 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 theair. 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.
NutrientsNutrients: 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.
UnderstoreyUnderstorey: 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.

13. Additional GlossaryAdditional Glossary
Buttress rootsButtress roots –– wide spreading roots like scaffolding that support the very tall emergent andwide 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 thisproduce food for the plant and oxygen. The plants need to have Chlorophyll in their leaves for this
to happento happen

14. 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.

15. 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