Tropical rainforests have 5 layers - emergent, canopy, understory, shrub and ground layers. The climate is hot and humid year-round with daily afternoon rains. Plants in each layer are adapted to the available sunlight. Threats to the forest include deforestation for timber, farmland, mining and development which can be seen destroying the forest in satellite images. Rainforests provide many useful products like foods, materials, medicines and hydroelectric power, though much remains undiscovered as many species are not yet studied.
3. 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.
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.
The climate is described as humid
4. Structure of the Forest
Emergents
Canopy
Under canopy
Shrub layer
Groundlayer
There are 5 layers in the forest
5. Structure of the Rainforest
SHRUB LAYER
UNDER CANOPY
GROUND LAYER
EMERGENT TREE
CANOPY
6. 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
7. 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
8. 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.
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.
9. 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.
10. 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.
11. 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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