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Geography
Tropical rainforest models
Tropical Rain Forest
Geography
Geography
Rain Forest Family Forever
United Streaming 13:28
Tropical Rain Forest
Geography
-found near the equator
-temperature varies little
from approximately 23°C
-the length of daylight
varies from 12 hours by
less than one hour
-rainforest>2000mm
Geography
How many species are lost from tropical forests
annually?
Over 20,000
How big is the Amazon Rainforest?
Half the size of the USA
Geography
Rainforests are home to over 50% of the
world’s species
Brazil has the world’s largest total tropical rain
forest acreage
Many acres are cleared to raise cattle.
There is now 50% less rain forests that 50
years ago.
Geography
Effects of Deforestation
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Tropical Rain Forest
-canopy trees up to 55 m tall
Geography
-soils are generally unfertile
-largest biome, on an area basis -nutrients and carbon stored
in plant biomass, not soils
Tropical Savanna/Seasonal Forest
Geography
Tropical Savanna/Seasonal Forest
Geography
-found in the tropics (but
> 10° latitude)
-pronounced dry season
with <5 cm rainfall in
some months
Temperate Forest
Geography
Temperate Forest
Geography
-distinct winter season,
frost a defining feature
-summer season usually
moist with
ppt > evapotranspiration
Temperate Forest
-relatively large tree biomass
-also called the deciduous forest,
but contains evergreen needle trees as well
Geography
Geography
Rainforest plants
And the enormous the number of different species of plants grow in
rainforests, with many species occurring only in one particular region.
Unlike other forests, rain forests have an abundance of :
Epiphytes
plants which live above the ground growing on
tree trunks and branches, Example orchids,
ferns, mosses
Climbing plants
including large woody climbers called lianas
which are rooted in the soil and usually reach the
canopy. The climbers twist around the tree trunks,
and loop from one tree to another in the canopy,
binding the trees together.
Strong scent of fruits attracts
animals, which feed on the
fruit and assist in dispersal
of the seeds
Thick, waxy surface of
leaves protects against
hot sun, heavy rain,
and strong winds
Aerial roots of
epiphytes absorb
moisture from the
air
Geography
Strong scent and bright
colours of flowers
attract insects which
assist in pollination
Tall straight trunks
no side branches
Thin, smooth bark
Shallow spreading
root system
Buttress roots
Geography
Pitcher plant - a carnivorous plant.
Parasitic plant
slippery rim
tendril
Orchid - sun-loving roots
attached themselves to
branches and absorb nutrients
Insects falling into the
pitcher are digested, and
nutrients which are released
are absorbed by the plant.
 Tom Abbott, Biddulph High School and made available through
www.sln.org.uk/geography and only for non commercial use in schools
Structure of the rainforest
Geography
The dominant plants in a rainforest are giant trees. The hot
wet climate enables them to grow all year round, and they
remain evergreen, continuously shedding their leaves and
growing new ones.
The average height of rainforest trees is about 45 metres,
although the emergence (trees which tower above the
others) may go as high as 90 metres. Smaller trees growing
the under story (layer between the canopy and the forest
floor).
Several layers can be identified within the forest
45
Geography
A Emergent
40 tree canopy
35
30
25 B Large trees
of Middle layer
20
15
C Lower tree
layer
10
D Shrub/small
tree layer
5
 Tom Abbott, Biddulph High School and made available through
www.sln.org.uk/geography and only for non commercial use in schools
E Ground vegetation
Canopy layer - formed by the crowns of the tall trees andGeography
contains a mass of branches, Leaves, flowers and fruit.
Conditions in the canopy vary, and include:
•Hot sunshine
•Heavy rainfall
•Tropical storms
Middle layer - the Vegetation here is more sparse. The
trees tend to have pointed crowns and, when a giant tree
falls, they grow quickly to fill a gap in the canopy
Conditions within the forest on more or less constant:
•There is little variation in temperature
•The air is moist and still
•Rain on the canopy drips to the forest floor several
minutes later
•A breeze is rare, even during storms
Geography
Shrub layer - scattered shrubs, saplings (young trees) and
ferns.
Herb layer - a few non-woody, soft stemmed plants with
thin leaves.
Leaf litter -
thin layer covers the forest floor.
Soil layer -
most roots growing the top 10 centimetres
whether nutrients are found.