2. You will learn:
about the relationship between climate and
vegetation
the global distribution of the different types of
forests
the characteristics of the different types of
forests
the benefits of natural vegetation to people
the case study of tropical rainforest in
Singapore
3. Today’s lesson, You will learn:
what is natural vegetation
what are primary and secondary vegetation
what are the three major types and seven
different sub-types of natural vegetation in
the world
how do climate affect the types of natural
vegetation in the world
4. What is Natural Vegetation?
Natural vegetation refers to
plants which have grown
naturally and not planted
by people.
5. Primary and Secondary Vegetation
Primary Vegetation
refers to untouched, unspoiled forest that
exists in its original condition
Secondary Vegetation
Refers to forest that has been disturbed in
some way, naturally or unnaturally
Areas with secondary vegetation have fewer
varieties of plants
7. Types of Natural Vegetation
There are many types of natural vegetation and
they can be grouped into three main major types
Forests
Grasslands
Deserts
Each major type of natural vegetation can be
subdivided into various sub -types
11. Forests
As you can see from the map:
Tropical rain forests are found mainly along the
equator between 23.5°N and 23.5°S of the
equator).
Temperate forests can be found mainly farther away
from the equator mainly 23.5oN and 66.5oN, and
between 23.5oS and 66.5oS.
Coniferous forests can be found mainly far from
the equator in the northern hemisphere (between
60°N and 70°N of the equator).
14. Why different types of natural
vegetation exist in different parts
of the Earth?
Temperature affects vegetation because if it is
too cold (less than 6°C), few plants can grow. On
the other hand, warm temperatures (above 20°C)
allow abundant plant growth
15. Why different types of natural
vegetation exist in different parts
of the Earth?
Precipitation (rainfall) also affect vegetation
because all plants require water to grow.
Most trees require more water to grow than
grass.
16. Why different types of natural
vegetation exist in different parts
of the Earth?
Hence, most forests grow in areas with high
rainfall (above 1000 mm a year).
In areas with moderate precipitation of between
200 mm and 1000 mm, grasslands are more
common.
In areas with less than 200 mm of rain, deserts are
found.
17. Climate – Vegetation
Relationship
In summary:
Natural vegetation is influenced mainly by climate
A climate-vegetation relationship exists because
rainfall and temperature determine the type of
natural vegetation found in a place
High rainfall - forests
Moderate rainfall - grasslands
Low rainfall - desert vegetation
18. Climate – Vegetation
Relationship
In summary:
Climate is a major factor that influences the
distribution of natural vegetation.
Other factors like the type of soil and altitude can
also affect its distribution.
19. Forests
Forests refer to large areas of land that consist
mainly of trees and a variety of other plants
They are usually found:
Distribution Climate
Temperature Rainfall (mm)
o
C
Between latitudes of -12 to 30 300 mm to 2000 mm
o o
66.5 S and 66.5 N
20. Tropical Rainforests
You will learn:
where are tropical rainforests found
what are the characteristics of a tropical
rainforest
a) The different layers of a tropical rainforest
b) The different types of plants found in the
different layers
c) At least one of the adaptations of the tropical
rainforest
21. Location of Tropical Rainforests
Distribution Climate Location
Temperature Rainfall
o
C (mm)
Between High High • Amazon Basin in
latitudes of Between 1000 South America,
o
23.5 N and 20 to 30 mm to • Malaysia and
o
23.5. S of the 2000 Indonesia in
Equator which mm Southeast Asia,
has a tropical • the Congo Basin
climate in Africa
23. Characteristics of Tropical Rainforests
1. Trees grow very close to each other, making the
forest very dense.
2. Plants grow in 3 distinct layers.
• Emergent
• Canopy
• Undergrowth
25. Characteristics of Tropical Rainforests
EMERGENT LAYER
• Reach heights of 40 to 50 metres
• Grow to receive more sunlight.
• Often have buttress roots to support the
tall and heavy trunks.
CANOPY LAYER
• Reach about 15 to 30 metres
• Crowns of trees interlock to form
continuous leaf cover (canopy)
• Cool and moist interior – blocks out
70% of sunlight
• Lianas are common – woody climbing
plants that hang down.
• Epiphytes are common – plants that
grow on other trees to get more sunlight
26. Characteristics of Tropical Rainforests
EMERGENT LAYER
CANOPY LAYER
}
UNDERGROWTH
• Made up of shrubs, grasses,
ferns, mosses and fungi.
• Plant growth is sparse
because of the lack of sunlight
27. Characteristics of Tropical Rainforests
• Some plants, called epiphytes overcome the
shortage of sunlight by growing high up on
tree branches to get sunlight (examples:
ferns, orchids).
• Other plants, known as lianas, grow upwards
to get more sunlight by winding around tree
trunks.
29. Tropical rainforests: Leaves
Tropical forest trees are evergreens as the
leaves remain green throughout the year.
This is unlike deciduous trees, which shed
their leaves in the autumn or in the dry
seasons.
The leaves are also broad to absorb as much as
much sunlight as possible.
They are also waxy and have drip tips to allow
water to drain off.
30. Tropical rainforests: Leaves
The bark of trees in the tropical rainforest is
thin because they are not required to protect
the trees from dry or cold conditions.
Branches are also located in the top one-
third portion of the trunks and they are
shaped like umbrellas to capture as much
sunlight as possible.
31. Tropical rainforests: Roots
Roots of tropical forest trees are
shallow because they do not need to
reach deep into the soil for water.
This also allows the roots to tap the
abundant nutrients found in the layer
of leaf litter of on the ground.
Tree roots
near the
Some of the tallest trees have buttress surface,
Malaysia
roots to support their great weight and
prevent them from falling over.
32. The Shrinking Rainforests
The world loses about 100 000 sq km of
rainforests each year
Forests are cleared for growing crops and
building houses and roads, and logged every
day
We must do our part to save the remaining
rainforests
33. The Shrinking Rainforests
Impacts of deforestation:
Flooding
Landslide due to soil erosion
Loss of biodiversity of plants and animals
Decrease in oxygen and increase in
carbon dioxide
34. Temperate Coniferous Forests
CLIMATE AND DISTRIBUTION
Distribution Climate Location
Temperature Rainfall
o
C (mm)
Only -12 to 10 300mm to • Japan
between 750mm • China
latitudes of • Europe
o
23.5 N and • North
o
66.5. N of America
the Equator
35.
36. Temperate Coniferous Forests
CHARACTERISITICS
1. Cone Shaped tree
(think Christmas Tree!)
• Allows snow to slide off the
tree branches easily.
• Prevents increase weight of
the snow on the branches
which can cause them to
break.
37. Temperate Coniferous Forests
CHARACTERISITICS
2. Trees are evergreen
• They adapt to extreme conditions instead of
shedding their leaves.
3. Forests have only one variety of tree in each
area. Example: Pine, Fir, Spruce
4. Only have one layer of vegetation
5. Very little undergrowth except for moss,
lichen and leaf litter on the forest floor.
38. Features and Adaptation - Trees
• Coniferous trees are cone-shaped and have
sloping and supple (easily bendable)
branches to allow snow to slide down without
snapping branches
39. Features and Adaptation - Leaves
• The leaves are
small, needle-
shaped, waxy &
leathery to:
• Minimise water
loss
• Prevent the
accumulation of
snow
40. Features and Adaptation – Barks
• Barks are
rough, tough &
contains resin
(thick, sticky
liquid) to protect
against cold and
to conserve
moisture
42. Features and Adaptation – Roots
• Coniferous trees have shallow spreading roots
which enable them to absorb water from the
surface during the short warm months.
• Roots do not go deep as the ground there may
be permanently frozen, even during the summer.
43. Features and Adaptation – Roots
• Coniferous trees have shallow spreading roots
which enable them to absorb water from the
surface during the short warm months.
• Roots do not go deep as the ground there may
be permanently frozen, even during the summer.
44. Quiz Time:
• State one difference and one similarity in the
characteristics of the natural vegetation found in
a Tropical Rainforest and a Temperate Coniferous
forest.
• Explain how these characteristics help the plants
to adapt to the living conditions in which they
are found.
45. BENEFITS OF FORESTS
You will learn:
what are some of the benefits of the
natural vegetation to the Earth and
humans.
46. BENEFITS OF FORESTS
Oxygen in the atmosphere:
• Plants play an important role in
maintaining the amount of oxygen in the air
Formation of rain:
• Plants add to the amount of water vapour in
the air through transpiration and hence
rainfall is usually high in places populated
by many plants
47. BENEFITS OF FORESTS
Natural resource:
• The hardwood trees in
rainforests provide wood
required to make things like
furniture and houses
Medicinal value:
• Many plants that grow in
tropical rainforests have
medicinal properties
49. BENEFITS OF FORESTS
Natural habitats:
• Loss of natural vegetation will result in
the loss of food and habitat for animals
Prevents erosion of soil
• Plants can prevent soil erosion
50. Case Study:
Bukit Timah Nature Reserve
In Singapore, only a few small areas of
rainforests are left.
The government has set aside areas covered
by rainforests as Nature Reserves are part of
conservation efforts.
• Bukit Timah Nature Reserve is 164
hectares in size.
• Believed to be only 0.2% of the rainforest
originally in Singapore.
• Last 1% of primary rainforest in Singapore.
51. Case Study:
Bukit Timah Nature Reserve
CHARACTERISTICS OF BUKIT TIMAH NATURE RESERVE
1. Tall trees (+30m) due to hot and wet climate
2. Trees have buttress roots to support themselves
3. Trees are evergreen and grow closely together.
4. Crowns interlock to form canopy that
prevents sunlight from reaching the forest floor.
5. Dark and damp forest floor.
6. Wide variety of trees and other plants.
• Different hardwood trees: seraya, meranti and nemusi
• Species of climbing palms: rattan
52. Case Study:
Bukit Timah Nature Reserve
VALUE OF TROPICAL RAINFORESTS
1.Medicinal Properties
2.Water Catchment areas
• When rain falls, the rainwater is trapped by
the leaves and falls to the ground. The
water will drain slowly into the ground and
eventually into nearby reservoirs.
53. Case Study:
Bukit Timah Nature Reserve
VALUE OF TROPICAL RAINFORESTS
3. Recreational Activities
• Such as trekking and jogging
4. National Heritage
• Part of our history and our national
heritage.
• Singapore is on of the only two cities to
have a sizeable amount of rainforest in a
built up area.
