THIS NOTES BELONG TO:
SEC 3 GEOGRAPHY
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A GEOGRAPHER
NATURAL VEGETATION (SET 1)
Objective:
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To describe the global distribution of different types of forest
To describe the characteristics of the Tropical Rainforest and Tropical Monsoon
Forests.
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Define natural vegetation.
 Natural vegetation refers to plants that grow naturally in a place with little or no
human interference.
 Natural vegetation plays an important role in the ecosystem. The plants and trees are
part of the community of living organisms and are interacting with them.
 For example in a forest ecosystem, trees and other plants provide food and shelter
for the animals and native people that live in the forest. Plants also depend on the
physical environment which includes soil, climate and water for growth and survivial.
Describe the three major types of natural vegetation.
 They can be grouped into 3 types of vegetation: forests, grasslands and deserts.
 These vegetation types are also known as biomes, which is a living part of the
ecosystem.
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PREPARED BY: MISS SUHAILA MOHAMED NOOR
SEC 3 GEOGRAPHY
Explain how climate affects vegetation growth?
 Temperature
o Most plants cannot grow where temperatures fall below 6oC. This explains the
general lack of vegetation growing in places with a polar climate where
temperatures are usually below 0oC.
o Plants like mosses and lichens can grow these as they are able to adapt to
very low temperatures
o Where temperatures are above 20oC, such as in places with a tropical
climate, the growth of plants especially trees are abundant.

Precipitation
o Plant growth is also influenced by precipitation because water is required by
plants to make food.
o Trees require more water to grow than grass. Hence forests are found in
areas where precipitation is high with 1000 millimetres per year.
o Areas with moderate precipitation of about 200 millimetres to 1000
millimetres, grasslands are more common.
o In areas with little or no precipitation of less than 250 millimetres per year, hot
desert and tundra dominate.
Describe the global distribution of natural vegetation.
 The distribution of natural vegetation is linked to the climatic types in the various
latitudes.
Type of Vegetation
Tundra Vegetation
Coniferous Forest
Tropical Rainforest,
Mangroves and Tropical
Monsoon Forests.
Latitude
66.5 and 90oN and S of
the Equator
60oN and 70oN of the
Equator.
o
23.5oN and S of the
Equator
Type of Climate
Polar Climates
Cool Temperate Climate
(low temperatures and
precipitation)
Tropical Equatorial Climate
(high temperatures and
precipitation)
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PREPARED BY: MISS SUHAILA MOHAMED NOOR
SEC 3 GEOGRAPHY
TROPICAL RAINFOREST
Describe the distribution of tropical rainforest.
 They are found in places that experience a tropical equatorial climate, between 10oN
and S of the equator.
 These places experiences high rainfall and temperature throughout the year.
 Some places include the Amazon Basin in South America, the Congo Basin in Africa
and parts of Southeast Asia such as Malaysia and Indonesia.
Describe the characteristics of Tropical Rainforest.
Layers
Emergent
Canopy
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Understorey
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Description
Tall trees reach a height of 30m to 50m.
Their crows appear above the canopy layer.
These trees have tall, thick and straight trunks.
The trees in this layer reach a height of 15m to 30m.
Their wide, shallow and umbrella-shaped crowns form a
continuous leaf cover, called a canopy.
The canopy will prevent the sunlight from penetrating into the
lower layers of the forest.
Their height range from 6m to 15m.
The trees here have narrower, oval-shaped crowns because
most of the sunlight is blocked by the canopy.
These trees grow where gaps in the canopy allow sunlight to
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PREPARED BY: MISS SUHAILA MOHAMED NOOR
SEC 3 GEOGRAPHY
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Shrub
Undergrowth (Leaf
Litter Zone)
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pass through.
Young trees of the emergent and canopy layers are found in
this layer.
The trees may grow up to 6m high.
Tree saplings and woody plant are found in this layer.
Plants in this layer reach a height of 5m.
The undergrowth of forest floor is made up of grasses, ferns,
mosses and fungi.
Plant growth is sparse because very little sunlight reaches this
layer.
Explain how the tropical rainforests adapt to the climate.
Features
Plants
The
undergrowth
layer
Plant Diversity
Density
Leaves
Flowers and
Fruits
Explanation
 Some plants have adapted to low light condition by growing on
tree branches to get more sunlight.
 Epiphytes and bird's nest fern grow on and use trees for physical
support. Rainwater and decaying leaves that collect at the joints of
branches provide these plants with water and nutrients.
 Lianas are wood vines that wind around tree trunks to reach for
sunlight and they can grow up to lengths of 90 metres.
 Very little sunlight reaches the forest floor.
 Fungi thrive in the moist and dark conditions on the forest floor by
growing on decomposing fallen logs and feeding on them.
 The leaf litter on the forest floor decomposes quickly and forms a
layer of humus due to high temperatures and rainfall.
 This layer of humus are rich in nutrients and supports the
abundant vegetation in the forest.
 The high temperature and rainfall promotes the growth of a large
variety of plants in the tropical rainforest.
 The high temperature and rainfall encourage a dense and
abundant vegetation growth.
 Tropical rainforests are evergreens as the leaves remain green all
year round.
 The leaf surfaces are large and broad to maximise the surface
area for photosynthesis.
 Leaf surfaces are waxy with drip-tips to allow rainwater to drain off
easily, thus preventing harmful bacteria growing on them.
 This protects the plants from disease as the high temperatures
and rainfall promote rapid growth of bacteria.
 The forest flower and produces fruits throughout the year with the
high temperature and rainfall.
 But the still air below the canopy does not allow pollination to be
carried out by wind. Therefore, flowers and fruits in the canopy
layer are colourful and sweet-smelling to attract insects for
pollination and animals for seed dispersal.
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PREPARED BY: MISS SUHAILA MOHAMED NOOR
SEC 3 GEOGRAPHY
Bark and
Branches
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Roots
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Trees have developed thin and smooth barks because there is no
need for protection against cold and dry conditions.
Branches only starts on the top one-third portion of the trunks to
get as much sunlight as possible due to the lack of sunlight
passing through the canopy.
The roots of the trees are shallow and spread widely as they do
not need to reach deep into the soil for water and nutrients.
All the nutrients are taken from the layer of humus that is
supplying nutrients at the topsoil.
Some of the tall trees have buttress roots which are thick and it
spreads widely to support the great weight of the trees.
TROPICAL MONSOON FOREST
Describe the distribution of the Tropical Monsoon Forest.
 Although they are also found in the tropics, the vegetation is only found in places that
experiences the tropical monsoon climate.
 These places experience high temperatures and rainfall but with distinct wet and dry
seasons.
 They are located in South Asia, Southeast Asia, southern China and northern
Australia.
Describe the characteristics of Tropical Monsoon Forest.
Layers
Canopy Layer
Understorey
Layer
Undergrowth
Description
 Trees can grow to 25m to 30m in height. The lack of water during
dry seasons does not allow tress to grow to great height.
 They are more spread out.
 Plants such as epiphytes, lianas and parasitic plants are also
found in this layer.
 Trees can grow up to 15m in height.

Bamboo thickets and grasses grow densely here during the wet
season. They are less dense during the dry season.
Explain how the tropical monsoon forest adapt to the climate.
Features
Plant diversity
Density
Explanation
 The inconsistent rainfall results in lesser species of plants as
compared to the tropical rainforest.
 Around 200 species of plants can be found in one hectare of the
forest.
 Plant growth is abundant in the tropical monsoon forest but it is less
dense than the tropical rainforest.
 The trees do not grow closely and hence their crowns do not
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PREPARED BY: MISS SUHAILA MOHAMED NOOR
SEC 3 GEOGRAPHY
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Leaves
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Flowers and
fruits
Bark and
Branches
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Roots
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interlock to form a continuous canopy.
More sunlight is able to filter through the gaps in the canopy
resulting in dense undergrowth filled with bamboo thickets.
During the wet season, the forest appears dense and during the dry
season, the forest appears sparse.
The trees are deciduous as they shed their leaves during the dry
season to minimise loss of water through transpiration. But the
leaves will grow again quickly during the rainy season.
The leaves are waxy with drip tips to allow water to drain off easily
during the wet season. This prevents the growth of harmful bacteria.
Bamboos plants have adapted to the lack of water during the dry
season. The narrow leaves of the bamboo plant minimise loss of
water through transpiration.
Many of the tree species flower and bear fruit during the dry season
while they are leafless.
The thick and coarse bark of the trees protects the trunk from heat
and dryness during the dry season.
The thick bark also helps the trees to withstand the extreme heat
from natural forest fires which break out occasionally.
The branches of the trees are located at the middle of the trunk
since the trees grow less densely than in a tropical rainforest.
Sunlight is able to reach the lower parts of the forest.
The trees have deep roots to tap water sources deep under the
ground because rainfall is not regular throughout the year.
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PREPARED BY: MISS SUHAILA MOHAMED NOOR