Forest Ecosystem
Intended
Learning Outcomes
At
the end of this Lecture, students will be able to
• Explain forest ecosystem
• Explain the types of forest ecosystem
• Discuss the characteristic features of
forest ecosystem
• Discuss the structure and functional of
the forest ecosystem
Content
• Introduction to forest ecosystem
• Types of forest ecosystem
• Characteristic features of forest
ecosystem
• Structure and functional of the forest
ecosystem
Forest
Ecosystem
• Forests are formed by a community of
plants which is predominantly structurally defined by its trees, shrubs,
climbers and ground cover
• Their distinctive appearance is a
fascinating aspect of nature
• Each forest type forms a habitat for a
specific community of animals that are adapted to live in it
• Forest ecosystem has two parts:
Non-living or abiotic aspects of the forest
Living or the biotic aspects of the forest
Forest
types in India
• Type of forest depends upon the abiotic
factors such as climate and soil characteristics of a region
• Forests in India can be broadly divided
into Coniferous forests and Broadleaved forests
• They can also be classified according to
the nature of their tree species
– Evergreen, deciduous, xerophytic or thorn
trees, mangroves, etc
• They can also be classified according to
the most abundant species of trees such as Sal or Teak forests
• In many cases a forest is named after the
first 3 or 4 most abundant tree species
• Coniferous
forests grow in the Himalayan mountain region, where the temperatures are
low
• These forests have tall stately trees
with needle like leaves and downward sloping branches so that the snow can slip
off the branches
• They have cones instead of seeds and are
called gymnosperms
•
Broadleaved forests have several types, such as
evergreen forests, deciduous forests, thorn forests and mangrove forests
• Broadleaved forests have large leaves of
various shapes
• Evergreen forests grow in the high
rainfall areas of the Western Ghats,
• These forests grow in areas where the
monsoon lasts for several months
• There is no dry leafless phase as in a
deciduous forest
• An evergreen forest thus looks green
throughout the year
• The trees overlap with each other to form
a continuous canopy, thus very little light penetrates down to the forest floor
• The forest abounds in animal life and is
most rich in insect life
• Deciduous
forests are found in regions with a moderate amount of seasonal rainfall
that lasts for only a few months
• Deciduous trees shed their leaves during
the winter and hot summer months
• The forest frequently has a thick
undergrowth as light can penetrate easily onto the forest floor
•
Thorn forests are found in the semi- arid regions
of India
• The trees, which are sparsely
distributed, are surrounded by open grassy areas
• Thorny plants are called xerophytic
species and are able to conserve water
• These plants have waxy leaves to reduce
water losses during transpiration
•
Mangrove forests grow along the coast especially in
the river deltas
• These plants are able to grow in a mix of
saline and fresh water
• The mangrove trees have breathing roots
that emerge from the mudbanks
Forest
utilisation
• Natural forests provide local people with
a variety of products
• Natural forest ecosystems play an
important role in controlling local climate and water regimes
• It is well-known that under the canopy of
a natural forest, it is cooler than outside the forest
• During the monsoon, the forest retains
moisture and slowly releases it through perennial streams during the rest of
the year
• Wood from different species of trees have
special uses. For instance a soft wood is used for the yok of a bullock cart
while a very hard wood is used for its axil
• Traditional types of agriculture needs
forest material such as branches and leaves, which are burnt to form wood ash
which acts as a fertiliser for crops such as rice
• Urban people use these forest resources
indirectly as all their food and other goods come from agricultural areas that
are dependent on the neighbouring forests
Direct uses
of forest products
• Fruits – mango, jamun, amla
• Roots – Dioscoria
• Medicine – Gloriosa, Foxglove
• Fuel wood – many species of trees and
shrubs
• Small timber for building huts and houses
• Wood for farm implements
• Bamboo and cane for baskets
• Grass for grazing and stall feeding
livestock
Indirect
uses of forest
• Building material for construction and
furniture for the urban sector
• Medicinal products collected and
processed into drugs
• Gums and resins processed into a variety
of products
• Raw material for industrial products and
chemicals
• Paper from bamboo and softwoods
What are
the threats to the forest ecosystem?
• As forests grow very slowly, we cannot
use more resources than they can produce during a growing season
• If timber is felled beyond a certain
limit the forest cannot regenerate
• Over utilizing forest resources is an
unsustainable way of misusing our limited forest resources
• Developmental activities such as rapid
population growth together with, urbanisation, industrialisation and the
increasing use of consumer goods, leads to over utilisation of forest produce
What if the
forests disappear?
• When forests are cut down tribal people
who depend directly on them for food and fuel wood and other products find it
very difficult to survive
• Rain that falls on deforested land flows
directly into nearby rivers, thus water is not retained under the ground
• Exposed soil is rapidly washed away
during the rains once the protective forest cover is removed, thus agriculture
is seriously affected.
How can
forest ecosystems be conserved?
• We can conserve forests only if we use
its resources carefully
• Need to grow more trees than are cut down
from forests every year for timber
• The natural forests with all their
diverse species must be protected as National Parks and Wildlife Sanctuaries
where all the plants and animals can be preserved
Summary
• Forests are formed by a community of
plants which is predominantly structurally defined by its trees, shrubs,
climbers and ground cover
• Forests
in India can
be broadly divided
into Coniferous forests
and Broadleaved forests
• Natural forests provide local people with
a variety of products
• Over utilizing forest resources leads to
forest degradation and finally changes the ecosystem
• We can conserve forests only if we use
its resources carefully