childrens this small full will be uploaded soon class 7

1. CH: 17
Forest: Our lifeline
Class: 7TH

2. Introduction
Forest is a large area of land coveredthickly with different kinds of trees,
shrubs, herbs, grasses, creepers, and climbers. Forest is a home to many
animals and plants species. Forest cover approximately one-third of the
earh’s total land surface, roughly about 3.9 greenlands. How do plants
depend on each other in a forest? Why are forest important to us? Why
are forests being cut at a faster rate? How has deforestation led to drastic
changes in environment? Let us find the answers of all these questions in
this chapter. But let us know the structure of a forest.

3. The structure of forest
The type of vegetation and animals found in different forests
vary depending on the climatic conditi0ns of the region the
forest is situated in. A forest consist of different layers of
vegetation. There are three main layers of a forest starting
from top to ground are canopy, understory, forest floor. The
[art of a tree above the trunk which consist of branches, is
known as crown of the tree. The crown are of different types
and sizes. The amount of sunlight available in each layer of
the forest decides which type of plants may grow and survive
there. It also decides the habit of various animals.

4. Canopy layer
The forest's top layer consists of the branches and leaves of tall trees forming a
kind of roof or umbrella over the smaller trees and other plants in the forest. The
uppermost branches and leaves of tall trees which act like a roof or a umbrella
over the smaller trees in the forest is calledcanopy. It has tall, evergreen trees with
large, green leaves. The branches overlap each other forming a continuous cover
of dense leaves. This layer is so dense that very little sunlight penetrates through
it and reaches the lower layers of the forest. A large variety of birds, bats,
monkeys and insects liv here. Some animals live solely in the canopy region They
do not move down to the ground at all.

5. UNDERSTOREY LAYER
The layer of vegetation in a forest just below the canopy is called
understory. It mainly has different horizontal layers. Below the tall trees
are -smaller trees and below which are the shrubs and tall grasses. The
lowest layer is formed of herbs. Plants such as orchids, palms and ferns
grow in this region. A large variety of insects, birds, snakes, lizards and
carnivorous predators such as jaguars, pythons and leopards live here.

6. FOREST FLOOR
This region receives very little amount of sunlight. Only plants adapted
to grow with very less light can survive in this damp, warm and dark
region of the forest. The forest floor has various kinds of small leafless
plants such as mosses and lichens. The floor is covered with a layer of
dead and decaying leaves, fruits, seeds, twigs and small worms. A large
variety of insects, millipedes, ants and beetles are found on the forest
floor. The largest animals in the forests such as tigers, lions, deer, bears,
etc., live on the forest floor.

7. IMPORTANCE OF FOREST
Forests provide us many things
we need. Besides, they play a
very important role in
maintaining the environmental
balance. Let us understand
how forests are important for
us.

8. 1. forest-a source of wood
A variety of trees growing in the forests like teak, sheesham, rosewood
and sal are the sources of wood. Good quality wood is used to make
furniture, boats, sports goods and for constructing houses. Wood is used
as a fuel (or firewood) in many households for cooking food. Wood is
also used for the production of paper which is used for making books,
magazines and newspapers.[9:51 PM, 2/16/2023] Shanvi Shakya: Several
plants that grow in forests are used in the preparation

9. 2. Forest-A source of variety of products
Several plants that grow in forests are used in the preparation of medicines. The
bark of Cinchona tree is the source of medicine called quinine, used for
treatment of malaria disease. A few trees contain a substance known as taxol
which helps fight certain types of cancer. Turpentine, which is produced from
resin or gum of pine trees, is used for thinning paints and varnishes. Rubber
comes from rubber trees. Gum trees (babool, kikar) yield gum. The oil extracted
from trees like Eucalyptus, and sandalwood is used to make dyes and perfumes.

10. 3. FOREST MAINTAIN BALANCE OF GASES
Forests maintain the natural balance of carbon dioxide and oxygen in the
atmosphere by using up photosynthesis. In this way, forests purify the air and
serve as green lungs in nature.

11. 4. Forest maintain water cycle in nature