Page 152 - Ripples SCIENCE 7 - TEJPUR Edition 2024 Answer Key

17. Forests: Our Lifeline

Chapter in a Nutshell

v A forest is a large area of land that is thickly populated with different species of trees, various
types of plants, animal, birds, insects & microorganisms.
v The various components of the forest are interdependent on one another for their

sustenance & growth.
v Forests are useful & important to us in many other ways.

v The vertical section of a forest is divided into following sections–emergent layer, canopy,
understory layer & forest floor.

v The topmost layer of branches of the tallest trees makes the emergent layer. Below the
emergent layer is the canopy. Located between the canopy & the forest floor is a very dark

layer of vegetation known as the understory. Forest floor is the ground layer of a forest.
v A forest product is any material derived from forestry for direct consumption or commercial
use.

v Certain forest products, such as timber, fuel wood & fodder is grown to meet the common
needs of the local communities. This is called social forestry.

v Forest product are divided into–major and minor forest products.
v Major products are obtained in large quantities mainly for commercial use, such as
pulpwood, sandalwood, timber, fire wood, etc.

v Minor products are obtained in lesser quantities & meant for small-scale consumption, such
as tamarind, honey, bamboo, tendu-patta, etc.

v Plants, animals & microorganism in a forest are interdependent for food, shelter, oxygen,
carbon dioxide, nutrients, pollination & dispersal of seeds.
v The transfer of food energy from the producers through a series of organisms (herbivores to

carnivores to decomposers) with repeated eating & being eaten is known as a food chain.
v The interwoven network of several interconnected food chains in a community is called a

food web.
v Flow of energy from one organism to the other is unidirectional.
v Decomposers break down dead plant & animal remains into simple substances that mix

with the soil.
v The decayed & decomposed plant or animal matter converts into an organic substance
known as humus that adds the required nutrients to the soil & makes it fertile.

v We should prevent deforestation by any means because forests are an important natural
resource.

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