The document discusses forests and their importance. It provides details about the different layers of a forest, including the canopy, understory, and forest floor. It explains that forests are vital because they produce oxygen, store carbon, purify water, and provide resources and habitat. Maintaining forests is important for both environmental and economic reasons.

1. Science Holiday
Homework
Forest our lifeline

2.  A forest, also referred to as a wood or the woods , is an area with a
high density of trees. As with cities, depending where you are in the
world, what is considered a forest may vary significantly in size and
have various classification according to how and what of the forest is
composed. These plant communities cover approximately 9.4% of
the Earth's surface (or 30% of total land area), though they once
covered much more (about 50% of total land area), in many different
regions and function as habitats for organisms, hydrologic flow
modulators, and soil conservers, constituting one of the most
important aspects of the biosphere. Although forests are classified
primarily by trees, the concept of a forest ecosystem includes
additional species (such as smaller plants, fungi, bacteria, and
animals) as well as physical and chemical processes such as energy
flow and nutrient cycling.

3.  A typical forest is composed of the overstory (canopy or
upper tree layer) and the understory. The understory is
further subdivided into the shrub layer, herb layer, and also
the moss layer and soil microbes. In some complex
forests, there is also a well-defined lower tree layer. Forests
are central to all human life because they provide a diverse
range of resources, they store carbon, aid in regulating our
climate, purify water and mitigate natural hazards such as
floods. Forests also contain roughly 90% of the world
terrestrial biodiversity.

4. SOME FOREST PLANTS
Forests are very
important to us they
serve as the green lungs
of the world. Trees
grow in forests. They
are very important to
NEEM us as they take in SHEESHAM
carbon-dioxide released
by us and give oxygen
taken in by us. That is
why forests are called
green lungs of the
world.eg: neem, semak,
BAMBOO bamboo, sheesham. SEMAL

5.  Honey Sealing wax
Wood products
Catechu Gum

6.  In biology, the canopy is the
aboveground portion of a plant
community or crop, formed by plant
crowns.
 For forests, canopy also refers to the
upper layer or habitat zone, formed by
mature tree crowns and including other
biological organisms
(epiphytes, lianas, arboreal animals, etc.).
 Sometimes the term canopy is used to
refer to the extent of the outer layer of
leaves of an individual tree or group of
trees. Shade trees normally have a dense
canopy that blocks light from lower
growing plants.

7. UNDERSTORY
 Understory (or under storey) is the term for
the area of a forest which grows at the
lowest height level below the forest
canopy. Plants in the understory consist of
a mixture of seedlings and saplings of
canopy trees together with
understory shrubs and herbs. Young
canopy trees often persist as suppressed
juveniles for decades while they wait for
an opening in the forest overstory which
will enable their growth into the canopy.
On the other hand, understory shrubs are
able to complete their life cycle in the shade
of the forest canopy. Also some small trees
such as dogwood and holly rarely grow tall
and are generally understory trees.

8. SOME FOREST ANIMALS
Deer Lion Monkey

9. WHY SAVE FORESTS
 Forests are the lungs of the Earth!
Not only do they purify the air we breathe, forests store carbon, help in maintaining
global climate as well as recharge our water sources.
Forests are therefore crucial for the survival of life on this earth!
Forests are home to some of the most unique plant and animal species and support a
diversity of life forms. The loss of forests has pushed many species to the brink of
extinction.
 Forests are life support systems for the rural poor. Almost 90% of the earth’s poverty
ridden communities depend on forests for food, fibre and energy.
 Forests provide free services to all life – water, soil and oxygen!
 About 30 million acres of forests are cleared globally every year! Almost 50% of the
logging in forests is illegal. Deforestation causes 20% of all carbon pollution causing
global climate change. Water sources are drying up and tons of soil is lost due to
erosion. Flash floods and landslides are causing loss of life.

13.  The water cycle, also known as the hydrologic cycle or H2O
cycle, describes the continuous movement of water on, above and below
the surface of the Earth. Water can change states
among liquid, vapour, and solid at various places in the water cycle.
Although the balance of water on Earth remains fairly constant over
time, individual water molecules can come and go, in and out of
the atmosphere. The water moves from one reservoir to another, such as
from river to ocean, or from the ocean to the atmosphere, by the
physical processes of
evaporation, condensation, precipitation, infiltration, runoff, and
subsurface flow. In so doing, the water goes through different phases:
liquid, solid, and gas.

15.  Groundwater is water located beneath the ground surface
in soil pore spaces and in the fractures of rock formations. A unit of
rock or an unconsolidated deposit is called an aquifer when it can yield
a usable quantity of water. The depth at which soil pore spaces or
fractures and voids in rock become completely saturated with water is
called the water table. Groundwater is recharged from, and eventually
flows to, the surface naturally; natural discharge often occurs
at springs and seeps, and can form oases or wetlands. Groundwater is
also often withdrawn for agricultural, municipal and industrial use by
constructing and operating extraction wells. The study of the
distribution and movement of groundwater is hydrogeology, also called
groundwater hydrology.

16.  The water table is the surface where the water pressure head is equal to
the atmospheric pressure (where gauge pressure = 0). It may be
conveniently visualized as the 'surface' of the subsurface materials that
are saturated with groundwater in a given vicinity.
However, saturated conditions may extend above the water table as
surface tension holds water in some pores below atmospheric
pressure. Individual points on the water table are typically measured as
the elevation that the water rises to in a well screened in the shallow
groundwater.

17. GROUNDWATER