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Protect the Forest,
Save the Water
By: Vaishnavi Vankayala and
Soha Anandani
Introduction
❏ Forests make a significant contribution to the
supply of water.
❏ They provide water for animals and plants
living under the huge canopies, allowing
organisms to survive and also by protecting
biodiversity
❏ Topics:
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6.
-Water Cycle
-Photosynthesis
-Runoff/erosion
-Water Pollution
-Aquifers
-Rainfall
Water Cycle
❖ In leaves, water combines with carbon
dioxide and sunlight to make
sugar(food)for the tree( photosynthesis).
Then, oxygen and water are released
through the leaves through a process
called transpiration. This moisture
contributes to the formation of rain
clouds, which release the water back
onto the forest.
❖ The soil absorbs precipitation that falls
from the clouds, and trees draw water
from the soil into their roots to support all
of their processes (growth, reproduction,
and maintenance)
Photosynthesis and growth
Trees and plants in our forests perform
photosynthesis when carbon dioxide, water,
and light energy circulate through the trunk,
needles, leaves and flowers.
Trees absorb carbon, which makes their
wood strong, helping them to grow taller day
in and day out and produce oxygen
throughout their lifetime.
Runoff/Erosion
❖ Forest vegetation exists in several layers of trees, shrubs, and smaller
plants
❖ Vegetation provides surface area that can collect water during storms
❖ Without forests, there would be increased run-off, topsoil erosion, and
flooding of rivers and streams
❖ Run-off in urban settings is often bound with pesticides, fertilizer, and
sediment from agricultural lands
❖ As a result, these pollutants enter surface water and jeopardize water
quality
Water pollution
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Various types of pollution can also impair water quality
Potential pollutants include excessive concentrations of
organic matter (leading to water eutrophication) and
agricultural or industrial chemicals.
Forest are an appropriate ground cover for drinking-water
because….
❖ they supply watersheds
❖ forestry activities generally use no fertilizers or
pesticides and avoid sewage pollution and industrial
processes.
❖ non-point source pollution from domestic, industrial and
agricultural use can be greatly reduced or even
eliminated by maintaining forest buffer zones
watercourses.
Harvesting trees beside streams can affect water quality by...
❖ reducing shading that regulates water temperature
❖ removing vegetation that stabilizes the streambanks
❖ these changes can harm aquatic life by limiting sources
of food, shade and shelter
❖ can pollute water easily
Types of water pollution
Rainfall
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Tropical forest- Precipitation is evenly distributed
throughout the year, with annual rainfall
exceeding 200 cm.
Temperate Forests- Precipitation (75-150 cm)
is distributed evenly throughout the year
Boreal Forests- Precipitation is primarily in the
form of snow, 40-100 cm annually.
moist conifer and evergreen broad-leaved
forests: wet winters and dry summers (rainfall
is concentrated in the winter months)
dry conifer forests: low precipitation.
mediterranean forests: precipitation is
concentrated in winter, less than 100 cm per
year.
temperate coniferous: mild winters, high
annual precipitation
temperate broad-leaved rainforests: mild,
frost-free winters, high precipitation
Floods
➔ Floods can negatively impact the forests growth through many ways,
such as soil depletion, destruction of plants, and loss of nutrients in
the forests
➔ Floods may carry various chemicals that have been picked up as
runoff from agricultural fields and other areas or from sewage. The is
detrimental to the growth of forests, as chemicals can pollute and
release toxins, harming the development of animals and plants who
may eat other things or drink water.
➔ Flooding of soil increases the pH of acid soils and decreases the pH
of alkaline soils.
➔ Deposits of silt or sand limit the supply of oxygen.
➔ heavy floods can cause soil around the base of the tree to be washed
away, exposing tree roots to further damage
Aquifers
❖ Aquifer - underground layer of permeable rock
from which groundwater can be extracted
❖ Aquifers, which supply our wells and city water
systems, provide most of our drinking water
❖ 60% of freshwater in the U.S. comes from
forests
❖ Trees in forests catch precipitation, then
cleanse and filter it into the soil to recharge our
aquifers
❖ Without high canopy trees, water is more likely
to face runoff and less likely to dissolve into
aquifers
Pros
❖ With forests, water is easily accessible to organisms under canopies, helping to maintain
biodiversity
❖ Water in forests allows for transpiration and photosynthesis
❖ Forest water involves less runoff and more filtration into aquifers
❖ Forests provide a major part of our drinking water
❖ Gives different species and plants the water they need to survive (some species need
more/less)- this can lead to biodiversity as different organisms will be able to thrive with proper
nourishment
❖ Natural forests and well-managed plantations can protect drinking-water supplies.
Cons
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pollutants can impair water quality
erosion results in higher amounts of sediment runoff
high amounts of rainfall can cause floods
unsustainable forest practices can affect the quality of the water
trees exposed to high levels of air pollution capture sulphur and
nitrogen and can increase water acidification.
❖ water shortages can impact forest growth
Outlook for the Future
❖ Forests work as a catalyst to the water cycle. Deforestation is leading to
less absorption of water and less rainfall, or drought. In turn, the drought
conditions make it harder to plant trees because of the hard and dry soil.
❖ In addition, as deforestation occurs, the amount of carbon dioxide in the
atmosphere builds up. As carbon dioxide increases, heat is trapped in the
atmosphere, leading to climate change.
❖ The added pollution in the atmosphere can also lead to acid rain when
gases mix with water in the clouds.
Acts and Regulations
❏ The 1972 Clean Water Act regulates the release of pollutants into U.S.
waterways
❏ The legislation dealt with water pollution by prohibiting the discharge
of pollutants unless the discharger obtains a permit from the
government.
❏ passed related legislation to ensure that all waters of the United States
was clear.
❏ In 1972, Congress passed the Marine Protection, Research, and
Sanctuaries Act, known as the Ocean Dumping Act, and in 1974 the
Safe Drinking Water Act.
Extra Info
★ Thinning out a forest can help to reduce the
water demand by the trees, but increases
erosion and produces holes/gaps in the canopy
which removes shade and shelter for other
forest species.
★ Maintaining a developed understory layer to
protect soil moisture reduces the water
requirements of forests, even if many trees are
cut down.
Bibliography
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http://csfs.colostate.edu/pages/forests-management.html
http://www.pefc.org/forest-issues/sustainability/water
https://www.nc-climate.ncsu.edu/edu/k12/.watercycle
http://www.anr.state.vt.us/anr/envrpts/Env99/waterfor.htm
http://www.ecokids.ca/pub/eco_info/topics/forests/threats.cfm