Topic: Role of Forest

Pogramme: M.Sc.(Environmental Science) Course: Natural Resource Management

Semester: II Code: MSESC2003C04

Note: These materials are only for classroom teaching purpose at Central

University of South Bihar. All the data/figures/materials are taken from several

research articles/e-books/text books including Wikipedia and other online

resources.

� A forest is a type of ecosystem in which there is high density of trees

occupying a relatively large area of land. An ecosystem is an ecological unit

consisting of a biotic community together with it’s a biotic environment.

� In the case of forest ,tress dominant the biotic landscape, although there

are also other plants and animals.

� There are many types of forest, such as tropical , evergreen, deciduous

and dry forest based on the climatic condition and types of trees present.

� Forests provide innumerable values to people, provide aspects that address

both physical needs as well as the internal nature of people.

1. Forest produces OxygenLets face it , we could not exit as we do if there were no trees. A mature leafy tree

produces as much oxygen in a season as 10 people inhale in a year. What many

people don’t realize is the forest also acts as a giant filter that cleans the air we

breath.

2 . Forests cleans the soil

The term phytoremediation is a word for the absorption of dangerous chemicals

and other pollutants that have entered the soil. Trees can either store harmful

pollutants or actually change the pollutant into less harmful forms. Trees filter

sewage and farm chemicals, reduce the effects of animal wastes, clean roadside

spills and clean water runoff into streams.

•Sounds fades in forests, making trees a popular natural noise barrier. The

muffling effects is largely due to rustling leaves, birds songs and just a few

well-placed trees can cut background sound by 5 to 10 decibels, or about

50 percent as heard by human ears.

•Trees muffle urban noise almost as effectively as stone walls.

4. Forest Slows Storm Water Runoff•Flash flooding can be dramatically reduce by forest or by planting trees.

•Underground water-holding aquifers are recharged with this slowing down

of water runoff.

•Tree roots are key allies in heavy rain, especially for low-lying areas like

river plains. They help the ground absorb more of a flash flood, reducing

soil loss and property damage by slowing the flow.

•Trees reduce storm water runoff by capturing and storing rainfall in

canopy and releasing water into the atmosphere .Trees helps to slow down

and reduce pollutant s by taking up nutrients and other pollutants from soil

and water through their roots .

•Trees ,acting as mini-reservoirs , control storm water at the source .

• The role of forests in the water cycle is to add water to the atmosphere

through the process of transpiration (in which plants release water from

their leaves during photosynthesis).

• This moisture contributes to the formation of rain clouds, which release

the water back into the forest. In the Amazon, 50-80 percent of

moisture remains in the ecosystem’s water cycle.

• When forests are cut down, less moisture goes into the atmosphere

and rainfall declines, sometimes leading to drought. These have been

made worse by deforestation, moisture generated by rainforests travel

around the world.

• Distant forests are therefore important to man everywhere according to

Clare and Janet (2013). Forests are a vital constituent of the global

water cycle, as they have a high evaporation rate, contributing to

atmospheric moisture circulation.

• Evapotranspiration is the combination of evaporation and transpiration

from vegetation to the atmosphere as forest canopy recycles water

more efficiently through evapotranspiration.

� Fig: Effect of Trees on Hydrological Cycle

� “Carbon sink” means that a forest stores more carbon dioxide than it releases into the atmosphere. To produce its food, a tree absorbs and locks away carbon dioxide in the wood, roots and leaves. Carbon dioxide is a global warming suspect.

• A forest is a carbon storage area or a “sink” that can lock up as much carbon as it produces. This locking-up process “stores” carbon as wood and not as an available ”greenhouse” gas.

7.Forest Clean the Air

� Forest help cleanse the air by intercepting airborne particles, reducing heat, and absorbing such pollutants as carbon monoxide, sulfur dioxide and nitrogen dioxide.

� Trees remove this air pollution by lowering air temperature, through respiration, and by retaining particulates.

� Plants are release huge amount of oxygen to the atmosphere and absorb carbon dioxide during the process known as photosynthesis.

� Shade resulting in cooling is what a tree is best known for. Shade from

trees reduces the need for air conditioning in summer.

� In Winter, trees break the force of winter winds, lowering heating costs.

� Studies have shown that parts of cities without cooling shade from trees

can literally be “heat islands” with temperature as much as 12 degrees

Fahrenheit higher than surrounding areas.

� A tree’s canopy acts like a parasol, blocking out up to 90% of the sun’s

radiation, and increasing the amount of heat that we lose to our

surroundings by cooling the ground beneath us.

� A windbreak (shelterbelt) is a planting usually made up of one or more

rows of trees or shrubs planted in such a manner as to provide shelter

from the wind and to protect soil from soil erosion.

� During windy and cold seasons, trees located on the windward side act

as windbreaks. A windbreak can lower home heating bills up to 30% and

have a significant effect on reducing snow drifts.

� A reduction in wind can also reduce the drying effect on soil and

vegetation behind the windbreak and help keep precious topsoil in place.

10.FOREST FIGHTS SOIL EROSION

� Erosion control has always started with tree and grass planting projects.

Tree roots bind the soil and their leaves break the force of wind and rain

on soil.

� Trees fight soil erosion, conserve rainwater and reduce water runoff and

sediment deposit after storms.

� Herbs, shrubs and trees in the forests hold the top most layer firmly by

their roots. This does not allow natural forces like wind and water to

carry away the top most fertile layer of the soil easily. Hence, forests

prevent soil erosion.

FIG: SOIL EROSION

� Forest are like giant sponges, catching runoff rather than letting

it roll across the surface, but they can’t absorb all of it.

� Water that gets past their roots trickles down into aquifers,

replenishing groundwater supplies that are important for

drinking, sanitation and irrigation around the world.

12.FOREST PAY IT FORWARD

� On top of flood control, soaking up surface runoff also protects

ecosystems downstream.

� Modern storm water increasingly carries toxic chemicals, from gasoline

and lawn fertilizer to pesticides and pig manure, that accumulate

through watersheds and eventually create low-oxygen “dead zone”.

� Some 300 million people live in forests worldwide including an

estimated 60 million indigenous people whose survival depends almost

entirely on native woods. Many millions more live along or near forest

fringes, but even just a scattering of urban trees can raise property

values and lower crime.

� Forest give us many natural medication, and increasingly inspire

synthetic spin-offs.

� The asthma drug theophylline comes from cacao trees, for one, while a

compound in eastern red cedar needles fights drug-resistance bacteria.

� About 70% of known plants with cancer-fighting properties occurs only

in rainforests, yet fewer than 1% of tropical rainforests plants have been

tested for medicinal effects.

� Even just walking in the woods can offer health benefits and a strong

immune system.

� The latter may be partly due to trees releasing airborne compounds

called phytoncides, which prompt our bodies to boost the natural killer

cells that attack infections and guard against tumors.

14.FOREST CREATE JOBS

� More than 1.6 billion people rely on forests to some extent for their

livelihoods, according to the U.N., 10 million are directly employed in

forest management or conservation.

� Forest contribute about 1 percent of the global gross domestic product

through timber production and non-timber products, the latter of which

alone support up to 80 percent of the population in many developing

countries.

� Forestry decision-makers need to promote the incorporation of forest

management in national and regional strategies, plans and programmes

related to river, watershed and groundwater management; and to work

with international and national organizations and institutions to increase

understanding of hydrological and environmental services of forests.

� Priority should be given to preventing forest degradation –including by

limiting grazing in forest lands –and promoting afforestation and

reforestation (including trees outside forests) for environmental

protection and local wood supply, especially fuel wood. Owing to the

critical condition of the forest and some people’s dependence on it for

their livelihoods.

� Countries should prepare source protection plans based on catchment

reforestation, including measures to control potential sources of

contamination such as septic systems and fuel tanks and identifying

alternative drinking-water sources in the event of contamination

CONCLUSION

� Forests and trees are very important tools in enhancing rainfall,

recharging ground water and preventing erosion and flooding.

� Since changes in land cover, including deforestation, can lead to

reduced evapotranspiration and enhanced surface temperatures,

disrupts hydrological cycle and decrease in moisture circulation, efforts

therefore should be geared toward aggressive afforestation,

conservation of the natural forest through strong policy formulation and

implementation to ensure ready water supply for the ever increasing

human population and mitigating hostile environmental condition

resulting from drought and dissertation

� https://www.researchgate.net/publication/310458060_IMPORTANCE_

OF_FOREST_AND_TREES_IN_SUSTAINING_WATER_SUPPLY_AND_RAIN

FALL

� https://wwf.panda.org/our_work/forests/importance_forests/

� http://www.mnn.com/earthmatters/wilderness-resources/why-forests-

are-important