类别 全部 - vegetation - soil - air - water

作者:Chocolatez Luvable 12 年以前

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Chapter 4 : Forest As a Resource

Forests play an essential role in maintaining the quality of soil, water, and air, which are crucial for sustaining life and environmental balance. The roots of vegetation in forests help to keep soil particles together, preventing soil erosion and maintaining soil quality.

Chapter 4 : Forest As a Resource

Chapter 4 : Forest As a Resource

1. Role of forests (Maintance)

Quality of soil
- Hence, preventing nutrients from being removed by soil erosion would maintain the quality of soil.
- prevent rain or wind from removing the soil.
- roots of vegetation hold the soil particles together
(Maintaining nutrients in soil)
Quality of Air
How vegetation replenishes O2 supply & removes CO2 ?

3. Trees & plants release O2 & replenish Earth's oxygen supply.

2. Trees & plants absorb CO2 during photosynthesis.

1. Animals release CO2 into amosphere during respiration.

- Reducing the amount of carbon dioxide in the amosphere prevents gobal temperatures from rising & helps to regulate temperature of the Earth.
- During photosynthesis, trees & plants in the forest take in carbon dioxide from the amosphere.
Forest = "Green Lungs of the Earth"
(Replenishing oxygen & removing carbon dioxide)
Quality of water
How forest maintain quality of water?

3. Hence, water collected in river is of better quality as it contains few soil particles & impurities.

2. Vegetation cover intercepts the rainwater & reduces the speed & flow of rainwater on ground. This prevents soil particles from being washed into river.

1. When rains, soil layers help to filter impurities found in rainwater by trapping them between pore spaces. Then, rainwater seeps underground to form groundwater.

How urban areas maintain quality of water?

3. As water in drains & canals contains more sediments & impurities, quality of water is poor.

2. Rainwater flows into drains & canals & eventually into the sea.

1. Urban area usually covered with concrete surfaces which don't allow water to seep through. More rainwater flows quickly over concrete surfaces & carries along with any impurities found on ground surface.

3. Uses of forests

Research & Education
Subtopic
- studying the interactions between forest animals & plants with environment.
Example: Scientists study forest plants to develop new medicines & new varieties of crops.
- Forests are places for conducting scientific research.
Recreation
- Examples: In singapore, National Parks Board (NParks), which manages nature reserves & parks, has provided boardwalks & walking trails to make forest accessible to public.
- forests provide people with a place to carry out recreational activies, such as hiking & camping.
Habitat for people
- They do not practise any type of farming & are fully dependent on forest for their source of food.
- Mostly are hunter-gartherers.
Providing Useful materials
5. Chemicals

- In coniferous forests, resin is extracted from pine & fir trees.

- Sap of mangrove trees in East Africa is used to make black dye.

- Examples: bark of Rhizophora from mangrove forests provides tannin (a chemical used to treat leather).

4. Medicines

- cough syrup, made from bark of Eastern White Pine tree found in Coniferous forests.

- Examples: Quinine, a drug for treating malaria, is extracted from Cinchona tree (originates form Brazilian rainforest)

(some plants in forests have medicinal value)

3. Food

- hunt animals living in the forests, such as wild deer for meat.

- hervest edible ferns, such as midin

- harvest sago, which is high in starch from sago palm for food.

2. Fuelwood & Charcoal

they rely on fuelwood as their main source of energy.

-In LDC such as Asia & Africa, people gather wood for cooking & heating.

1. Timber & other sources of building materials

Examples: chengal & meranti trees in tropical rainforests, pine trees in coniferous forests are logged & used to manufacture furniture.

Timber is used to manufacture furniture & paper, and to construct buildings.

2. Role of forests

Habitat for Flora(plants) and Fauna(animals)
Many interesting species are found in different types of forests.

2. Grizzly bears are found in Coniferous forests of North America.

1. Tiger & rare species of orchids are found in Tropical rainforests of Peninsular Malaysia.

A habitat is the environment where plants & animals live in.
Natural treatment of waste water
- Soil in mangrove forests contains bateria, can break down biodegradable wastes & convert them into nutrients for mangroves.
- Roots of mangrove trees help trap waste materials & filter the water before flowing into sea.
- Waste materials : vegetation, dead animals & fish, household rubbish & human waste.
- Mangrove forests are able to process waste materials carried by water from streams & rivers.
Protecting Coasts
- Mangrove forests protect coastal areas from storms & strong waves.
Preventing floods
- Hence, likelihood of flooding is higher when forests are cleared.
- soil that is deposited on river bed makes the river bed shallower & reduces river's ability to contain water.
(by reducing the likelihood of river from overflowing its banks)