Chapter 4 : Forest As a Resource

Preventing floods

(by reducing the likelihood of river from overflowing its banks)

- soil that is deposited on river bed makes the river bed shallower & reduces river's ability to contain water.

- Hence, likelihood of flooding is higher when forests are cleared.

Protecting Coasts

- Mangrove forests protect coastal areas from storms & strong waves.

Natural treatment of waste water

- Mangrove forests are able to process waste materials carried by water from streams & rivers.

- Waste materials : vegetation, dead animals & fish, household rubbish & human waste.

- Roots of mangrove trees help trap waste materials & filter the water before flowing into sea.

- Soil in mangrove forests contains bateria, can break down biodegradable wastes & convert them into nutrients for mangroves.

Habitat for Flora(plants) and Fauna(animals)

A habitat is the environment where plants & animals live in.

Many interesting species are found in different types of forests.

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

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

Providing Useful materials

1. Timber & other sources of building materials

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

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

2. Fuelwood & Charcoal

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

they rely on fuelwood as their main source of energy.

3. Food

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

- hervest edible ferns, such as midin

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

4. Medicines

(some plants in forests have medicinal value)

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

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

5. Chemicals

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

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

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

Habitat for people

- Mostly are hunter-gartherers.

- They do not practise any type of farming & are fully dependent on forest for their source of food.

Recreation

- forests provide people with a place to carry out recreational activies, such as hiking & camping.

- Examples: In singapore, National Parks Board (NParks), which manages nature reserves & parks, has provided boardwalks & walking trails to make forest accessible to public.

Research & Education

- Forests are places for conducting scientific research.

Example: Scientists study forest plants to develop new medicines & new varieties of crops.

- studying the interactions between forest animals & plants with environment.

Subtopic

Quality of water

How urban areas maintain quality of water?

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.

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

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

How forest maintain quality of water?

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.

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

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

Quality of Air

(Replenishing oxygen & removing carbon dioxide)

Forest = "Green Lungs of the Earth"

- During photosynthesis, trees & plants in the forest take in carbon dioxide from the amosphere.

- Reducing the amount of carbon dioxide in the amosphere prevents gobal temperatures from rising & helps to regulate temperature of the Earth.

How vegetation replenishes O2 supply & removes CO2 ?

1. Animals release CO2 into amosphere during respiration.

2. Trees & plants absorb CO2 during photosynthesis.

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

Quality of soil

(Maintaining nutrients in soil)

- roots of vegetation hold the soil particles together

- prevent rain or wind from removing the soil.

- Hence, preventing nutrients from being removed by soil erosion would maintain the quality of soil.