Notes on Natural Vegetation

1. With reference to examples, describe:
(a) The distribution of tropical rainforests
(b) The diversity of plant species in tropical rainforests
(a) The distribution of tropical rainforests
• Spreads like a green belt around the Earth.
• Found between the Equator and 10° to 20° North and South of the Equator.
• Examples include Amazon basin in South America and Congo basin in Africa.
(b) The diversity of plant species in tropical rainforests
• High biodiversity.
• Over 400 species per hectare.
• Mostly hardwoods such as Meranti, Mahogany, Seraya, Ebony and Balsa.

2. Describe the structure of a tropical rainforest.
The top canopy is between 30 – 50 m in height. The tee trunk is straight and has buttress roots. The middle layer is between 10 – 30 m. The canopy is almost continuous and many creepers and ferns can be found in this layer. The undergrowth is very sparse. The ground is always damp and dark with very little sunlight. The trees are evergreen and had many different types of species.

3. Explain how trees in tropical rainforests adapt to the hot and wet environment.
• Tropical environment refers to areas with high annual temperatures and rainfall with no dry season.
• This encourages high growth rate in natural vegetation and high decomposition of fallen leaves and branches.
• Leathery leaves with drip tips allow excess water to flow off easily.
• Trees are tall (more than 40 m) to compete for sunlight.
• Roots are shallow as they do not need to grow deep into soils to get water and minerals. • Buttress roots to support the tall trees.
• Fruits and flowers are colourful and sweet smelling to attract agents of pollination
4. With reference to examples, describe
(a) The distribution of mangrove forests.
(b) The diversity of plant species in a mangrove forests.

(a) They are found along tropical and subtropical coastal areas. Usually found along low-lying, sheltered coats with muddy and waterlogged land such as in Australia, Southeast Asia and West Africa.
(b) They have fewer species than tropical rainforests. The dominant species are generally those that have breathing roots or prop roots to enable them to survive in water logged environments. Examples include the red mangrove and white mangrove.

5. Describe the structure of a mangrove forest.
The trees can grow to a height of 2m to 40m. There are horizontal zones of mangrove species - saltwater mangrove trees grow near the coast but freshwater mangrove trees grow further inland
fewer species as as not many plants can adapt to saline water and oxygen deficient
soil. The four main species which are known as halophytes are Avicennia, Sonneratia, Rhizophora, Bruguiera.
6. Explain how trees in mangrove forests adapt to tropical and waterlogged environment.• The leathery leaves with drip tips allow water to flow off easily.
• Some have special salt glands to prevent the build up of excess salt.
• The excess salt is excluded by the roots and stored in the older leaves and discarded when the leaves wither and fall off.
• The trees have prop roots to help them anchor into the muddy ground.
• Others have aerial roots to take in oxygen from the atmosphere directly.

The fruits of the tree are tube-like and they start to germinate while they are still on the tree.
They have pointed ends to anchor them to the mud when they fall into the ground so that they will not be washed away by the tides before they can take root.

7. With reference to examples, describe the distribution of tropical monsoon forests.
They are found mainly in areas from latitude 15° to just beyond the Tropic of Cancer and the Tropic of Capricorn. It is dominant in areas which experience the tropical monsoon climate, as Bangladesh, Thailand and regions such as the southern part of China.

8. Describe the structure of a tropical monsoon.

The forest has three layers: the top canopy layer consists of trees with height varying from 25m to 35m. There are lianas and epiphytes on the trees. The second layer is made up of shorter trees of about 15m tall and the third layer is the dense undergrowth of shrubs and herbs. It is less dense than the tropical rainforest.

9. Explain how trees in the tropical monsoon forest adapt to the tropical monsoon climate.
• They have fewer species than the tropical rainforest due to the dry season.
• The trees are spaced further apart and are shorter due to the lower amount of rainfall received.
• The more scattered forest results in the development of thicker undergrowth.
• They have similar Ieaves like the tropical rainforest to help drain off the excess water during the wet season.
• These deciduous trees shed their leaves during the dry season to prevent excess water loss
• They have deep roots to enable them to tap the underground water during the dry month.

10. With reference to examples, describe the distribution of temperate coniferous forests.They are found mainly between latitudes 40° and 65° and mostly in the northern hemiisphere namely in North America, in a wide belt across Canada, Siberia, northern Europe and n~ region of Asia.
11. With reference to the climate, explain the diversity of species in a temperate coniferous forest

• The climate has a relative short growing season so there are very few species coniferous type of vegetation.
• Sometimes an entire forest may have only one or two species.
• The species are mainly softwood such as spruce, pine, cedar and fir.
12. Explain how trees in temperate coniferous forests adapt to the temperate environment.• The trees are cone-shaped and have compact, down-sloping and springy branches which allow the snow to slide off easily without breaking the branches.
• The leaves are needle-like to reduce the loss of moisture due to the low rainfall. The leaves are also drought-resistant and can store water for the long cold winter when the ground is frozen.
• The trees have thick barks to protect them from the severe winter winds and summer fires.
• The fruits are contained in cones which protect them from the long harsh winter.
• Coniferous trees have shallow roots to help the trees absorb water from the melting of the top soils.

13. Describe the positive impact of forests on the environment.

• Forests are important catchment areas.
The water, soils and trees in catchment areas are renewable resources. The quality and quantity of the water in the lakes and rivers depend on the size and quality of the catchment areas.
• Forests are also important in controlling flooding in the lowlands. They intercept the rainfall and decrease the amount of surface runoff.

14. Describe the social and economic benefits a forest has on a country and its people.
• Economic benefits: timber (hardwood) is used to manufacture a variety of timber-related products. The timber trade is estimated to be worth more than US$200 billion a year. Softwoods are also used for housing, construction, furniture, flooring and production of paper.
• Social benefits: Forests are popular for outdoor activities and relaxation such as camping, fishing hiking and gaming. In less developed countries, timber is often used as fuel for keeping warm and cooking.
• Forests also produce other equally valuable products such as medicinal and cosmetic products. The cinchona plant is used to produce quinine, a medication for malaria.
15. With reference to a named location,
(a) Explain five causes of deforestation in a tropical rainforest.
(b) Describe three problems caused by deforestation.

(a) Explain five causes of deforestation in a tropical rainforest.
• Settlements: The need to build settlements for the large population. For example, Brazil is trying to resettle people from densely populated cities such as Rio de Janeiro to less densely populated parts of the country. Similarly, a transmigration policy in Indonesia resettles poor and landless Indonesians from densely populated islands such as Java and Bali to less populated islands such as Kalimantan and Sulawesi.
• Rapid Urbanisation: Rapid urbanisation requires large tracts of land to be opened up for development of infrastructure such as transport system, e.g. the Transamazonian highway across the Amazon forest. Forested lands are also cleared for building of housing, schools and many other facilities.
• Agriculture: In Brazil, farming has resulted in large-scale damage to the Amazon forest. Commercial farming, cattle ranching alone accounts for 80 per cent of the deforestation of the Amazon forest. Commercial crops such as sugar cane, coffee and more recently soya beans are grown on land once occupied by the rainforest. The collective actions of subsistence farmers have also brought much damage to the forest. These farmers are poor and they could not keep up the productivity of the land given to them by the government. Once the land is not fertile, they will go deeper into the forest to open up more lands.
• Forest Fires: Forest fires burn up thousands of square kilometres of Amazon forest every year. These fires can be started by natural or human causes. The situation is worsened when forest land is also burnt to create farmlands.
• Economic Development and Debt Repayment: Countries like Brazil need to reduce its huge national debt. As a result, Brazil needs to exploit its natural resources to pay off its debt. The world demand for forest products such as tropical hardwoods is worth US$8 billion a year. Therefore extensive commercial logging and over logging, both legal and illegal, are difficult to control in Brazil as it is a form of lucrative business. The forest is also rich in minerals. Another problematic area is the mining for oil. Over the years the mining for oil has enabled Manaus to become a city and an industrial centre. The need for cheap fuel such as hydroelectric power has seen huge areas of rainforests destroyed such as the building of the Itaipu Dam on the Parana River which has flooded and destroyed 700 sq km of rainforest.

(b) Describe three problems caused by deforestation.
• Global Warming: As forests such as the Amazon forest helps to significantly absorb carbon dioxide and release oxygen into the atmosphere, the removal of trees can affect the atmospheric conditions. Deforestation can result in an increase of carbon dioxide in the atmosphere as less is absorbed by plants which will lead to global warming.
• Soil Deterioration: Trees help to improve the soil fertility by absorbing nutrients into the roots before these nutrients are dissolved and removed from the soil by water flowing downwards. When the trees die, they decompose and the nutrients are released back into the soils. However, deforestation takes away this storage mechanism. Thus, the topsoil is no longer protected and causes increased soil erosion to take place.
• Floods and Water Quality: When land is cleared, interception of rainfall by the trees is reduced and surface runoff increases. This will lead to flooding in the lower areas. Furthermore, the topsoil together with its decomposed materials washed off by the runoff is deposited on the river beds. Thus affecting the quality of the river water as these decomposed materials may decrease the pH level and change the living environment of the aquatic life.
• Air Pollution: Forest fires have created haze and smoke clouds which have caused airports to close and have also affected many people with respiratory illness. An example is the 1997 haze caused by the forest fires in Sumatra and Kalimantan which affected countries like Singapore and Malaysia.
• Loss of Biodiversity: Deforestation has also led to the extinction of flora and fauna, many of which have yet to be discovered. Their destruction and eventual extinction will cause a reduction in biodiversity in the long run and lessen the chances of survival of the other living organisms.
• Impact on Inhabitants: Deforestation also disrupts the culture and lifestyle of the many tribes that live in the forest. As these groups are forced to resettle in the cities, their culture, knowledge and way of life will be lost. Many of them, like the Kayapo, can no longer survive by living in the forest.
16. "The effects of deforestation are mostly environmental." Do you agree? Explain your answer.No.
Economically, the survival of shifting cultivators, hunters and gatherers will be greatly affected as they are heavily dependent on the forest for their farmlands.
Socially, deforestation has also taken away land needed for recreation and relaxation.
Educationally, humans have lost a huge laboratory to discover and do their studies on flora and fauna that have yet to be discovered.

17. With reference to examples, discuss the effectiveness of measures taken by a government to manage a tropical rainforest.
Governments have tried to promote sustainable management of the forest. This will allow the use of the forest and its resources in a way and at a rate that maintains the biodiversity, vitality and regenerative capacity of the forest.

They have done this through the following measures:
• Selective cutting: This allows the cutting of only selected single or groups of trees that have met a certain criteria. For example, only trees of a certain minimum circumference can be cut and only a certain number of trees per hectare of forest can be harvested. However, this measure requires strict law enforcement and often, it is difficult to carry out such enforcement.
• Establishment of laws and policies: Some governments have issued clearing permits and established measures against illegal loggings. In 1988, the Brazilian government withdrew its financial support and tax incentives in order to limit the clearing of forest for new cattle ranches. However, illegal logging remains a problem, accounting for 80 per cent of logging activities because of weak enforcement and corruption
• Agro-forestry: Agro-forestry is another measure to help reduce deforestation by growing trees in farms. For example, in 2005, Brazilian cedar and mahogany were grown on almost 10 000 hectares of land near Manaus. However, such a project requires a lot of capital and can only be undertaken by big companies and with government support. There is also a long period of waiting for the trees to mature before harvesting.
• Conservation: Efforts have also been made to set aside forest lands as reserves. Currently, only 4 per cent of the Amazon rainforest is protected as environmental reserves. Another 20 per cent has been set aside as tribal reserves. This is only effective if the tribal groups such as the Amazonian Indians do not sell off the land to commercial investors looking to exploit the forest.

18. Explain why it is difficult to put into practice conservation of the Amazon Basin?
The Amazon Basin is shared by many countries , such as Brazil, Venezuela, Peru, Columbia and Ecuador, and each has vested interest in conserving the Basin. It is difficult to come together to decide on a single plan to conserve the forest.
Many of the countries need to export timber to exchange for much needed revenue for the development of the countries. To stop or reduce the rate of deforestation would mean less revenue and economically, these countries would suffer.
Secondly, there is also a high demand for timber products from many developed countries. Therefore, to satisfy world wide consumer demand for timber, more forest are being destroyed.
Thirdly, in many developing countries where timber industry is important, the government authorities are usually not effective in implementing and enforcing strict rules and regulations to prevent the clearing of the forests indiscriminately. In many cases, there is widespread corruption among government officials which prevent the government from carrying out the laws effectively.
Fourthly, with increasing population, there is increasing demand for land for residential, industrial and agricultural development. As a country becomes more developed, infrastructure such as highways and bridges need to be built in order to improve accessibility among settlements.
Lastly, the practice of selective cutting which can help to minimise damages to flora and fauna in a forest is more costly to be implemented as compared to clear cutting. Hence most timber companies practice clear cutting as it is far more convenient and less costly.

Case study of deforestation in Kalimantan:
Deforestation in Kalimantan
• Rapid rate of deforestation for the last 25 years.
• Between 2000 and 2002, deforestation rose to 12 000 square kilometres a year in Kalimantan.
• The rapid deforestation is brought about by human activities like agriculture, mining and logging.

Causes of Deforestation in Kalimantan

Agricultural landuse• One cause of deforestation in Kalimantan is the increase in demand for land due to increase in agricultural activities.
• More people was moved from Kalimantan to ease overcrowded area like Java and Sumatra.
• There was also a demand of landuse from plantation companies especially for the planting of oil palms.

Growth of settlements· As population increases in Kalimantan, more land is cleared for housing.
· More people are moving to urban settlement such as towns and cities to live and work.
· This expansion is known as urbanisation.
· Balikpapan in East Kalimantan is an example of a town that is affected by urbanisation.

Improved transport networks· Transport networks like road and railways are constructed to link settlements in Kalimantan.
· The transport network allow access to previously remote forested areas in Kalimantan.
· This has made it easier for people to destroy more areas of the rainforest.

Growth of Industries
o Heavy logging has resulted in West Kalimantan
· loosing an average of 1 656 square kilometers of forest each year.
Mining companies has caused loose soil to wash away into a nearby river. Use of chemicals has led to the poisoning of animals.

Forest fires· Forest fires caused the destruction of 23 750 square kilometres of rainforest in Kalimantan between 1997 and 1998.
· Vegetation debris such as tree stumps, branches, twigs and leaves catch fire easily during the dry season, causing forest fires.

Problems caused by deforestation
Loss in biomass
§ The Earth’s biomass refers to the combined weight of all organisms which is measured in terms of kilocalories of stored energy.
§ The reduction of biomass in Kalimantan reduces its ability to support plant and animal life.

Loss of biodiversity
· The Kalimantan rainforests are home to more than 380 bird species and 10 000 plant species.
· Due to deforestation, the biodiversity of plants and animals are reduced which leads to extinction of species.
· Question: Give an example of an endangered animal from the Kalimantan forest.

Changes in the nutrient cycle
· The removal of vegetation following deforestation results in the loss of leaf litter and affects the nutrient cycle.
· Soils are leached due to the absence of roots.
· Absorption of rainwater is reduced , the soil becomes infertile and cannot support vegetation.

Changes in quantity of water
· When trees are removed, less transpiration takes place.
· Cloud formation is reduced and there is low rainfall.
· Flood could also be triggered by deforestation.

Changes in quality of water
o When rainforests are cleared, soil is eroded and is washed away easily by rain into nearby rivers.
o This increases the sediment level of the rivers and makes the water muddy.
o The sediment changes the pH level, making the water acidic.
· Question: What happens to aquatic life when the water becomes acidic?

Air pollution
§ Huge forest fires cause dust and smoke to be suspended in the air. This results in haze.
§ Haze can cause people to suffer from health problems.
§ It will indirectly affects the tourism industry.

Managing the Rainforets in Kalimantan
· The Ministry of Forestry(MOF) - MOF issues licences to timber companies and monitor their activities.
· Community involvement - MOF involves local people such as local governments, native people and villagers.
· Sustainable management -refers to the careful use of resources, such as forests to allow people to continue using the resources in future.
Four Main Policies of MOFAfforestation and reforestation
o Afforestation - afforestation refers to the planting of trees on areas that were not covered with forests.
o Effectiveness, success and limitations of measures - significant restorations of forests have been made possible. rates of which forests are restored are slower than rates at which they are cleared.

Controlled logging
· Controlled logging - controlled logging involves careful management of forests that are being logged.
· Effectiveness, success and limitations of measures - selective cutting minimises soil erosion. However it is difficult to monitor logging and detect illegal logging activities. A significant variety of plant species could be damaged in the process.

§ Conservation refers to the careful use of resources to protect forests from destruction. For example forests could be set aside as nature reserves.
§ Effectiveness, success and limitations of measures - Betung Kerihun Nature Reserve is the largest reserve in West Kalimantan. However Illegal logging activities are difficult to monitor.

Controlling forest fires
· Forest fires - Indonesian government has implemented a policy that makes it illegal to clear forests by burning. Campaigns to discourage the local people from using fire to clear forests for farmland.
· Effectiveness, success and limitations of measures - some plantation companies continue to burn forests because it is the cheapest way to clear land.

Our Role in Forest Conservation
• Simple actions such as making use of both sides of a piece of paper can help to reduce wastage of forest resources.
• To help reduce deforestation in other countries, we can buy furniture made of timber from sustainably managed forests.

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