Back

Man-Land Relationship

- DESERTIFICATION
- <TROPICAL RAIN FOREST
- Soil DEEGRATION Cleaned
-

Study Integrated pg.175.

1. Read pg.175 Fig.7.27, name the very severe and sever regions of desertification. Sahel, Africa, China, USA

2. Match the answer of Q1 with Fig.9.29 on pg.207 and Fig.7.2 on pg.163, describe the locational characteristics of these regions. Desertification region = regions of high rainfall variability (phy. Constraint) = semi-desert regions

3. Explain the quotation from the textbook.

a. “The semi-arid lands are fragile environment?”

fragile = easily changed by human & phy factors

b. The main cause of desertification is “people’s mismanagement of their resources.”

exploitation > carrying capacity of land = mismanagement
resources: water (limited)

4. Solutions towards desertification

a. Base on pg.176, Fig.7.28, what should be done to prevent desertification?

low rainfall => more rain (high technology, e.g. cloud seedling, artificial rain)
high evaporation => block the evaporation e.g. tent to cover the plant
overcultivation …. => change attitude by education, government subsidies
high pop => pop control
wind, rain, soil erosion => afforestation

5. Recently, the Chinese government decided to carry out new measures to tackle desertification.

i. What are the measures?

ii. Stop the harvest of 髮菜，冬虫草

iii. Why did the government carry out such measures?

decrease the coverage to protect the surface -> less wind, rain & soil erosion

desertification is very serious -> more drought => vicious cycle

6. Evaluate the effectiveness of such measures.

Ineffective:

- nomadic herders depend on it for $ as high pop growth -> great demand for food & $

- govt: no remedial actions/subsidies for nomadics

Tropical Rain Forest

Case: The forest of south-west Australia

Study Integrated pg.286-289.

1. Pressure on the forest (Fig.11.42)

a. Why is the forest under continuous stress?

high econ. Value -> lumbering
high demand of woodchips from Japan

b. What's the important of forest? Why do we need to protect the forest?

Importance of forest: homes for wildlife, own natural habitats/ ecosystem

Why?

decrease rapidly & takes long time to replant
maintain global climatic balance

2. What can be done?

a. Regeneration programme in the (karri) forest has faced lots of obstacles. What are the obstacles?

drought
large demand for forest -> shorten the regeneration programme

3. Evaluation

What can be done? (pg.289)	Evaluation/Difficulties	Possible in China?
Replanting	Takes long time	yes
Grow fast growing timber for quick return	Possible, if they know the techniques	Yes, under the technical help from govt
Agroforestry	Farmers don’t know how to maintain a balance	Farmers have great demand for food -> exploitation Unless with govt subsidies
Creation of National Parks, conservation parks and nature reserves	Protect the species (favour) But tourists -> Pollution Disturb ecosystem	No, increase Ind & Urb -> great demand for land

4. Conclusion

a. How to maintain a balance between development (production of paper) and protection of trees and wildlife (ecosystem)?

envir’ protection -> decrease pressure on land, slow down the speed of exploitation

selective cutting

secondary growth

THE FOREST FIRES IN INDONESIA 1997-98

I. Background

In the forest fires in Indonesia in 1997-98, 1.5 million ha have been burnt. They started in August 1997 and were only calmed by belated monsoon rains in mid-November. Unfortunately, the fires resurged in January 1998, became out of control in early March, and were again subdued by rainfall in June.

II. Causes

1. “The forest fires are the combined effect of human and physical (pg.252 Fig.2)

factors.” Discuss the validity of this statement. Which factor do you think is

more important? Why?

Human:

- ↑deforestation (shifting, lumbering, plantation, cattle ranching, firewood collector)

migrant farmers (free logging rights, license to burn forest -> paddy fields)
commercial exploitation
government: forest = green gold -> encouragement

=> ignored the bans of burning as it was the cheapest way to clear the forest

- shifting cultivators: not the main cause (since with lots of experience)

Physical:

less rainfall than expected, rain came in wrong season
El Nino => drought => flammable
Impact to citizen -> unprepared to dryness -> can’t change the attitude -> ignore the carrying capacity of the land (vicious cycle)

Human factor is more important than physical factor. Although El Nino effect triggered the drought, human mismanagement of land exist long & leads to such disaster.

III. Impact

1. “The forest fires in Indonesia represent an unprecedented ecological disaster.” What are the ecological impacts of hill fire to the ecosystem?

Abiotic	Atmospheric: - lower T C (6.5 C) as the haze block the sunlight (short term) - deforestation =>more Co2 => higher T c (long term) Hydrospheric : - acid rain - increase sedimentation -> change water pH Lithospheric: less organic matter decomposition => poorer soil, soil erosion
Biotic(Biospheric)	- blocking sunlight & poorer soil => lower productivity => less food - biodiversity loss (90% of canopy trees will be killed), change the habitats
Energy flow	- producers = lowest trophic level, beginners of food chain - less producers => energy flow is shortened or retarded.
Nutrient cycling	Refer to the diagram of nutrient cycling

2. What are the other negative impacts brought forward by the hill fires?

Economic loss: (US$1.38b):

airport closed because of low visibility, evacuation of citizen, closing of schools…..

Health damages:

high API (500): smoke pollution => respiratory diseases

IV. Evaluation

1. Why can’t the hill fire be stopped immediately?

physical barriers: remoteness, less roads, El Nino: no monsoon rain
economic problems: lack of resources, equipment
human factor: lack of organization and expertise, government faced other financial and economic problems too, i.e. low priority

2. Why is it important to preserve rain forest of the world?

TRF:

6% world’s total land, 2 million plant and species = large biomass, structural

complexity

regulate Co2 emission, maintain global T C balance

3. What lesson can be learnt from the hill fires to preserve TRF or to control hill fires in the future?

better management system (land use control)
tightening laws (control deforestation rate)
higher penalties (for illegal logging)
international aids ($ & technology)

EL NINO EFFECT

Refer to the textbook & the video.

I. What is El Nino effect?

El Nino is characterized by a large scale weakening of the trade winds and warming of the surface layers in the eastern and central equatorial Pacific Ocean. The exact formation of El Nino is still unknown.

II. Normal condition and El Nino condition

	Normal condition (pg.234 Fig. 9.71)	El Nino condition (pg.235 9.72)
Extent & location of surface water T C > 28 C => Why?	Small West Pacific Region As trade wind blows warm water westwards Peru: cold ocean currents	Large extent to East Pacific Ocean As trade wind weakens -> less upwelling cold water
Location of ITCZ	N	S
Position of rising air (low pressure region) => result	Near Indonesia -> heavy rain	Peru -> California => wet
Position of descending air (high pressure region) => result	Peru => dry	Indonesia => dry
Movement of cold water near South America => result	Upwelling => fishing	Inactive => no fishing
Overall climatic impact -Western Pacific -Eastern Pacific	West Pacific: Wet East Pacific: dry	West Pacific: dry -> drought -> hill fire East Pacific: wet -> flooding

III. Evaluation

1. How to know the coming of El Nino?

test sea surface temperature by buoys
less fishing in Peru

2. “El Nino can be both destructive and beneficial.” Discuss.

Destructive:

a. change global climatic balance

wet region (Indonesia) -> dry region => affect human activities
dry region (Peru) -> wet region => flooding -> landslide

b. Threatened the traditional human activity

e.g. mixed farming in Australia, fishing industry in Peru

c. Economic loss

decline of fishing, farming => unemployment

Ecological loss

no fish -> no food for sea bird (destroy the food chain)

Greenhouse effect becomes more serious: as less marine life to take up Co2 = more Co2

global warming

d. Affect our health

e.g. drought -> hill fire -> smog (e.g. Columbia: Air Pollution Index: >500 -> respiratory disease)

e. loss of life

crop failure/famine => no food/starvation

Constructive

a. nourish fishing industry in other regions (e.g. California)

b. change global climatic balance

less typhoon in certain regions, e.g HK (cooling of sea T C near West Pacific)

Conclusion

1. Is there any linkage between greenhouse effect & El Nino Effect? What is it?

A positive relation.likely exists.

More Co2 -> greenhouse effect -> Co2 being trapped in the lower atmosphere -> find ways to go -> go to ocean -> increase the T C of the ocean.

2. El Nino plays a significant role in affecting global climate. What should individual do in order to lessen the negative impact brought by El Nino?

Environment conservation -> decrease Co2

Related websites:

http://www.pmel.noaa.gov/toga-tao/el-nino-story.html

http://www.pmel.noaa.gov/toga-tao/ensodefs.html

Man-Land Relationship

decline of fishing, farming => unemployment

Ecological loss

no fish -> no food for sea bird (destroy the food chain)

Greenhouse effect becomes more serious: as less marine life to take up Co2 = more Co2

global warming