Natural Vegetation Flashcards
0
Q
Describe the climate of tropical rainforests by referring to the temperature.
A
- High temperature throughout the year. very small range.
- sun is always high in the sky directly over head.
- days and nights are almost equal in length.
- temp rarely below 22 an rarely above 32. due to clouds.
1
Q
Where do tropical forests occur on earth?
A
- it is located within 5 degrees N and S of the equator.
- this region is called the equatorial regions.
- e.g. Amazon, Congo, coastal regions of central west africa.
- the Equatorial line is broken by the Andes, East african plateau.
2
Q
Describe the climate of tropical rainforests referring to the rainfall.
A
- annual rain exeeds 2000mm in the form of thunder storms.
- rain occur mostly in the afternoon.
- lot of humidity due to high morning evapouration .
- nog n klop strooi wat ek nie weet hoe sy dit gaan vrae nie.
3
Q
Describe the natural vegetation of tropical rainforests.
A
- Most luxuriant vegetation system in the world.
- trees has adapted to high temperature, heavy rainfall and continuous growing season.
- plants also had to adapt to local soil, flooding and compitition.
4
Q
Describe and explain the rainforest structures. ( 4 layers )
A
- Forest floor.
- gloomy twilight prevail.
- very little sunlight. few plants are able to grow well there.
- lots of decaying leaves.
- at river openings sunlight is able to penetrate the growth. - Under-canopy or shrub layer.
- grows beneath the canopy.
- mostly shrubs.
- top streching towards sunlight. - Forest of upper canopy.
- Wide crowns of trees interlock.
- roots stand above ground to anchor trees.
- The top branches turns into hanging gardens form orchids and ferns.
- they are non parasitic.
- lianas use large trees to support in their efforts to reach leaves. - Emergents.
- The tallest trees.
- 40m
- Stand above the rest of the forest.
- Branchless on lower parts.
- crowns take most light, heat and punishment from winds.
5
Q
Name the adaptations of the Rainforests vegetation.
A
- Can grow up to 40m for sunlight.
- Evergreen appearance. ( because the trees shed leaves at different times)
- Leave have drips to shed the heavy rainfall.
- larger leaves has ridges to drain away water.
- tree trunks are straight and branchless to the effort to grow tall.
- lianas use large trees for support to climb up to the canopy.
- the forest floor is dark and damp with little undergrowth..
- near rivers or in clearings dense undergrowth developes where sunlight can penetrate.
- large trees has buttress roots above ground for support.
6
Q
What is the importance of Rainforests?
A
- 1100 different species of plants in little more than a 1km square.
- contain huge variety of fauna and flora.
- provides timber, oil, medical herbs, fruits, rubber and livelihood for indigenous people.
- replenishes oxygen and absorbs carbon dioxide.
- returns huge amounts of water vapour back into the air.
- they control run off in areas with large rainfalls.
7
Q
What is deforestation?
A
- it is the cutting, clearing and removal of rainforests for system like pasture, cropland or plantations.
8
Q
Why is the tropical rainforests being cleared?
A
- Demand for wood.
- mining reasons.
- oil and gas extractions.
- Cattle ranching
- agriculture like cash crops.
- for new settlers.
9
Q
Name a three ways how to harvest and regenerate forests for commercial forestry. ( moeilik om n vraag te maak. )
A
- Selection - small paches of trees cut. new seeds planted in clearing.
- Clear cutting - cutting down large area in one operation. forests either grows back or planted with seedling.
-Shelter wood - First cut the emergents, allow under canopy to grow tall to the point where they can be harvested as well.
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10
Q
Name a few ways how the tropical forests can be substained in an area cleared for agriculture.
A
- plantation forestry: trees are planted on areas which were cleared. due to climate, the forests will grow back fast and can be harvested again.
- Forest reserves: areas are designated as national parks or game reserves.
- Agro-forestry: indigenous people survive by planting food crops in frested areas without clearing vast areas.
- Shade cropping: an over-story of trees is used to provide shade for crops.
11
Q
Where does Tropical savanna occur?
A
- between tropical rainforests and deserts,
- central parts of continents.
12
Q
describe the climate of savannas.
A
- Alternation wet and dry seasons.
- frequent thunderstorms during summer rain season.
- winters are cold and dry.
- much greater range of temp that rainforests.
13
Q
Describe the vegetation of the savanna.
A
- where it merge with tropical rainforests, vegetation is dense woodland with patches of tall grass.
- mostly typical savanna grasslands with scattered trees.
- most common trees are acacia.
14
Q
Describe the dry and wet seasons of the savanna.
A
Wet season:
- Hot, wet conditions with grasses growing quickly.
- periodic fires altered the vegetation of the regions.
- trees and shrubs have been removed for fuel and cooking.
Dry season:
- Scattered deciduous trees loses leaves.
- Grasses turns yellow.
- ground becomes dusty brown colour.
