Deforestation Flashcards
How much of the worlds forests have been lost?
1/3 of the original forest area due to human activities
The loss of forests has continued but rate has dropped in the last 30 years
What does deforestation include?
Any activities that cause a reduction in forest area
List the causes of forest loss
Agriculture
Mineral extraction
Reservoirs
Urbanisation
Transport infrastructure
2 ways that agricultural expansion causes the loss of forests
- the growth of the local population increases the demand for food, so more land must be cleared for farming
-forest clearance for commercial cash crop agriculture-product taken to cities or exported
Give 2 examples of where agriculture has resulted in forest loss
Rainforest clearance in South America to grow sugar cane,soy beans or ranch cattle
Rainforest clearance in south east Asia to grow palm oil
How does mineral extraction result in forest loss?
Forests are cleared for mining and the associated infrastructure
It affects a relatively small total area, but can have important local impacts
How do reservoirs cause forest loss?
They can replace forests when they are created for public supply, irrigation or HEP
Expansion of HEP in South America has caused the loss of large areas of tropical rainforests
How has urbanisation caused forest loss?
Expansion of urban areas=direct loss of forest
It can reduce forest loss further because of a then increased demand for fuel and food
3 ways that transport infrastructure caused forest loss
- Area of forest lost by the construction of roads,railways, airports
2.roads and railways can create barriers for the movement of wildlife-cause population fragmentation - Improved transport systems increases availability and makes it easier for activities that further increase forest clearance e.g. agriculture
3 ways forests have been exploited that are unsustainable
For timber resources,fuel and livestock fodder
How have forests been exploited unsustainable for timber resources?
Softwood produced by conifers is often produced sustainable with replanting to replace harvested areas e.g. in Scandinavia & Canada
Hardwood species e.g. teak grow mulch slower so it is more difficult to commercially manage hardwood plantations because they take longer to produce, therefore hardwoods may come from mixed forests that are felled and not replanted
How have forests been been exploited unsustainable for fuel?
Wood=domestic energy source, especially important in LEDCs that cannot afford alternatives
In towns and cities there is more of a demand for charcoal that produces less smoke when burned
The production of charcoal, involves the partial combustion of wood with a shortage of air
Much of the energy value of the wood is lost in this process which increases the rate of forest clearance
How have forests been exploited unsustainably for livestock fodder?
Forests aren’t usually cleared to produce food for livestock
But in LEDCs, farmers may cut branches off trees if there is a shortage of ground-level grazing
If this exceed s the growth of trees then the forest may gradually be degraded and disappear
5 effects of deforestation
Loss of forest resources
Ecological impacts
Changes to hydrology
Impact on soil
Climate impacts
Loss of forest resources as an effect of deforestation
Forest products are renewable but they can be depleted
Deforestation stops their production completely
E.g. timber,fuel,fibres, medicine
