Deforestation Flashcards
How much of the worlds original forests have been lost due to human activities?
over 1/3
What are the 2 main causes of deforestation?
Deliberate removal of forests to make space for another land use
Unsustainable exploitation
What are the causes of forest loss?
Agriculture
Mineral extraction
Reservoirs
Urbanisation
Transport infrastructure
How does agricultural expansion cause the loss of forest? (2 main ways)
Growth of the local population increases demand for food more land cleared for farming
Forest clearance for cash crops where yield taken to cities or exploited
What are some real examples of forest clearance for agriculture?
Rainforest in South America to grow sugar cane and soya beans or cattle ranch
Clearance in SE Asia for palm oil
How does mineral extraction cause deforestation?
mining and its associated infrastructure affects a small area but have important local impacts
Land clearance for open pit
What is a real world example of deforestation for mining?
Copper and gold mines in Brazil
Why are reservoirs created?
Public supply
Irrigation
HEP
What is a real world example of reservoirs causing deforestation?
Expansion of HEP in South America causing large scale tropical forest loss
Yangtze in china
How does urbanisation cause deforestation?
Expansion of urban areas causes direct removal of forests
Demand is increased for fuel and food (more loss)
What is a real world example of urbanisation causing forest loss?
The mass expansion of Chinese cities like Beijing
Is the forest loss from transport infrastructure large?
No, relatively small
What sort of transport infrastructure may cause forest loss?
roads
railways
airports
What other impacts can transport infrastructure have on forests?
Road and rail can create barriers to wildlife movement (population fragmentation)
Improved transport systems increase accessibility- easier to take resources (felled trees agricultural produce)
What is a real world example of forest loss by transport infrastructure?
The development of HS2
What reasons may cause unsustainable exploitation of forests?
Timber resources
Fuel
Livestock fodder
Is soft wood production of timber sustainable?
Yes as generally replanting to replace harvested areas occurs in Scandinavia and Canada
What are some examples of soft wood?
Conifers- pine, spruce and fir
What are some examples of hard wood?
Teak and Mahogany
Why is sustainable management of hardwood plantations hard?
Hardwood grows more slowly than conifers meaning it may take longer to produce saleable crop so most comes from clear felled mixed forests
Where is demand for charcoal as fuel high?
In towns and cities as it produces less smoke
How is the production of charcoal causing unsustainable management of forests?
Involves partial combustion of wood with a shortage of air
Much of wood energy value lost increasing clearance to satisfy demand
What are the effects of deforestation?
Loss of forest resources
Ecological impacts
Changes to hydrology
Impact on soil
Climate impacts
How does deforestation cause a loss of forests resources?
Production of forests resources sustainable as long as trees not deforested (timber, fuel, fibre, medicines)
What are the ecological impacts of deforestation?
Reduced biodiversity
Loss of species
Fragmentation of remaining forest areas
How does deforestation change the hydrology of an area?
Reduced interception and transpiration
Increased run-off
What is an example of deforestation affecting hydrology?
Boscastle flood 2004 upland deforestation
What is the impact on the soil when deforestation occurs?
Reduced soil formation
Less DOM
Increased soil erosion
Less protection of soil by vegetation and leaf litter
Reduced soil organic matter
Reduced root binding
What is an example of the affect of deforestation on soil?
Forest clearance in the Amazon have led to increased surface runoff and more sediment in the Amazon river increasing turbidity and reducing biodiversity
What are the climate impacts of deforestation?
Reduced albedo
Reduced carbon sequestration and carbon reservoir
Reduced rainfall downwind
What countries have large scale tree planting projects?
China
Cuba
Bhutan
What are the features of a sustainably manged forest?
Harvesting rates below MSY
Mixed species plantations
Indigenous species
Mixed age structure
Selective logging
How must harvesting rate be controlled in woodland to ensure sustainability?
Resource removal must be no greater than maximum sustainable yield
How can sustainability of woodlands be manged with mixed species plantations?
wildlife biodiversity increased by growing multiple species because there is an increase in food choices, inter-species relationships and niches
How can sustainability be increased in forests by planting indigenous species?
if indigenous species are cultivated its more likely that other indigenous species will benefit e.g. birds and insects
How does mixed age structure increase sustainability of forests?
produces greater diversity of abiotic factors (light levels, temperature and wind velocity) , potential to increase biodiversity
When is selective logging used?
In mixed species plantations or natural forests where trees are ready at different times
What are the issues with selective logging?
More expensive due to being more labour intensive
What are the benefits of selective logging?
Maximum benefit from forest timber resource over time
Good for wildlife as removal creates small clearings (smaller impact on survival of remaining wildlife population)
Wildlife doesn’t have to move far to find new habitat
