Rainforests Flashcards
What is are epiphytes
Plants that grow on other plants.
there are many in the rain forest
they get access to light by growing high up on other plants but dont have access to nutrients in soil. They dependent on rainfall to provide water and nutrients
Lack of wind near rainforest floor effect on plants
lack of wind means many plants rely on bees, butterflies, or other animals for pollination
Tropical rainforest layered structure
Emergents
Main canopy
Under canopy
Shrub layer
What is emergents layer
Tallest trees which poke out of the main canopy layer
Straight trucks and only have branches and leaves at top where they can get light
What is main canopy layer
A continuous layers of trees
like emergent with leaves at the top. the dense layers of leaves shade the rest of the forest
What is under canopy
younger trees that have yet to reach their full height
Only survive where there are breaks in the canopy to,let a little bit of light through
What is shrub layer
nearest to the ground where its quite dark
have large broad leaves to absorb as much light available
Plant adaptations
epiphytes
Pointed tips (called drip-tips) channel the water to a point so it runs off. This way the weight of water doesnt damage plant and no stand of water for fungi and bacteria to grown in rotting plant
waxy layer to help leaves repel rain
lianas. these plants cling their stem and climb up trees to sunlight
Deforestation is a direct threat to tropical rain forests why
Subsistence farming
Commercial farming
Mining
Demand for biofuels
HEP
Subsistence farming and type
subsistence farmers, making enough food for their own family’s survival.
Slash and Burn Farming (also know as shifting cultivation) farmers clear small areas (2 hectares) by cutting and burning the trees
the ash from burning adds nutrients to the soil
the land is farmed for food for 5 years but after that the soil becomes infertile and the farmers move to the next area
Commercial farming
Forest is cleared to make space for cattle grazing or for palm oil or soy plantation
Why mine in tropical rainforest
minerals (e.g gold) are often found in tropical rain forests. Explosives are sometimes uses to clear earth or deep pits are dug to reach the deposits
Carajas complex is the largest iron ore mine on the planet. The rainforest has had to be cut down to access the resources
Demand for biofuels
Growing the crops needed to make biofuels take up large amounts of land. Trees need to be cut down
Nutrient Cycle
way nutrients move through an ecosystem
nutrients are stored in 3 ways:
- living organisms (biomass)
- dead organic material, e.g fallen leaves (litter)
- the soil
In this cycle nutrients are transferred between these three stores
Deforestation environmental impact
With no trees to hold the soil together, heavy rain washes it away (soil erosion). this can lead to landslides and flooding
Without a tree canopy to intercept rainfall and tree roots absorb it, more reaches the soil. This can reduce fertility as nutrients are washed away out of reach for plants
Trees remove CO2 from atmosphere. Also burning vegetation to clear forest produce CO2. So deforestation means more CO2 in atmosphere which adds to greenhouse effect
Indirect threat climate change effects to tropical rainforest.
In some areas temperature is increasing and rainfall is decreasing which leads to droughts
Droughts lead to ecosystem stress, plants and animals living in tropical rainforests are adapted to moist conditions. So many species die in dry weather. Frequent or long periods of drought could lead to extinction of some species
droughts can also lead to forest fires which can destroy large areas of forest
Rates of Deforestation increasing in some areas why
e.g nigeria and Borneo
Poverty
Population growth and poverty means there are many more small-scale subsistence farmers and greater use of fuel wood (as other are expensive), e.g in nigeria
Economic development
road and rail projects to promote development open up areas of the rainforest to logging, mining and farming, e.g Borneo had huge palm plantations for biofuels
What is HEP
Many tropical rainforests have large rivers. Building dams to generate hydroelectric power (HEP) floods large areas of forest behind the dams
Rates of Deforestation decreasing in some areas why
e.g costa rico and brazil
international condemnation. puts pressure on companies by naming those that are involved in deforestation. many companies have pledged zero-deforestion as a result
monitoring systems. e.g Global Forest Watch (GFW) provide satellite data to track forest loss. this means authorities can act quick and stop illegal logging
sustainable forest management
forest is used in a way the prevents long-term damage whilst allowing people to benefit from resources it provide in the present and in future
e.g selective logging and replanting
sustainable forest management/economic
expensive so it can be difficult to persuade private companies to adopt sustainable methods
sustainable management are only seen in longterm. this affects poorer countries who need income immediately
sustainable forest management/environment
trees that are replanted for logging in the future can be very slow growing. companies may chop down more natural forest whilst they are waiting for new trees to mature
even selective logging can damage lots of trees in the process of removing that target tree
sustainable forest management/social
generally provides fewer jobs for local poeple than conventional forestry so many locals wont see the benefits some many turned to illegal logging
alternative to forest protection
making a living of the forest
e.g ecotourism and sustainable farming
