Do now: Describe the following cycles of the tropical rainforest: The water cycle The nutrient cycle

Check your answers Rainforest water cycle The roots of plants take up water from the ground and the rain is intercepted as it falls - much of it at the canopy level. As the rainforest heats up, the water evaporates into the atmosphere and forms clouds to make the next day's rain. This is convectional rainfall. Rainforest nutrient cycle The rainforest nutrient cycling is rapid. The hot, damp conditions on the forest floor allow for the rapid decomposition of dead plant material. This provides plentiful nutrients that are easily absorbed by plant roots. However, as these nutrients are in high demand from the rainforest's many fast-growing plants, they do not remain in the soil for long and stay close to the surface of the soil. If vegetation is removed, the soils quickly become infertile and vulnerable to erosion. If the rainforest is cleared for agriculture it will not make very good farmland, as the soil will not be rich in nutrients.

Deforestation of the tropical rainforest Everyone – understand the concept, causes and impacts of deforestation within the tropical rainforest Most – will understand the varying global rates of deforestation Some – understand the value of the systems and how it will help maintain the globe against issues such as climate change. Deforestation of the tropical rainforest LO : understand the concept deforestation, causes, impacts and values of the ecosystem.

What is the scale of deforestation? There 62 countries with forests within their boarders. About half the worlds tropical rainforest has now been cleared. The scale and accelerating rate of the deforestation are truly worrying. Using the above graph describe deforestation on a global scale.

Global rate of deforestation is estimated to be: 1 hectare per second (10000m square) 60 hectares per minute (600000 m square) 86000 hectares par day (860 km square) 31 million hectares per year (310 000 km square)

Deforestation v forest degradation Human use of the rainforest doesn’t always lead to deforestation in many cases it can be forest degradation. This makes it difficult to determine the extent of deforestation. Forest degradation A degraded forest is a secondary forest that has lost, through human activities, the structure, function, species composition or productivity normally associated with a natural forest type expected on that site. Hence, a degraded forest delivers a reduced supply of goods and services from the given site and maintains only limited biological diversity. Biological diversity of degraded forests includes many non-tree components, which may dominate in the under-canopy vegetation. Secondary forest growth

Causes of deforestation Main causes – exploiting activities Logging Mineral extraction Energy development Illegal trade in wildlife Main causes of forest clearing Commercial farming – cattle Commercial farming – crops Road building Settlement & population growth

Draw a pie chart using the following data Cattle Ranching Small scale agriculture Commercial agriculture Logging Fires, mining, urbanisation, road construction and dams 60% 33% 1% 3% What to include: your graph need to have a heading and a key

Your graph should look like the one below

Using the graph below describe deforestation within the Amazon over the last 32 years.

The impacts of deforestation Global impacts Global warming Loss of biodiversity Local impacts of climate change Local impacts Soil erosion and fertility River pollution Decline in indigenous tribes Conflict Soil erosion

Value of the tropical rainforest The resources offered by the tropical rainforest are known as goods and services. Goods are things obtained directly from the rainforest whereas services are benefits that the forest provides. Goods Services Native food Wild meat and fish Building materials Energy (HEP) Water Medicines Air purification Water and nutrient recycling Protection against soil erosion Wildlife habitat Biodiversity Employment opportunities Some of the goods supplied by the forest: cocoa, sugar, bananas, spices, rubber, chemicals, perfumes, soaps etc.

Single most important issue today is climate change Global warming will only checked by: Greatly reducing the burning of fossil fuels Greatly reducing the rate of deforestation One of the worlds largest carbon sinks is the tropical rainforest. Protecting the forest requires: Make sure most of it is left untouched – making nature reserves / national parks Only using the goods and services of the rainforest in a sustainable manner

Additional reading Threats and solutions to the tropical rainforest https://www.kerboodle.com/system/images/W 1siZiIsIjIwMTQvMDcvMjQvMTEvMTUvMjUv MzAzL0dGNDk1LnBkZiJdXQ/GF495.pdf Threats to the tropical rainforest https://www.kerboodle.com/system/images/W 1siZiIsIjIwMTQvMDcvMjQvMTEvMjcvMDAv NTYvR0Y2NTMucGRmIl1d/GF653.pdf Case study – Brazil https://www.kerboodle.com/system/images/W 1siZiIsIjIwMTQvMDcvMjQvMTQvMjQvMjQv ODY0L2dhMjkxLnBkZiJdXQ/ga291.pdf Causes of deforestation http://deforestationamazonia.weebly.com/caus es.html