Presentation on theme: "The effects of large deforestation (in the Amazon)"— Presentation transcript:
The effects of large deforestation (in the Amazon)
Soil Leaves intercept rainwater Break power of falling rain Roots hold soil in place Fairly little soil erosion under natural forest
Fewer leaves to protect soil from heavy rain No roots to bind soil in place Loose soil washed away Gullies develop on slopes Plants cant grow again
Soil nutrients Falling leaves drop to forest floor Rapid decomposition in hot wet climate Nutrients enter soil dissolved in rainwater Nutrients absorbed by plant roots Nutrients fixed in leaves during photosynthesis Nutrient cycling
Plants no longer drop dead leaves Less nutrients in the soil Soil nutrients leached (washed away) by heavy rains Soil loses its fertility and nothing will grow. Soil is degraded.
Local Climate Change Leaves intercept falling rain. Water evaporates back to the air Water drips to forest floor and infiltrates the soil Water absorbed by roots Water lost from leaf in transpiration Rains again over inland forest
Fewer trees so less transpiration Less water in atmosphere Less rainfall here and further inland Less water for plants to grow Land is turning to desert – desertifcation
Carbon Dioxide in atmosphere Trees absorb carbon dioxide in photosynthesis Trees release oxygen Forests nicknamed the lungs of the world.
Burning trees releases more carbon dioxide Carbon dioxide is the main greenhouse gas Carbon dioxide increases the greenhouse effect The increased heating is called global warming Rain forest destruction is one cause of global warming
Food ChainThe rainforest ecosystem has great biodiversity The rainforest ecosystem has great fragility All species are interconnected Changes have knock on effects
If trees are removed – the herbivores suffer If herbivores decline the carnivores suffer The food chain is broken – some species become extinct. Remaining plants no longer have insects for pollination our animals to spread seeds