Forests Under Threat

• tropical rainforest plant adaptations - emergants grow above the canopy due to lack of light beneath it, drip tip leaves allow water to run off leaves instead of being absorbed (too much water in rainforest), buttress roots make sure roots are shallow but stable (nutrient layer is only on the top of the soil)
• taiga plant adaptations - needle-shaped leaves (do not drop leaves to maximise photosynthesis, needle shaped and waxy to reduce water loss), cone-shaped trees (to shed heavy snow), simple ecosystem (coniferous trees dominate. trees grow close together to reduce wind damage)
• during the short taiga summer, huge amounts of insects attract birds which then migrate south during the cold winter
• taiga animal adaptations - moose eat pine needles, brown bear build up up fat layers in summer for hibernation in winter, non-migrating birds often have feathers that turn white in winter for camouflage
• rainforest nutrient cycle - plants grow all year in huge numbers, dead matter drops to warm forest floor where it decomposes quickly, fast growing plants take up nutrients, constant precipitation leaches nutrients through the rainforest soil so they stay on the top layer
• taiga nutrient cycle - plants only grow in 3-5 months of summer, litter accumulates as decomposition only happens in summer, soils are thin, low in nutrients, and acidic, plants grow slowly
• productivity - a measure of the biomass the ecosystem can support
• biomass - renewable organic material that comes from plants or animals
• causes of tropical rainforest deforestation - wood for fuel, agricultural (subsistence and commercial), commercial hardwood logging, biofuels, mining, electricity (hydroelectric power dams)
• climate change threats to the rainforest - warmer temperatures mean a northward shift in the atmosphere (that brings constantly wet weather to rainforests) which makes them hotter and drier, plants and animals can't survive heat spikes, plants can't survive a long drought (some die and others are stressed), stressed plants have less resistance to disease, drier rainforests are at risk of forest fires
• direct threats to the taiga - logging for softwood, paper production
• indirect threats to the taiga - mining for minerals and fossil fuels, hydroelectric dams
• climate change risks to taiga - siberian tiger has heavy fur coat and high levels of body fat making them heat intolerant, warmer temperatures allow more diseases to spread (animals and plants won't have resistance to these so will die), forest fires in Russia's taiga (30-50 percent more common than 20 years ago)
• protecting the rainforest - CITES. protects 35,000 different species, any country that signs up agree to stop exports/inports of endangered species. huge international influence (181 countries). difficult to check all countries are enforcing the rules.
• protecting the rainforest - REDD. supports schemes that reduce the rate of deforestation. UN monitors by the use of remote sensing and visits. large sums of money available for REDD projects. not clear what they mean by forest ( palm tree plantations have been funded, but these destroy rainforest)
• sustainability - the ability to keep something at the same rate or level
• something is sustainable if it: keeps going without using up natural resources, doesn't require lots of money to keep it going, meets the needs of people now and in the future
• sustainable biosphere management.. ensures the ecosystem can recover quickly, prevents damage to environment, helps local people to benefit from their environment and understand why this management benefits them
• possible tensions - economic (individuals and companies usually just want to make as much money as possible, so use resources without thinking of the long term effects), social (if everyone has to benefit, it could put the environment at risk), environmental (not harming natural resources could clash with making money and improving living standards)
• reasons to protect the taiga - fragile ecosystem (plants grow slowly, very few species, animals and plants are highly specialised)
• protecting the taiga - national parks and protected wilderness (prevent any exploitation of natural resources. conservation restores natural habitat, scientific research develops knowledge surrounding ecosystem, education informs visitors)
• protecting the taiga - sustainable forestry (replanting trees)
• problems in parks and reserves (taiga) - migration (parks cannot protect migrating species), money (taiga has oil and gas, governments under pressure to export this as it could lift countries out of poverty), pollution (taiga is easily damaged, but parks can't be too far from cities because they need tourists)
• problems in sustainable forestry (taiga) - sustainable management is expensive long term. only possible with large companies, however these companies usually want to maximise profit by deforestation