Presentation on theme: "Deforestation Causes, effects and impacts. 2 Aims and objectives 1. What is deforestation? 2. Why have tropical rainforest been cleared? 3. What are the."— Presentation transcript:
Deforestation Causes, effects and impacts
2 Aims and objectives 1. What is deforestation? 2. Why have tropical rainforest been cleared? 3. What are the impacts of deforestation? 4. Are there ways to manage the rain forest in a sustainable way?
3 Where the forests are
4 Deforestation is cutting down tress – not just cutting down forests – as we saw last week cutting down trees in the savannah is called that too – even though the savannah can hardly be called a forest. Many primary forests in temperate countries have almost disappeared after centuries of logging or land clearance for farming, industry and housing. But it is relatively recently that large scale deforestation has taken place in the tropical forests. Meanwhile there are some temperate areas where reforestation is taking place. It speed has raised alarm with the scientists and conservationists. What are they concerned about?
6 What are the scientists and conservationists concerned about? Biodiversity is a major concern. Rainforest are one of the most biologically diverse regions of the world. Over a million species of plants and animals are known to live in the forests and millions more are not classified. The unique environment of the rainforest allows for such biodiversity to exist. What is most of it cut down for?
7 What are causes of deforestation in tropical rain forests? Logging; Ranching; Farming; Road building; Mining; HEP schemes
8 What do the governments think about it? Some of the logging is illegal But in many case the governments encourage it. Often these are LICs with few ways of raising money So the temptation to pay off debts and increase the standard of living of their people is a hard one to pass up What do they gain from allowing deforestation? Revenue from timber, drugs (legal ones) and minerals – and more recently exports of animal feed (soya) and biofuels (palm oil) Land to house and feed their increasing population
9 So what are the main impacts of increased deforestation? The impact of deforestation on a large scale can be divided in two Local Impacts are those that affect the immediate area from where the trees are being removed. Worldwide/International Impacts are those aspects which affect everyone everywhere.
10 What are the local impacts of increased deforestation? Local Climate Change When an area of rainforest is either cut down or destroyed, there are various climate changes that happen as a result. The following is a list of the various climate changes with a brief description of why they come about. Desiccation of previously moist forest soil What happens is because of the exposure to the sun, the soil gets baked and the lack of canopy leaves nothing to prevent the moisture from quickly evaporating into the atmosphere. Thus, previously moist soil becomes dry and cracked. Dramatic Increase in Temperature Extremes Trees provide shade and the shaded area has a moderated temperature. With shade, the temperature may be 37 degrees Centigrade during the day and 16 degrees at night. With out the shade, temperatures would be much colder during the night and around 54 degrees during the day.
11 What are the local impacts of increased deforestation? Moist Humid Region Changes to Desert This is related to the desiccation of previously moist forest soil. Primarily because of the lack of moisture and the inability to keep moisture, soil that is exposed to the sun will dry and turn into desert sand. Even before that happens, when the soil becomes dry, dust storms become more frequent. At that point, the soil becomes useless. Soil Erosion Deforestation contributes to run-off of rainfall and intensified soil erosion. Bare ground, with little added humus, increase the rate of sheet and gulley erosion.
12 What are the local impacts of increased deforestation? Changes in rainfall pattern The daily rainfall common in many parts of tropical rainfall is called convection rainfall. Heavy rainfall in these areas occurs frequently in the afternoon. Why? When it rains, the trees intercept much of the water, slowing its rate of descent, allowing much of it to percolate into the soil as the ground is shaded and so much cooler than the air above. Much of the water that has percolated the soil will be taken in by the roots of trees and shrubs, which will transpire it into the atmosphere in first part of the day when the sky is clear and so the temperature rises. This warm moist air rises in the atmosphere and eventually cools and condenses into clouds in time for the next teatime downpour
13 Every morning
14 Every Afternoon
15 About 4 o’clock nearly every day animated version of this is on the wiki under the lesson files
16 So what happens when the trees are cut down? The shrinking forest cover that there are no longer trees to intercept, retain and transpire precipitation. The deforested areas become sources of surface water runoff, which moves much faster than subsurface flows and can cause flash flooding and more localized floods than would occur with the forest cover. With decreased evapotranspiration, atmospheric moisture is reduced the regular rainfall is reduced. According to one preliminary study, in deforested north and northwest China, the average annual precipitation decreased by one third between the 1950s and the 1980s.
17 What are the international impacts of increased deforestation? Less Carbon Dioxide and Nitrogen Exchange The rainforests are important in the carbon dioxide exchange process. They are second only to oceans as the most important "sink" for atmospheric carbon dioxide. Deforestation may account for as much as 10% of current greenhouse gas emissions. Greenhouse gases are gases in the atmosphere that literally trap heat. There is a theory that as more greenhouse gasses are released into the atmosphere, more heat gets trapped. Thus, there is a global warming trend in which the average temperature becomes progressively higher.
18 A summary
19 Tropical rainforests, which account for only seven percent of the world’s total land mass, harbour as much as half of all known varieties of plants. Experts say that just a four-square-mile area of rainforest may contain as many as 1,500 different types of flowering plants and 750 species of trees, all which have evolved specialized survival mechanisms over the millennia that mankind is just starting to learn how to appropriate for its own purposes. Rainforests are a Rich Source of Medicines Scattered pockets of native peoples around the world have known about the healing properties of rainforest plants for centuries and perhaps longer. But only since World War II has the modern world begun to take notice, and scores of drug companies today work in tandem with conservationists, native groups and various governments to find, catalogue and synthesize rainforest plants for their medicinal value. Medicines and Rainforests
20 Rainforest Plants Produce Life-saving Medicines Some 120 prescription drugs sold worldwide today are derived directly from rainforest plants. And according to the U.S. National Cancer Institute, more than two-thirds of all medicines found to have cancer-fighting properties come from rainforest plants. Examples abound. Ingredients obtained and synthesized from a now- extinct periwinkle plant found only in Madagascar (until deforestation wiped it out) have increased the chances of survival for children with leukemia from 20 percent to 80 percent. Some of the compounds in rainforest plants are also used to treat malaria, heart disease, bronchitis, hypertension, rheumatism, diabetes, muscle tension, arthritis, glaucoma, dysentery and tuberculosis, among other health problems. And many commercially available anesthetics, enzymes, hormones, laxatives, cough mixtures, antibiotics and antiseptics are also derived from rainforest plants and herbs. Medicines and Rainforests
21 The Untapped Potential of Rainforest Medicines Despite these success stories, less than one percent of the plants in the world’s tropical rainforests have even been tested for their medicinal properties. Environmentalists and health care advocates alike are keen to protect the world’s remaining rainforests as storehouses for the medicines of the future. The Challenge of Preserving Valuable Rainforests But saving tropical rainforests is no easy task, as poverty-stricken native people try to eke out a living off the lands and many governments throughout the world’s equatorial regions, out of economic desperation as well as greed, allow destructive cattle ranching, farming and logging. As rainforest turns to farm, ranch and clear-cut, some 137 rainforest-dwelling species—plants and animals alike—go extinct every single day, according to noted Harvard biologist Edward O. Wilson. Conservationists worry that as rainforest species disappear, so will many possible cures for life-threatening diseases. Medicines and Rainforests
So what can be done about it?
23 Managing Rainforests There are 4 basic ways of approaching rainforest management: International – for example REDD which was implemented as a result of Copenhagen in December – well not exactly as they did not actually agree anything very much there but under the auspices of REDD some good things are happening – see later National approach – some countries are taking decisions to manage their rainforests sustainably International NGOs – such as the Rainforest Alliance, Forest Stewardship Council among others Small and local – indigenous people with the help of small enterprises attempt to create sustainable ways to live with the rainforest.
24 In a bit more detail … As the whole world is concerned with greenhouse gas emissions, and over the recent past deforestation has proved to have quite an impact on this. This has 2 parts to it: 1. The gases that are released due to deforestation 2. The greenhouses gases that are not being sequestered (locked up) by trees that are no longer there. For this reason, the whole idea of how the rich countries can encourage the poor ones to stop cutting down their trees has crawled unwilling up the international ‘to do’ list.
25 REDD - Reducing Emissions from Deforestation and Forest Degradation in Developing Countries The problem of emissions of greenhouse gases as a result of rainforest destruction was supposed to be part of the Kyoto discussion in Japan in But it was put in the ‘too hard’ box because no-one could agree how it might work. Nor could they agree how it would be funded. It was not until the Montreal round of discussion in 2005 that the Coalition of Rainforest Nations brought up the suggestion again. Finally firm proposals were agrees at the 2007 Bali round, and it is at Copenhagen that agreement over its working should have been fully implemented
26 REDD - Reducing Emissions from Deforestation and Forest Degradation in Developing Countries Why was the original problem? 1. Who gets the money? The governments, the big land owners, the indigenous people? 2. If you are going to pay people to protect rainforests, then they need to say that they would cut them down if you don’t. What about those people who don’t want to cut them down – does that mean they get nothing to protect them? and 3. Where does the money come from? The rich countries wanted to ‘offset’ their wasteful ways and carry on polluting. Environmentalists say the HICs need to cut down and pay up to offset their previous harm 4. A lot are sceptical that this will really stop deforestation – all that illegal logging and farming that happened before does not breed confidence
27 REDD - Reducing Emissions from Deforestation and Forest Degradation in Developing Countries Why is it so important to climate change? As much as 25% of the man-made emissions arise from rainforest clearance. How come it is that much? Trees absorb CO 2 and give out 0 2. Much of the carbon, combined with water make the sugar, lignin and are stored up for a very long time – they are a huge carbon sink. Once the trees are cut down they no longer do this any more. But many of the cut trees are burned – thus releasing their stored carbon – it is these 2 together than cause the problems.
28 REDD - Reducing Emissions from Deforestation and Forest Degradation in Developing Countries The Basics: reforestation and afforestation were part of off- setting from the start – but reducing deforestation had been deliberately excluded – remember the ‘too hard’ box? However, after 2007, this came under the remit of REDD and was included. REDD was also charged with monitoring the situation, and with addressing the social and economic issues that had led to deforestation in the first place. Also REDD acknowledges is the biodiversity issue – all those useful plants and special animals we may loose unless we get a move on. How is it doing? It was never fully implemented at Copenhagen - but then nothing much was. However countries such Norway, Denmark and the UK are already in discussion with LICs such as Democratic Republic of Congo, Tanzania and Papua New Guinea.
29 National approach – some countries are taking decisions to manage their rainforests sustainably Tanzania has since the 1990s tried to run a joint government-local joint scheme to manage their forests sustainably. But hard times financially has meant that they have not always managed to do this to a high standard. But now REDD is there to help, Tanzania has set up a system to make it possible for the village communities to take advantage of the chance to improve sustainability and reduce poverty.
30 NGOs The FSC ( Forestry Stewardship Council) They certify providers of sustainable wood They then certify the produced of goods that use certified wood So that customers in HICs can buy wood products that come from wood from certified supplies. This encourages sustainable logging that does not lead to deforestation.
31 NGOs The rainforest alliance also certify goods as being from sustainable sources, but their range is far wider. They include food such as coffee, cocoa, chocolate, tea, nuts, fruits and also tourist venues. But they do far more in the field beyond registering. They work with Sustainable Agriculture Network (SAN) to ensure sustainable production.
32 An example of SAN at work Cocoa that is produced as part of an ecosystem with a mix of trees around is much less damaging to the environment. In Ecuador, farmers have learned to properly sort, dry and ferment the beans using a cooperative processing facility, which reduces the number of defective and rotten beans, and also happens to preserve the chocolate's anti-oxidant properties as well as its potassium content. Drying their cocoa using solar rather than gas powered dryers and selling their product through a cooperative, these farmers have increased their production and lowered their costs, resulting in better living conditions for their families.
33 Small scale developments Harvesting products from the native forest rather than cutting them down: It has been estimated that the products from some areas of rainforest, if regularly harvested give an income of ½ the value of the wood EVERY YEAR. Forests products Fruit market in Madagascar by R. Butler
34 Agroforestry Agroforestry is a form of agriculture that seeks to copy nature more carefully than large-scale commercial monoculture (i.e. growing one crop) or cattle ranching. Rather than clearing the rainforest completely (clear felling), only the older larger trees are felled, and shrubs, other food plants (such as vanilla) and flowers are grown in the clearings. It is also possible to plant legumes which add nitrogen to the soil.
35 What are the benefits and advantages of agroforestry? Soil protection and improvement Maintenance and retention of soil moisture Biodiversity balance Low impact to the environment Pleasant environment to work Harvest and income staggered Reducing the use of defensive chemicals Production of healthy foods Environmental services
36 An example of it working in Madagascar Savoka (or permaculture) gardens are planted on fallow plots and are planned as "a carefully selected succession of trees and plants on the fallow land that re-enriches the soil at the same time as producing a steady stream of food crops and other useful products." For example, the use of wild ginger adds phosphorus to soils while leguminous plants can fix nitrogen that is lost with traditional rice cultivation. The addition of perennials— crops which continue to produce for a number of years like citrus, manioc, vanilla, banana, mango, pepper, cacao, coffee, and rubber—can help restore nutrients to degraded soils and remain productive for decades while generating a diversified income and/or diet. A bonus of such agroforestry techniques is that they maintain forest systems, soils, and biological diversity at a far higher level than do conventional agricultural techniques. As long as such fields are adjacent to secondary and old- growth forest, many species will continue to thrive.
37 Ecotourism Rainforest ecotourism involves both environmental conservation and sustainable development, which is a good way to protect the rainforest, and is like a perfect development strategy for undeveloped areas of the world. Tourism itself brings added dollars to an area's economy, but ecotourism has the added bonus of travellers who want to take care of the area they're visiting, through a combination of careful living methods that do less damage to the environment, and through bringing money which encourage the inhabitants to take care the forest is kept pristine.
38 Costa Rica: Pacuare Reserve Lodge The beautiful and well constructed Lodge overlooks the beach and a freshwater lagoon which opens on to the main Tortuguero canal. There is no electricity — this is the jungle after all!! Light comes form candles and storm lamps but there is gas for cooking and refrigeration.
39 Costa Rica: Pacuare Reserve Lodge The Pacuare Nature Reserve was established by the Endangered Wildlife Trust in 1989 and protects 800 hectares of lowland tropical rainforest and six kms. of deserted beach on Costa Rica's Caribbean coast. It is located about 25 kms. north of Limón and lies between the sea and the Tortuguero canal. The special mission of the reserve has been to protect the Leatherback Turtles, which nest along its beach - one of the most important nesting sites in Central America for this critically endangered species. The Reserve is rich in wildlife, and is home to about 20 species of mammal and many reptiles. Monkeys are plentiful and Howler monkeys regularly provide a dawn chorus
40 Homework You have met the issues. Our Case study will be the Amazon. Research these questions Qu 1: What are the main causes of deforestation in the Amazon? (figures and/or graphs if you can) There no real impacts that are specific to the Amazon. But there are special ways it can be managed Qu 2: Find 2 different examples of sustainable management of the Amazon rainforest