hey folks so I want to take you through one of our biggest case studies and that is tropical rainforests or TRF and we're gonna have a look at specifically the Amazon rainforest now I know there's others that we can study but for this one I'm gonna try and simplify it as much as I can but this one's gonna hopefully cover everything you need to know really in one infographic okay so the first thing we just need to look at very very quickly if we imagine this is the earth this little circle and the reason they're called tropical rainforest you have the equator that works its way around the planet and then either side of the equator and you've got the tropics the Tropic of Cancer and the Tropic of Capricorn and it's between those two that we find tropical rainforests and generally speaking they have an average temperature of 27 degrees Celsius and that's what we need we need high temperature and we also need that daily rainfall which comes from and is linked to that temperature if you're thinking about your global air circulation model which you might be it's the Hadley cell and we know in the Hadley cell there is rising air and it's that rising warm air but then cools down condensates and we get that daily rainfall often around lunchtime and in terms of rainfall it's 2,500 millimeters per year on average so considerably more you'll note than anything we experienced here in the UK all right there's just a bit of background about where we find them and what sort of conditions now I want to take you through to start with the kind of vegetation that you might expect and to do that I'm actually gonna draw straight um really big big tree okay with large buttress roots and this isn't obviously a real tree but just one branch there we go and there we go right really not the best example of a tree but it's gonna help us understand a little bit more ok so there's four levels in the rain forest right so we're gonna draw a line for the first one which is the forest floor this is sometimes called the shrub layer there is only 2% sunlight right down here it's in fact we just draw it someone write some there I'll just remind us what we're thinking about so right down here there's very very little sunlight so if the forest floor we then have this layer called the under canopy okay and this this is some slightly brighter is a bit more sunlight coming through and certainly the rain coming through but it's this area that basically exists underneath the main foliage the main canopy the main amount of leaves really okay so we have this under canopy even as you can imagine what comes next is the canopy and if you're looking down on the rain forest and from above you will actually see this it looks like a blanket of trees it's like you can't imagine how and any sunlight could could actually penetrate that the canopy is a really dense layer of vegetation but then there's this other level which is the emergent layer and this layer just can put an arrow going opposite it it can be over 40 meters high sometimes much more than that so I'm just put over 40 meters high and then so when you are looking down on the rain forest imagine like a drone shot you would see the odd tree just dotted about here there and wherever that's significantly higher than the canopy layer okay let's talk about some of the adaptations now you'll notice my tree didn't go straight down it's come out and that's because trees that are in the rain forest these very very tall emergent trees they need a solid base because I don't want to fall over so these are called buttress roots they're a wide very stable and they anchor the tree and part of the reason that they are needed is because the roots of these really large trees they don't go deep down into the ground they spread out and they don't go deep down because the soil the soil is actually quite infertile meaning it doesn't have loads of nutrients and there's no need for those roots to go down they're getting daily rainfall the rainfall is hitting hitting them here they don't need to dig for water and as they point going into infertile soil and the reason it's infertile is because of that daily rainfall it's been leached of all its nutrients so that's why the roots are quite shallow now what's next let's have a look at some of the things that live in the rain forest so if you draw it sort of curly wurly line up here and this is a vine okay lots of vines live in the rain forest the one we're thinking of is a Liana which had a student once called Yana I always love teaching this when she was in the lesson so Liana its it's a vine think Tarzan and Jane really flying through the jungle but it climbs its way up the trees using the trees for support because they are tall and they are straight they are growing for one thing and one thing only that's sunlight yeah so the amount Liana's use that they're going for the Sun too and they just climb their way up the tree they're not helping the tree the tree doesn't need them they're using the tree and another thing that uses the tree my tree doesn't want just to enjoy it like this that's nice to be like a bit of a grouse ready another one over here yeah hairy armpit isn't it it's a parasitic plant it's called an F fight and it's felt a bit strangely a fight like that but if you remember it's a parasitic plant which means this plant isn't just leaning on the tree for support its actively feeding off the tree its roots up into the bark and it is using the tree it's landed there maybe as a seedling and it is now growing on the tree so it's not not in any way helpful but without the tree it couldn't live there now the tree itself the leaves if I just do an example of the leaves so this is you know a leaf imagine that is on the tree [Music] the important but isn't the size of the leaves or anything else the important bit is that they're there and that is called a drip tip and that's because of the leaf drips water and so when that heavy rain comes which it comes you know daily in the rain forest the leaves don't collect the water and suffer because think you know all that weight of the water could actually harm the leaves it could break the leaves could ya break branches if the branch became too heavy too wet but not only that it's very warm it's very humid in the rain forest and having water that's collected on a leaf could actually cause the leaf to become a bit kind of almost moldy you know bacteria will build up and then suddenly that leaf it cant photosynthesize in the same way as it needs to to collect that energy from the Sun so it's really sensible that when the water clicks the drip bit of the leaf just just lets the water drip off and it will fall to the ground and the other really cool thing about these leaves so don't fall in autumn there's no seasons in the rain forest it's the same well there's a wet season for six months and a slightly drier season for another six months but the leaves actually fall I'm just going to draw a line like this they fall all year round and that's a good thing because when those leaves fall just gonna draw another one here okay they provide something called leaf litter and it builds up on the forest floor because it's so warm remember average 27 degrees it actually decomposes really quickly so we'd get that rapid decomposing due to the humidity and when it's decomposing then the nitrogen and other things that are in the leaf can get so it's back up by those wonderful buttress roots and it will essentially feed the tree again I'm feed other things remember though that some of those nutrients are gonna get washed away by the daily rainfall washed out by rain fall okay so if you can talk confidently in an exam question about fights lianna's and the fact that leaves drop all year but traceroutes the emergent layer you're gonna do really well but that's your vegetation let's not forget that animals live in the rainforest and they're actually some of the most interesting um now the one we're gonna focus on got to actually sorry and is the howler monkey and the three-toed sloth so I'm really bad at these well have a go um so the howler monkey monkey face that's the West there we go and body and then long limbs awful I know there we go there's our little monkey um and he's called a howler monkey now there's other monkeys obviously live in the Amazon rainforest but he can be our example and when you're thinking about him the things you want to mention ah long limbs okay he's got long arms and legs which means he can easily move around the forest long limbs for easy movement across across the canopy layer that's the main place that he exists and the other thing just gonna join our room this tale okay it's prehensile and prehensile essentially means it's like a fifth limb it could grip like a hand it's got muscles in it in fact he can hold his whole weight on his tail so prehensile tail for gripping branches because let's face it if he falls 40 metres he's dead so they need these adaptations in order to survive in the rainforest okay so the other one we're gonna do and I'm porous probably even worse is something called a three-toed sloth and I'm trying to to draw that now really bad that's last but there we go so a three-toed sloth it's a creature very slow-moving creature moves incredibly slowly through the forest and it's often camouflaged as well so you can't really told it they're there for quite a while before they sort of surprising and they have moss and things on their back so they're really tricky to actually spot so it's known as the three-toed sloth and it's key point as it moves slowly move slowly um it's kind of flushed and which makes it hard to spot so hopefully doesn't become prey for anyone okay so we've got our vegetation and we've got our animals now we need to think about why the Amazon rainforest is being cut down such fast rate and to do this to draw a road roads are integral to development and above the road if you just draw three circles and then like that so you're logging you've probably guessed by now is one of the main reasons that the Amazonas formed it's not the main reason okay this is all obviously to get money through economic reasons but logging is one of them and it's one that is used around the world as well the next one probably less familiar with this is supposed to be gold is mining and the reason is under the rainforest in the Amazon and other rainforest as well actually is gold gold mining and this is opencast mining which if you're not too sure about um basically they don't go too deep they spread out over quite a wide area and it causes a lot more disruption and a lot more damage and then the next one apologies again my drawing is supposed to be a cow oh it's got a terrible face let's put some black and white spots on night vision sure there are this color actually I'm pretty sure their room which is brown but anyway is farming okay cattle farming and actually that is number one at the moment I'll put number one next to it so the thing is with this is they require a lot of space to graze so often they go hand in hand with logging because they'll take the trees down put the ground to grass essentially and then farm it and because there's no trees there the ground suffers so actually they have to keep moving the cattle on and it makes the soil really infertile so if we just put that there leeching leeching is where the nutrients get sort of rush brushed out through rainfall so remember the rains still coming but the the trees aren't there to hold the ground together so leaching from lack of tree cover okay makes the soil really infertile okay and all of these new require rights because you have to move cattle you have to move gold you have to move machinery you have to you know be able to get trucks in for logging so creating the road also creates a lot of problems now there's economic social and environmental effects that we're going to look at now so if we just put ICI here that's for social and environmental that I'm going to run look at all of these so free economic festival what's the main reason that they do all of this well it's for money isn't it so if we put a net income reducing debt that they owe okay and then for social obviously what about people so just draw some sticking people quickly often in the process of this people get moved and it's often tribes who might have lived there for a long time so we've got native people being moved out of where they live the other thing it is often these these native people aren't used to the kind of diseases that perhaps we carry that you know they won't come across which unfortunately haven't got the health care in place yeah they often end up dying because they will catch something relatively low-key that we're not too fussed about we've got immunity too in our systems like another flu they're not used to it and they work this will actually cause unnecessary deaths say and deaths from disease and then of course on the environmental impacts it's the co2 emissions mostly you know which are increasing global warming because if you haven't got the trees you haven't got the co2 store you know taking away that store your parts burning the logs or you're you know you're causing higher rates of carbon dioxide the other thing which we mentioned was the soil erosion without the tree cover and then both of those together in a way are sprays but also a separate point is a loss of biodiversity one tree one emergent arey definitely can provide a home to thousands of species and it's an integral part of the ecosystem so just cutting down even one tree can be really detrimental to that entire you know ecosystem and also to the food chain and things like that so why do they do that and let's look at the value of tropical rainforests okay and if we look at that in terms of goods and services so one hand its food in the obvious you know vegetation animals etc and the flowers are often in perfume so if you go to a nice perfume shop here in the UK it's likely that you are purchasing a perfume that has got flowers and scents from the rain forest in it obviously one of the goods that you can sell as well is the the timbre itself and then a big one is the rainforest contains a quarter of all prescription medicines in the UK so if you go to the pharmacy for your medicine it's likely that even a basic antibiotic might well be linked to some of the plants that live there now in terms of services it's a natural carbon store and I mentioned that earlier so trees taking carbon dioxide and they hold it in their trunk in in the timber itself and it's I mean it's crazy to think that we're trying to create ways to do that when nature does it for us so it's a really good thing in fighting climate change so in fact if we just write it traps co2 into its biomass okay so there's a lot of good reasons why we want to try and protect the rainforest and and not be logging it now when we think about managing the rainforest thinking about the vegetation the animals reasons for logging the value of the rainforest there are three ways that I want you to think about and I'm gonna start with the best okay now know right management quickly you could get a question just asking you about management so the best one number one is debt reduction I remember one of the main reasons we talked about so economic yeah was actually that they're trying to get this income to reduce debt that they owe many of these countries are actually struggling for money it's not that they're chewing up the rainforest because they want to they often don't seem to have another choice so debt reduction is huge okay it's where rich countries for example us so the UK or the USA no Norway and Sweden other countries they cancel debt in return for carbon credit now all that means is they basically make the poorer country promise to not chop down the trees and it's all done legally you know with with an agreement or certain area of land and essentially then it's not that the UK or the USA owns that land it's that they are not allowing Brazil for example of Peru to to cut down the trees in return they will write off the debt that they owe or a good proportion of it so that is the best one and to kind of illustrate that I just want to do a little trophy because that is number one right number two he is over here eco tourism if you've ever been on holiday somewhere in seeing a rainforest you probably took part in ecotourism it's it's wonderful it's where you go on holiday you visit the rainforest you learn about the animals that are there you take part in kind of conservation activities it's brilliant and it teaches people about the rainforest while at the same time making money but the problem is it's very small scale so if we just put that sort of an educational holiday stroke conservation experience okay so it's really good it is bringing money and but and there is a purse and very small scale which is why it's not as good debt reduction and then number three our last one is something called selective logging now you'll hear this talked about and often mistakenly talked about as if it's the best one it's really not though companies like to suggest that they're doing a really good thing by choosing which tree that we cut down it's not it's not the case okay so if I if I just judged tea trees like this so what they do is that they will go along they will pick the biggest tallest tree often they're called both trees they're quite hollow inside they don't really contribute much to the ecosystem and they'll go in and they'll take that tree down and they will sell it as if they're doing a selective looking and it's great and they left all these healthy trees but the facts are for every one tree taken down thirty trees are damaged and not only that but 75% of the trees in that area will be felled in three years so it's actually not not good at all okay so I'm just gonna put in there the hard facts actually which is for every mature tree felled what did I say thirty trees are damaged I'm really running out of room on this one thirty trees are damaged and 75% of trees felled in three years okay so that's the facts that's what we've got to work with so when we think about management always always think about debt reduction first okay it's increasing in popularity but ecotourism and then eventually and at the very last thing to think about is some selective logging well I hope that helps you with your case study on the Amazon rainforest I remember a lot of this is applicable to other rainforests as well and yeah it should really help you with your exam questions