1/2 The Oak Tree, Natures Greatest Survivor - August to February

One Tree is an icon of the British countryside it is of course the oak [Music] today we begin an extraordinary experiment we want to understand the species as never before and to do that we will film this one remarkable specimen for an entire year armed with the latest technology we will investigate how our battles to survive through four very different seasons in autumn we go underground to see how its roots stocks up on precious resources what we're looking at is a highly dynamic system in winter we discover the sophisticated strategies our tree uses to take on everything the elements can throw at it in spring we find out how it senses the world and how it even has its own form of language it talks to itself there's a chattering goes on across the whole canopy and in summer we'll see it fight predators hell-bent on eating it alive [Music] over the next 12 months I want to see the world as our tree does and tell its amazing story Wow in the coming year I can't predict exactly how well it'll fare badly or well but I can promise you one thing you will never look at an oak tree in this same way again [Music] [Music] the oak we've chosen to follow for our year-long experiment stands in white and woods just outside Oxford it's a rather special tree for a start it's almost 400 years old that means it was a sapling during the battles of the English Civil War it was laying down its roots as Isaac Newton described gravity and it matured as Britain underwent its Industrial Revolution what's more our oak is in a rather special place in 1942 the University of Oxford acquired y-term woods our Oaks home specifically so scientists could research British woodland and I know these woods extremely well I taught biology at Oxford for 20 years and my students and I used to come and study the countless insects that live here the climate bird populations the soil scientists know a lot about whiting and this will help us better understand our tree and how it changes as we follow it through the year [Music] our year-long experiment begins in late August and the first task is to assess our trees condition to do this forestry scientist dr. Matt Disney and dr. Eric Casella will create an incredibly accurate three-dimensional map of our tree this is done by firing almost two billion pulses of laser light at our oak the end result is this beautiful image a virtual oak a year from now it'll help us find out how I rope has fared how much it's grown and how much new wood it's made even how much oxygen it's released we get some information straight away our tree is some 19 metres tall and 30 metres wide but for me there's another quite astonishing and quite unexpected detail one of the really interesting things that we can get from these data is we can estimate the total number of leaves on the tree and then from that without counting them without counting them manually and I tell I'll tell you I have manually counted leaves on an oak tree just recently and it's not a fun job and being able to do it in an automatic way without getting your hands dirty like this how many well we think that there are around 700,000 fleas on this tree to me the fact that you can tell how many leaves us trees got is just it's amazing isn't it the total area of those leaves is about 700 meters squared so to put that in a bit of context that's about three tennis courts worth of leaf area eirick needs all these leaves because they capture sunlight the source of all this energy but now in late August our tree is acutely aware that sunlight will soon become a precious commodity [Music] as often approaches the day's shorten and the temperature begins to drop [Music] to survive our oak must transform itself [Music] well it may look as if not much it's happening but all across our tree a dramatic process is taking place our oak is beginning a colossal redistribution of its resources well it's been through this process hundreds of times before but each time is no less challenging to see what our oak is really up to we need to picture what's going on beneath its bark as often begins throughout all the branches and leaves hubbub of chemical messages are now being sent and received these chemicals are known as hormones and our trees producing them to prepare itself for the autumn that may seem odd but just like us trees have hormones these chemical messengers flow through the body of the tree controlling and managing all sorts of important processes in us these hormones are responsible for some of the biggest changes we'll go through in life like pregnancy and puberty in our tree they're responsible for an equally crucial change as autumn gets underway driven by hormonal signals trees begin to break down pigments and nutrients in their leaves to store over the winter and begin to eat themselves the result is a spectacular change in the color of the leaves once the nutrients have been extracted [Music] trees like our oak will then start to shed their leaves to conserve water and energy in the coming months [Music] but how exactly there's our tree know when it's time to begin this huge change for a very long time people assume changes in autumn were triggered simply by a drop in temperature but what happens if there's an unusually cold spell in summer how does our tree know not to drop all its leaves it turns out that trees rely on a far more sophisticated method than temperature alone to sense the changing seasons in their own way they can see what's going on well this should give you an idea of how most plants see the world while you and I could perceive a wide range of colors trees like a rogue are only able to sense the red light in the spectrum and they can do this thanks to an incredible chemical pigment in their leaves called phytochrome phytochrome a substance in our oak leaf cells is incredibly sensitive to the red light that makes up part of the sun's rays it's a kind of chemical stopwatch that is also able to measure the hours of sunlight and darkness so as the nights get longer the phytochrome acts like a signal telling the tree that autumn has begun this means that all the hormones that prepare the tree for the cold months kick in at exactly the right time it's now October and our tree is not only dropping leaves it's also time for our oak to release its most precious cargo autumn is not just a time for preparing for the cold it's also when our oak releases its offspring out into the world we're all familiar with acorns but this really is a masterpiece of evolution inside this little capsule is not only the genetic code to make one of these it also comes packed with food and protection from the elements meaning this seed has all it needs to survive the winter to spread acorns the tree relies on the help of animals like Jays and squirrels who often store them underground and then forget where they are but the oak has an ingenious trick to improve its acorns chances it varies the number of a concert produces from year to year some years there are thousands others like this year there are very few while acorns are the perfect food for our friend here the fact that she can't rely on Oaks all the time means she has to find other sources of food but every 5 or 10 years Oaks have what is called a mast year they produce such a deluge of acorns that all the Acorn eaters just simply can't cope they're overwhelmed no matter how hard they try and this means the chances are one acorn germinating and surviving becomes dramatically increased with help from the local wildlife at least one of our oaks acorns drop this autumn is likely to germinate next year and when it does it will be a spectacular event fuelled by nutrients locked up within the Acorn our trees offspring is brought to life [Music] a shoot reaches upwards to find sunlight [Music] while a route penetrates beneath to find water [Music] in just a few months this acorn has developed into an infant oak as it's very own leaves this tiny organism is now able to fend for itself the success of the oak is largely dependent on the animals that help disperse its acorns and there's one species that in the last 300 years has been particularly helpful and that's us in the 18th and early 19th century there was a frenzy of oak planting in Britain in just six years it was reported that one military officer managed to plant nine hundred and twenty-two thousand oaks the reason for this surge was simple Britain had the world's most powerful Navy and nearly all of her ships were made of oak this is the HMS Victory famous for defeating the French fleet at the Battle of Trafalgar the ship is a product of almost 6,000 oak trees reimagined by some of Britain's finest ship rights this vessel and hundreds like it with a reason for Britain's insatiable demand for oak climb inside and you see oak everywhere this is the lower gundeck of the HMS Victory many of these sturdy old Timbers have been here since a ship first set sail in 1765 at night hundreds of men would sleep jammed together in hammocks slung from oak beams and at mealtimes they would eat together at these oak tables for the crew of the HMS Victory oak surrounded them it encased them and it kept them alive against the elements the oak Timbers of the victory withstood the terrifying power of the scene they managed to cross the Atlantic Ocean in hurricane season they survived serious battles and innumerable volleys of cannon fire they saw death and destruction on a colossal scale and it was an oak howl the crave of Lord Nelson as he bled to death each of these spectacular oak planks has borne witness to and survived the many violent and dangerous battles on board HMS Victory but this food actually predates the building of the ship by hundreds of years this wood is a product of medieval acorns that dropped all over Britain and if you look closely you can still see the story of their lives edged into the drain the way Oaks live the battles they face in the natural world and their incredible adaptations now what makes this species so uniquely useful for building ships the curved bows of the oak evolved to support the vast canopies of leaves allows ships to be curved yet maintain the strength to withstand the full force of the ocean by planting and cultivating oaks humans have been able to travel between continents and spread our species to almost every corner of the planet harnessing the strength of this unique organism we have been able to overcome even the most treacherous of oceans back at our tree it's now late October and autumn is well underway our oak is now getting six hours less sunlight per day than it was in peak summer and as the Sun is the trees only energy source it must stock up and store resources for the winter crucial to how it does this is the trees root system a hidden subterranean world every bit as complex as the world above I'm extremely keen to investigate how this works but that's no easy task digging up our tree to see its roots would kill it so to investigate we're going to excavate the root system of an oak sapling in its entirety [Music] this is east mauling research in Kent for over a hundred years they have been experimenting with roots and plants to help develop better yields and they have given us a unique opportunity to get an insight into what's going on beneath the ground the process begins by digging a meter and a half deep trench it's only then the real hard work can begin an oaks root system even a very young one like this is incredibly complex and fragile and that means it can only be excavated by hand we are trying to ensure that no root no matter how small is damaged that means the team must be meticulous in their work it's a painstaking process that will take 10 people almost two weeks to complete but once it's done we can begin to understand the subterranean world of the oak well this is absolutely incredible look at how much soil they've had to remove to expose the root system of this tree it's only 15 years old and several tons of Earth have had to be shifted this is something you'll never see in a month of Sundays and it's something I haven't seen ever before but just look at the size of this look how far they go out and as you go further and further right these reutlitz get finer and finer and finer until you're almost will you're further out then the tree is tall virtually [Music] with the roots exposed we can get a glimpse into their hidden world under extreme magnification we can see these strange threads they are known as mycorrhizal fungi they grow all over the oaks roots and help them extract phosphates a vital nutrient locked inside rocks in the soil now I've just pulled out this this little piece of rock here and I think I can see yep so that fungal threads that were actually attached onto this rock yes see there's plant inaccessible phosphate in that rock and what the mycorrhizae do is they go inside of the rock and they pull out the phosphate and they can transport that Baney into the plant and into the root system whereas the plant wouldn't be able to do that when its own so the oak tree simply isn't able to access the phosphate in this without the fungi no I fear is much smaller and it can penetrate inside of the rock and take the nutrients back into the plant the tips of the fungi can apply pressure equivalent to the inside of a car tire and this means they can physically penetrate parts of the rock to extract nutrients these are the hidden helpers that allow Oaks to get food from the most inaccessible of places so essentially what we've got here is an oak tree like like any other oak tree which is totally dependent on a vast army of microscopic yeah fungal filaments without which it wouldn't survive and it's just a win win for each them in the end they're helping each other they both require each other to survive if you stretched up the root system of a mature plant you would expect it to have about five miles miles and miles of their root system however if you then stretched out the micro riser network that actually would spread around the entire world so a single tree for a single tree the more I I see this system than well you know what what I thought of as a complex system is actually probably 100 times more complex [Music] to see this root system in its full glory we are going to take our sapling out of the ground and put it on display in one of the outbuildings at East Moline [Music] this is what an oak tree in autumn really looked like at the top we see leaves are being drained of their nutrients below a vast branching lattice of roots evolved to keep the tree standing and extract water and minerals from the soil it is here that our oak will store much of its food over the winter months but laid out like this the roots are not just beautiful they also tell us a fascinating story now Peter to the untrained eye this just looks like a tangle of roots but you can tell a story about the tree now I think we can because what we can see is a root as you can see going down here before it heads off out in in that direction there and this is almost certainly the the root that was inside the acorn and it's headed on down in this direction it's grown on down and then in in the place that this was growing we've got some rock underneath some sandstone and this root has hit that rock and you can see it's it's branched is sent out many branches to try and find a way around the obstacle and it sent this one often in that direction beneath a rope have items' the roots like this sapling will be a kind of map showing the structure and composition of the earth in which they live within the forest there's a very heterogeneous distribution of nutrients it's not uniform and this particular tree has responded to that by producing this plethora of roots this network of roots in this area to fully exploit that resource and presumably once that particular patch of resource here has been used up it'll just go away yes these these roots are ephemeral they'll die off very quickly and the plant will invest it its resources elsewhere so it's a highly dynamic system it's not just fixed and immobile absolutely not what we're what we what we're looking at here is something which is sensing its environment responding to its environment and utilizing resources in a very dynamic way at fifteen years old the sapling has developed an amazing system of roots our tree at white and will have roots many times thicker spreading out anywhere up to 30 metres from the trunk it may seem excessive but our tree will need them not just for nutrients but to keep itself standing as his last leaves are finally shed our oak is now fully prepared for the difficult conditions to come [Music] as winter begins our oath now enters its most perilous seas [Music] to survive it has strict itself of leaves revealing an otherworldly beauty our tree needs to stay alive using almost no energy but in this dormant state a rope will have to face everything from gale force winds to sub-zero temperatures well it's no the depths of winter our tree is bare and it's facing some of the harshest conditions it will have to endure all year at night the temperatures gonna drop well below freezing and out of the shelter of the forest the winds are going to be hitting the top of this tree at full force to get some idea of what the tree experiences I'm going to be sleeping or trying to sleep 40 feet up there while our tree looks lifeless in winter Oaks provide a home to species ranging from spiders and wood lice to bats and owls they all utilized the great size and stability of the oak to provide shelter a tree is not just a tree it's a home I've always wanted to experience what it might be like to live in an oak tree and now I'm finally getting the chance even if it is just for one night [Music] getting up to my perch is no mean feat but it gives me a totally new perspective [Music] once I'm safely Escala is time to try and get some sleep at this height you get a sense of how big a space this really is for a hibernating bat or nesting owl our oak would provide everything they need to stay safe over the winter but for me sleep is not coming easily I did see a couple of noises earlier wish I saw myself in deer or I'm sure a head of Fox well it's about three o'clock morning and it's pretty cool it's just under three degrees and I'm toasty in my sleeping bag he ever got these layers of down that really insulates me pretty effectively from the cold and that is working pretty much like the bark of the tree which is an effective insulator the same principle that is keeping me warm is also keeping our oak and its inhabitants warm his sake Bart is acting like a blanket but temperatures in winter can drop below minus ten and in those conditions the bark is not enough [Music] because water expands as it freezes if our oak were actually to freeze solid in winter it could cause catastrophic damage so the oak has an additional strategy in the lead up to winter it withdraws some of the fluid from its delicate living cells it dehydrates itself what liquid is left contains high concentrations of sugars that act as a kind of antifreeze it's what allows our all to survive not just one cold night but many tens of thousands of them I came up at night last night in the dark and it's now apparent just quite how high I am off the ground thankfully for me it was a pretty still nice cold but it's it's not windy and the view you get from here is certainly worth it but it does give me a an absolutely unique experience of life in an oak tree from up here you really begin to appreciate the scale of our tree it is a huge habitat in winter while our tree might look lifeless is actually a vital part of the ecosystem whiten our oak is crucial to the survival of countless thousands of insects and other animals over the inhospitable winter months [Music] it's now mid-january and we're going to take a new and very different digital scan of our tree by imaging the tree with out its leaves in these still conditions we should be able to get a much more accurate estimate of the weight of our oaks wood and this will be essential to understanding how the tree changes over the year dr. Eric Casella from the Forestry Commission is braving the cold for us and the model he is creating will allow us to see our tree in a totally new way Erick's scan reveals the sheer complexity of our oak using this model we can work out that a tree is made up of almost ten tons of wood but the scan also reveals more his branches are distinctly clustered to one side of the tree our oak has directed the growth of its branches away from the side shaded by the forest and towards the area that receives most sunlight it's uniquely optimize its shape to suit its position but this phenomenon is not just above-ground and Oaks root system adapts to help loose stay standing in winter to see how this works I want to try something that has never been done before I want to simulate the effects of gale force winds on an oak this is a Forestry Commission research site just outside Edinburgh and here they're doing pioneering work examining the strength and stability of many different tree species they have allowed me in for the afternoon to come and watch one of their experiments today for the first time they're going to study how an oak tree behaves during a storm some people might be a little bit shocked that you're just about to pull down a perfectly healthy oak tree what you know what's the reason for doing it well one of the reasons that we do this is to assess the stability of trees and forests and without doing this we don't know what happens when I when the storm hits you're trying to simulate the sorts of forces that that tree would experience in a high winds exactly before we pull it the tree must be rigged with sensors to monitor exactly how it behaves under stress once everything is set is time to get back to a safe distance and begin the pool [Music] beautiful with the tree down Paul and his team can now analyze the results at what angle did the tree suddenly become sufficiently you know so out over the deep it fell on its own and in this case it was only six degrees that's nothing that's that's that's bad that's correct yeah yeah so that tree actually you know it's got very shallow roots it's not very big no that's exactly what it is you can see when we looked at the ritz that it was very shallow while at first glance it may seem this oak came down quite easily it would have taken a forced n storm to produce the same effect as Paul's winch that size a storm can produce 12 meter waves at sea and has gusts of wind anywhere up to 90 miles an hour this oak was in fact amazingly stable given its relatively shallow roots it's likely our oak has grown much deeper roots and with this huge spread of branches it is able to dissipate the force of the winds much more effectively it means that our tree can withstand much harsher conditions that a large heavy structure like a rogue can remain standing over four hundred winters is a remarkable feat of evolutionary engineering and much of what has made it so successful at surviving the cold and the storms of winter has also made it useful to us for thousands of years oak has been an essential building material by slicing and shaping trunks of oak into regular lengths we are able to build all manner of shelters to protect us from the elements in the harsh winter months old timber houses have kept us safe for centuries and thanks to the durability of the wood many of these incredibly old buildings still endure today but there is perhaps one building above any other that showcases the extraordinary properties of oak Timbers and just what they can help us create built in the 13th century it remains one of the most imposing and impressive structures in the British Isles I let its heart is oak [Music] this is Salisbury Cathedral it's one of the masterpieces of British medieval architecture looking at its size and scale it's hard to believe this building was created almost 800 years ago and throughout its incredible structure everywhere you look oak has been put to use during its construction an incredible 2641 tonnes of awkward to help build the cathedral [Music] but it's not until you ascend above the vaulted plaster ceilings that you can really understand how important this single species of tree has been this building has within it whole forests reimagined and remoulded by human hands [Music] that these old beams have been here for a very long time in fact these are among the oldest of the oak beams here yeah the area we're in now is 13th century timber it's been tested and it was felled in 12 spring of 1222 the roof here can be dated so precisely thanks to patterns in the wood as an oak grows it makes large amounts of new tissue in the spring followed by a much smaller amount of denser wood later in the year this rapid then slow growth gives the appearance of rings if the summer weather is good a tree will grow a much wider ring and that gives us a tantalizing snapshot of the past and its climate by looking at similar patterns across many different samples it's possible to date pieces of oak with extreme precision it's even possible to tell where an individual oak tree was growing and it turns out to build this amazing roof the local craftsman used oak from as far afield as Ireland these two don't look quite the same to me no if you look at the Rings closely this is Irish oak the tree rings are really tight together because the summer in the winter almost blend into one another English oak they have hotter summers so they have a better growth rate during the summer it makes it strong then it's also slightly lighter as well which when you're putting thousands of tons yeah walk into a roof structure you know with Salisbury's spectacular roof completed its builders decided to add one extraordinary feature a monumental spire that must have filled the medieval population in the surrounding area with absolute or today it still remains the largest spire in the UK an inside is an incredible lattice of oak Timbers tell you if you didn't didn't like heights this would be this would be not much fun for somebody this is quite an amazing feat of Engineering really and it was essentially an afterthought after the cathedral was built and they've had to do this ingenious framework to help them build it yeah the thousand people were working on it they were doing it to get closer to God if you like so it was their vocation their way of life to be closer to heaven but you just look up a marvel and you and you almost think divine intervention isn't it really it is probably one of the most amazing structures I've ever seen [Music] well you do get an amazing sense of the countryside from up here but don't forget it's the old forest drawing down there the fact that they can withstand all that the weather has to throw at them even in the harshest of winter and the strength and durability and resilience of the wood that they gave that made structures like this possible at all oké is an incredible building material but even today we have yet to come anywhere close to creating structures with the economy and beauty of the oak tree in its natural form [Applause] as the winter deepens and temperatures drop down below freezing our oak structure will really be put to the test I want to find out exactly how healthier roark is and how many more winters like this it might be able to endure thanks to some ingenious new technology we now have the power to look inside it and find out this is very similar to the MRI scanner that we use on the body so it takes slices through the body we take slices through the tray and we're just trying to determine whether the wood is is sound or not as electric currents are passed through the tree a map is created that will reveal the internal structure of our oak well there's the image what does that show us well what it's showing is is that we've got wet and dry areas basically George and the dry areas are in red some of them around the outside of the stem the bulk of the stem in the middle is blue but there are breaks in that and that suggests it was that there's something wrong with the inside of the stem it's not a natural picture clearly something has happened and we need to investigate that further this tiny gap between the roots of our oak may look unremarkable but inside is a hidden world let's get this into position so you can see and we can see a lot of decayed wood so we've got a very very large cavity where the heartwood is missing you know we can see fingers of wood hanging down where the fungus has rotted out the wood between it we call it the Eiffel Tower fungus really only affects the lower part of the stem and leaves the tree effectively standing on its buttresses like this good to see a bit like the Eiffel Tower and it's four legs we got multiple legs hence the name no I mean even though that is quite a big hole it's clearly not having a hugely harmful effect the tree it's still here it's still growing absolutely it's still got these feet in the ground if you like and still drop nutrients and water and give it a firm footing in the ground even though the hearts gone in it and it could still be there the five it's likely our oak will still be standing here alive and growing in the landscape of the 26th century [Music] but after this vast span of time has passed the fungus eating away at her trees inside and the age of its wood will mean it looks quite different scattered across the UK are a select few Oaks that have survived over a thousand years and they give us clues about our trees ultimate fate [Music] this is the bow thought oak in Lincolnshire and over the last 1,000 years its insights have been almost entirely hollowed out by fungus ravaged by the bitter cold of a thousand winters its bark looks like the surface of an alien world the booth or poke is a window into our trees distant future but for now our tree is thriving it has endured everything the winter has thrown at it and is ready and waiting to once again come to life [Music] this oak is going to have an epic growth spurt [Music] this is just an enormous Cathedral light space the multitude of flavors that whiskies possess are testament to the complexity of the Oaks would look at that the just the most beautiful thing since we've been filming our tree has released an incredible 234 thousand liters of oxygen into the atmosphere enough to keep me alive for a whole year [Music] you

Channel: Paul Go

Views: 39,975

Rating: 4.9083095 out of 5

Keywords: Oak Tree, Oak, Tree, Survivor, Natures Greatest Survivor, BBC, Documentary

Id: R0OeSRm1yKc

Length: 48min 32sec (2912 seconds)

Published: Sat Dec 22 2018