 Hello and welcome to this event from the British Library, part of our season on nature and environment, the natural word. I'm Brett Walsh of the Cultural Events Department and it's my absolute pleasure to welcome you to tonight's conversation between Suzanne Simard and Justin Rolat. Suzanne is going to be talking about her new book, Finding the Mother Tree, discovering the wisdom of the forest and that is out today. But before I hand over to Justin and Suzanne I've just got a few points of housekeeping. If you'd like to submit a question please use the Q&A form which is just below the video. And you can order a copy of Suzanne's book, you'll just need to click on the bookshop button which is in the menu above. Now our chair tonight is Justin Rolat. He's the BBC's chief environment correspondent and has over 15 years of groundbreaking environmental reporting to his name. He's interviewed Greta Thunberg, Al Gore, the Dalai Lama and Bill Gates. And his adventures as Newsnight's ethical man were widely celebrated. Justin will be leading the BBC's coverage of the COP26 conference in Glasgow. So without further ado I will hand over to Justin and Suzanne. Thank you very much. Well thank you so much for joining us and we are so lucky tonight to be joined by Suzanne Simard. Now it is hard to overstate how much she's changed our understanding of how forests and in fact many ecosystems operate. She's an amazing scientist who's also lived an amazing life and her wonderful new book, I've got a very uncharismatic version of it, this is a sort of proof copy, a wonderful new book, Finding the Mother Tree weaves both together the story of the science and the story of her life into a wonderful, exciting, profoundly moving and very beautiful story. Now some of you will know the amazing science that Suzanne has been working on. We're going to literally dig down into it in a moment but if you don't know the science get ready to have your ideas about nature transformed. And before we begin, look you can buy the book on the website now. I suggest at the end, I guarantee at the end of this you're going to want to buy it so you may as well go for it now. You can buy it on the website and also you're going to have questions, you're going to be things that you definitely want to ask about this. So as soon as you think of a question put it in the box and fill it in and therefore then we're much more likely to get to your questions and you won't forget them. So fill in questions and of course by the book you certainly won't regret it. With no more ado, welcome to the British Library Suzanne. It's a real pleasure to have you here. First of all though I want to know where are you? How far are you from a forest? Well first of all thank you Justin for having me. This is a great honour and I live in British Columbia and I live in what's called the inland rainforests which are just west of the Rocky Mountains. So these are lush forests, there's lots of rainfall and they're some of our most productive forests in Western Canada. And you, your whole life has been around forests hasn't it? In fact your fam, for generations the Simard family have been around the forests of Canada. Tell us when did Simard's first arrive in Canada? What's your, what's this kind of a link that you've got, this deep, deep link, these deep roots I should say that go into the soil of BC? Yeah that's a great question. I mean I actually live in the home forest where I grew up. They're called the Kootenay Forest and the Monashii Mountains. So I'm definitely a home girl but I came, my family actually came from France originally and emigrated to Quebec and lived in Quebec and logged in Quebec for quite a while. They lived in the Trois-Berviers area but they couldn't make a go of it like it was too hard and so they emigrated to the west and through Saskatchewan stayed there for a while in the cold, cold winters and that didn't work out well so they thought they would head to California. And so they took the train across Canada in this cattle car on the way to California and the train stopped and the doors opened up and the sun came shining through and they thought we're in California. And so that all the kids and parents jumped out up to snow, up to their eyeballs and they weren't in California, they were in central British Columbia and in these rainforests and they stayed and yeah and so they homesteaded on what's called the Chouchouac River now and it was First Nations territory. The Splatsun Nation lived there and my family established themselves as horse loggers and so that's where I came from. It was that whole emigration from France that took a couple hundred years but this is where we live now. So when did you arrive? When did they jump off the train? What year was it? It would have been I think around 1902, something like that. It was my great-grandfather Napoleon Samard and he was married to Maria Samard and they have like nine kids and one of those kids was my grandfather Henry Samard and then of course and all of his brothers and sisters. And we're going to come on to a reading in a moment but first tell me what is a horse log or what was life like? How tough was it logging these forests? Well really tough. I mean you can imagine you know growing up in Mabel Lake and sitting around the kitchen table with all my great uncles and uncles and none of them had many fingers left. Their thumbs and fingers were missing because they'd been ripped off by chainsaws or by saws or by chokers and so it was and my grandfather was hunched over because a tree had fallen off his back. He was missing an ear because the tree had taken his ear off and so yeah I mean their injuries just told the story that it was dangerous work but that's how I grew up and my my grandfather and my uncles and my dad and all his my uncle great uncles and uncles they all horse logged and so that means and they built all their own equipment their own loggers houseboats which we used to stay in and their own barges that they would move these horses across this huge interior lake and then take the horses up in the mountains they built their own log flumes their own water wheels that generated electricity for the houseboats and and they'd horse logged so they were way up in these inland rainforests on the mountainside with these horses and you know doing just to be clear horse logging you cut these huge trees and the trees are truly gargantuan and then you use the horses to manipulate manipulate them often into the rivers which they then wash down the rivers and you've got these I mean there are wonderful pictures in your book of you know people standing on the logs marshalling the logs in the rivers with these great iron hooks kind of pulling the logs I mean possibly dangerous you know no health and safety officer whatever allow anything like that to happen now unbelievably dangerous work unbelievably kind of you know unbelievably um you know uh unbelievably uh physical labor really yes it was um and and you know and people got killed and they blew off their limbs with you know so like you mentioned the logs being they they used to tug the logs across the lake at the end of the logging season and then they would send them down what was called the skookum check narrows and the logs would get jammed up and so they'd have to use dynamite and and there were like men who blew off their hands you know because it was so dangerous or they got squished between the logs that were you know rushing down these rivers so yeah so it was super dangerous but you know as a kid that's not what I saw I I just lived around this family that's what we were and um yeah so the horse logging itself was extremely dangerous and you did describe it well they basically you know the those horses there was uh you know they had huge draft horses that were two thousand pounds and they would haul these great big old growth logs to these flumes that my grandfather and uncles had built by hand and then they would send you know they would basically use these uh pvs and pike poles to get these logs into the flume and then the flumes were full of water and then they would shoot down to the lake and that's where my dad's job was and I have this little passage here from my book that I could read uh if you would like okay so I'll read this is from uh starting on page thirty seven it's just a couple minutes here but um so my dad left the bush work while he was young the incident that triggered this decision he described it for us went on one day when we were on a treasure hunt up in the forest by the flumes with the sun lowering as we sat on the logs and the metal chokers we were happily unearthing piled nearby and it came when he was only thirteen and my uncle Jack was fifteen years old they'd quit high school to help grandpa Henry and uncle Wilfred their job was to wait on the floating logs lashed together with raw hide into a boom on Mabel Lake as each piece of buck cedar banged the walls of the flume snaking a kilometer down Samard mountain and thundering toward them like a luge once the log hit the water it was up to dad and uncle Jack to steer it into the boom while shivering one morning in the spring rains dad panicked wooden pike pole in hand iron lats spliced to its end he tried to stay balanced on the log rolling below him it's coming uncle Jack shouted his feet barely keeping pace with his own churning log while dad's gathered momentum momentum as the waves lapped the cedar log launched from the bottom of the flume like a skier off an olympic jump arching higher than usual before piercing the water 20 meters in front of them straight into the bottomless lake there was no telling where it where it would explode back it back like a missile to the surface time stopped dad told us his mind had snapped back to an essay he'd written about world war two before he quit high school when he wrote all night long the cannons went boom boom boom for 500 words his teacher had asked him for 500 words but dad had no idea how to string so many words together to describe a soldier's terror and he was sure the log was about to shoot up and pulverize him run Pete Jack yelled but he couldn't not even when Jack ran towards the shore screaming at dad to follow him to get the hell out of the chance of the of the logs path but dad couldn't hear a thing seconds ticked by then boom the log shot sky high 20 meters behind them before landing with a big swoosh yeah it's so wonderful and you're kind of I mean I don't know I mean it feels to me like at a very glamorous way to live you know I'm in a really kind of rough and tumble and you know really engaged with the environment I think it's quite clear reading it that you feel that same sense of glamour and excitement at the work that they were doing and in fact you then decided that you wanted to be a forester and this is what back in the 70s and I guess there weren't well I know because you said you're both there weren't that many women who wanted to be foresters at that time were there how did that work out what what jobs were you doing well yeah so I was either going to become an English major or a or a forester and my friend from the Kootenays convinced me that forestry was a play to thing to do and I I had no idea what forestry meant even even though I grew up in the logging family but it wasn't something that girls did right we would either go into nursing or teaching or or you know whatever whatever they would allow us and forestry was closed to women at the time but but luckily for me I was allowed in I was among the first cohort of girls and you know every summer if we were lucky we would get jobs you know doing forestry work and I got a job in the forest industry I was so fortunate and I was working for a logging company so that logging company was it was in the early 1980s and and they you know it was the beginning of industrial clear cutting that means like these big clear cuts which were not at all like how I'd grown up I'd grown up watching my grandfather and uncles you know pull out single trees single tree selection leaving intact forest basically that seeded it and regenerated right away but what I started as a young forestry working in the industry was I was my job was actually to try to repopulate these big clear cuts with seedlings and to me it was like really like why are we doing this but anyway I loved it I I loved being a forester I love that I had this you know it was a dangerous job too um but you know I took to it and I and I yeah I never looked back but you know there were also lots of issues so I'm sure we'll talk about those well that's what I was going to come on to because as you say the forestry that your family had done was very different they go into the woods and seek out the you know I mean in truth the big valuable trees take them out but leave the other trees standing and you found that the this new form of you know with this great machinery that people had to hand this new form of logging was much much more destructive and you felt quite confident I mean what's interesting I you know you're actually quite sympathetic coming from a logging family coming from a forestry family and you know being a forestry you're quite sympathetic towards the foresters and why they do what they do and you're quite understanding that this did seem like quite a sensible practice but you had deep deep doubts about it didn't you tell us about that kind of conflict because that became you know the first couple of years after a couple of years of this you became quite uncomfortable didn't you about dealing with that conflict yeah so I can like I I'm a person of the forest I grew up in the forest right I understand forest as much as I understand my own family but when I came into into the forest industry and seeing that they weren't they weren't just taking out the odd tree you know my grandfather went after white pines which were beautiful but they also logged these understory trees for telephone poles the cedars which was interesting because we were putting telephones across Canada at that time but then when I started it was like they took everything they took the big ones the small ones everything and to me this was shocking like it created such a big open space that that was colder it was hotter you know it was drier than in the forest it was a different climate and then my job was to plant seedlings that were all of one species and whereas the forest themselves had many many species of trees but but the foresters and the industry had decided that you know if we can get value from Douglas fir we're just going to plant Douglas fir you know or we can if we get value from spruce we're just going to plant spruce and so that right away to me I'm like but but we took a lot of different species and now we're putting back one how is that going to work that doesn't seem right and then on top of that you know we the government decided that it also didn't like other tree trees or plants that were competing with these valuable crop trees they called them crop trees and so then they got into this thing about you know herbiciding and spraying and getting rid of other the other trees like the birches and aspens and even at the time they were getting rid of cedars and pines and so it was it just was it just seemed wrong to me I mean it seemed wrong but then you know that is how farming operates and you can kind of see the logic that says right we've cleared this land this land is we want to make this land as productive as possible we'll plant the plants that we want and we'll kill off all the weeds which you do if you were growing weed wouldn't you and that's exactly the kind of logic that they were following it was a policy known as free to grow wasn't it that actually they were legally obliged weren't they the foresters to allow the trees to be free to grow as part of their contract with the government and then they could leave the plot of land let these trees grow and then what a hundred years people would come back the idea was people would come back and cut them but you noticed and some very very vivid writing you know about how upset you are when you go into the these I was going to call them forests they aren't forests anymore these great kind of you know barren valleys that they left behind to look at how the seedlings were getting on and you found you know you described pulling them up and looking at these sort of stunted roots and and you know being really shocked by how hard they were finding it to regenerate yeah I mean it started right right early on when I was working for the industry and noticing that well I was working with these spruce plantations at high elevation for us which I mean really they had no business logging anyway because they were so high elevation at harsh sites but but the trees out the trees were yellow and I started digging them up and noticing that you know their roots look like you know they look like dead carrots I mean that's a good way to say it like they didn't have little roots growing out of them they they were black and they just they were rotting basically and so then I would pull up you know these naturally regenerated seedlings the furs and the spruces that had just seeded in and they had these immense root systems covered with fungi and I thought what the heck why doesn't you know what we're planting look like that what are we doing wrong and I started to think about the fungi um yeah and but I you know I also knew that some fungi actually killed plants like there's pathogens that kill plants but then I eventually learned that there's also fungi that help plants and that's what I was seeing if we may we'll come on to that because I want to whiz back in your life to another episode that you describe again really vividly about your personal connection we call it fungi but the fungi in the soil there's a great passage where you talk about eating soil eating home and how for some reason you still don't really understand it I think your family used to tolerate you you eating the uh the loamy soils and eating these and tasting the different soils yeah you know it shows a very strong connection to the soil ingesting well I think the first picture my mum has of me as a kid is I'm in the sandbox with my mouth full of worms and soil like you know it's like what kind of kid is that right so anyway that's who I was um she always was deworming me because it just was a fact of life every two weeks I'd have to drink this awful of taking stuff tasting stuff to get rid of my worms but yeah there was there was an incident later you know when I was when we were living at Mabel Lake um living on the on the loggers houseboat that my uncle jack had built and um and our dog jigs got you know he was actually the family dog the extended family dog he's a beagle dog and he was always getting into trouble right in fact I think that jigs and I were of the same you know the same breed anyway jigs one morning we all wake up on the houseboats and we hear and it was jigs in trouble again it's like what jigs what are you doing now and so then we all run up the gang planks into the forest and he had fallen in the outhouse and my uncle wilfred comes up and he opens up the outhouse door and all the flies go out and there's jigs down the hall so you don't have to interject for our British largely British audience here who may not know what an outhouse is an outhouse of course is an outdoor toilet please so jakes is in the toilet he's in the toilet and he's six six feet down so you an outhouse you know yeah you dig down the six feet deep hole put a little house over the top for privacy and that's where you go to the bathroom so jigs I don't know what he was after that day but he ended up down there six feet down and so all my uncles and uh and grandpa uh and great uncles they got their pickaxes and shovels and they had to dig them out they had to dig out the sides of the outhouse to get him out because he was so far down and of course I was just like this in seventh heaven I mean dirt and poop and dog and like I just I just laid there on the edge of the outhouse while they're digging out the forest floor and the roots and the soil and watching this whole thing and I just got I just got I was just in love with the soil right it was like this big layer cake with all these colors and roots and mushrooms and yeah I think it was like my home what you were seeing I mean obviously some of this is with the you know wisdom of hindsight but what you were seeing then in this wonderful multicolored layers of kind of of organic material was what well so these are rainforests right so rainfall is what shapes these soils and so when the rain comes down it brings litter and um you know twigs and leaves and that litter falls down and it starts to decay and that's what's called the forest floor and in the forest floor that's all that organic matter gets eaten by different bugs and worms and the bugs and worms each eat each other and that cycles nutrients and then underneath that it's called the forest floor there's a white layer it's like icing on a cake and that white layer is from the bug guts and the minerals in the soil basically washing down through the forest floor in the rainfall like all the drop drop drop drops of rain pulling that you know dead bugs and minerals and iron and it washes it out of that that that layer of icing and it deposits it in an underlayer which is called a B horizon an A and a B horizon that B horizon is like it's like your heart right that's the heart of the soil and not just as at the living part of the soil it actually looks like a heart it's deep red and it's deep red because of all the iron in the soil and all that water filtering through and oxygenating because the soil particles are really coarse which is typical of our of our soils in western Canada because these are glaciated soils and so when they when they weather and you know into smaller bits they they create more sandy particles anyway so as they dug down that they went through this deep heart full red layer called the B horizon and then it got kind of yellow sort of like the sun setting over the you know when the sun sets or rises in the morning it's that beautiful glowing yellow color and then underneath that these big boulders which are you know that's the glacial tail and when they got down to that they still weren't at jigs because he was still further down and so then they had to jiggle these big rocks out and throw them out and then you know this took quite a long time it took the whole morning basically to get jigs out and poor jigs was getting pretty anxious but yeah but what you were seeing partly in those layers of soil was the was the fungi the fungi as you call it that lairs through the forest this incredible network of fungi and and your kind of knowledge of that then your you know scroll forward and you're in one of these clear-cut areas pulling up the self-seeded plants and seeing the strands of fungi on the the roots and this starts to get you thinking doesn't it about the role of fungi in you know in the forest in the in the relationship of the plants between each other tell us what you were thinking yeah well you know when I was when I was in forestry school I was taught there was like basically one group of fungi the pathogens or and the saprotrophs too those are the ones that do the decaying but pathogens were a big deal to the forestries because they infect trees and they can kill them and so I didn't really know that much about these other kind of fungi that just live on the root tips of of living plants but I before long I did learn that they were called mycorrhizal fungi a whole different group a third group so the saprotrophs the pathogens and the mycorrhizes and these mycorrhizes are yeah they grow all of the trees all over the world depend on these obligate associations with these kinds of fungi and the way it works is that the fungi grow through the soil in these big webs these big networks and they pick up nutrients and water from the soil and they bring it back to the tree and trade it for photosynthetic that the tree produces in its leaves and so it's this mutualism where they both benefit from it this is what you discovered you didn't know it at this time though did you I didn't know no the the dying plants don't have these fungi attached to their roots and the ones that have self seeded seem to be connected by this web of this sort of you know spider's web of fungi something seems to be going on here so you didn't know that then did you I did not know it and you began to explore it because you know I mean other people had seen that there was this this fungi but they hadn't really kind of made that the leaps that you subsequently did why do you think it was you kind of saw that this might offer a kind of a new explanation for the way in which forests work that's a really great question you know I think I saw the forest in a different way than my than my colleagues and keeping in mind like I was like the only girl that worked at the forest industry for that company and and them you know and and all you know most foresters were male and so they saw the forest more as a place of competition and I just saw it as this you know the connected network of of plants that grew up and over each other and I saw them as companions to each other so I guess my outlook from the very beginning was a bit off compared to the mainstream but then you know as I eventually became a you know I got my degrees and I started becoming a researcher looking at these plantations and I discovered that yes in the United Kingdom there had been researchers who had been studying these mycorrhizas for quite a long time in fact I think that the term mycorrhizas was coined by Frank in the late night late 1880s I think he was German actually but then the actual work on mycorrhizas didn't really start up until the 70s and 80s and you guys you in the UK have a beautiful man Sir David Reed who did the first really seminal experiment where he grew in the laboratory these little pine seedlings in like a garden box and he colonized or inoculated them with a single mycorrhizal fungus that actually linked those two seedlings together so it wasn't just like helping one seedling it actually connected them together and he used radioactive carbon to label one of the seedlings and he was able to trace the movement of that carbon from one seedling to another and so I read about this when I was trying to figure out what the heck is wrong with our forests why are the seedlings dying and I thought well I wonder if this is the missing link literally and so I started looking for them in the old growth forests of British Columbia but then we just before because we're going to come on to the sort of seminal experiment the Eureka moment but how this was heresy wasn't it the idea that there could be this interconnected and the plant you know trees might be helping each other was forest heresy I mean when you talked about this with your I mean did you talk about it with your colleagues and and if you did when you mentioned these ideas how did they go down with fellow foresters and the forest service that for a long time you actually worked for yeah well when I first started thinking about them I never said a word I mean that would be like I might who would ever listen to me for one and everybody was so focused on getting rid of the native plants and the birches and the aspens that you know I was nobody and so I'm just like okay just keep your mouth shut until you know more and so then I went back and and went to graduate studies and I eventually started you know making these discoveries and and I started to challenge the you know the the sort of the status quo I started I started saying you know maybe it's not all about competition which of course had a huge you know there's a huge theoretical underpinning from Darwin which is about evolution and that got to that let's do okay that's your seminal experiment so you knew so David Reid had done this experiment and proved yeah that they that that two trees could exchange you say carbon it's it's actually the sort of sugary you know it's the it's the product of photosynthesis the kind of the fuel for trees they could exchange it but along these fungal links you took that step further this was these were two trees of the same species you speculated there might be more going on and this is where the real challenge to Darwin comes isn't it so what was the experiment you did that's true so you know I was okay so I was worried that when they they weeded out birch trees that the furs were dying so it it wasn't just because they didn't have my horizons it's because there were pathogens infecting them and so I wanted wondered what are we doing if we're taking birches out because we think they're competitors but we're making it worse and so I thought maybe they're not just competitors maybe you know when we take the birch out we're severing these linkages if they exist between birch and fir I didn't know if they did it all or not all I knew was that David Reed founded these two little seedlings of the same species could be linked together and so I started I worked I started with my phd trying to figure out you know aren't birch and fir in some kind of special community and is that community effect important to keeping the system in balance and without disease and so I did this experiment where I grew birch and fir and cedar together and I discovered through various little experiments that birch and fir did share a lot of these mycorrhizal fungal species in common which meant they were linked together below ground I knew that western red cedar only forms another kind of mycorrhiza called our busketer mycorrhiza and can't at all link in with birch and fir so I planted it nearby and then I labeled my birches and firs with two different isotopes to see whether or not that carbon isotope carbon 14 and carbon 13 would move between them so let's just be clear what's happening you thought that the birches grow a bit faster than the the furs and they overshadow the furs so the theory was that they steal the light from the furs and the furs are going to suffer they're not going to grow as well so maybe there's a bit more to this than that so you thought we'll plant them together stayed the furs so that they're not getting any light and then see whether there's any transfer between the birch and the fir and the idea that two tree species might be communicating in this way was really heretical and a real challenge to science so if I may I've very quickly summarized the experiment so you instead of metabolizing carbon dark straight carbon dioxide you used carbon dioxide with a with a rare radioactive carbon molecule in it which meant that when it got into the plant you could track it through the soil and across so just because so you bagged the the stem of the of the birch put the radioactive carbon dioxide in let it photosynthesize for a while then what happened then what did you do you had a geiger counter didn't you I had a geiger counter yeah and keep in mind I did this to the birch tree at the same time was carbon 13 I put a bag over it and injected carbon 13 and so then we I had an assistant Dan actually I think I was his assistant but anyway we waited for about two hours for the plants to photosynthesize these isotopes and then we went back out and we pulled the bags off and all the you know whatever was left in the bags kind of filtered into the air but you know we were hopeful that a good portion of that ended up in the plants and so we got the geiger counter and I took that geiger counter and I went to the first plant so the one that was labeled with the paper birch that was labeled with carbon 14 and I held the geiger counter up to its leaves hoping that we'd labeled it and it just the geiger counter just exploded it was like right it was it was so alive and so I'm thinking oh thank god you know thank god we got that label because if that didn't work there's no way we detected in a neighbor so just to be clear Suzanne that means that the the birch tree had taken in some of this radioactive carbon yeah processing it in its in its body yeah it was a glowing tree full of radioactivity at that point and so then so then I thought I wonder and we knew based on David Reed's experiment that we should wait about a week for any if there's any transmission to neighbors the birch or the furs nearby it would take about a week and so we were gonna we waited a week but I thought I'm gonna just see now and see if there's any activity like right when we were testing whether the birches were labeled and so I took that one this is hours later hours later yeah the really tree think how quickly alloy takes so fast yeah so fast yeah they photosynthesize and they immediately are sending through their flow them sugars down into their roots literally it's in like tick tick tick it just happens and and Dan's going it's not you know we're not going to detect anything like don't worry about it we'll just wait till we take it to the lab and run it through this big machine called a scintillation counter Suzanne be calm down it's you know calm down yeah you're a scientist yeah and I'm like I can't I can't wait that long and so I took the Geiger counter and I I held it up to the fur and it went it was it was a radioactive two so that was the first sign right that that birch had moved carbon 14 carbon 14 had moved from the birch tree to this neighbouring fir tree that was only like 50 centimetres away then what does that mean see like what is the birch tree what is it doing so what the birch tree is doing it's linked to the Douglas fir with various ectomycorrhizal species these fat fungi that link them together and the birch is rich in photosynth data it's photosynthesises that really high rates the fir not about half the same half the rate birch is also full of nitrogen because it's got all these associative nitrogen fixing bacteria living on its roots so it's chocolate block full of nitrogen fur doesn't have so much so there's this big source of carbon and nitrogen in the fir plant or the birch and very little in the fir and so it's kind of like if you think of it like it's going down a slide that the carbon moves from a source where there's high concentrations of carbon and nitrogen and it goes right down like it's going down like I said a water slide and it goes down into the where it's low concentration in the mycorrhizal network with water you know creating a pressure gradient really and it goes from the source tree the birch to the little sink tree which was the fir which was you know low in these carbon and carbon and nitrogen because you've been shading it so essentially what the birch yeah is feeding the fir tree but what is so extraordinary about that is these are two species that everybody assumes arrivals that seem to be literally linking hands under the soil by the fungi and helping each other and that really was scientific heresy wasn't it I mean it was with the implications of what you've discovered yeah I mean literally as the birch was competing and the more it was competing by shading the fir the more it shaded it the more carbon it gave to fir at the same time and so it was this bell there was a balance between its competitiveness and its collaboration so yeah this was heresy because you know you know ecologists had adopted the theories of evolutionary biologists that competition was all that mattered right that is the underpinning theory of of natural selection which is a good theory but the translation of that theory wholesale into ecology really took hold and that governed how we were managing the forest get rid of the birch as a competitor without ever even thinking or understanding or even being curious that it might collaborate as well so the development of this story just gets better and better because the development of this story is you write it up and you're a doctoral student you know you're quite a year you're not a serious scientist you're somebody who's you know kind of on the road to being a scientist being kind of trying out you're a doctoral student and you wrote up your study this this birch fir cedar study the cedar was the because it's not connected to the network you could show that there was no radiation in the cedar it wasn't getting any of the benefit of this just a tiny amount just tits the amounts but yeah hardly any but the whole thing that you then wrote this up and you I think you said to your you know your doctoral advisor you know what do you think shall I send it as an article and you've decided to send it to to nature and just for people who don't know how important the magazine nature is in the world of science give us an idea of how significant nature is well you know I didn't really know I was like I said I was a young doctoral student in my early 30s and nature science oh that sounds like a good name you know I mean I knew that those are magazines existed but who you know I was a forester like it didn't it didn't really matter if we even published our work but but yeah my advisor nature is the journal of record for the biological sciences isn't it it is the the most prestigious it is the most prestigious journal yeah upstart young doctoral student has done this wacky research out in the mountains of British Columbia writes it up sends it in then there are a few revisions you have to make weren't there and then they publish it as the lead article on the front page yeah well then you forgot one step you forgot one step at first they rejected it the first round they rejected it and so then I was because I there was too much in it and so then I thought and they sent me it back these comments and normally I think at my point of the career now I would have gone oh nature rejected my article that's it I'm not going to try again but I was so young and naive I thought oh I'll just make these changes and send it back you know and so that's what I did without even asking anybody I thought oh I'll just change it send it back and a few days later they accepted it and I'm just like oh my god that was that was cool yeah and so then it ended up on the front cover of that issue you know out winning the genome of the fruit fly which was incredible a discovery at that time and they showed a picture of our rainforest which my best friend had taken that photo so I was very proud this is like exploding these you know these heretical ideas of yours exploding into the scientific community in a really really you know in a really you know dramatic way I mean in science that is really very dramatic presumably then the world of forestry sat up and listened and said what's Suzanne got to say how are we going to change our practices what happened next the opposite of that so um you know I think that I think that my my supervisor was like oh that's interesting but the Forest Service was like it was like a nerd right they didn't have any idea what this meant and but I got an I got an interview with a journalist with the Globe and Mail like that probably the week of the article coming out and I was I was pregnant right I was due to have my first baby in about a week and I got this phone call from this journalist and the journalist is asking me you know we're talking about having babies and I'm like yeah I gained 60 pounds and she's going oh and then she says and what about that study you did you know and I said and I was talking about you know the forest practices and and I and she says well what does it mean for forest practices and I said well for all the good they're doing they might as well paint rocks and so then we finished our interview and I waddled over to my boss Alan Vise's office and I said yeah and then she asked me and I said they might as well paint rocks and he's like you said what yeah and so anyway he got on the phone trying to get this journalist and say please don't write that please don't print that line and she's going well I'll see okay so the next day I get up I open the newspaper and there it is right on the front page Forrester says you might as well paint rocks and so I was just like and my baby came that same day but let me just be clear because what you're saying is rather than painting the forest with with with with weed killer which is what they were doing you might as well just paint the rocks they're not you know yeah might as well go paint a rock is for all the good you're doing right just get the red paint and your practices are stone age literally you know these aren't gonna these aren't gonna solve the problem and then you had your kid but this is but and and actually and that was what 97 wasn't it yes and actually it took years didn't it yes you know there were attempts to undermine the fear theory and manage your forest and you did more and more research it took years before this became established science I mean how much of a battle was that and how how kind of you know how difficult was it as a scientist to fear as if you'd discover this amazing thing this amazing really important thing about forests and then have the kind of well turn on you and sort of you know yeah I mean I had two children at that time and it was just overwhelming right I did all this backlash and and I'm like what's going on here like all I did was my PhD and found this cool stuff out and then I'm just getting dumped on by all these you know established scientists and foresters and and I'm thinking I'm going to just stop doing this like this even though I thought it was fascinating and I knew that it could turn the world upside down but I was so distraught by being attacked like that that I just decided I wasn't going to do that anymore I was just going to drop that area of research I was just going to do something easy like maybe study climate change but then I ended up I actually ended up leaving the forest service because I was I was basically getting more and more marginalized in in the forest service they started you know every time I wrote a paper they would have it re-reviewed and I couldn't start new initiatives I was getting squeezed right because because I didn't embarrass them I guess with my painted rocks comments and then all my studies verifying the work and showing you know we could do things differently they just didn't want to know about it and I was lucky that then I actually stumbled into an academic job which changed my world again because then you had your own team of researchers who could go out and do the research yeah now listen we're getting lots and lots of questions in but we want loads more so do put any questions that you've got into the into the the box provided let me go to a couple of the questions I hope I'm going to pronounce the names right Lucia Caskioli Do you think the forestry industry says Lucia is rethinking their practices how do you see the forest industry changing which is almost exactly the subject we're on so 1997 2021 how much of practices changed well you know you know within about I don't know 10 years they started reducing the amount of herbicide they were spraying on forest at least in the southern half of British Columbia so they they actually did listen to you know that I was saying Birch is actually good for these ecosystems that reduces disease that there's this community effect but today you know in British Columbia in the northern half there's still helicopter spraying Birch and Aspen to get rid of them because they view them still view them as competitors and that's because there's less pressure from the public because there's a lower population up there and so they really haven't you know really fully understood and grasped what this means that these that these these other species are are important for the productivity of the forest and then the other thing that has not changed is that you know this planting of single species then weeding follows along another practice which is called clear cutting and clear cutting is you know now I know a lot more about it but we're still clear cutting just like we did back in the late 1970s in fact it's gotten a lot worse it's gone from a province of old growth forest where I grew up to now it's a province of clear cuts and so those there are you know multiple practices in there that that have not really changed that much over all these decades now let's move on to the the title of the book Finding the Mother Tree because that is the kind of ultimate the direction that the book and your research led you we've established these incredible connections and actually they're much richer than just passing you know the sugars through to each other they pass minerals phosphorus nitrogen to each other in these complex webs they some of the fungus fights off other funguses literally kind of eats away the roots of of funguses that threaten the trees do you get a sense of what the in fact nature called right back in 97 nature called the wood wide web you've established this but tell us what you know what is this idea of the mother tree yeah so you know I think that the field of study got kind of stuck in that there are a couple things that scientists were were really focused on one is what did the this network look like in the ground like can you see it you know what you can't see is hard to believe sometimes and these fungal hyphae that link trees together are so fine that you know in some forests or some kind of like grasslands you certainly couldn't see them the words you probably couldn't see them but in certain forests you can if you peel back the forest for you can see them but for the most part you can't see them so I wanted to prove that you could you know that they existed because we were just kept you know every experiment I did it's like does the network exist like having to go back and prove this over and over again so I felt stuck in that and then the other thing the other part of it doesn't really is it really matter for trees can they grow better can they survive better and so what I did is I got a graduate student Kevin Beiler and I worked with another scientist Dan Durall and we matched the network what that network looked in a Douglas for Forest and these Douglas for Forest are primary forests meaning that they were not logged they were multi-aged and multi-layered forests so there were big old trees that were like 300 years old and every age in between down to little seedlings in the forest so it was like a very complex forest but mostly of Douglas for and then we looked at one species of fungus rhizopogon vinicolor and vesiculose as their sister species amongst you know hundreds that actually exist in that forest so we just looked at two and we mapped we used DNA techniques to map what that network looked like and what we discovered is that for one every tree is linked to every other tree sometimes it's through a series of hop skips and jumps but they are all linked together but most importantly that the biggest oldest trees are the most highly connected and so those in complex graph theory are called hubs and the pattern of that network where you have a few big old trees or hubs and a lot of smaller trees is what is called a biological neural network and so we discovered that the network was a biological neural network and that these old trees were the hubs of the network and so then we started calling them after doing multiple experiments of you know what they did for seedlings growing up around them and realizing that they actually enhanced the survival of seedlings that are germinating around them we started calling them other trees because of that nurturing capability so the idea is that they sit at the center of this network helping and sustaining that you've got all sorts of experiments to show you could plant seedlings Douglas fir seedlings in the shade where they shouldn't by rights grow and then you could see the transfer of all these nutrients they needed and they could flourish there and obviously there's a there is a benefit there to the Douglas fir because as the mother tree goes there are trees to replace them listen let me get to a couple of the questions Daniela Cato says I live in a rural community to the southwest of Tokyo in Japan where forests are woefully neglected and state forestry is virtually non-existent how is it possible she says to engage local communities and reverse the current decay well that's a really I mean that's the crux of our environmental problem I think that not just in Japan it's happening worldwide and I think it's because people have become disconnected from nature because well there's a lot of us we're moving into cities we've got social media and it's easy just to you know to focus your life on that so the solution to the the decay of the environment is to re to re-engage with nature you know all of us to whatever it takes because if we re-engage then we start to care about those little patches of forest and then we'll start to actually be responsible for them and and culture and nurture them ourselves but yeah it's really the key is to reconnect with nature whether it means like going to a park or a forest or even a boulevard or even growing a plant in your house all of those things matter right they all develop those connections that we so need with plants and nature and I love the way your book talks about the connections in your life and your links to the forest and it's a and it's a really moving story of your own family life you know there's tragedy your brother dies there's this kind of joy the birth of your daughters you know the breakup of your man I don't want to go through all the marriage that you fall back and love you get cancer but you through it all you talk about the interconnectedness of families and friends and our links with the natural environment and there's also a great theme of the kind of healing power for you of the forest it seems to me whenever the worst things happen to you you're in your dire straits you sort of strap on a pair of skis and go off and punish yourself on some hideous you know long-distance ski run or you go running in the forest it's in your you seem deeply connected but you obviously feel the power of that connection is something you want to share through your book yeah I mean well just being in the forest like right if it is healing there's something magical and mysterious about that place with those great big old organisms those big old trees that have lived for sometimes thousands of years and just and the whole chemistry of the places it just takes you in and it can heal you right because you've you breathe in that deep air that you know and there's all kinds of biochemistry in the soil that we could dissect your part and say well that's why you're feeling so good and that's why it smells like that but really it you know it is it is just in the whole emergent property of it all is a magical place and so that was always my place of solace but you know what the trees really did teach me too that I knew in my heart from you know from my kid but that connection is what it's all about it's our relationships that heal us and so and in the forest you know it's the relationships with all the other plants and the fungi and trees that heals the forest from disturbances or sickness you know that that healing goes on there too but when I yeah when I was going through my cancer treatments I I formed a network with some really good friends we were all going through chemo together and you know even today like we're constantly in contact that was like nine years ago and we are on a daily connection with each other and I attribute my success and all of us are still alive today that we've that we've done so well because of each other now it's that sense of connectedness is such a powerful theme and there's an absolutely brilliant question here this comes through from Joanna Pocock who I do wonder whether Joanna you've read the book already or you know something about the background of this because she asked this you're going to love this question Suzanne are there connections between your discoveries of tree communication with how some of the first nations people in British Columbia see the tree see tree connections and communities in their myths and practices and that is another big theme of the book it is yeah so yes I mean the simple answer is is connection and and interdependence this you know this yeah that this web of life that we're all together that we're all part of this you know this this biosphere this ecosystem is is the world view of our Aboriginal people and and and that shows up in all of their practices and their art and culture and just their whole world view but yeah I mean that connection is is is what I was trying you know I was trying to grasp with you know how come I was seeing this connection and my fellow foresters weren't and the academics were arguing and and yet when I start talking to the first nations they're like well of course that's how it works right like they already knew about these fungal connections in the soil and they wrote about them and talked about them because they've been observing them for thousands and thousands of years and you know it was I felt like fortunate that I could take western science and just make these discoveries that they'd already known right just by being and living and being connected in the forest as a as as their livelihood you know as their life giving homes really let me go to another question there's a very good one here so this is from Caroline Crookshank who says on a recent holiday to the Rockies in British Columbia she says during Covid-19 we drove through acres and acres of dead trees wasting away was this caused by the methods used in the 70s or is it a disease due to global warming there is a complex story there but you know I mean I'm sort of guessing I think you're probably guessing what she's seeing there as well what do you think she was seeing and and why might that have happened now yeah so there's there are more just more disturbances on our landscape which are directly associated with climate change so through the Rocky Mountains in the in the 1990s there was a mountain pine be the mountain pine beetle outbreak which affected 18 million hectares in British Columbia also moved into the Rocky Mountains and killed a lot of the logical pines and the reason that the beetle took off is because you know it's an endemic in our environment meaning it's always there but as climate has warm as temperatures have warmed up the ability for the beetle to reproduce has gone way up so it can have like a couple of generations in a single year and as opposed to one but also we'd been suppressing fire at the same time and the logical pine forest that it established during settlement of British Columbia in the late 1800s had all grown to a perfect size and age that the beetle just loved and so by the time 1990s rolled around they were a hundred years old the beetles they were just the right thickness that the beetles could breed in them and flourish and these warm temperatures and it just took off and it just killed like like I said millions of hectares of trees including in the Rocky Mountains and there's also been fires that have come along since then and the fires are getting a little bigger a little more severe and that's driven also by climate change and also fire suppression as well as fuels have built up in our forests but yeah I mean we've done things that have made that have that have freed and snapped some of these connections those right that keep the system in a balance it's become out of balance because of climate change and also forest management kind of like I don't know if you're able to help with this and if anyone has any questions we've got a couple of minutes left so do send in questions but I was in the British countryside in a place called Somerset you may not be able to help with this but and I we had a Dutch-owned disease which I'm sure you've heard of it's right through Britain when I was a kid then we've had ash dieback which is a current disease afflicting ash trees and my brother-in-law had cut down lots of the trees on their land because of fears that ash dieback would and it was killing them already but then there are really worrying things like British oak trees now find it really hard to germinate in forests and I just I felt like you know all these really big these are the big trees that used to mark the British landscape used to be the sort of signature trees of British forests all seem to be suffering I mean is that coincidence or is it to do with you know us traveling around the world and spreading diseases to different places or is there some other causes perhaps climate change or some other cause at root I mean you may not be able to answer it and please feel free to say you know it's not your area you know usually the when you have big diebacks it's multiple things spiraling together so climate change probably does have a role but I think you know the oaks are native to to the UK right but the ash trees maybe not I don't think that they are but what happens is like if you for one if you plant a single species and and get get rid of the diversity around it that makes those forests more vulnerable because if something does come along to kill them or you know an insect then those and they're targeting that species then you're going to lose those species whereas if you had mixed plant or mixed forest then you wouldn't lose everything and they also kind of have these protective mechanisms because they can communicate with each other about about whatever you know the herbivores in the forest and and that increases protection but the other thing that can happen is that if you if the trees die and and then it takes you know and then it takes a while if there's a fallow period for a year or more the mycorrhizal fungi you know even if they were compatible between the previous generation of elm trees for example and the oaks if they're compatible that's helpful but they might not be right they might be of different species and they might have died out between the the death and the fallow period and the regeneration of the oaks and so then you need to reintroduce that mic that native microbial that microbiome basically the mycorrhizas and and then trying to establish native native trees like native oaks I think that they'll have a you know they they co-evolved with their native fungi in the area and they should have a better chance and then also mixing species with other native species also improves the chances that these forests will will be will be thrifty even with climate change and I mean it's important that we have thrifty forests as climate is changing because they sequester a lot of the carbon and they make our lives a lot more pleasant so let me ask one last question we're coming to the end of this now Phil Wheeler says since the mother trees are such key links in the network does that mean that even the small scale selective logging that your family carried out could have been having a major impact on the forest? I don't think so you know my family would take out individual trees never you know or maybe a little small cluster when you have just small disturbances like that the four the soil is full of those micro rises still and if there are you know if there of course trees all around that are photosynthesizing and providing energy into the soil it keeps those micro rises alive and then they also provide seed and so they just naturally burst with life again so yeah those selective cuttings are you know there's there's there's nothing wrong with doing that but you need to be careful too and that you know as oftentimes when people do selective cutting they'll just go for the biggest trees because they're the most valuable and what my work suggests is that yeah you can take some trees out but don't always take the big ones out because they've got they've got the genes because they've lived a long time they've got a whole host of diversity of fungi that they're a scaffolding of diversity themselves and so so selective cutting is okay but you know if you can if you can try to focus in leaving these old trees that's that's best so one last question for me how long having established this science now and there's a wealth of other scientists have backed up the work you've done how long will it be until you think forestry practices will change and we'll get the kind of mixed forests that you you say would be far healthier and far better I mean that's the other argument that you make you say this would be far better for the forestry industry in the long term because massive wood is far greater in these diverse forests yeah well I think that the changes are starting to happen already we're having these conversations you know the public people are becoming aware of these connections and the importance of trees in our lives because of the work and the media and I mean a back home where I'm from I can't say that there's been a change in forest practices because we're still clear cutting like way too much one thing that's changed is that instead of planting just one species we're now planting three or four that's good but the amount of cutting is too much and then when we do cut we need to be leaving some of these old trees behind so that they can bootstrap the next generations so I think that that's going to happen I think that we're you know we're in a transformational change and it's all up to us the public and you know understanding to push for those changes push our governments push the industries and because they can do it it can be done we have the science behind it you've made the science well on that note we'll leave it there we've been talking now for an hour it's about finding the mother tree I'm just slightly have you got a copy of the book there because my copy is not you know what I don't have a copy of the book yet because the actual cover is much more attractive than this they said that's the response reading copies and they make them very ungamorous so we'll all which I will go by the book and it's it is real form from a bookshop you should do the same you can buy it on the British Library website if you wish thank you very much indeed for joining us I hope you enjoyed tonight and Suzanne Simard thank you very much indeed it's been an absolute joy talking to you a really exciting conversation thank you very much indeed thank you it's it's my pleasure and thank you for those really great questions thank you a massive thank you to Suzanne and Justin for that fascinating conversation and just a reminder that if you want to buy a copy of Suzanne's new book Finding the Mother Tree you can do so using the bookshop button in the menu above if you enjoyed this event please do check out our season on nature and environment the natural word and please do consider donating to the British Library the library is a charity and your donations help us to continue sharing the world's knowledge I hope you enjoyed this event thank you and good night from the British Library