Transcript: CAMILLE DEFRENNE on Forest Symbiosis /213
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Ayana Young At age 7, Camille Defrenne promised herself to be a paleontologist. She is now digging soil, not looking for dinosaurs’ bones, admittedly, but looking for somethings equally fascinating: plant roots and their fungal partners, called mycorrhizal fungi.
Camille Defrenne The most effective strategy is to protect our existing forest, and especially the beautiful old growth forest of the Pacific Northwest.
Ayana Young Camille spent four years during her Ph.D. studying Douglas-fir trees alongside Dr. Suzanne Simard. Camille found Douglas-fir trees rely as much on their roots and fungi as they do on their needles to adapt to the climate. Since then, Camille crossed the border and invaded the peatlands of Minnesota, a type of wetlands which are the world’s largest natural terrestrial carbon store. Supported by Dr. Colleen Iversen, she is now a postdoctoral research associate spying on roots and their fungal friends in one of the world’s largest peatland warming experiments.
Well Camille, thank you so much for joining me today on For The Wild Podcast. I’m really excited to dive into all things fungi and forest with you.
Camille Defrenne Yeah, thank you so much for having me.
Ayana Young Before we begin I just want to take a moment to honor mycorrhizal fungi, and fungi in general. As I prepared for this interview, I remembered my time in Cordova, Alaska where I learned about the inseparable relationship between salmon and fungi, as salmon rely on certain fungi as sensory markers that aid them in returning to their natal waters, which is such a tender reminder of how powerful these profound actors are...to lose, alter, or jeopardize the health of these connectors will undoubtedly create a profound domino effect in our dynamic ecosystems.
And, many of our listeners are familiar with the forest as a cooperative, resilient system - where vast mycorrhizal networks link one tree to another. However, this interdependence also creates serious vulnerabilities. So to begin our conversation, I’d like to talk about how mycorrhizal networks are faring through land and habitat degradation, perhaps beginning with traditional logging and clearcutting. I imagine mycorrhizal networks are being seriously compromised by clear-cutting, soil compaction, and degradation - could you give us some more details?
Camille Defrenne I want to start first by, you know, saying that mycorrhizal networks are formed by mycorrhizae fungi. And really those fungi engage in a symbiotic relationship with plants, and they physically associate with plant fibers to form those networks. And they eventually link many plant’s fine roots together using their microscopic filaments. So you know, when we think about forestry as an industry, you know, forestry mainly focuses on the trees in a forest, but like human societies, forest ecosystems consist of thousands of interactions and interconnectedness among the plants, the animals, so you mentioned the salmons, and also the microbes that live above and below the surface.
So you were talking about traditional forestry practices, which are cutting and replanting in the Pacific Northwest. And so of course, those practices disrupt the connection between the trees and their symbiosis, symbiotic, fungal partners. So you know, when clear cutting removes all the trees, it can rapidly decrease the amount and diversity of mycorrhizal fungi, because those fungi really need to partner with trees for their survival. And eventually, the decrease in the diversity of these mycorrhizal fungi may lead to a decrease in the productivity of the natural regenerating seedlings. But I also want to emphasize that even when mycorrhizal fungal networks are disrupted because of logging and clear cutting and harvesting, there are still mycorrhizal fragments or mycelial fragments that are left in the soil. And so those fragments are really the seeds that can reform works fairly quickly. And actually research led by Dr. Suzanne Simard, at the University of British Columbia, has shown that when mycorrhizal networks of trees remain in the soil, even if the trees were left after harvest, then those fungal fragments can still colonize the regenerating seedlings, and it can actually dramatically increase their establishment, their survival, and their growth. So really, you know, mycorrhizal networks can withstand forestry as long as there are some trees that are left behind to help the next generation of trees?
Ayana Young I want to bring up another point regarding forestry. Forestry is increasingly becoming more and more poisonous, as fungicides, pesticides, and herbicides are continuously used without any hesitation or regard for their long-lasting and tremendous impacts...Where I am, I currently bear witness to private timber companies’ use of Imazapyr, used for vegetation control...And while the makers of this silent killer, will continue to deny this - Imazapyr, like most pesticides and herbicides, is carcinogenic, so I’m really curious about the long term effects of herbicides on fungal networks?
Camille Defrenne Yeah, so yeah, I'm actually sad to hear that too. But, you know, when you use fungicides, of course, all of the living fungi in the forest will be impacted. So it includes the mycorrhizal fungi but also the fungi that decompose wood in the forest, that are the saprotrophs and also the pathogenic fungi that colonize the plant fine roots. So, yes, by suppressing mycorrhizal fungi using fungicides, you will severely damage the fungal networks. And that's a vicious cycle. Because if you damage the mycorrhizal networks, then less tree fine roots will be colonized by those mycorrhizal fungi. And so it will be even more difficult to form mycorrhizal networks.
So I also want to emphasize that I'm not myself very familiar with research on herbicides and pesticides in the forest. But I can say that based on research in the forest of British Columbia, we know that plants are adapted to their soil environments, really, they are adapted to the microbes that live in the soil, and especially to my present fungi. And so that is what we refer to as local adaptation. And so of course, if we remove the plants, or the insects with the use of herbicides and pesticides, we will certainly disrupt the communities of organisms in the soil, which may then negatively impact the plants and the fungi that rely on them.
Ayana Young Mm hmm. Yeah, that makes a lot of sense. You studied under Dr. Suzanne Simard who so thoughtfully introduced the term mother trees into the scientific lexicon, by proving that not only do older trees recognize their kin, but they actively provide them with larger mycorrhizal networks, reduce their own root competition for them, communicate when danger is present, and even send farewell messages prior to their death...You now work with the Mother Tree Project, which is building upon these findings and contextualizing them with forest resilience. And so, as we talk about disturbances to forest ecosystems, I’d like to ask you a little bit more about what happens when we lose these mother trees and what role do they play in forest regeneration?
Camille Defrenne Right. So as you said, you know, discovering that trees are a cooperative organism was an important paradigm in the way we see forest and the way we manage forest. And so yes, you talked about the mother tree. And this is a project led by Dr. Suzanne Simmard at the University of British Columbia, in Canada. And this project started in 2015, with the core goal of designing forest practices that would be based on ecology, so that we can create more resilient forests, more forests that would be healthy and be able to deal with climate change and to deal with uncertainties.
So this experiment was designed to apply harvesting intensities that would minimize losses. And so minimize losses of carbon, minimize losses of biodiversity, and productivity. So forests can withstand global change without changing their basic structure and functions. And so that means that we want to know how we can best retain the mother trees during harvesting. Because, as you know, the mother trees are the biggest and oldest trees in the forest. And they also have the greatest connections with the other trees, through mycorrhizal networks. And those trees also have the highest photosynthetic activity, which means that they can send a lot of carbon under the crown to assist their fungal partners. So they contribute the most to the maintenance of mycorrhizal networks. And so, the research that we have been doing with mother trees, is showing that the survival rates of seedlings that were planted near the mother trees would increase by two to four times. So it's really important that we try to understand the ecological roles of these mother trees after harvesting, and we tried to really design practices that would help the mother trees to then head the forest.
Ayana Young Well, thinking about mother trees, and the care they provide in stressed forests leads me to think about climate change and how many of our forests, like arctic and boreal forests, are radically changing under hotter and drier climates. Globally, our forests support almost two-thirds of the Earth’s terrestrial species and so, to see them change, will no doubt have profound implications...How are drier and hotter climates impacting mycorrhizal networks and the resiliency of the forest? Will these networks cease to exist or will they just work differently?
Camille Defrenne Yes. So, you know, it's important because many scientists around the world are currently working to understand the impact of climate change on soil microbial communities. And it's crucial because, you know, when we think about these interactions, they just happen at the scale of the millimeters in the soil, but they have global scale consequences for soil carbon sequestration, and also for lessening the gravity of climate change. So we know that elevated temperature and associated crowd, tell the community composition of fungi and also the functional composition, but we have to keep in mind that the impact of climate change on microbial communities are highly context dependent.
So for example, in Alaska, some fungi will prefer to ensure their survival and the warming and drying, so they would maintain the functioning of their cells, rather than feeding on carbon in the case of saprotrophs. We also know that climate change in the Arctic Tundra would favor mycorrhizal fungi that form extensive mycelial networks. And actually my research in northern Minnesota, there's a similar story. So I work on the spruce and peatland responses and their changing environments experiment, and this experiment is funded by the Department of Energy's Office of Science, it's really designed to know how the northern peatland ecosystem will respond to rising temperatures and innovative atmospheric carbon dioxide.
And so what we do with Dr. Colleen Iversen, is to look at the fungal growth and look at the root growth, by remotely operating robotic cameras installed under the ground at the spruce. And we really want to know, as you said, how a drier and hotter climate would impact the world below our feet. And so we recently found that warming in this peatland can lead to a loss of fungal functional diversity. But interestingly, whole ecosystem warming may benefit the formation of mycorrhizal networks, because we observe extensive fungal networks forming, and so if you want to judge for yourself and visualize these changes, you can visit Dr. Iversen’s website, where we actually share snapshots of this hidden world in the spruce experiment
Ayana Young In preparing for this interview, I learned that Dr. Simard has run experiments with douglas firs and ponderosa pines to learn how they will behave amidst climate change, because ponderosas, as lower-elevation species, are expected to begin replacing doug firs... And sure enough, it was shown that in areas where doug firs are mother trees, when they are injured, not only do they dump their carbon into the network so that the ponderosas can have it, but defense enzymes are up-regulated in all seedlings - which underscores again the importance of mycorrhizal networks as trees navigating changing climate regimes, as well as an example of how native species are aiding new species when they recognize that they may no longer be the dominant species. It’s so amazing-
Camille Defrenne Yeah, exactly. So really, the trees have evolved in, you know, a cooperation relationship with the trees of the same species, but also the trees of different species. And so you mentioned that trees can recognize their offspring, they can recognize their kin and send more carbon to their kin through the mycorrhizal fungal networks. And so you mentioned Dr. Suzanne Simard research on ponderosa pine and Douglas fir. But she also showed that Douglas fir can collaborate with deciduous trees. So when those deciduous trees lose their leaves during the fall and the winter, then the Douglas fir trees can send more carbon to them, to help them deal with the fact that they lose their leaves. So they cannot photosynthesize enough to gain enough carbon to sustain the roots.
Ayana Young So incredible, well I’m also curious about how fungi are affected by forest fires, and if changing fire regimes mean anything for tree communication? How are mycorrhizal networks impacted by fire?
Camille Defrenne Yeah, so I want to emphasize first that fire is part of a natural ecosystem soil. So fires are part of the functioning of a natural ecosystem. But when you have changes in fire regime, or shares, changes in fire intensity and severity with climate change, then that's becoming a problem to the ecosystem, because the natural ecosystem would not be adapted to the specific changes. So depending on the severity and the frequency of fire, they can severely impact the microbial communities in the soil, but they do not necessarily kill all the microbes in the soil, they mainly change the community composition of the microbes. And so of course, if you think that, you know, some species rely on certain microbes, or on certain mycorrhizal fungal species to survive, and then if the species cannot withstand fire than those plant species might just disappear because they will not have their partner to sustain their growth. So really, when the forest is reduced to ashes, microbes are really the first step for the forest to regenerate.
Ayana Young That's fascinating, too. Last night I was in this incredible national forest that has definitely been hit by fire. And there's a mosaic of old growth, and probably second, third, growth from old logging sites and then these fire patches. And what's coming up in those fire patches is so much abundance and food and medicine and biodiversity. So I could really see how the forest is regenerating relatively quickly and bringing in so many animals to these fire burned areas to create new life. And yet, like I said, just so much more diversity than even just the forest 100 feet away that didn't get burned. And so just being in a forest that had had this mosaic of burns, and really understanding the evolution of what happens after a fire, it was an incredible space to be in to have a different perspective on the conventional or the kind of the majority fear of forest fires in general.
Camille Defrenne Yeah, exactly. And it's how you say it, you know, it creates diversity, it's part of the natural cycle in nature. And really, after a fire, you can have many different fungal species that would actually take advantage of the high temperature and disperse their spore because they like fire. So it creates new communities of plants, and fungi. And you know, eventually, when the forest develops and evolves, then we might end up with a forest hundred years from now, that would look the same as a forest that you can see that didn't have fire or didn't burn. So it's really creating a mosaic of different patches on the landscape and it's actually really beautiful.
Ayana Young I’d like to transition our conversation to discuss restoration, reforestation, and afforestation and how these goals have really been bolstered by scientific studies that highlight their possibility to cut down atmospheric carbon dioxide by 25 percent...and so in the past couple of years, governments, corporations, and NGOs have really become hyper obsessed with mass reforestation and afforestation in the name of carbon sequestration, but even a sort of cursory dive into this reveals that, like any other quick fix, it is riddled with problems.
And I know I’m going to go on here for a bit, but for listeners, I want to share a short story of what this looks like. In Japan, during World War II, huge swaths of forest were cut down because of a booming demand for timber. In the aftermath, Japan instituted a large-scale tree planting initiative, but of course, there wasn’t an ecological approach to this, the government just wanted to reforest as quickly as possible so there would be future resources and they could mitigate mass rain runoff and landslides caused by earlier deforestation...so they only planted two species; fast-growing hinoki and sugi, or Japanese cypress and cedar, essentially converting over 40% of Japan’s total forest cover to just these two species. And today, the ramifications of this move are really tremendous. For example, because evergreens don’t drop their leaves as often; the surrounding rivers now have less fish because water sources are without minerals, and Japan has a mass hay fever problem. Unfortunately, this isn’t just in Japan, many countries continue to make the same mistake by using single species...Countries like China, Brazil, and Australia, which coincidentally, alongside Russia, the US, and Canada make up more than 50 percent of global tree reforestation potential.
So, I wonder if you can talk about the inner workings and the problems of these one-track-minded solutions to carbon emissions and the ramifications of putting trees where they don’t belong?
Camille Defrenne Yes, exactly. So I didn't know this problem with Japan. And I think that's a very good example of bad reforestation practices. So I want to emphasize you know that trees and forest ecosystems help limit global warming because they reduce the concentration of carbon dioxide in our atmosphere. And so you know, regrowing and expanding existing forests, which is reforestation, and growing new forests, which is afforestation are good ways to capture and store additional carbon from the atmosphere.
But, you know, effectively planting trees to capture carbon dioxide, you have to think about several criterias, and you cannot just plant trees everywhere. You cannot just plant the tree species that you think will be best for this area, there are many things to consider. And the first criteria is the location of trees, right? So, trees would not naturally grow in some areas such as savannas, grasslands, or tundra ecosystems, and so if you plant trees in those types of ecosystems, the carbon dioxide could actually be released into the atmosphere instead of being removed.
And so it's also a big problem in peatland ecosystems, because many peatlands have been trained for tree planting. But we know now that the carbon that was stored for millennia into the peat was released because trees were planted in those ecosystems. So actually, tropical ecosystems and especially the Amazon rainforest, have the greatest potential for both large scale restoration and afforestation. And, you know, I mentioned those different criterias and the location of trees are important, but also, the choice and management of tree species are of crucial importance.
So you know, we want to plant a large diversity of native tree species, because that's the more effective way to store carbon, more than monoculture. So you were talking about the example of Japan, but we have many more examples around the globe where fast growing pine and Eucalyptus and poplar were planted, and usually those species are not native to the location where they are planted. So it's a big problem. And it's actually not storing as much carbon as we want it to. And also, we have to think about what happens to the carbon after it becomes a tree. Right? How can we store the carbon when we replant the forest. And so the carbon can be stored as wooden projects, it can be stored in the soil, and it can be stored in sediments. And all of this would help global warming or would limit global warming. But it's really important to consider the afterlife of a tree.
Ayana Young Mm hmm. Just thinking more about Japan, and even what I've heard from folks in Australia, that in some areas native forests are actually cut down and have been cut down and replaced by a more lucrative plantation forest. But of course, that can also be deemed as a carbon sequestration project. And if you don't look at the fine print, you're not realizing what's actually happening to then sequester the carbon or the other thing, the current national Japanese forestry laws mandate that whenever tugi or hinoki trees are cut down, it must be replanted with a seedling of the same species. So it's not even really possible to do ecologically minded holistic reforestation in some of these areas, even if somebody wanted to. So yeah, there's a lot of complexity here. And I'm just so fascinated with this whole world of the reforestation industrial complex, especially in my own work. And it has been a real shocker to learn all this stuff about tree planting, because from the outside, it seems so good. It seems like there, what could possibly be wrong with planting more trees, but then you open up that wormhole. And you realize there's a lot going on there.
Camille Defrenne Yes, I also want to mention, you know, many NGOs that are trying to help society to offset our carbon emission, some of the NGOs to not want to invest in planting trees, because as you said, there are so many things to consider and forest takes a lot of time to regenerate and to grow. And so it can be a very effective strategy to tackle climate change, but you know more in the long term, but in the short term, there are projects that might be better suited to mitigate climate change than planting trees, especially if you plant trees without having a good management strategy plan.
Ayana Young Absolutely. Well, before we delve deeper into the reforestation industrial complex, I’m thinking back to my conversation with Peter Wohlleben, who reminds us that trees that grow slower and under canopy are stronger, they have more fungal connections and they are a part of this truly powerful system...but like we were just talking about, human desire - institutional desire, is to just plant trees that grow fast so we can see our success and feel like we’ve fixed the problem - but how do we reconcile our desire for tree growth if it comes at the expense of biodiversity? And so I’m thinking about how a lack of wisdom on our part, and our desire for fast global solutions has profound implications on ecologies, as well as how, if we sever old-growth, we sever the wisdom amongst trees. And I wonder if maybe you can speak to the importance of saving old-growth forests in relation to these mycorrhizal networks?
Camille Defrenne Yes, exactly. So, as you say that the most effective strategies to protect our existing forest and especially the beautiful old growth forest of the Pacific Northwest, and so, it is really tied to the research of Dr. Teresa Ryan and Dr. Suzanne Simard on the salmon forests of the Pacific Northwest, because they show that the nutrients that are taken up by the salmon from the sea are returning to the forest through the predators such as the wolf, and the bears, and the eagles, eating the salmons. And so eventually, you know, those predators leave the salmon carcasses on the forest floor, and the nutrients from the salmon are then, you know, decomposed and taken up by the roots, and the mycorrhizal fungi. And those nutrients are then transferred through different trees, through the fungal networks. And we can find the signature of the salmon nutrients in the tree rings. And these memories, these signatures, are stored in tree rings for centuries. And so it really provides a memory bank of historical salmon runs. And so really, the circle of life depends on the trade of mutual respect. And so, you know, this is a good example of how people are sustainably embedded in these complex adaptive systems that are a forest and the societies and so, you know, we really need to protect this memory, because at the end of the day, it is the memory of our societies. So we need to protect old growth forests.
Ayana Young I could not agree with you more on that. Something that I’m really witnessing is the ways in which restoration and reforestation are by-products of extractive industry, that is the framework they exist in, and so I’m really questioning, what are we putting into motion? And I come back to a question Suzanne Simard poses, which is: how can we reinforce and help the forests rather than weakening them? And, to me, so much restoration work actually does weaken the forest, it is not in servitude to these ecosystems, it serves corporations and companies that are backing these projects for image boosting or job generation... So my question here is, how can we cultivate restoration work that is truly in servitude to the forest, while also creating integrated and dignified jobs and experiences for each other?
Camille Defrenne So when forestry, when forest practices are based on ecology, we want to, you know, help forests to withstand global changes, we want to help them, you know, sustain their biodiversity and keep storing carbon and keep being productive. And so really trying to protect existing forests is the best way we can, we can do that. But when we recruit and expand existing forests, we need to think about those three things, right? So carbon storage and biodiversity and productivity. And when you plant a mixture of native species, and you manage them sustainably, this might be a very encouraging way that we can save the forests and we can have the forests be more resilient to future disturbances.
Ayana Young Yeah, I think about, there are some restoration projects that are happening near me. And I kind of put the restoration in air quotes because they're wanting to do road decommissioning. And that means, you know, to them well, what it actually really looks like is, for this instance, particularly, it's a logging road right by a creek and it has been growing back for the past 30 or 40 years. And so there's huckleberries and redwoods and Doug firs and red rood and white thorns have all grown up on this old logging road and the buffer zones in between it. So there's no sedimentation coming off this road anymore. And it's been taken over by plants, but they want to bring in bulldozers and excavators and dig up all of this road that has been overgrown, so take out all of the trees and plants that have grown on it, dig up the soil, which of course is going to create even more sediment, which will then affect the creeks and the rivers, potentially really injuring the salmon in terms of the beds that they lay their eggs in or even suffocating them and their gills. And so I'm looking at this project, knowing that it's funded by Bank of America and the likes, you know, getting major, major grants and massive funding to basically go in use more fossil fuels, use these large machines that are compacting the soil, ripping up what's already grown just in the name of restoration. And like this is just a way to keep the economic capitalist model moving forward. It's just a way to continue eating up fossil fuels, get subsidies, and disturb the forest even more. And so it's, yeah, I definitely have a lot of frustrations when it comes to modern day restoration projects that have been created by the logging industry. And then I know there's so many well, meaning people like myself who didn't understand this, and really just wanted to support restoration and reforestation, not realizing that there's so many nuances to how it's done. And yeah, so I just had to give you that little rant, because I'm so frustrated by it all.
Camille Defrenne I do understand this, this frustration, Yes. I cannot comment on specific examples. But, you know, if we keep in mind that whenever we want to restore an ecosystem, you know, we have to think about the ecology of the ecosystem. First, we have to think about the consequences, and what is the context? And why would you restore the ecosystem, you know, what's your primary goal? And, you also have to think long term, right? And so many of the projects around the world might not have these long term perspectives. And it's really, it's really important, because ecosystems are taking a long time to grow, or they're taking a long time to establish those interactions and interconnectedness that makes them resilient to disturbances, resilience to climate change. So we need to give nature more time.
Ayana Young Yeah, yeah, I'm with you there. And I think that when we try to speed up a forest and say, oh, we're gonna speed up this process and make it be old growth, sooner. It's like, well, we can't make old growth sooner. I mean, it's just old growth is old growth, because it takes time and it's complex, and things grow and the soil builds, it's like really such a human supremacist mindset to think that we can somehow create old growth in our lifetimes, or within five years or 10 years.
Camille Defrenne I'm really with you on that. And I would say, as an individual, I strongly feel that we cannot create nature, you know, we can thrive to understand, and we can thrive, to help nature to then try to help us, you know, mitigating climate change and sustaining your local communities, but we really have to be humble with that. And and I think this is really what the Mother Tree Project is about, you know, trying to help for us be more resilient, and trying to take the knowledge that you know Suzanne Simard and colleagues have accumulated for decades, trying to really understand what are the role of mother trees and how we can, you know, maintain those trees, those extremely important trees so they can better head the next generation of forest to deal with changes. And the same way as society has to deal with changes too so we also have to take the ecosystem as examples and you know, take more time and create more interactions. It is pretty hard right now with our situations, but it is really important.
Ayana Young In context to reforestation and restoration, I do want to ask you a bit about the mycorrhizal networks you observe...when we introduce trees and plants that are grown outside of that soil, into clearcuts, where the soil has been damaged, does this impact tree growth? Does it make sense to relocate native fungal strains into forests that have been damaged like they do wish trees and other plants.
Camille Defrenne I don’t really have a lot of knowledge on this topic. And I'm not, I'm not really an expert in, you know, reintroducing native fungal strains. I think, as an individual, as an individual, I feel that the ecosystem could take many different roads, could take many different paths. And it's really hard to anticipate how an ecosystem would react to the introduction of an external agent, even if it's native from the soil of a given area, right? Because, you know, you have so many interactions, and so many interconnections that, you know, if you remove one of the nodes, that are the trees, or the plants and the links that are the fungi, you don't really know how the ecosystem will recover. And so this is the same principle, if you add one, link, one agent to the ecosystem, you don't really know how the others part of the ecosystem would react to it.
Ayana Young Right? Yeah, it's complex for those of us who do want to be engaged with reforestation, in a holistic ecological minded way, learning from the First Nations people who hold the Traditional Ecological Knowledge, you know, I guess, do you see any forms of replanting, or re-introducing different species into a damaged, let's say, clear cut area, do you think that is beneficial at all? Or do you think the forest should just be allowed to repopulate on its own? Or so yeah, it's like, are you on either end of that spectrum? And if you are on the spectrum, that “Yeah, we can introduce things”, what do you think is the best way to do that?
Camille Defrenne Right. So I think the context is really important, trying to understand what's the history of the forest that was cut, you know, what are the native species? What was the connection, you know, what is the, the microbial communities of the soil and as an individual, I do think that reforestation projects are very important, and and, you know, research shows that they, they can help us mitigate climate change, but really trying to understand what are the issues that you want to plant? What are the long-term consequences, you know, trying to take all of that into account. And you know, planting trees is not just about putting a plant into the soil, it’s really trying to help the plant be resilient to what's going to happen to it, right. And for that the plants need the microbial community and the right microbial community. So you have to take all of that into account, before replanting trees. But I do think that you know, first protecting existing forests and then second, planting trees are the best solutions to help our forest be more resilient to future conditions.
Ayana Young Well Camille, for my final question I’d like to ask you about a project you are currently working on which assesses the response of northern forested peatlands to increasing temperatures and carbon dioxide levels. And for those who are unfamiliar, peatlands are so vital when it comes to climate change because they hold around a third of the world’s carbon...So, what are you learning about the mycorrhizal networks in peatlands under climate change and what kind of rapid changes are they going to experience?
Camille Defrenne Yes, so thanks for, you know, telling people that peatlands are extremely important because they actually store more carbon than all other vegetation types combined, but they are highly vulnerable to climate change and mainly because of the combined risk of rising temperature and changing the hydrologic conditions in the peatlands.
And so I'm working on this experiment called SPRUCE, and it's located in the peatlands of northern Minnesota. And it was really designed to know if climate change would lead to a release of carbon from this ecosystem. And so what we’ve found so far is that whole ecosystem warming has extended the active season of the trees and shrubs that are growing in the systems. And so that means that the trees such as the Tamarack, the Spruce and the shrubs such as rhododendrons will have more time to grow.
And some other research on the SPRUCE project also shows that mycorrhizal fungi decompose faster when the soil is warm, and when the air is warm. And also, the shrubs are really happy in this warmer environment and their growth is exploding. And I want to emphasize that all of these changes have converted this specific peatland from an ecosystem gaining carbon to an ecosystem losing carbon at a pretty high rate. And so, you know, if we think globally, you know, if we think about peatlands around the world, it's possible that we might lose carbon from this peatland, that can be as high as 50% of the amount of carbon dioxide emitted by each car in the US. So you can, you know, think about it and realize that it's sort of a lot of carbon that we might be losing. So I want to emphasize that trying to protect boreal peatland biodiversity is crucial if we really want to lessen the impact of global change, so you know, you can try to get engaged with NGOs that are trying to protect this fragile ecosystem. And you can yourself, you know, educate yourself on the importance of this ecosystem, but also on the importance of Arctic tundra, and on the importance of tropical forests, and it's free, but your knowledge and what you can do with that.
Ayana Young I know I said that was my last question. But I, I would love to hear just a little bit more about the peatlands and I'm wondering if you could kind of orient us geographically to where many of them are located. Maybe what they look like, or even what the site that you've been working on looks like, feels like, where it is, just because I really want the audience to be able to visualize these peatlands with us.
Camille Defrenne Yeah, yeah, no, peatlands are extremely beautiful. So the term peatlands refers to the peat soil and the wetland habitats that grow on it. So you know, the peat layers are partially decomposed materials that have accumulated over the boreal landscape or the tropical landscape for thousands and thousands of years. And so, peatlands are generally located in the northern hemisphere, and we talked about northern peatland or boreal peatlands, but you also have a significant area of the globe that is covered by peatland in tropical forest or in the tropical biome.
And so in northern Minnesota where the spruce experiment is located. We are working in a peat bog. And so this ecosystem is waterlogged. The whole year it's it's very wet. And we have a lot of mosses that grow above and create the most beautiful moss carpets and we have the mosses, some green, some red. So it really creates a landscape, a mosaic of different colors. And then the mosses are surrounded by the trees and the shrubs that are also a part of the ecosystem. And so we have some trees such as spruce, that are conifer species that never never lose their needles. But we also have tammaracks, that lose their needles. So that's deciduous coniferous trees, and those beautiful large trees, before they lose their needles, they turn yellow. So if you have the chance to be in Minnesota, and to see those peatlands in the fall, you can see that the whole landscape will become yellow, because of the large trees. So that's that, that's extremely beautiful.
Ayana Young I didn't want you to stop. I was just with you.
Camille Defrenne If you really have the chance to go to northern Minnesota, the SPRUCE experiment is open to the public. So you can really see the huge greenhouses, that encompass the trees and really see for yourself the importance of peatland, and you know, what scientists have to do to understand their response to global change. And so, the SPRUCE team has gigantic greenhouses of seven meters tall. And so the way it works is that we have different greenhouses with different temperature treatments. So in some greenhouses, you enter, and you feel that it's really warm, it may be four degrees warmer than the outside air temperature, that in some greenhouses you enter, it's actually plus nine degrees Celsius. So it's, it's really warmer than what you can experience if you are out in the natural peatland.
So it's really interesting, visually, to look at the changes in the species’ community composition and to look at these changes or so in the number of mushrooms that can grow above the moss carpet. So you might have a lot of mushrooms growing in those really warm green houses. And then if you go to a greenhouses, that would be less warm. What you can see is way more mosses, but less mushrooms, and the trees are greener, in those less, or in those colder greenhouses.
So it's really interesting to judge visually what's happening. And actually, I would encourage listeners to go to the SPRUCE website, because the SPRUCE team has installed cameras in each of the experimental enclosures, where you can actually visualize what is going on live. And then you can look at the change in the species, the pattern of the growth, and the spring green dawn and autumn green dawn of the trees and shrubs. You can look at that with the videos that we are taking. So if you're interested in that you can visit this website.
Ayana Young I will yeah, I have a bit but I will again. Well Camille, this has been so wonderful. Thank you so much for talking about the forest with me, which is definitely one of my favorites, if not my favorite topic to jump into. So yeah, this has been really lovely.
Camille Defrenne Yeah, thank you so much Ayana and thank you for having such a wonderful, wonderful Podcast.
Francesca Glaspell Thank you for listening to another episode of For The Wild Podcast. The music you heard today was by Harrison Foster, If By Whiskey and Ali Dineen. For The Wild is created by Ayana Young, Erica Ekrem, Francesca Glaspell, and Melanie Younger.