Mycorrhizal Network - Largest Living Organism

Chelsi Abbott, a technical advisor and education specialist at the Davey Institute, talks about the mycorrhizal network including how it works and how it connects to plants. 

In this episode we cover:  

• What is mycorrhizae fungi (1:14)
• The beneficial relationship between the fungi and trees (1:59)
• Seeing mycelium in real life (4:07)
• How mycorrhizae fungi finds plants (4:45)
• How big mycorrhizal networks can be (6:52)
• How to help mycorrhizae help your plants (8:16)
• Things you might be doing that harm mycorrhizae (9:13)
• Is mycorrhizae okay for vegetable plants? (10:00)
• How Chelsi educates through her job (11:59)
• What Chelsi enjoys abut educating (13:03)
• Chelsi's Davey Tree journey (13:40)
• Benefits of mycorrhizae fungi for the plants (15:56)

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To learn more about the work Chelsi and the Davey Institute do, click here.

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Connect with Doug Oster at www.dougoster.com. 

 
Have topics you'd like us to cover on the podcast? Email us at podcasts@davey.com. We want to hear from you!    

Transcript

Doug Oster: Welcome to the Davey Tree Expert Company's podcast, Talking Trees. I'm your host, Doug Oster. Each week, our expert arborists share advice on seasonal tree care, how to make your trees thrive, arborists' favorite trees, and much, much more. Tune in every Thursday to learn more, because here at the Talking Trees podcast, we know trees are the answer. This week I'm joined again by Chelsi Abbott. She's a technical advisor and education specialist for the Davey Institute. She's based out of Chicago, but joining us from Ontario. Welcome back, Chelsi. I can't wait to talk again.

Chelsi Abbott: Oh, thank you for having me and you know I can't wait to talk about today's subject. [chuckles]

Doug: Before we came on, we chit-chatted a little bit and said, well, Chelsi, we're going to talk about mycorrhizal fungi and networks, and she literally raised her hands up in the air, swung them back and forth, has the biggest smile on her face, so you're going to have to help me understand this. As an education specialist, you have a new challenge, teaching me about mycorrhizal and what it is and how it works and how it connects to plants.

Chelsi: Challenge accepted, my friend.

[laughter]

Doug: When I hear the word mycorrhizal fungi, I think of just some kind of network under the ground. I don't know what it does, but it's there and it's linked together. Am I close?

Chelsi: You're actually very close. Very close indeed. Mycorrhizal fungi, they are what we call beneficial fungi, so they are helpers. We talked a lot on this podcast, I think, about parasitic fungi, so ones that are causing diseases, but mycorrhizae actually form associations with our trees and there are some benefits that come from both parties. It's a mutual or symbiotic relationship where both hosts are benefiting.

Before we get to the network, I'll just say what each one of them gets out of it. It's a fungi, forms an association with a root. It gets a home and it gets a little bit of carbohydrates from the tree, and then the tree itself gets this network in which can increase things like nitrogen and phosphorus, but also increase things like water uptake because essentially, the fungi themselves are increasing the surface area of the roots.

Doug: Does someone get more out of this?

Chelsi: There's more too.

Doug: Oh, okay. Go ahead.

Chelsi: Well, does someone get more out of this? That's a very, very good question. The answer is yes. A lot of people like to call it the tree internet or the wood wide web. They always put a lot of it on trees getting all the benefit, but in reality, the fungi is the one who's benefiting the most out of this relationship because they will often form associations with larger trees, so they can have a larger amount of carbohydrates and they can actually make as many connections as they want, whereas trees usually at one certain time will only really be associating with one or two fungi or these fungi, they're connecting all bunch of trees together. Most of the fungi get most of the good stuff.

Doug: Let's just say that they're hooked up with a couple trees, the fungi.

Chelsi: Yes.

Doug: They're getting this, what they want out of it as those trees feed them and they're feeding the trees. Does that mean that the mycorrhizal fungi can get bigger because of that, because they've got that stuff they're getting from and then find another symbiotic relationship?

Chelsi: Yes, certain fungi, the bigger the tree, the more carbohydrates source, and then that feeds them so they can produce more hyphae and hyphae are essentially these little tiny threads. That's what's actually growing under the soil. The more trees that they hook up with, yes, the more that they'll get out of the relationship and then it just feeds itself in a little bit of a way.

Doug: Can you see it, or have you ever seen it, or is it under a microscope or what does it look like?

Chelsi: You can't see hyphae, but you can see what's called mycelia, which might be a term that you'd be more familiar with. Hyphae essentially make up mycelia. Mycelia is just a mass of hyphae, and you've probably seen it before if you've ever looked at mulch or maybe a bunch of leaves on the ground and you see this white stuff coating all of the mulch, that's mycelia. Typically that's growing in the ground, but sometimes it comes up and does some other things from a decomposition standpoint.

Doug: In general, is the mycorrhizal fungi there already, or is it something sometimes we're adding?

Chelsi: That's the golden question. I can actually bring you all the way back to when plants first colonized the land. It was because of mycorrhizal fungi that they were able to do so. Plants have been forming these associations with fungi all the way back to that era. It's something that naturally occurs. Now a lot of people do want to add mycorrhizal into the soil because they're like, "Oh, it benefits my tree," but the likelihood is, is that they're already there unless there's been some kind of ecological disaster, like a huge flooding event or like drought, they're probably already forming associations as part of the natural environment.

Doug: In general, we're not adding it when we plant. There's probably no benefit to doing that unless, like you said, there's some kind of disaster.

Chelsi: Right. Some people are out there doing that, they're adding it in with plantings. Again, the science is a little bit hazy on whether that's actually going to work. Because one of the other things to keep in mind is mycorrhizae form specific relationships, and not every mycorrhizae matches up with a tree. We don't know, are we adding the right mycorrhizae, are the conditions correct for it?

It's a very complex dance that they do together. Sometimes adding it in might not be beneficial, but one of the fun facts, if I can tell you, is oftentimes when animals deposit, like say acorns naturally, they'll also maybe have some excrement around and sometimes they can actually deposit the mycorrhizae because of what they forage. If they eat some of the mushrooms, they'll bring the spores over when they deliver the acorn. Then suddenly, bam, that acorn has its mycorrhizal relationships already sort of formed before it starts growing, so in some cases, yes.

Doug: Then how about the network? It can be huge is my understanding, right?

Chelsi: Yes. It's pretty much think about if you've ever heard of the humongous fungus, which is an Armillaria species, it's in Oregon and it covers something like 1.3 square miles underground and it's all one fungus. The whole thing is just one organism. It's the second largest organism in the whole world. It's just the network in the soil of these mycorrhizae is just pretty much everywhere, the whole ground. Again, it'll depend on what type of soil we have, which mycorrhizae will be present, but there are fungal threads growing all over this earth.

Doug: Are there some trees that don't connect with a mycorrhizal, have a relationship, or do most trees, most shrubs do they have this relationship?

Chelsi: Most trees and most shrubs do. A woody plant typically would, and even some palms have specific relationships with specific types of mycorrhizae. So there are several different types of mycorrhizae. For example, oaks will form with one type, whereas palms will form with another type. Not all of them are forming with the same mycorrhizae, but they're subsets of them. Yes.

Doug: See, it sounds so great from a plant-growing perspective. I have to think that people are trying to figure out like, how do I help my mycorrhizal fungi do their thing? Is there a way we can help?

Chelsi: Absolutely. Rather than adding more in, it's about build it and they will come kind of scenario. Mycorrhizae are soilborne, meaning their house is the soil. If the soil is not great, if it's super dry or super wet or doesn't have any organic matter, then the mycorrhizae might not be able to thrive in said soil. Anytime you're thinking about how do I benefit the fungi in the soil, just fix the soil. If you can add any mulch, if you can make sure you're watering appropriately, but not too much, compost, aerating the soil to relieve compaction, all of these things can significantly help the mycorrhizae and then hopefully form some more associations, which will then in turn help your lovely tree.

Doug: Are there negatives that we can be doing that would hurt the mycorrhizal? Are the mycorrhizal affected by pesticides, herbicides, chemical fertilizers?

Chelsi: It's a good question, and I'm going to tell you unknown.

Doug: Oh, okay.

Chelsi: Right now, most of the negatives that we know for sure are environmental conditions like drought or flooding or tillage. If you completely turn over the soil and don't put any organic mattering, that can destroy whatever might be living in it at the time, but as far as like fungicides go, typically, the fungicides that are being used are very keyed up for the parasitic fungi and don't have a lot of effect, but we just simply, no one's really done that. I can't say for sure, but unlikely I would say.

Doug: In like our vegetable garden, is mycorrhizal fungi helping us there or is this more like for woody plants?

Chelsi: It's more for woody plants because they need that carbohydrate source, which comes from the stores inside the woody tissue. However, if we can deviate a little bit, there are things called epiphytic fungi, which they live essentially, think of them like the staph on our skin or the bacteria in our gut, where they're not actually harming or doing any negative side effect, but they just sort of live and they can help with things like drought stress. A lot of like our non-woody plants do form associations. Sometimes that doesn't get much of a benefit, but sometimes it helps a little bit with things like water retention. They're there, everything's there.

Doug: All I want you to tell me is I'm doing the right thing by not tilling, okay?

Chelsi: You're doing the right thing by not tilling. [laughs]

Doug: Because that's my theory. It is based on just observation, no science, where Chelsi, everything you're talking about is based on real science. I just, in my gut, I feel that if I turn that over, that whatever's there, whatever's naturally there, you're going to take all season to probably come back together. I've had success, no till, and it's easier, and now keep encouraging me.

Chelsi: Yes, I will say that is absolutely correct, but I will add one little asterisk. If you have compacted soil where nothing is probably growing, it actually is important to, and I'm using air quotes, till the soil, because we do want to turn it over to introduce water and air back into the soil so mycorrhizae can live. If you have uncompacted soil or soil that is fairly good in organic matter, then yes, you don't need to be doing that.

Doug: With a new title, working with education, I can, we've talked how many times? Three, four, five times.

Chelsi: Not enough.

Doug: Yes, and I always learn something, and I can tell that you have a passion for teaching. Talk a little bit about that part of your job. Who are you teaching, and what are you teaching them?

Chelsi: With the new promotion in that, just getting involved more with internal trainings as well as external training that Davey offers. One of the cool things that I'm working on is building a curriculum on arboriculture and trying to ensure consistency across the whole company on what we're all being taught. It's more of a, I would say, wide ranging sort of a supervisory role, as well as doing some fun little design builds for what should we be teaching? What do people need to know? Yes, you better believe there's going to be a mycorrhizal unit.

Doug: What do you get out of that part of your job of creating that curriculum and spreading this information through the company?

Chelsi: Honestly, what don't I get out of it? It's like you said, it's, I believe that curiosity and continued learning is the true root of my happiness, and for a lot of people, probably the same. If I can give even just one person one fun fact that they can walk home with and take with them, then I'm like, all right, check, good for today. Any more people that I can get interested in learning and continuing to be curious, that makes me happy.

Doug: We've talked about it before, but talk a little bit about your journey into this job that you're doing now. Obviously, when we've talked at least twice about fungi, that's like your number one subject, right? You just, I was going to say queen of fungi, but then I was like, I don't know if that sounds right.

Chelsi: You can call me the fun gal. That's what I call myself.

Doug: Ah, that's good, the fun gal.

Chelsi: Yes, fungi and bacteria. I've always, had a complete obsession with microbes as well as plants. I stumbled across plant pathology, which is the beautiful marriage of both botany and microbiology. Yes, then I was a tech advisor for a very long time, which was mostly just helping people with diagnostics of diseases in insects as well as building management plans. Then I just wanted more and I was already sort of doing a lot with the education department. I was like, okay, let's make this official. We created the position and it's just opened more doors to explore from the education side so I can teach as many people as possible.

Doug: I know usually we talk, you're based in Chicago, but that's usually where we do this podcast when we're talking to you, which I didn't realize you had such a wide area that you cover, right? Talk about where you're going from Chicago and what you're covering.

Chelsi: I cover Illinois, Wisconsin, and Iowa in the States, but I also cover Eastern Canada, which is just Ontario. There's nothing else outside of the provinces. I'm doing that as a temporary while we find someone for Ontario, but it's because I'm from Ontario, so I get to come home and see my family as well as support the offices up here.

Doug: We've talked a lot about the benefits for the fungi. How about the benefits for the trees or other woody plants?

Chelsi: Sure. I mentioned already that the mycorrhizae, the actual filaments, the mycelia, really just increased the surface area of the roots, which means greater uptake of things like water and nutrients. I mentioned how it could actually be about 100% of the nitrogen can come from that relationship. One of the other fun things that we've alluded to, but not quite gone over, is the connection from plant to plant and what that can do.

There's actually this thing that happens where plants can connect through the mycorrhizal network with their kin. That oak tree that dropped that acorn, when it forms the mycorrhizal connections and plugs into the network, that parent oak tree can actually dump carbon as it dies into that new tree to give it a leg up so that it becomes the progeny that will success and be the queen of the forest, as we say, after it. As that oak tree sort of decays and ends its life, it will literally carbon dump specifically to its kin using the mycorrhizal network.

Things like even defense alerts. If there's a hurt, like something feeding on a tree, they'll send out a signal so that everybody attached knows to up your defense mechanisms because there's something coming around and feeding on the leaves. Now, it can be used for other things too, like certain pathogens can also use the mycorrhizal network to get from tree to tree, but we won't talk about that. We're just talking about benefits.

Doug: Chelsi, it's always fascinating to talk to you. I finally understand mycorrhizal and how it works and that's great stuff. What else should we talk about in the future when it comes to trees and science and the things that you love to teach about? Think about something.

Chelsi: Oh, man.

Doug: Then, yes, finally I stumped you. I knew I could--

Chelsi: Yes, you got me, damn.

Doug: I knew this question would do it because--

Chelsi: It was because all I ever wanted to talk about it was this and now that I've done it, I'm like, oh, there are no ideas. [chuckles]

Doug: Well, I know that we'll talk again and there'll be something cool that we can talk about. As soon as we're done, you'll think of something and you'll email me and we'll set you--

Chelsi: I was going to say, I actually just thought of something.

Doug: What is it? Okay, I gave you a minute.

Chelsi: I would love to talk to you about agrobacterium and its use in genetic engineering. [chuckles]

Doug: I'm going to set it up. We're going to do it down the road a little bit. I have no idea what any of that means that you just told me but that's part of being an education specialist, right?

Chelsi: You're going to-

Doug: That's right.

Doug: -educate this old dude about all sorts of stuff. That's going to be our next podcast together, all right?

Chelsi: Unless something else comes up, of course. You might get an email at 3:00 AM of all these ideas.

Doug: I'll take them, Chelsi. Thanks again. I appreciate it as always and we'll talk to you soon.

Chelsi: Absolutely. Thank you for having me.

Doug: Chelsi's enthusiasm and ability to take complex scientific facts and make them understandable to you and I makes her such a great guest. Now tune in every Thursday to the Talking Trees podcast from the Davey Tree Expert Company. I'm your host, Doug Oster. Do me a favor, subscribe to the podcast so that you'll never miss one of these educational episodes. I'd love to hear from you too. Send me an email to podcasts@davey.com. That's P-O-D-C-A-S-T-S@D-A-V-E-Y.com. As always, we'd like to remind you on the Talking Trees podcast, trees are the answer.

[00:19:36] [END OF AUDIO]